ant.c
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ant.c
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	#if defined(__GNUC__) && !defined(__clang__)
	#pragma GCC optimize("O3,inline")
	#endif

	#include <compat.h> // IWYU pragma: keep

	#include "ant.h"
	#include "common.h"
	#include "arena.h"
	#include "utils.h"
	#include "runtime.h"
	#include "internal.h"

	#include <uv.h>
	#include <oxc.h>
	#include <assert.h>
	#include <pcre2.h>
	#include <stdarg.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <time.h>
	#include <utarray.h>
	#include <uthash.h>
	#include <float.h>
	#include <tlsuv/tlsuv.h>
	#include <tlsuv/http.h>

	#ifdef _WIN32
	#include <sys/stat.h>
	#else
	#include <sys/time.h>
	#include <sys/stat.h>
	#include <sys/resource.h>
	#endif

	#define MCO_USE_VMEM_ALLOCATOR
	#define MCO_ZERO_MEMORY
	#define MCO_DEFAULT_STACK_SIZE (1024 * 1024)
	#define MINICORO_IMPL
	#include <minicoro.h>

	#include "modules/fs.h"
	#include "modules/timer.h"
	#include "modules/fetch.h"
	#include "modules/symbol.h"
	#include "modules/ffi.h"
	#include "modules/child_process.h"
	#include "modules/readline.h"
	#include "modules/process.h"
	#include "modules/json.h"
	#include "modules/buffer.h"
	#include "esm/remote.h"

	#define CORO_MALLOC(size) calloc(1, size)
	#define CORO_FREE(ptr) free(ptr)

	#define D(x) ((double)(x))

	_Static_assert(sizeof(double) == 8, "NaN-boxing requires 64-bit IEEE 754 doubles");
	_Static_assert(sizeof(uint64_t) == 8, "NaN-boxing requires 64-bit integers");
	_Static_assert(sizeof(double) == sizeof(uint64_t), "double and uint64_t must have same size");

	#if defined(__STDC_IEC_559__) \|\| defined(__GCC_IEC_559)
	#elif defined(__FAST_MATH__)
	#error "NaN-boxing is incompatible with -ffast-math"
	#elif DBL_MANT_DIG != 53 \|\| DBL_MAX_EXP != 1024
	#error "NaN-boxing requires IEEE 754 binary64 doubles"
	#endif

	typedef struct {
	jsval_t *stack;
	int depth;
	int capacity;
	} this_stack_t;

	typedef struct call_frame {
	const char *filename;
	const char *function_name;
	const char *code;
	uint32_t pos;
	int line;
	int col;
	} call_frame_t;

	typedef struct {
	call_frame_t *frames;
	int depth;
	int capacity;
	} call_stack_t;

	typedef enum {
	CORO_ASYNC_AWAIT,
	CORO_GENERATOR,
	CORO_ASYNC_GENERATOR
	} coroutine_type_t;

	typedef struct coroutine {
	struct js *js;
	coroutine_type_t type;
	jsval_t scope;
	jsval_t this_val;
	jsval_t super_val;
	jsval_t new_target;
	jsval_t awaited_promise;
	jsval_t result;
	jsval_t async_func;
	jsval_t *args;
	int nargs;
	bool is_settled;
	bool is_error;
	bool is_done;
	jsoff_t resume_point;
	jsval_t yield_value;
	struct coroutine *prev;
	struct coroutine *next;
	mco_coro* mco;
	bool mco_started;
	bool is_ready;
	struct for_let_ctx *for_let_stack;
	int for_let_stack_len;
	int for_let_stack_cap;
	UT_array *scope_stack;
	} coroutine_t;

	typedef struct {
	coroutine_t *head;
	coroutine_t *tail;
	} coroutine_queue_t;

	typedef struct {
	struct js *js;
	const char *code;
	size_t code_len;
	jsval_t closure_scope;
	jsval_t result;
	jsval_t promise;
	bool has_error;
	coroutine_t *coro;
	} async_exec_context_t;

	static const UT_icd jsoff_icd = {
	.sz = sizeof(jsoff_t),
	.init = NULL,
	.copy = NULL,
	.dtor = NULL,
	};

	static const UT_icd jsval_icd = {
	.sz = sizeof(jsval_t),
	.init = NULL,
	.copy = NULL,
	.dtor = NULL,
	};

	static UT_array *global_scope_stack = NULL;
	static UT_array *saved_scope_stack = NULL;

	static this_stack_t global_this_stack = {NULL, 0, 0};
	static call_stack_t global_call_stack = {NULL, 0, 0};
	static coroutine_queue_t pending_coroutines = {NULL, NULL};

	typedef struct {
	const char *name;
	jsoff_t name_len;
	bool is_loop;
	bool is_block;
	} label_entry_t;

	static const UT_icd label_entry_icd = {
	.sz = sizeof(label_entry_t),
	.init = NULL,
	.copy = NULL,
	.dtor = NULL,
	};

	static UT_array *label_stack = NULL;

	static const char *break_target_label = NULL;
	static jsoff_t break_target_label_len = 0;
	static const char *continue_target_label = NULL;
	static jsoff_t continue_target_label_len = 0;

	#define F_BREAK_LABEL 1U
	#define F_CONTINUE_LABEL 2U
	static uint8_t label_flags = 0;

	typedef struct esm_module {
	char *path;
	char *resolved_path;
	jsval_t namespace_obj;
	jsval_t default_export;
	bool is_loaded;
	bool is_loading;
	bool is_json;
	bool is_text;
	bool is_image;
	bool is_url;
	char *url_content;
	size_t url_content_len;
	struct esm_module *next;
	UT_hash_handle hh;
	} esm_module_t;

	typedef struct {
	esm_module_t *modules;
	int count;
	} esm_module_cache_t;

	typedef struct ant_library {
	char name[256];
	ant_library_init_fn init_fn;
	UT_hash_handle hh;
	} ant_library_t;

	static const char *INTERN_LENGTH = NULL;
	static const char *INTERN_BUFFER = NULL;
	static const char *INTERN_PROTOTYPE = NULL;
	static const char *INTERN_CONSTRUCTOR = NULL;
	static const char *INTERN_NAME = NULL;
	static const char *INTERN_MESSAGE = NULL;
	static const char *INTERN_VALUE = NULL;
	static const char *INTERN_GET = NULL;
	static const char *INTERN_SET = NULL;

	static const char *INTERN_ARGUMENTS = NULL;
	static const char *INTERN_CALLEE = NULL;
	static const char *INTERN_IDX[10] = {NULL};

	typedef struct interned_string {
	uint64_t hash;
	char *str;
	size_t len;
	struct interned_string *next;
	} interned_string_t;

	static interned_string_t *intern_buckets[ANT_LIMIT_SIZE_CACHE];

	typedef struct {
	jsoff_t obj_off;
	const char *intern_ptr;
	jsoff_t prop_off;
	jsoff_t tail;
	} intern_prop_cache_entry_t;
	static intern_prop_cache_entry_t intern_prop_cache[ANT_LIMIT_SIZE_CACHE];

	typedef struct promise_handler {
	jsval_t onFulfilled;
	jsval_t onRejected;
	jsval_t nextPromise;
	} promise_handler_t;

	static const UT_icd promise_handler_icd = {
	.sz = sizeof(promise_handler_t),
	.init = NULL,
	.copy = NULL,
	.dtor = NULL,
	};

	typedef struct promise_data_entry {
	jsval_t value;
	UT_array *handlers;
	uint32_t promise_id;
	uint32_t trigger_pid;
	jsoff_t obj_offset;
	int state;
	bool has_rejection_handler;
	UT_hash_handle hh;
	UT_hash_handle hh_unhandled;
	} promise_data_entry_t;

	static promise_data_entry_t *promise_registry = NULL;
	static promise_data_entry_t *unhandled_rejections = NULL;
	static uint32_t next_promise_id = 1;

	static promise_data_entry_t *get_promise_data(uint32_t promise_id, bool create);
	static uint32_t get_promise_id(struct js *js, jsval_t p);
	static bool js_try_grow_memory(struct js *js, size_t needed);

	typedef struct map_entry {
	char *key;
	jsval_t value;
	UT_hash_handle hh;
	} map_entry_t;

	typedef struct set_entry {
	jsval_t value;
	char *key;
	UT_hash_handle hh;
	} set_entry_t;

	typedef struct proxy_data {
	jsoff_t obj_offset;
	jsval_t target;
	jsval_t handler;
	bool revoked;
	UT_hash_handle hh;
	} proxy_data_t;

	typedef struct dynamic_accessors {
	jsoff_t obj_offset;
	js_getter_fn getter;
	js_setter_fn setter;
	UT_hash_handle hh;
	} dynamic_accessors_t;

	typedef struct descriptor_entry {
	uint64_t key;
	jsoff_t obj_off;
	char *prop_name;
	size_t prop_len;
	bool writable;
	bool enumerable;
	bool configurable;
	bool has_getter;
	bool has_setter;
	jsval_t getter;
	jsval_t setter;
	UT_hash_handle hh;
	} descriptor_entry_t;

	typedef struct {
	jsoff_t obj_off;
	jsoff_t key_off;
	} propref_data_t;

	static const UT_icd propref_icd = { sizeof(propref_data_t), NULL, NULL, NULL };
	static UT_array *propref_stack = NULL;

	typedef struct parsed_param {
	jsoff_t name_off;
	jsoff_t name_len;
	jsoff_t default_start;
	jsoff_t default_len;
	jsoff_t pattern_off;
	jsoff_t pattern_len;
	bool is_destruct;
	} parsed_param_t;

	typedef struct parsed_func {
	uint64_t code_hash;
	jsoff_t body_start;
	jsoff_t body_len;
	int param_count;
	bool has_rest;
	bool is_strict;
	jsoff_t rest_param_start;
	jsoff_t rest_param_len;
	UT_array *params;
	UT_hash_handle hh;
	} parsed_func_t;

	static const UT_icd parsed_param_icd = {
	.sz = sizeof(parsed_param_t),
	.init = NULL,
	.copy = NULL,
	.dtor = NULL,
	};

	static parsed_func_t *func_parse_cache = NULL;
	static ant_library_t *library_registry = NULL;
	static esm_module_cache_t global_module_cache = {NULL, 0};
	static proxy_data_t *proxy_registry = NULL;
	static dynamic_accessors_t *accessor_registry = NULL;
	static descriptor_entry_t *desc_registry = NULL;

	typedef struct map_registry_entry {
	map_entry_t **head;
	UT_hash_handle hh;
	} map_registry_entry_t;

	typedef struct set_registry_entry {
	set_entry_t **head;
	UT_hash_handle hh;
	} set_registry_entry_t;

	static map_registry_entry_t *map_registry = NULL;
	static set_registry_entry_t *set_registry = NULL;

	void ant_register_library(ant_library_init_fn init_fn, const char *name, ...) {
	va_list args;
	const char *alias = name;

	va_start(args, name);
	while (alias != NULL) {
	ant_library_t lib = (ant_library_t )ant_calloc(sizeof(ant_library_t));
	if (!lib) break;

	strncpy(lib->name, alias, sizeof(lib->name) - 1);
	lib->name[sizeof(lib->name) - 1] = '\0';
	lib->init_fn = init_fn;

	HASH_ADD_STR(library_registry, name, lib);
	alias = va_arg(args, const char *);
	}
	va_end(args);
	}

	static ant_library_t* find_library(const char *specifier, size_t spec_len) {
	ant_library_t *lib = NULL;

	char key[256];
	if (spec_len >= sizeof(key)) return NULL;
	memcpy(key, specifier, spec_len);
	key[spec_len] = '\0';

	HASH_FIND_STR(library_registry, key, lib);
	return lib;
	}

	enum {
	TOK_ERR, TOK_EOF, TOK_NUMBER, TOK_STRING, TOK_SEMICOLON, TOK_BIGINT,
	TOK_LPAREN, TOK_RPAREN, TOK_LBRACE, TOK_RBRACE, TOK_LBRACKET, TOK_RBRACKET,

	// identifier-like
	TOK_IDENTIFIER = 50,
	TOK_ASYNC, TOK_AWAIT, TOK_BREAK, TOK_CASE, TOK_CATCH, TOK_CLASS, TOK_CONST, TOK_CONTINUE,
	TOK_DEFAULT, TOK_DELETE, TOK_DO, TOK_DEBUGGER, TOK_ELSE, TOK_EXPORT, TOK_FINALLY, TOK_FOR,
	TOK_FROM, TOK_FUNC, TOK_IF, TOK_IMPORT, TOK_IN, TOK_INSTANCEOF, TOK_LET, TOK_NEW, TOK_OF,
	TOK_RETURN, TOK_SUPER, TOK_SWITCH, TOK_THIS, TOK_THROW, TOK_TRY, TOK_VAR, TOK_VOID, TOK_WHILE, TOK_WITH,
	TOK_YIELD, TOK_UNDEF, TOK_NULL, TOK_TRUE, TOK_FALSE, TOK_AS, TOK_STATIC, TOK_TYPEOF,
	TOK_WINDOW, TOK_GLOBAL_THIS,
	TOK_IDENT_LIKE_END,

	// operators
	TOK_DOT = 100, TOK_CALL, TOK_BRACKET, TOK_POSTINC, TOK_POSTDEC, TOK_NOT, TOK_TILDA,
	TOK_UPLUS, TOK_UMINUS, TOK_EXP, TOK_MUL, TOK_DIV, TOK_REM,
	TOK_OPTIONAL_CHAIN, TOK_REST,
	TOK_PLUS, TOK_MINUS, TOK_SHL, TOK_SHR, TOK_ZSHR, TOK_LT, TOK_LE, TOK_GT,
	TOK_GE, TOK_EQ, TOK_NE, TOK_SEQ, TOK_SNE, TOK_AND, TOK_XOR, TOK_OR, TOK_LAND, TOK_LOR, TOK_NULLISH,
	TOK_COLON, TOK_Q, TOK_ASSIGN, TOK_PLUS_ASSIGN, TOK_MINUS_ASSIGN,
	TOK_MUL_ASSIGN, TOK_DIV_ASSIGN, TOK_REM_ASSIGN, TOK_SHL_ASSIGN,
	TOK_SHR_ASSIGN, TOK_ZSHR_ASSIGN, TOK_AND_ASSIGN, TOK_XOR_ASSIGN,
	TOK_OR_ASSIGN, TOK_LOR_ASSIGN, TOK_LAND_ASSIGN, TOK_NULLISH_ASSIGN,
	TOK_COMMA, TOK_TEMPLATE, TOK_ARROW, TOK_HASH,
	TOK_MAX
	};

	static const uint8_t prec_table[TOK_MAX] = {
	[TOK_LOR] = 4,
	[TOK_LAND] = 5,
	[TOK_NULLISH] = 5,
	[TOK_OR] = 6,
	[TOK_XOR] = 7,
	[TOK_AND] = 8,
	[TOK_EQ] = 9, [TOK_NE] = 9, [TOK_SEQ] = 9, [TOK_SNE] = 9,
	[TOK_LT] = 10, [TOK_LE] = 10, [TOK_GT] = 10, [TOK_GE] = 10,
	[TOK_INSTANCEOF] = 10, [TOK_IN] = 10,
	[TOK_SHL] = 11, [TOK_SHR] = 11, [TOK_ZSHR] = 11,
	[TOK_PLUS] = 12, [TOK_MINUS] = 12,
	[TOK_MUL] = 13, [TOK_DIV] = 13, [TOK_REM] = 13,
	[TOK_EXP] = 14,
	};

	static const uint8_t body_end_tok[TOK_MAX] = {
	[TOK_RPAREN] = 1, [TOK_RBRACE] = 1, [TOK_RBRACKET] = 1,
	[TOK_SEMICOLON] = 1, [TOK_COMMA] = 1, [TOK_EOF] = 1,
	};

	static const uint8_t expr_context_tok[TOK_MAX] = {
	[TOK_ASSIGN] = 1, [TOK_LPAREN] = 1, [TOK_COLON] = 1, [TOK_LBRACKET] = 1,
	[TOK_COMMA] = 1, [TOK_NOT] = 1, [TOK_Q] = 1, [TOK_OR] = 1, [TOK_AND] = 1,
	[TOK_RETURN] = 1, [TOK_ARROW] = 1, [TOK_LAND] = 1, [TOK_LOR] = 1,
	[TOK_PLUS_ASSIGN] = 1, [TOK_MINUS_ASSIGN] = 1, [TOK_MUL_ASSIGN] = 1,
	[TOK_DIV_ASSIGN] = 1, [TOK_REM_ASSIGN] = 1, [TOK_AND_ASSIGN] = 1,
	[TOK_OR_ASSIGN] = 1, [TOK_XOR_ASSIGN] = 1, [TOK_NULLISH] = 1,
	};

	static const char *typestr_raw(uint8_t t) {
	const char *names[] = {
	"object", "prop", "string", "undefined", "null", "number",
	"boolean", "function", "coderef", "cfunc", "err", "array",
	"promise", "typedarray", "bigint", "propref", "symbol", "generator", "ffi"
	};

	return (t < sizeof(names) / sizeof(names[0])) ? names[t] : "??";
	}

	static jsval_t tov(double d) { union { double d; jsval_t v; } u = {d}; return u.v; }
	static double tod(jsval_t v) { union { jsval_t v; double d; } u = {v}; return u.d; }

	static bool is_tagged(jsval_t v) {
	return (v >> 53) == NANBOX_PREFIX_CHK;
	}

	size_t vdata(jsval_t v) {
	return (size_t)(v & NANBOX_DATA_MASK);
	}

	#define PROPREF_STACK_FLAG 0x800000000000ULL
	#define PROPREF_PRIM_FLAG 0x400000000000ULL
	#define PROPREF_INDEX_MASK 0x3FFFFFFFFFFFULL
	#define PROPREF_OFF_MASK 0x7FFFFFULL
	#define PROPREF_PAYLOAD 0x7FFFFFULL
	#define PROPREF_SAFE_MASK 0x7FFFFFULL
	#define PROPREF_KEY_SHIFT 23U

	typedef struct {
	jsval_t prim_val;
	jsoff_t key_off;
	} prim_propref_data_t;

	static UT_icd prim_propref_icd = { sizeof(prim_propref_data_t), NULL, NULL, NULL };
	static UT_array *prim_propref_stack = NULL;

	static jsoff_t coderefoff(jsval_t v) { return v & PROPREF_OFF_MASK; }
	static jsoff_t codereflen(jsval_t v) { return (v >> PROPREF_KEY_SHIFT) & PROPREF_OFF_MASK; }

	static jsval_t get_slot(struct js *js, jsval_t obj, internal_slot_t slot);
	static void set_slot(struct js *js, jsval_t obj, internal_slot_t slot, jsval_t value);

	static jsval_t get_proto(struct js *js, jsval_t obj);
	static void set_proto(struct js *js, jsval_t obj, jsval_t proto);

	static void clear_break_label(void) {
	break_target_label = NULL;
	break_target_label_len = 0;
	label_flags &= ~F_BREAK_LABEL;
	}

	static void clear_continue_label(void) {
	continue_target_label = NULL;
	continue_target_label_len = 0;
	label_flags &= ~F_CONTINUE_LABEL;
	}

	static inline propref_data_t *propref_get_entry(jsval_t v) {
	uint64_t data = v & NANBOX_DATA_MASK;
	if (!(data & PROPREF_STACK_FLAG)) return NULL;

	int idx = (int)(data & PROPREF_INDEX_MASK);
	if (!propref_stack \|\| idx < 0 \|\| idx >= (int)utarray_len(propref_stack)) return NULL;

	return (propref_data_t *)utarray_eltptr(propref_stack, (unsigned)idx);
	}

	static jsoff_t propref_obj(jsval_t v) {
	propref_data_t *entry = propref_get_entry(v);
	if (entry) return entry->obj_off;

	uint64_t data = v & NANBOX_DATA_MASK;
	return (data & PROPREF_STACK_FLAG) ? 0 : (data & PROPREF_OFF_MASK);
	}

	static jsoff_t propref_key(jsval_t v) {
	propref_data_t *entry = propref_get_entry(v);
	if (entry) return entry->key_off;

	uint64_t data = v & NANBOX_DATA_MASK;
	return (data & PROPREF_STACK_FLAG) ? 0 : ((data >> PROPREF_KEY_SHIFT) & PROPREF_OFF_MASK);
	}

	static inline jsoff_t offtolen(jsoff_t off) { return (off >> 3) - 1; }
	static inline jsoff_t align64(jsoff_t v) { return (v + 7) & ~7ULL; }

	static void saveoff(struct js *js, jsoff_t off, jsoff_t val) {
	memcpy(&js->mem[off], &val, sizeof(val));
	}

	static void saveval(struct js *js, jsoff_t off, jsval_t val) {
	memcpy(&js->mem[off], &val, sizeof(val));
	}

	static const char *typestr(uint8_t t) {
	if (t == T_CFUNC) return "function";
	if (t == T_ARR) return "object";
	if (t == T_NULL) return "object";
	return typestr_raw(t);
	}

	void js_set_needs_gc(struct js *js, bool needs) {
	js->needs_gc = needs;
	}

	void js_set_gc_suppress(struct js *js, bool suppress) {
	js->gc_suppress = suppress;
	}

	uint8_t vtype(jsval_t v) {
	return is_tagged(v) ? ((v >> NANBOX_TYPE_SHIFT) & NANBOX_TYPE_MASK) : (uint8_t)T_NUM;
	}

	static jsval_t mkval(uint8_t type, uint64_t data) {
	return NANBOX_PREFIX \| ((jsval_t)(type & NANBOX_TYPE_MASK) << NANBOX_TYPE_SHIFT) \| (data & NANBOX_DATA_MASK);
	}

	jsval_t js_obj_to_func(jsval_t obj) {
	return mkval(T_FUNC, vdata(obj));
	}

	jsval_t js_mktypedarray(void *data) {
	return mkval(T_TYPEDARRAY, (uintptr_t)data);
	}

	void *js_gettypedarray(jsval_t val) {
	if (vtype(val) != T_TYPEDARRAY) return NULL;
	return (void *)vdata(val);
	}

	jsval_t js_get_slot(struct js *js, jsval_t obj, internal_slot_t slot) {
	return get_slot(js, obj, slot);
	}

	void js_set_slot(struct js *js, jsval_t obj, internal_slot_t slot, jsval_t value) {
	set_slot(js, obj, slot, value);
	}

	jsval_t js_mkffi(unsigned int index) {
	return mkval(T_FFI, (uint64_t)index);
	}

	int js_getffi(jsval_t val) {
	if (vtype(val) != T_FFI) return -1;
	return (int)vdata(val);
	}

	static jsval_t mkcoderef(jsval_t off, jsoff_t len) {
	return mkval(T_CODEREF, (off & PROPREF_OFF_MASK) \| ((jsval_t)(len & PROPREF_OFF_MASK) << PROPREF_KEY_SHIFT));
	}

	static jsval_t mkpropref(jsoff_t obj_off, jsoff_t key_off) {
	if (obj_off <= PROPREF_SAFE_MASK && key_off <= PROPREF_SAFE_MASK) {
	return mkval(T_PROPREF, (obj_off & PROPREF_OFF_MASK) \| ((jsval_t)(key_off & PROPREF_OFF_MASK) << PROPREF_KEY_SHIFT));
	}

	if (!propref_stack) utarray_new(propref_stack, &propref_icd);
	if (utarray_len(propref_stack) > 1024) utarray_clear(propref_stack);

	propref_data_t entry = { obj_off, key_off };
	utarray_push_back(propref_stack, &entry);
	int idx = (int)utarray_len(propref_stack) - 1;

	return mkval(T_PROPREF, PROPREF_STACK_FLAG \| (uint64_t)idx);
	}

	static jsval_t mkprim_propref(jsval_t prim_val, jsoff_t key_off) {
	if (!prim_propref_stack) utarray_new(prim_propref_stack, &prim_propref_icd);
	if (utarray_len(prim_propref_stack) > 256) utarray_clear(prim_propref_stack);

	prim_propref_data_t entry = { prim_val, key_off };
	utarray_push_back(prim_propref_stack, &entry);
	int idx = (int)utarray_len(prim_propref_stack) - 1;

	return mkval(T_PROPREF, PROPREF_PRIM_FLAG \| (uint64_t)idx);
	}

	static inline bool is_prim_propref(jsval_t v) {
	if (vtype(v) != T_PROPREF) return false;
	uint64_t data = v & NANBOX_DATA_MASK;
	return (data & PROPREF_PRIM_FLAG) != 0;
	}

	static inline prim_propref_data_t *prim_propref_get(jsval_t v) {
	uint64_t data = v & NANBOX_DATA_MASK;
	if (!(data & PROPREF_PRIM_FLAG)) return NULL;

	int idx = (int)(data & PROPREF_INDEX_MASK);
	if (!prim_propref_stack \|\| idx < 0 \|\| idx >= (int)utarray_len(prim_propref_stack)) return NULL;

	return (prim_propref_data_t *)utarray_eltptr(prim_propref_stack, (unsigned)idx);
	}

	inline size_t js_getbrk(struct js *js) {
	return (size_t) js->brk;
	}

	static inline bool is_err(jsval_t v) {
	return vtype(v) == T_ERR;
	}

	static inline bool is_null(jsval_t v) {
	return vtype(v) == T_NULL;
	}

	static inline bool is_undefined(jsval_t v) {
	return vtype(v) == T_UNDEF;
	}

	#define T_OBJECT_MASK (TYPE_FLAG(T_OBJ) \| TYPE_FLAG(T_ARR) \| TYPE_FLAG(T_FUNC) \| TYPE_FLAG(T_PROMISE))
	#define is_object_type(v) ((1u << vtype(v)) & T_OBJECT_MASK)

	static inline bool is_true(jsval_t v) {
	return vtype(v) == T_BOOL && vdata(v) != 0;
	}

	static inline bool is_false(jsval_t v) {
	return vtype(v) == T_BOOL && vdata(v) == 0;
	}

	static inline uint8_t unhex(uint8_t c) {
	return (c & 0xF) + (c >> 6) * 9;
	}

	static inline int is_body_end_tok(int tok) {
	return body_end_tok[tok];
	}

	static inline bool is_assign(uint8_t tok) {
	return tok >= TOK_ASSIGN && tok <= TOK_NULLISH_ASSIGN;
	}

	static inline bool is_identifier_like(uint8_t tok) {
	return tok >= TOK_IDENTIFIER && tok < TOK_IDENT_LIKE_END;
	}

	static inline bool is_keyword_propname(uint8_t tok) {
	return (tok >= TOK_ASYNC && tok <= TOK_GLOBAL_THIS) \|\| tok == TOK_TYPEOF;
	}

	static inline bool is_contextual_keyword(uint8_t tok) {
	return tok == TOK_FROM \|\| tok == TOK_OF \|\| tok == TOK_AS \|\| tok == TOK_ASYNC;
	}

	static inline bool js_stack_overflow(struct js *js) {
	if (js->stack_limit == 0 \|\| js->cstk == NULL) return false;
	volatile char marker;
	uintptr_t base = (uintptr_t)js->cstk;
	uintptr_t curr = (uintptr_t)&marker;
	size_t used = (base > curr) ? (base - curr) : (curr - base);
	return used > js->stack_limit;
	}

	static inline bool is_valid_param_name(uint8_t tok) {
	return tok == TOK_IDENTIFIER \|\| is_contextual_keyword(tok);
	}

	static bool is_valid_arrow_param_tok(uint8_t tok) {
	static const uint64_t bits[4] = {
	0x000C000000000FCCull,
	0x041CC0100BC00808ull,
	0x0000000000800100ull,
	0x0000000000000000ull
	};
	return (bits[tok >> 6] >> (tok & 63)) & 1;
	}

	static inline bool is_block_tok(uint8_t tok) {
	static const uint64_t bits[4] = {
	0x2108000000000110ull,
	0x0000000000124075ull, 0, 0
	};
	return (bits[tok >> 6] >> (tok & 63)) & 1;
	}

	static inline bool is_asi_ok_tok(uint8_t tok) {
	static const uint64_t bits[4] = {
	0x0000000000000212ull, 0, 0, 0
	};
	return (bits[tok >> 6] >> (tok & 63)) & 1;
	}

	static inline bool is_unboxed_obj(struct js *js, jsval_t val, jsval_t expected_proto) {
	if (vtype(val) != T_OBJ) return false;
	if (vtype(get_slot(js, val, SLOT_PRIMITIVE)) != T_UNDEF) return false;
	jsval_t proto = get_slot(js, val, SLOT_PROTO);
	return vdata(proto) == vdata(expected_proto);
	}

	uint32_t js_to_uint32(double d) {
	if (!isfinite(d) \|\| d == 0) return 0;
	double sign = (d < 0) ? -1.0 : 1.0;
	double posInt = sign * floor(fabs(d));
	double val = fmod(posInt, 4294967296.0);
	if (val < 0) val += 4294967296.0;
	return (uint32_t) val;
	}

	int32_t js_to_int32(double d) {
	uint32_t uint32 = js_to_uint32(d);
	if (uint32 >= 2147483648U) return (int32_t)(uint32 - 4294967296.0);
	return (int32_t) uint32;
	}

	typedef struct {
	const char *code;
	jsoff_t clen, pos;
	uint8_t tok, consumed;
	} js_parse_state_t;

	#define JS_SAVE_STATE(js, state) do { \
	(state).code = (js)->code; \
	(state).clen = (js)->clen; \
	(state).pos = (js)->pos; \
	(state).tok = (js)->tok; \
	(state).consumed = (js)->consumed; \
	} while(0)

	#define JS_RESTORE_STATE(js, state) do { \
	(js)->code = (state).code; \
	(js)->clen = (state).clen; \
	(js)->pos = (state).pos; \
	(js)->tok = (state).tok; \
	(js)->consumed = (state).consumed; \
	} while(0)

	static jsoff_t vstr(struct js js, jsval_t value, jsoff_t len);
	static size_t strstring(struct js js, jsval_t value, char buf, size_t len);
	static size_t strkey(struct js js, jsval_t value, char buf, size_t len);

	static inline jsoff_t loadoff(struct js *js, jsoff_t off) {
	assert(off + sizeof(jsoff_t) <= js->brk); jsoff_t val;
	memcpy(&val, &js->mem[off], sizeof(val)); return val;
	}

	static bool is_arr_off(struct js *js, jsoff_t off) {
	return (loadoff(js, off) & ARRMASK) != 0;
	}

	static jsoff_t vstrlen(struct js *js, jsval_t v) {
	return offtolen(loadoff(js, (jsoff_t) vdata(v)));
	}

	static inline jsval_t loadval(struct js *js, jsoff_t off) {
	return (jsval_t )(&js->mem[off]);
	}

	static jsval_t upper(struct js *js, jsval_t scope) {
	return mkval(T_OBJ, loadoff(js, (jsoff_t) (vdata(scope) + sizeof(jsoff_t))));
	}

	#define EXPECT(_tok, ...) \
	if (next(js) != _tok) { \
	__VA_ARGS__; \
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "parse error"); \
	} else js->consumed = 1

	#define EXPECT_IDENT(...) \
	if (!is_valid_param_name(next(js))) { \
	__VA_ARGS__; \
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected"); \
	} else js->consumed = 1

	static bool is_digit(int c);
	static bool is_proxy(struct js *js, jsval_t obj);
	static bool bigint_is_zero(struct js *js, jsval_t v);

	static bool streq(const char buf, size_t len, const char p, size_t n);
	static bool is_this_loop_continue_target(int depth_at_entry);
	static bool code_has_function_decl(const char *code, size_t len);
	static bool parse_func_params(struct js js, uint8_t flags, int *out_count);
	static bool try_dynamic_setter(struct js js, jsval_t obj, const char key, size_t key_len, jsval_t value);

	static size_t strbigint(struct js js, jsval_t value, char buf, size_t len);
	static size_t tostr(struct js js, jsval_t value, char buf, size_t len);
	static size_t strpromise(struct js js, jsval_t value, char buf, size_t len);
	static size_t js_to_pcre2_pattern(const char src, size_t src_len, char dst, size_t dst_size);

	static jsval_t js_stmt_impl(struct js *js);
	static jsval_t js_expr(struct js *js);
	static jsval_t js_call_valueOf(struct js *js, jsval_t value);
	static jsval_t js_call_toString(struct js *js, jsval_t value);
	static jsval_t js_eval_slice(struct js *js, jsoff_t off, jsoff_t len);
	static jsval_t js_eval_str(struct js js, const char code, jsoff_t len);
	static jsval_t js_stmt(struct js *js);
	static jsval_t js_assignment(struct js *js);
	static jsval_t js_arrow_func(struct js *js, jsoff_t params_start, jsoff_t params_end, bool is_async);
	static jsval_t js_async_arrow_paren(struct js *js);
	static jsval_t js_var_decl(struct js *js);

	static jsval_t do_op(struct js *, uint8_t op, jsval_t l, jsval_t r);
	static jsval_t do_instanceof(struct js *js, jsval_t l, jsval_t r);
	static jsval_t do_in(struct js *js, jsval_t l, jsval_t r);
	static jsval_t resolveprop(struct js *js, jsval_t v);

	static jsoff_t lkp(struct js js, jsval_t obj, const char buf, size_t len);
	static jsoff_t lkp_interned(struct js js, jsval_t obj, const char search_intern, size_t len);

	static inline bool is_slot_prop(jsoff_t header);
	static inline jsoff_t next_prop(jsoff_t header);

	static jsval_t js_import_stmt(struct js *js);
	static jsval_t js_export_stmt(struct js *js);

	static jsval_t builtin_Object(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_promise_then(struct js js, jsval_t args, int nargs);

	static jsval_t proxy_get(struct js js, jsval_t proxy, const char key, size_t key_len);
	static jsval_t proxy_set(struct js js, jsval_t proxy, const char key, size_t key_len, jsval_t value);
	static jsval_t proxy_has(struct js js, jsval_t proxy, const char key, size_t key_len);
	static jsval_t proxy_delete(struct js js, jsval_t proxy, const char key, size_t key_len);
	static jsval_t call_js(struct js js, const char fn, jsoff_t fnlen, jsval_t closure_scope);
	static jsval_t call_js_internal(struct js js, const char fn, jsoff_t fnlen, jsval_t closure_scope, jsval_t *bound_args, int bound_argc, jsval_t func_val);

	static jsval_t call_js_with_args(struct js js, jsval_t fn, jsval_t args, int nargs);
	static jsval_t call_js_code_with_args(struct js js, const char fn, jsoff_t fnlen, jsval_t closure_scope, jsval_t *args, int nargs, jsval_t func_val);

	static inline bool push_this(jsval_t this_value);
	static inline jsval_t pop_this(void);

	static jsoff_t lkp_proto(struct js js, jsval_t obj, const char key, size_t len);
	static jsval_t get_prototype_for_type(struct js *js, uint8_t type);
	static jsval_t get_ctor_proto(struct js js, const char name, size_t len);
	static jsval_t setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v);

	static descriptor_entry_t lookup_descriptor(jsoff_t obj_off, const char key, size_t klen);
	static const char bigint_digits(struct js js, jsval_t v, size_t *len);

	typedef struct { jsval_t handle; bool is_new; } ctor_t;

	static ctor_t get_constructor(struct js js, const char name, size_t len) {
	ctor_t ctor;

	ctor.handle = get_ctor_proto(js, name, len);
	ctor.is_new = (vtype(js->new_target) != T_UNDEF);

	return ctor;
	}

	static jsval_t unwrap_primitive(struct js *js, jsval_t val) {
	if (vtype(val) != T_OBJ) return val;
	jsval_t prim = get_slot(js, val, SLOT_PRIMITIVE);
	if (vtype(prim) == T_UNDEF) return val;
	return prim;
	}

	static jsval_t to_string_val(struct js *js, jsval_t val) {
	uint8_t t = vtype(val);
	if (t == T_STR) return val;
	if (t == T_OBJ) {
	jsval_t prim = get_slot(js, val, SLOT_PRIMITIVE);
	if (vtype(prim) == T_STR) return prim;
	}
	return js_call_toString(js, val);
	}

	bool js_truthy(struct js *js, jsval_t v) {
	static const void *dispatch[] = {
	[T_OBJ] = &&l_true,
	[T_FUNC] = &&l_true,
	[T_ARR] = &&l_true,
	[T_SYMBOL] = &&l_true,
	[T_BOOL] = &&l_bool,
	[T_STR] = &&l_str,
	[T_BIGINT] = &&l_bigint,
	[T_NUM] = &&l_num,
	};

	uint8_t t = vtype(v);
	if (t < sizeof(dispatch) / sizeof(*dispatch) && dispatch[t])
	goto *dispatch[t];
	return false;

	l_true: return true;
	l_bool: return vdata(v) != 0;
	l_str: return vstrlen(js, v) > 0;
	l_bigint: return !bigint_is_zero(js, v);
	l_num: {
	double d = tod(v);
	return d != 0.0 && !isnan(d);
	}
	}

	static bool has_ready_coroutines(void);
	static bool coro_stack_size_initialized = false;

	static void free_coroutine(coroutine_t *coro);
	static void for_let_swap_with_coro(struct js js, coroutine_t coro);

	typedef struct {
	jsval_t scope;
	UT_array *scope_stack;
	} coro_saved_state_t;

	static inline coro_saved_state_t coro_enter(struct js js, coroutine_t coro) {
	extern UT_array *global_scope_stack;
	coro_saved_state_t saved = { js->scope, global_scope_stack };
	js->scope = coro->scope;
	global_scope_stack = coro->scope_stack;
	for_let_swap_with_coro(js, coro);
	return saved;
	}

	static inline void coro_leave(struct js js, coroutine_t coro, coro_saved_state_t saved) {
	extern UT_array *global_scope_stack;
	coro->scope = js->scope;
	coro->scope_stack = global_scope_stack;
	js->scope = saved.scope;
	global_scope_stack = saved.scope_stack;
	for_let_swap_with_coro(js, coro);
	}

	static size_t calculate_coro_stack_size(void) {
	if (coro_stack_size_initialized) return 0;
	coro_stack_size_initialized = true;
	const char *env_stack = getenv("ANT_CORO_STACK_SIZE");
	if (env_stack) {
	size_t size = (size_t)atoi(env_stack) * 1024;
	if (size >= 32 * 1024 && size <= 8 * 1024 * 1024) return size;
	}
	return 0;
	}

	static void mco_async_entry(mco_coro* mco) {
	async_exec_context_t ctx = (async_exec_context_t )mco_get_user_data(mco);

	struct js *js = ctx->js;
	coroutine_t *coro = ctx->coro;
	jsval_t result;

	jsval_t saved_super = js->super_val;
	jsval_t saved_new_target = js->new_target;
	if (coro) {
	js->super_val = coro->super_val;
	js->new_target = coro->new_target;
	}

	if (coro && coro->nargs > 0 && coro->args) {
	result = call_js_code_with_args(js, ctx->code, (jsoff_t)ctx->code_len, ctx->closure_scope, coro->args, coro->nargs, js_mkundef());
	} else result = call_js(js, ctx->code, (jsoff_t)ctx->code_len, ctx->closure_scope);

	js->super_val = saved_super;
	js->new_target = saved_new_target;

	ctx->result = result;
	ctx->has_error = is_err(result);

	if (ctx->has_error) {
	jsval_t reject_value = js->thrown_value;
	if (vtype(reject_value) == T_UNDEF) {
	reject_value = js_mkstr(js, js->errmsg ? js->errmsg : "Unknown error", js->errmsg ? strlen(js->errmsg) : 13);
	}
	js->flags &= (uint8_t)~F_THROW;
	js->thrown_value = js_mkundef();
	js_reject_promise(js, ctx->promise, reject_value);
	} else js_resolve_promise(js, ctx->promise, result);
	}

	static void enqueue_coroutine(coroutine_t *coro) {
	if (!coro) return;
	coro->next = NULL;
	coro->prev = pending_coroutines.tail;

	if (pending_coroutines.tail) {
	pending_coroutines.tail->next = coro;
	} else pending_coroutines.head = coro;
	pending_coroutines.tail = coro;
	}

	static void remove_coroutine(coroutine_t *coro) {
	if (!coro) return;

	if (coro->prev) {
	coro->prev->next = coro->next;
	} else pending_coroutines.head = coro->next;

	if (coro->next) {
	coro->next->prev = coro->prev;
	} else pending_coroutines.tail = coro->prev;

	coro->prev = NULL;
	coro->next = NULL;
	}

	inline bool js_has_pending_coroutines(void) {
	return pending_coroutines.head != NULL;
	}

	static bool has_ready_coroutines(void) {
	coroutine_t *temp = pending_coroutines.head;
	while (temp) {
	if (temp->is_ready) return true;
	temp = temp->next;
	}
	return false;
	}

	void js_poll_events(struct js *js) {
	fetch_poll_events();
	fs_poll_events();
	child_process_poll_events();

	int has_timers = has_pending_timers();
	if (has_timers) {
	int64_t next_timeout_ms = get_next_timer_timeout();
	if (next_timeout_ms <= 0) process_timers(js);
	}

	process_immediates(js);
	process_microtasks(js);

	for (coroutine_t temp = pending_coroutines.head, next; temp; temp = next) {
	next = temp->next;
	if (!temp->is_ready \|\| !temp->mco \|\| mco_status(temp->mco) != MCO_SUSPENDED) continue;
	remove_coroutine(temp);

	coro_saved_state_t saved = coro_enter(temp->js, temp);
	mco_result res = mco_resume(temp->mco);
	coro_leave(temp->js, temp, saved);

	if (res == MCO_SUCCESS && mco_status(temp->mco) != MCO_DEAD) {
	temp->is_ready = false;
	enqueue_coroutine(temp);
	} else free_coroutine(temp);
	}
	}

	typedef enum {
	WORK_MICROTASKS = 1 << 0,
	WORK_TIMERS = 1 << 1,
	WORK_IMMEDIATES = 1 << 2,
	WORK_COROUTINES = 1 << 3,
	WORK_COROUTINES_READY = 1 << 4,
	WORK_FETCHES = 1 << 5,
	WORK_FS_OPS = 1 << 6,
	WORK_CHILD_PROCS = 1 << 7,
	WORK_READLINE = 1 << 8,
	} work_flags_t;

	static inline work_flags_t get_pending_work(void) {
	work_flags_t flags = 0;
	if (has_pending_microtasks()) flags \|= WORK_MICROTASKS;
	if (has_pending_timers()) flags \|= WORK_TIMERS;
	if (has_pending_immediates()) flags \|= WORK_IMMEDIATES;
	if (js_has_pending_coroutines()) flags \|= WORK_COROUTINES;
	if (has_ready_coroutines()) flags \|= WORK_COROUTINES_READY;
	if (has_pending_fetches()) flags \|= WORK_FETCHES;
	if (has_pending_fs_ops()) flags \|= WORK_FS_OPS;
	if (has_pending_child_processes()) flags \|= WORK_CHILD_PROCS;
	if (has_active_readline_interfaces()) flags \|= WORK_READLINE;
	return flags;
	}

	#define WORK_TASKS (WORK_MICROTASKS \| WORK_TIMERS \| WORK_IMMEDIATES \| WORK_COROUTINES \| WORK_FETCHES)
	#define WORK_PENDING (WORK_TASKS \| WORK_FS_OPS \| WORK_CHILD_PROCS \| WORK_READLINE)
	#define WORK_BLOCKING (WORK_MICROTASKS \| WORK_IMMEDIATES \| WORK_COROUTINES_READY)

	void js_run_event_loop(struct js *js) {
	work_flags_t work;

	while ((work = get_pending_work()) & WORK_PENDING) {
	js_poll_events(js);
	work = get_pending_work();

	if (work & WORK_READLINE) {
	uv_run(uv_default_loop(), UV_RUN_NOWAIT);
	}

	if (!(work & WORK_BLOCKING) && (work & WORK_TIMERS)) {
	int64_t ms = get_next_timer_timeout();
	if (ms > 0) usleep(ms > 1000 ? 1000000 : (useconds_t)(ms * 1000));
	} else if ((work & WORK_READLINE) && !(work & WORK_BLOCKING)) uv_run(uv_default_loop(), UV_RUN_ONCE);
	}

	js_poll_events(js);
	}

	static jsval_t start_async_in_coroutine(struct js js, const char code, size_t code_len, jsval_t closure_scope, jsval_t *args, int nargs) {
	jsval_t promise = js_mkpromise(js);
	async_exec_context_t ctx = (async_exec_context_t )CORO_MALLOC(sizeof(async_exec_context_t));
	if (!ctx) return js_mkerr(js, "out of memory for async context");

	ctx->js = js;
	ctx->code = code;
	ctx->code_len = code_len;
	ctx->closure_scope = closure_scope;
	ctx->result = js_mkundef();
	ctx->promise = promise;
	ctx->has_error = false;
	ctx->coro = NULL;

	size_t stack_size = calculate_coro_stack_size();
	mco_desc desc = mco_desc_init(mco_async_entry, stack_size);
	desc.user_data = ctx;

	mco_coro* mco = NULL;
	mco_result res = mco_create(&mco, &desc);
	if (res != MCO_SUCCESS) {
	CORO_FREE(ctx);
	return js_mkerr(js, "failed to create minicoro coroutine");
	}

	coroutine_t coro = (coroutine_t )CORO_MALLOC(sizeof(coroutine_t));
	if (!coro) {
	mco_destroy(mco);
	CORO_FREE(ctx);
	return js_mkerr(js, "out of memory for coroutine");
	}

	coro->js = js;
	coro->type = CORO_ASYNC_AWAIT;
	coro->scope = closure_scope;
	coro->this_val = js->this_val;
	coro->super_val = js->super_val;
	coro->new_target = js->new_target;
	coro->awaited_promise = js_mkundef();
	coro->result = js_mkundef();
	coro->async_func = js->current_func;
	if (nargs > 0) {
	coro->args = (jsval_t )CORO_MALLOC(sizeof(jsval_t) nargs);
	if (coro->args) memcpy(coro->args, args, sizeof(jsval_t) * nargs);
	} else { coro->args = NULL; }
	coro->nargs = nargs;
	coro->is_settled = false;
	coro->is_error = false;
	coro->is_done = false;
	coro->resume_point = 0;
	coro->yield_value = js_mkundef();
	coro->next = NULL;
	coro->mco = mco;
	coro->mco_started = false;
	coro->is_ready = true;
	coro->for_let_stack = NULL;
	coro->for_let_stack_len = 0;
	coro->for_let_stack_cap = 0;

	extern UT_array *global_scope_stack;
	utarray_new(coro->scope_stack, &jsoff_icd);
	jsoff_t glob_off = (jsoff_t)vdata(js_glob(js));
	utarray_push_back(coro->scope_stack, &glob_off);

	ctx->coro = coro;
	enqueue_coroutine(coro);

	coro_saved_state_t saved = coro_enter(js, coro);
	res = mco_resume(mco);
	coro_leave(js, coro, saved);

	if (res != MCO_SUCCESS && mco_status(mco) != MCO_DEAD) {
	remove_coroutine(coro);
	free_coroutine(coro);
	return js_mkerr(js, "failed to start coroutine");
	}

	coro->mco_started = true;
	if (mco_status(mco) == MCO_DEAD) {
	remove_coroutine(coro);
	free_coroutine(coro);
	}

	return promise;
	}

	static void free_coroutine(coroutine_t *coro) {
	if (coro) {
	if (coro->mco) {
	if (mco_running() == coro->mco) fprintf(stderr, "WARNING: Attempting to free a running coroutine\n");
	async_exec_context_t ctx = (async_exec_context_t )mco_get_user_data(coro->mco);
	if (ctx) CORO_FREE(ctx);
	mco_destroy(coro->mco);
	coro->mco = NULL;
	}
	if (coro->args) CORO_FREE(coro->args);
	if (coro->for_let_stack) free(coro->for_let_stack);
	if (coro->scope_stack) utarray_free(coro->scope_stack);
	CORO_FREE(coro);
	}
	}

	static jsval_t resume_coroutine_wrapper(struct js js, jsval_t args, int nargs);
	static jsval_t reject_coroutine_wrapper(struct js js, jsval_t args, int nargs);

	static size_t cpy(char dst, size_t dstlen, const char src, size_t srclen) {
	if (dstlen == 0) return 0;
	size_t len = srclen < dstlen - 1 ? srclen : dstlen - 1;
	memcpy(dst, src, len); dst[len] = '\0';
	return len;
	}

	static inline size_t uint_to_str(char *buf, size_t bufsize, uint64_t val) {
	if (bufsize == 0) return 0;
	if (val == 0) {
	buf[0] = '0';
	buf[1] = '\0';
	return 1;
	}
	char temp[24];
	size_t len = 0;
	while (val > 0 && len < sizeof(temp)) {
	temp[len++] = '0' + (val % 10);
	val /= 10;
	}
	if (len >= bufsize) len = bufsize - 1;
	for (size_t i = 0; i < len; i++) {
	buf[i] = temp[len - 1 - i];
	}
	buf[len] = '\0';
	return len;
	}

	#define MAX_STRINGIFY_DEPTH 64
	#define MAX_MULTIREF_OBJS 128

	static jsval_t stringify_stack[MAX_STRINGIFY_DEPTH];
	static int stringify_depth = 0;
	static int stringify_indent = 0;

	static jsval_t multiref_objs[MAX_MULTIREF_OBJS];
	static int multiref_ids[MAX_MULTIREF_OBJS];
	static int multiref_count = 0;
	static int multiref_next_id = 0;

	static void scan_refs(struct js *js, jsval_t value);

	static int find_multiref(jsval_t obj) {
	for (int i = 0; i < multiref_count; i++) {
	if (multiref_objs[i] == obj) return multiref_ids[i];
	}
	return 0;
	}

	static bool is_on_stack(jsval_t obj) {
	for (int i = 0; i < stringify_depth; i++) {
	if (stringify_stack[i] == obj) return true;
	}
	return false;
	}

	static void mark_multiref(jsval_t obj) {
	for (int i = 0; i < multiref_count; i++) {
	if (multiref_objs[i] == obj) {
	if (multiref_ids[i] == 0) multiref_ids[i] = ++multiref_next_id;
	return;
	}
	}
	if (multiref_count < MAX_MULTIREF_OBJS) {
	multiref_objs[multiref_count] = obj;
	multiref_ids[multiref_count] = 0;
	multiref_count++;
	}
	}

	static void scan_obj_refs(struct js *js, jsval_t obj) {
	if (is_on_stack(obj)) {
	mark_multiref(obj);
	return;
	}

	if (stringify_depth >= MAX_STRINGIFY_DEPTH) return;
	stringify_stack[stringify_depth++] = obj;

	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (!is_slot_prop(header)) {
	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));
	scan_refs(js, val);
	}
	next = next_prop(header);
	}

	jsval_t proto_val = get_slot(js, obj, SLOT_PROTO);
	if (vtype(proto_val) == T_OBJ) scan_refs(js, proto_val);

	stringify_depth--;
	}

	static void scan_arr_refs(struct js *js, jsval_t obj) {
	if (is_on_stack(obj)) {
	mark_multiref(obj);
	return;
	}

	if (stringify_depth >= MAX_STRINGIFY_DEPTH) return;
	stringify_stack[stringify_depth++] = obj;

	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (!is_slot_prop(header)) {
	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));
	scan_refs(js, val);
	}
	next = next_prop(header);
	}

	stringify_depth--;
	}

	static void scan_func_refs(struct js *js, jsval_t value) {
	jsval_t func_obj = mkval(T_OBJ, vdata(value));

	if (is_on_stack(func_obj)) {
	mark_multiref(func_obj);
	return;
	}

	if (stringify_depth >= MAX_STRINGIFY_DEPTH) return;
	stringify_stack[stringify_depth++] = func_obj;

	jsoff_t next = loadoff(js, (jsoff_t) vdata(func_obj)) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (!is_slot_prop(header)) {
	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));
	scan_refs(js, val);
	}
	next = next_prop(header);
	}

	stringify_depth--;
	}

	static void scan_refs(struct js *js, jsval_t value) {
	switch (vtype(value)) {
	case T_OBJ: scan_obj_refs(js, value); break;
	case T_ARR: scan_arr_refs(js, value); break;
	case T_FUNC: scan_func_refs(js, value); break;
	default: break;
	}
	}

	static int get_circular_ref(jsval_t obj) {
	if (is_on_stack(obj)) {
	int ref = find_multiref(obj);
	return ref ? ref : -1;
	}
	return 0;
	}

	static bool is_circular(jsval_t obj) {
	return is_on_stack(obj);
	}

	static int get_self_ref(jsval_t obj) {
	return find_multiref(obj);
	}

	static void push_stringify(jsval_t obj) {
	if (stringify_depth < MAX_STRINGIFY_DEPTH) {
	stringify_stack[stringify_depth++] = obj;
	}
	}

	static void pop_stringify(void) {
	if (stringify_depth > 0) stringify_depth--;
	}

	static size_t add_indent(char *buf, size_t len, int level) {
	size_t n = 0;
	for (int i = 0; i < level * 2 && n < len; i++) {
	buf[n++] = ' ';
	}
	return n;
	}

	static inline jsoff_t get_prop_koff(struct js *js, jsoff_t prop) {
	return loadoff(js, prop + (jsoff_t) sizeof(prop));
	}

	static void get_prop_key(struct js js, jsoff_t prop, const char key, jsoff_t klen) {
	jsoff_t koff = get_prop_koff(js, prop);
	*klen = offtolen(loadoff(js, koff));
	key = (char ) &js->mem[koff + sizeof(koff)];
	}

	static jsval_t get_prop_val(struct js *js, jsoff_t prop) {
	jsoff_t koff = get_prop_koff(js, prop);
	return loadval(js, prop + (jsoff_t) (sizeof(prop) + sizeof(koff)));
	}

	static bool is_small_array(struct js js, jsval_t obj, int elem_count) {
	int count = 0;
	bool has_nested = false;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	jsoff_t length = 0;
	jsoff_t scan = next;

	while (scan < js->brk && scan != 0) {
	const char *key; jsoff_t klen;
	get_prop_key(js, scan, &key, &klen);
	if (streq(key, klen, "length", 6)) {
	jsval_t val = get_prop_val(js, scan);
	if (vtype(val) == T_NUM) length = (jsoff_t) tod(val);
	break;
	}
	scan = loadoff(js, scan) & ~(3U \| FLAGMASK);
	}

	for (jsoff_t i = 0; i < length; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%u", (unsigned) i);
	jsoff_t idxlen = (jsoff_t) strlen(idx);
	jsoff_t prop = next;
	jsval_t val = js_mkundef();
	bool found = false;

	while (prop < js->brk && prop != 0) {
	const char *key; jsoff_t klen;
	get_prop_key(js, prop, &key, &klen);
	if (streq(key, klen, idx, idxlen)) {
	val = get_prop_val(js, prop);
	found = true;
	break;
	}
	prop = loadoff(js, prop) & ~(3U \| FLAGMASK);
	}

	if (found) {
	uint8_t t = vtype(val);
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) has_nested = true;
	count++;
	} else count++;
	}

	if (elem_count) *elem_count = count;
	return count <= 4 && !has_nested;
	}

	static bool is_array_index(const char *key, jsoff_t klen) {
	if (klen == 0) return false;
	for (jsoff_t i = 0; i < klen; i++) {
	if (key[i] < '0' \|\| key[i] > '9') return false;
	}
	return true;
	}

	static jsoff_t get_array_length(struct js *js, jsval_t arr) {
	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	if (!off) return 0;
	jsval_t val = resolveprop(js, mkval(T_PROP, off));
	return vtype(val) == T_NUM ? (jsoff_t) tod(val) : 0;
	}

	static jsval_t get_obj_ctor(struct js *js, jsval_t obj) {
	jsval_t ctor = get_slot(js, obj, SLOT_CTOR);
	if (vtype(ctor) == T_FUNC) return ctor;
	jsval_t proto = get_slot(js, obj, SLOT_PROTO);
	if (vtype(proto) != T_OBJ) return js_mkundef();
	jsoff_t off = lkp_interned(js, proto, INTERN_CONSTRUCTOR, 11);
	return off ? resolveprop(js, mkval(T_PROP, off)) : js_mkundef();
	}

	static const char get_func_name(struct js js, jsval_t func, jsoff_t *out_len) {
	if (vtype(func) != T_FUNC) return NULL;
	jsoff_t off = lkp(js, mkval(T_OBJ, vdata(func)), "name", 4);
	if (!off) return NULL;
	jsval_t name = resolveprop(js, mkval(T_PROP, off));
	if (vtype(name) != T_STR) return NULL;
	jsoff_t str_off = vstr(js, name, out_len);
	return (const char *) &js->mem[str_off];
	}

	static const char get_class_name(struct js js, jsval_t obj, jsoff_t out_len, const char skip) {
	const char *name = get_func_name(js, get_obj_ctor(js, obj), out_len);
	if (!name) return NULL;
	if (skip && out_len == (jsoff_t)strlen(skip) && memcmp(name, skip, out_len) == 0) return NULL;
	return name;
	}

	static size_t strarr(struct js js, jsval_t obj, char buf, size_t len) {
	int ref = get_circular_ref(obj);
	if (ref) return ref > 0 ? (size_t) snprintf(buf, len, "[Circular *%d]", ref) : cpy(buf, len, "[Circular]", 10);

	push_stringify(obj);
	jsoff_t first = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	jsoff_t length = get_array_length(js, obj);

	jsoff_t class_len = 0;
	const char *class_name = get_class_name(js, obj, &class_len, "Array");

	int elem_count = 0;
	bool inline_mode = is_small_array(js, obj, &elem_count);
	size_t n = 0;

	if (class_name) {
	n += cpy(buf + n, len - n, class_name, class_len);
	n += (size_t) snprintf(buf + n, len - n, "(%u) ", (unsigned) length);
	}

	if (length == 0) {
	n += cpy(buf + n, len - n, "[]", 2);
	pop_stringify();
	return n;
	}

	n += cpy(buf + n, len - n, inline_mode ? "[ " : "[\n", 2);
	if (!inline_mode) stringify_indent++;

	for (jsoff_t i = 0; i < length; i++) {
	if (i > 0) n += cpy(buf + n, len - n, inline_mode ? ", " : ",\n", 2);
	if (!inline_mode) n += add_indent(buf + n, len - n, stringify_indent);

	char idx[16];
	snprintf(idx, sizeof(idx), "%u", (unsigned) i);
	jsoff_t idxlen = (jsoff_t) strlen(idx);

	bool found = false;
	jsval_t val = js_mkundef();
	for (jsoff_t p = first; p < js->brk && p != 0; p = next_prop(loadoff(js, p))) {
	const char *key; jsoff_t klen;
	get_prop_key(js, p, &key, &klen);
	if (streq(key, klen, idx, idxlen)) {
	val = get_prop_val(js, p);
	found = true; break;
	}
	}
	n += found ? tostr(js, val, buf + n, len - n) : cpy(buf + n, len - n, "undefined", 9);
	}

	for (jsoff_t p = first; p < js->brk && p != 0; p = next_prop(loadoff(js, p))) {
	jsoff_t header = loadoff(js, p);
	if (is_slot_prop(header)) continue;

	const char *key; jsoff_t klen;
	get_prop_key(js, p, &key, &klen);
	if (streq(key, klen, "length", 6) \|\| is_array_index(key, klen)) continue;

	n += cpy(buf + n, len - n, inline_mode ? ", " : ",\n", 2);
	if (!inline_mode) n += add_indent(buf + n, len - n, stringify_indent);
	n += cpy(buf + n, len - n, key, klen);
	n += cpy(buf + n, len - n, ": ", 2);
	n += tostr(js, get_prop_val(js, p), buf + n, len - n);
	}

	if (!inline_mode) {
	stringify_indent--;
	n += cpy(buf + n, len - n, "\n", 1);
	n += add_indent(buf + n, len - n, stringify_indent);
	}

	n += cpy(buf + n, len - n, inline_mode ? " ]" : "]", inline_mode ? 2 : 1);
	pop_stringify();
	return n;
	}

	static size_t array_to_string(struct js js, jsval_t obj, char buf, size_t len) {
	if (is_circular(obj)) return cpy(buf, len, "", 0);

	push_stringify(obj);
	size_t n = 0;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	jsoff_t length = 0;
	jsoff_t scan = next;

	while (scan < js->brk && scan != 0) {
	const char *key; jsoff_t klen;
	get_prop_key(js, scan, &key, &klen);
	if (streq(key, klen, "length", 6)) {
	jsval_t val = get_prop_val(js, scan);
	if (vtype(val) == T_NUM) length = (jsoff_t) tod(val);
	break;
	}
	scan = loadoff(js, scan) & ~(3U \| FLAGMASK);
	}

	for (jsoff_t i = 0; i < length; i++) {
	if (i > 0) n += cpy(buf + n, len - n, ",", 1);
	char idx[16];
	snprintf(idx, sizeof(idx), "%u", (unsigned) i);
	jsoff_t idxlen = (jsoff_t) strlen(idx);
	jsoff_t prop = next;
	jsval_t val = js_mkundef();
	bool found = false;

	while (prop < js->brk && prop != 0) {
	const char *key; jsoff_t klen;
	get_prop_key(js, prop, &key, &klen);
	if (streq(key, klen, idx, idxlen)) {
	val = get_prop_val(js, prop);
	found = true;
	break;
	}
	prop = loadoff(js, prop) & ~(3U \| FLAGMASK);
	}

	if (found) {
	uint8_t vt = vtype(val);
	if (vt == T_STR) {
	jsoff_t slen, soff = vstr(js, val, &slen);
	n += cpy(buf + n, len - n, (const char *)&js->mem[soff], slen);
	} else if (vt != T_UNDEF && vt != T_NULL) n += tostr(js, val, buf + n, len - n);
	}
	}

	pop_stringify();
	return n;
	}

	static size_t strdate(struct js js, jsval_t obj, char buf, size_t len) {
	jsval_t time_val = js_get_slot(js, obj, SLOT_DATA);
	if (vtype(time_val) != T_NUM) return cpy(buf, len, "Invalid Date", 12);

	double timestamp_ms = tod(time_val);
	time_t timestamp_sec = (time_t)(timestamp_ms / 1000.0);
	struct tm *tm_local = localtime(&timestamp_sec);

	if (!tm_local) return cpy(buf, len, "Invalid Date", 12);

	char date_part[64];
	strftime(date_part, sizeof(date_part), "%a %b %d %Y %H:%M:%S", tm_local);

	time_t now = timestamp_sec;
	struct tm *gm = gmtime(&now);
	struct tm local_copy = *tm_local;
	time_t local_time = mktime(&local_copy);
	time_t gmt_time = mktime(gm);
	long offset_sec = (long)difftime(local_time, gmt_time);
	int offset_hours = (int)(offset_sec / 3600);
	int offset_mins = (int)(labs(offset_sec) % 3600) / 60;

	char tz_name[64];
	strftime(tz_name, sizeof(tz_name), "%Z", tm_local);

	return (size_t) snprintf(buf, len, "%s GMT%+03d%02d (%s)", date_part, offset_hours, offset_mins, tz_name);
	}

	static bool is_valid_identifier(const char *str, jsoff_t slen) {
	if (slen == 0) return false;
	char c = str[0];
	if (!((c >= 'a' && c <= 'z') \|\| (c >= 'A' && c <= 'Z') \|\| c == '_' \|\| c == '$')) return false;
	for (jsoff_t i = 1; i < slen; i++) {
	c = str[i];
	if (!((c >= 'a' && c <= 'z') \|\| (c >= 'A' && c <= 'Z') \|\| (c >= '0' && c <= '9') \|\| c == '_' \|\| c == '$')) return false;
	}
	return true;
	}

	static size_t strkey(struct js js, jsval_t value, char buf, size_t len) {
	jsoff_t slen, off = vstr(js, value, &slen);
	const char str = (const char ) &js->mem[off];

	const char *sym_desc = get_symbol_description_from_key(str, slen);
	if (sym_desc) {
	size_t n = 0;
	n += cpy(buf + n, len - n, "[", 1);
	n += cpy(buf + n, len - n, sym_desc, strlen(sym_desc));
	n += cpy(buf + n, len - n, "]", 1);
	return n;
	}

	if (is_valid_identifier(str, slen)) {
	return cpy(buf, len, str, slen);
	}
	return strstring(js, value, buf, len);
	}

	static bool is_small_object(struct js js, jsval_t obj, int prop_count) {
	int count = 0;
	bool has_nested = false;

	jsoff_t obj_off = (jsoff_t)vdata(obj);
	jsoff_t next = loadoff(js, obj_off) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	const char *key; jsoff_t klen;
	get_prop_key(js, next, &key, &klen);
	const char *tag_sym_key = get_toStringTag_sym_key();
	bool should_hide = streq(key, klen, STR_PROTO, STR_PROTO_LEN) \|\| streq(key, klen, tag_sym_key, strlen(tag_sym_key));

	if (!should_hide) {
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key, klen);
	if (desc && !desc->enumerable) should_hide = true;
	}

	if (!should_hide) {
	jsval_t val = get_prop_val(js, next);
	uint8_t t = vtype(val);
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) has_nested = true;
	count++;
	}

	next = next_prop(header);
	}

	descriptor_entry_t desc, tmp;
	HASH_ITER(hh, desc_registry, desc, tmp) {
	if (desc->obj_off != obj_off) continue;
	if (!desc->enumerable) continue;
	if (!desc->has_getter && !desc->has_setter) continue;
	count++;
	}

	if (prop_count) *prop_count = count;
	return count <= 4 && !has_nested;
	}

	// todo: split into smaller functions
	static size_t strobj(struct js js, jsval_t obj, char buf, size_t len) {
	jsval_t obj_proto = js_get_proto(js, obj);
	jsval_t date_proto = js_get_ctor_proto(js, "Date", 4);
	if (obj_proto == date_proto) return strdate(js, obj, buf, len);

	int ref = get_circular_ref(obj);
	if (ref) return ref > 0 ? (size_t) snprintf(buf, len, "[Circular *%d]", ref) : cpy(buf, len, "[Circular]", 10);

	push_stringify(obj);

	size_t n = 0;
	int self_ref = get_self_ref(obj);
	if (self_ref) {
	n += (size_t) snprintf(buf + n, len - n, "<ref *%d> ", self_ref);
	}

	const char *tostring_tag_key = get_toStringTag_sym_key();
	jsoff_t tag_off = lkp_proto(js, obj, tostring_tag_key, strlen(tostring_tag_key));
	bool is_map = false, is_set = false, is_arraybuffer = false;
	jsoff_t tlen = 0, toff = 0;
	const char *tag_str = NULL;
	int prop_count = 0;
	bool inline_mode = false;

	if (tag_off == 0) goto print_plain_object;

	jsval_t tag_val = resolveprop(js, mkval(T_PROP, tag_off));
	if (vtype(tag_val) != T_STR) goto print_plain_object;

	toff = vstr(js, tag_val, &tlen);
	tag_str = (const char *) &js->mem[toff];
	is_map = (tlen == 3 && memcmp(tag_str, "Map", 3) == 0);
	is_set = (tlen == 3 && memcmp(tag_str, "Set", 3) == 0);
	is_arraybuffer = (tlen >= 11 && memcmp(tag_str + tlen - 11, "ArrayBuffer", 11) == 0);

	jsval_t ta_slot = js_get_slot(js, obj, SLOT_BUFFER);
	if (vtype(ta_slot) == T_TYPEDARRAY) {
	TypedArrayData ta = (TypedArrayData )vdata(ta_slot);
	if (ta && ta->buffer) {
	static const char *ta_type_names[] = {
	"Int8Array", "Uint8Array", "Uint8ClampedArray",
	"Int16Array", "Uint16Array", "Int32Array", "Uint32Array",
	"Float32Array", "Float64Array", "BigInt64Array", "BigUint64Array"
	};

	const char *type_name = NULL;
	size_t type_len = 0;

	jsval_t proto = js_get_proto(js, obj);
	jsval_t buffer_proto = get_ctor_proto(js, "Buffer", 6);
	if (vtype(proto) == T_OBJ && vtype(buffer_proto) == T_OBJ && vdata(proto) == vdata(buffer_proto)) {
	type_name = "Buffer";
	type_len = 6;
	} else if (ta->type <= TYPED_ARRAY_BIGUINT64) {
	type_name = ta_type_names[ta->type];
	type_len = strlen(type_name);
	} else {
	type_name = "TypedArray";
	type_len = 10;
	}

	n += cpy(buf + n, len - n, type_name, type_len);
	n += (size_t) snprintf(buf + n, len - n, "(%zu) ", ta->length);
	n += cpy(buf + n, len - n, "[ ", 2);

	uint8_t *data = ta->buffer->data + ta->byte_offset;

	for (size_t i = 0; i < ta->length && i < 100; i++) {
	if (i > 0) n += cpy(buf + n, len - n, ", ", 2);

	switch (ta->type) {
	case TYPED_ARRAY_INT8:
	n += (size_t) snprintf(buf + n, len - n, "%d", (int)((int8_t*)data)[i]);
	break;
	case TYPED_ARRAY_UINT8:
	case TYPED_ARRAY_UINT8_CLAMPED:
	n += (size_t) snprintf(buf + n, len - n, "%u", (unsigned)data[i]);
	break;
	case TYPED_ARRAY_INT16:
	n += (size_t) snprintf(buf + n, len - n, "%d", (int)((int16_t*)data)[i]);
	break;
	case TYPED_ARRAY_UINT16:
	n += (size_t) snprintf(buf + n, len - n, "%u", (unsigned)((uint16_t*)data)[i]);
	break;
	case TYPED_ARRAY_INT32:
	n += (size_t) snprintf(buf + n, len - n, "%d", ((int32_t*)data)[i]);
	break;
	case TYPED_ARRAY_UINT32:
	n += (size_t) snprintf(buf + n, len - n, "%u", ((uint32_t*)data)[i]);
	break;
	case TYPED_ARRAY_FLOAT32:
	n += (size_t) snprintf(buf + n, len - n, "%g", (double)((float*)data)[i]);
	break;
	case TYPED_ARRAY_FLOAT64:
	n += (size_t) snprintf(buf + n, len - n, "%g", ((double*)data)[i]);
	break;
	case TYPED_ARRAY_BIGINT64:
	n += (size_t) snprintf(buf + n, len - n, "%lldn", (long long)((int64_t*)data)[i]);
	break;
	case TYPED_ARRAY_BIGUINT64:
	n += (size_t) snprintf(buf + n, len - n, "%llun", (unsigned long long)((uint64_t*)data)[i]);
	break;
	default:
	n += (size_t) snprintf(buf + n, len - n, "%u", (unsigned)data[i]);
	break;
	}
	}

	if (ta->length > 100) n += cpy(buf + n, len - n, ", ...", 5);
	n += cpy(buf + n, len - n, " ]", 2);
	pop_stringify();
	return n;
	}
	}

	if (is_arraybuffer) {
	jsval_t buf_val = js_get_slot(js, obj, SLOT_BUFFER);
	if (vtype(buf_val) == T_NUM) {
	ArrayBufferData ab_data = (ArrayBufferData )(uintptr_t)tod(buf_val);
	size_t bytelen = ab_data ? ab_data->length : 0;

	n += cpy(buf + n, len - n, tag_str, tlen);
	n += cpy(buf + n, len - n, " {\n", 3);
	n += cpy(buf + n, len - n, " [Uint8Contents]: <", 20);

	if (ab_data && ab_data->data && bytelen > 0) {
	for (size_t i = 0; i < bytelen; i++) {
	if (i > 0) n += cpy(buf + n, len - n, " ", 1);
	n += (size_t) snprintf(buf + n, len - n, "%02x", ab_data->data[i]);
	}
	}

	n += cpy(buf + n, len - n, ">,\n", 3);
	n += cpy(buf + n, len - n, " [byteLength]: ", 16);
	n += (size_t) snprintf(buf + n, len - n, "%zu", bytelen);
	n += cpy(buf + n, len - n, "\n}", 2);
	pop_stringify();
	return n;
	}
	}

	bool is_dataview = (tlen == 8 && memcmp(tag_str, "DataView", 8) == 0);
	if (is_dataview) {
	jsval_t dv_data_val = js_get_slot(js, obj, SLOT_DATA);
	if (js_type(dv_data_val) == JS_NUM) {
	DataViewData dv = (DataViewData )(uintptr_t)tod(dv_data_val);
	if (dv && dv->buffer) {
	n += cpy(buf + n, len - n, "DataView {\n", 11);
	n += cpy(buf + n, len - n, " [byteLength]: ", 16);
	n += (size_t) snprintf(buf + n, len - n, "%zu", dv->byte_length);
	n += cpy(buf + n, len - n, ",\n", 2);
	n += cpy(buf + n, len - n, " [byteOffset]: ", 16);
	n += (size_t) snprintf(buf + n, len - n, "%zu", dv->byte_offset);
	n += cpy(buf + n, len - n, ",\n", 2);
	n += cpy(buf + n, len - n, " [buffer]: ArrayBuffer {\n", 26);
	n += cpy(buf + n, len - n, " [Uint8Contents]: <", 22);

	if (dv->buffer->data && dv->buffer->length > 0) {
	for (size_t i = 0; i < dv->buffer->length; i++) {
	if (i > 0) n += cpy(buf + n, len - n, " ", 1);
	n += (size_t) snprintf(buf + n, len - n, "%02x", dv->buffer->data[i]);
	}
	}

	n += cpy(buf + n, len - n, ">,\n", 3);
	n += cpy(buf + n, len - n, " [byteLength]: ", 18);
	n += (size_t) snprintf(buf + n, len - n, "%zu", dv->buffer->length);
	n += cpy(buf + n, len - n, "\n }\n}", 6);
	pop_stringify();
	return n;
	}
	}
	}

	if (is_map) {
	jsval_t map_val = js_get_slot(js, obj, SLOT_MAP);
	if (vtype(map_val) == T_UNDEF) goto print_tagged_object;

	map_entry_t map_ptr = (map_entry_t)(size_t)tod(map_val);
	n += cpy(buf + n, len - n, "Map(", 4);

	unsigned int count = 0;
	if (map_ptr && map_ptr) count = HASH_COUNT(map_ptr);
	n += (size_t) snprintf(buf + n, len - n, "%u", count);
	n += cpy(buf + n, len - n, ") ", 2);

	if (count == 0) {
	n += cpy(buf + n, len - n, "{}", 2);
	} else {
	n += cpy(buf + n, len - n, "{\n", 2);
	stringify_indent++;
	bool first = true;
	if (map_ptr && *map_ptr) {
	map_entry_t entry, tmp;
	HASH_ITER(hh, *map_ptr, entry, tmp) {
	if (!first) n += cpy(buf + n, len - n, ",\n", 2);
	first = false;
	n += add_indent(buf + n, len - n, stringify_indent);

	size_t key_len = strlen(entry->key);
	n += cpy(buf + n, len - n, "'", 1);
	n += cpy(buf + n, len - n, entry->key, key_len);
	n += cpy(buf + n, len - n, "'", 1);
	n += cpy(buf + n, len - n, " => ", 4);
	n += tostr(js, entry->value, buf + n, len - n);
	}
	}
	stringify_indent--;
	n += cpy(buf + n, len - n, "\n", 1);
	n += add_indent(buf + n, len - n, stringify_indent);
	n += cpy(buf + n, len - n, "}", 1);
	}
	pop_stringify();
	return n;
	}

	if (is_set) {
	jsval_t set_val = js_get_slot(js, obj, SLOT_SET);
	if (vtype(set_val) == T_UNDEF) goto print_tagged_object;

	set_entry_t set_ptr = (set_entry_t)(size_t)tod(set_val);
	n += cpy(buf + n, len - n, "Set(", 4);

	unsigned int count = 0;
	if (set_ptr && set_ptr) count = HASH_COUNT(set_ptr);
	n += (size_t) snprintf(buf + n, len - n, "%u", count);
	n += cpy(buf + n, len - n, ") ", 2);

	if (count == 0) {
	n += cpy(buf + n, len - n, "{}", 2);
	} else {
	n += cpy(buf + n, len - n, "{\n", 2);
	stringify_indent++;
	bool first = true;
	if (set_ptr && *set_ptr) {
	set_entry_t entry, tmp;
	HASH_ITER(hh, *set_ptr, entry, tmp) {
	if (!first) n += cpy(buf + n, len - n, ",\n", 2);
	first = false;
	n += add_indent(buf + n, len - n, stringify_indent);
	n += tostr(js, entry->value, buf + n, len - n);
	}
	}
	stringify_indent--;
	n += cpy(buf + n, len - n, "\n", 1);
	n += add_indent(buf + n, len - n, stringify_indent);
	n += cpy(buf + n, len - n, "}", 1);
	}
	pop_stringify();
	return n;
	}

	print_tagged_object:
	n += cpy(buf + n, len - n, "Object [", 8);
	n += cpy(buf + n, len - n, (const char *) &js->mem[toff], tlen);
	n += cpy(buf + n, len - n, "] {\n", 4);
	goto continue_object_print;

	print_plain_object:
	inline_mode = is_small_object(js, obj, &prop_count);

	jsval_t proto_val = js_get_proto(js, obj);
	bool is_null_proto = (vtype(proto_val) == T_NULL);
	bool proto_is_null_proto = false;
	const char *class_name = NULL;
	jsoff_t class_name_len = 0;

	do {
	if (is_null_proto) break;
	uint8_t pt = vtype(proto_val);
	if (pt != T_OBJ && pt != T_FUNC) break;

	jsval_t proto_proto = js_get_proto(js, proto_val);
	jsval_t object_proto = get_ctor_proto(js, "Object", 6);
	proto_is_null_proto = (vtype(proto_proto) == T_NULL) &&
	(vdata(proto_val) != vdata(object_proto));

	class_name = get_class_name(js, obj, &class_name_len, "Object");
	} while (0);

	if (prop_count == 0) {
	if (is_null_proto) {
	n += cpy(buf + n, len - n, "[Object: null prototype] {}", 27);
	} else if (class_name && class_name_len > 0) {
	n += cpy(buf + n, len - n, class_name, class_name_len);
	if (proto_is_null_proto) {
	n += cpy(buf + n, len - n, " <[Object: null prototype] {}> {}", 33);
	} else n += cpy(buf + n, len - n, " {}", 3);
	} else if (proto_is_null_proto) {
	n += cpy(buf + n, len - n, "<[Object: null prototype] {}> {}", 32);
	} else n += cpy(buf + n, len - n, "{}", 2);
	pop_stringify();
	return n;
	}

	if (is_null_proto) {
	n += cpy(buf + n, len - n, "[Object: null prototype] ", 25);
	} else if (class_name && class_name_len > 0) {
	n += cpy(buf + n, len - n, class_name, class_name_len);
	if (proto_is_null_proto) {
	n += cpy(buf + n, len - n, " <[Object: null prototype] {}> ", 31);
	} else n += cpy(buf + n, len - n, " ", 1);
	} else if (proto_is_null_proto) {
	n += cpy(buf + n, len - n, "<[Object: null prototype] {}> ", 30);
	}

	n += cpy(buf + n, len - n, inline_mode ? "{ " : "{\n", 2);

	continue_object_print:;

	if (!inline_mode) stringify_indent++;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	bool first = true;

	jsoff_t obj_off = (jsoff_t)vdata(obj);
	int prop_capacity = 64;

	jsoff_t prop_offsets = malloc(prop_capacity sizeof(jsoff_t));
	int num_props = 0;

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));

	const char key = (char ) &js->mem[koff + sizeof(koff)];
	const char *tag_sym_key = get_toStringTag_sym_key();
	bool should_hide = streq(key, klen, STR_PROTO, STR_PROTO_LEN) \|\| streq(key, klen, tag_sym_key, strlen(tag_sym_key));

	if (!should_hide) {
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key, klen);
	if (desc && !desc->enumerable) should_hide = true;
	}

	if (!should_hide) {
	if (num_props >= prop_capacity) {
	prop_capacity *= 2;
	prop_offsets = realloc(prop_offsets, prop_capacity * sizeof(jsoff_t));
	}
	prop_offsets[num_props++] = next;
	}
	next = next_prop(header);
	}

	for (int i = num_props - 1; i >= 0; i--) {
	jsoff_t prop = prop_offsets[i];
	jsoff_t koff = loadoff(js, prop + (jsoff_t) sizeof(prop));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t val = loadval(js, prop + (jsoff_t) (sizeof(prop) + sizeof(koff)));

	if (!first) n += cpy(buf + n, len - n, inline_mode ? ", " : ",\n", 2);
	first = false;
	if (!inline_mode) n += add_indent(buf + n, len - n, stringify_indent);

	bool is_special_global = false;
	if (vtype(val) == T_UNDEF && streq(key, klen, "undefined", 9)) {
	is_special_global = true;
	} else if (vtype(val) == T_NUM) {
	double d = tod(val);
	if (isinf(d) && d > 0 && streq(key, klen, "Infinity", 8)) {
	is_special_global = true;
	} else if (isnan(d) && streq(key, klen, "NaN", 3)) is_special_global = true;
	}

	if (is_special_global) {
	n += tostr(js, val, buf + n, len - n);
	} else {
	n += strkey(js, mkval(T_STR, koff), buf + n, len - n);
	n += cpy(buf + n, len - n, ": ", 2);
	n += tostr(js, val, buf + n, len - n);
	}
	}
	free(prop_offsets);

	descriptor_entry_t desc, tmp;
	HASH_ITER(hh, desc_registry, desc, tmp) {
	if (desc->obj_off != obj_off) continue;
	if (!desc->enumerable) continue;
	if (!desc->has_getter && !desc->has_setter) continue;

	if (!first) n += cpy(buf + n, len - n, inline_mode ? ", " : ",\n", 2);
	first = false;
	if (!inline_mode) n += add_indent(buf + n, len - n, stringify_indent);
	n += cpy(buf + n, len - n, desc->prop_name, desc->prop_len);
	n += cpy(buf + n, len - n, ": ", 2);

	if (desc->has_getter && desc->has_setter) {
	n += cpy(buf + n, len - n, "[Getter/Setter]", 15);
	} else if (desc->has_getter) {
	n += cpy(buf + n, len - n, "[Getter]", 8);
	} else n += cpy(buf + n, len - n, "[Setter]", 8);
	}

	if (!inline_mode) stringify_indent--;
	if (inline_mode) {
	n += cpy(buf + n, len - n, " }", 2);
	} else {
	if (!first) n += cpy(buf + n, len - n, "\n", 1);
	n += add_indent(buf + n, len - n, stringify_indent);
	n += cpy(buf + n, len - n, "}", 1);
	}
	pop_stringify();
	return n;
	}

	static size_t fix_exponent(char *buf, size_t n) {
	char *e = strchr(buf, 'e');
	if (!e) return n;

	char *src = e + 1;
	char *dst = src;

	if (src == '+' \|\| src == '-') {
	dst++;
	src++;
	}

	while (*src == '0' && src[1] != '\0') src++;

	if (src != dst) {
	memmove(dst, src, strlen(src) + 1);
	return strlen(buf);
	}
	return n;
	}

	static size_t strnum(jsval_t value, char *buf, size_t len) {
	double dv = tod(value);

	if (isnan(dv)) return cpy(buf, len, "NaN", 3);
	if (isinf(dv)) return cpy(buf, len, dv > 0 ? "Infinity" : "-Infinity", dv > 0 ? 8 : 9);
	if (dv == 0.0) return cpy(buf, len, "0", 1);

	char temp[64];
	int sign = dv < 0 ? 1 : 0;
	double adv = sign ? -dv : dv;

	double iv;
	double frac = modf(adv, &iv);
	if (frac == 0.0 && adv < 9007199254740992.0) {
	return (size_t) snprintf(buf, len, "%.0f", dv);
	}

	for (int prec = 1; prec <= 17; prec++) {
	int n = snprintf(temp, sizeof(temp), "%.*g", prec, dv);
	double parsed = strtod(temp, NULL);
	if (parsed == dv) {
	size_t result = (size_t)snprintf(buf, len, "%s", temp);
	return fix_exponent(buf, result);
	}
	(void)n;
	}

	size_t result = (size_t)snprintf(buf, len, "%.17g", dv);
	return fix_exponent(buf, result);
	}

	static jsoff_t vstr(struct js js, jsval_t value, jsoff_t len) {
	jsoff_t off = (jsoff_t) vdata(value);
	if (len) *len = offtolen(loadoff(js, off));
	return (jsoff_t) (off + sizeof(off));
	}

	static size_t strstring(struct js js, jsval_t value, char buf, size_t len) {
	jsoff_t slen, off = vstr(js, value, &slen);
	const char str = (const char ) &js->mem[off];
	size_t n = 0;
	n += cpy(buf + n, len - n, "'", 1);
	for (jsoff_t i = 0; i < slen && n < len - 1; i++) {
	char c = str[i];
	if (c == '\n') { n += cpy(buf + n, len - n, "\\n", 2); }
	else if (c == '\r') { n += cpy(buf + n, len - n, "\\r", 2); }
	else if (c == '\t') { n += cpy(buf + n, len - n, "\\t", 2); }
	else if (c == '\\') { n += cpy(buf + n, len - n, "\\\\", 2); }
	else if (c == '\'') { n += cpy(buf + n, len - n, "\\'", 2); }
	else { if (n < len) buf[n++] = c; }
	}
	n += cpy(buf + n, len - n, "'", 1);

	return n;
	}

	static const char intern_string(const char str, size_t len) {
	uint64_t h = hash_key(str, len);
	uint32_t bucket = (uint32_t)(h & (ANT_LIMIT_SIZE_CACHE - 1));

	for (interned_string_t *e = intern_buckets[bucket]; e; e = e->next) {
	if (e->hash == h && e->len == len && memcmp(e->str, str, len) == 0) return e->str;
	}

	interned_string_t entry = (interned_string_t )ant_calloc(sizeof(interned_string_t) + len + 1);
	if (!entry) return NULL;

	entry->str = (char *)(entry + 1);
	memcpy(entry->str, str, len);
	entry->str[len] = '\0';
	entry->len = len;
	entry->hash = h;
	entry->next = intern_buckets[bucket];
	intern_buckets[bucket] = entry;

	return entry->str;
	}

	bool is_internal_prop(const char *key, jsoff_t klen) {
	if (klen < 2) return false;
	if (key[0] != '_' \|\| key[1] != '_') return false;
	if (klen == STR_PROTO_LEN && memcmp(key, STR_PROTO, STR_PROTO_LEN) == 0) return false;
	if (klen >= 9 && key[2] == 's' && key[3] == 'y' && key[4] == 'm' && key[5] == '_' && key[klen-1] == '_' && key[klen-2] == '_') return true;
	return true;
	}

	struct func_format {
	const char *prefix;
	size_t prefix_len;
	const char *anon;
	size_t anon_len;
	};

	static const struct func_format formats[] = {
	[0] = { "[Function: ", 11, "[Function (anonymous)]", 22 },
	[1] = { "[AsyncFunction: ", 16, "[AsyncFunction (anonymous)]", 27 },
	};

	static size_t strfunc(struct js js, jsval_t value, char buf, size_t len) {
	jsoff_t name_len = 0;
	const char *name = get_func_name(js, value, &name_len);

	jsval_t func_obj = mkval(T_OBJ, vdata(value));
	jsval_t code_slot = get_slot(js, func_obj, SLOT_CODE);
	jsval_t builtin_slot = get_slot(js, func_obj, SLOT_BUILTIN);
	jsval_t async_slot = get_slot(js, func_obj, SLOT_ASYNC);

	bool is_async = is_true(async_slot);
	bool has_code = (vtype(code_slot) == T_CFUNC);

	const struct func_format *fmt = &formats[is_async];

	if (vtype(builtin_slot) == T_NUM) {
	if (name && name_len > 0) {
	size_t n = cpy(buf, len, fmt->prefix, fmt->prefix_len);
	n += cpy(buf + n, len - n, name, name_len);
	n += cpy(buf + n, len - n, "]", 1);
	return n;
	}
	return cpy(buf, len, fmt->anon, fmt->anon_len);
	}

	if (!has_code) {
	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);
	bool is_native = (vtype(cfunc_slot) == T_CFUNC);
	size_t n;

	if (name && name_len > 0) {
	n = cpy(buf, len, fmt->prefix, fmt->prefix_len);
	n += cpy(buf + n, len - n, name, name_len);
	n += cpy(buf + n, len - n, "]", 1);
	} else {
	n = cpy(buf, len, fmt->anon, fmt->anon_len);
	}

	if (!is_native) return n;

	jsval_t proto = get_slot(js, func_obj, SLOT_PROTO);
	uint8_t pt = vtype(proto);
	if (pt != T_OBJ && pt != T_FUNC) return n;

	jsoff_t ctor_off = lkp(js, proto, "constructor", 11);
	if (ctor_off == 0) return n;

	jsval_t ctor = resolveprop(js, mkval(T_PROP, ctor_off));
	uint8_t ct = vtype(ctor);
	if (ct != T_FUNC && ct != T_CFUNC) return n;

	jsoff_t ctor_name_len = 0;
	const char *ctor_name = get_func_name(js, ctor, &ctor_name_len);
	if (ctor_name && ctor_name_len > 0) {
	n += cpy(buf + n, len - n, " ", 1);
	n += cpy(buf + n, len - n, ctor_name, ctor_name_len);
	}
	return n;
	}

	if (name && name_len > 0) {
	size_t n = cpy(buf, len, fmt->prefix, fmt->prefix_len);
	n += cpy(buf + n, len - n, name, name_len);
	n += cpy(buf + n, len - n, "]", 1);
	return n;
	}

	return cpy(buf, len, fmt->anon, fmt->anon_len);
	}

	static void get_line_col(const char code, jsoff_t pos, int line, int *col) {
	int l = 1, c = 1;
	for (jsoff_t i = 0; i < pos && code[i]; i++)
	code[i] == '\n' ? (l++, c = 1) : c++;
	*line = l;
	*col = c;
	}

	static void get_error_line(const char code, jsoff_t clen, jsoff_t pos, char buf, size_t bufsize, int *line_start_col) {
	jsoff_t line_start = pos;
	while (line_start > 0 && code[line_start - 1] != '\n') {
	line_start--;
	}

	jsoff_t line_end = pos;
	while (line_end < clen && code[line_end] != '\n' && code[line_end] != '\0') {
	line_end++;
	}

	jsoff_t line_len = line_end - line_start;
	if (line_len >= bufsize) line_len = (jsoff_t)(bufsize - 1);

	memcpy(buf, &code[line_start], line_len);
	buf[line_len] = '\0';
	*line_start_col = (int)(pos - line_start) + 1;
	}

	static void format_error_stack(struct js js, size_t n, int line, int col, bool include_source_line, const char *error_line, int error_col) {
	if (!js->errmsg) {
	js->errmsg_size = 4096;
	js->errmsg = (char *)malloc(js->errmsg_size);
	if (!js->errmsg) return;
	}

	const char *dim = "\x1b[90m";
	const char *reset = "\x1b[0m";
	size_t remaining;

	if (include_source_line && error_line && *n < js->errmsg_size) {
	remaining = js->errmsg_size - *n;
	n += (size_t) snprintf(js->errmsg + n, remaining, "\n%s\n", error_line);

	if (*n < js->errmsg_size - 1) {
	remaining = js->errmsg_size - *n;
	for (int i = 1; i < error_col && remaining > 1; i++) {
	js->errmsg[(*n)++] = ' ';
	remaining--;
	}
	if (remaining > 1) {
	js->errmsg[(*n)++] = '^';
	}
	js->errmsg[*n] = '\0';
	}
	}

	remaining = js->errmsg_size - *n;
	if (remaining > 20) {
	const char *file = js->filename ? js->filename : "<eval>";

	for (int i = global_call_stack.depth - 1; i >= 0 && remaining > 20; i--) {
	call_frame_t *frame = &global_call_stack.frames[i];
	const char *fname = frame->function_name ? frame->function_name : "<anonymous>";
	const char *ffile = frame->filename ? frame->filename : "<eval>";

	if (frame->line < 0 && frame->code) {
	get_line_col(frame->code, frame->pos, &frame->line, &frame->col);
	}
	int fline = frame->line > 0 ? frame->line : 1;
	int fcol = frame->col > 0 ? frame->col : 1;

	n += (size_t) snprintf(js->errmsg + n, remaining, "\n at %s %s(%s:%d:%d)%s", fname, dim, ffile, fline, fcol, reset);
	remaining = js->errmsg_size - *n;
	}

	if (global_call_stack.depth > 0 && remaining > 60) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\n at Object.<anonymous> %s(%s:1:1)%s", dim, file, reset);
	remaining = js->errmsg_size - *n;
	}

	if (global_call_stack.depth == 0 && remaining > 20) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\n at %s%s:%d:%d%s", dim, file, line, col, reset);
	remaining = js->errmsg_size - *n;
	}

	if (remaining > 60 && js->filename && strcmp(js->filename, "[eval]") != 0) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\n at Module.executeUserEntryPoint [as runMain] %s(ant:internal/modules/run_main:149:5)%s", dim, reset);
	remaining = js->errmsg_size - *n;
	}

	if (remaining > 40 && js->filename && strcmp(js->filename, "[eval]") != 0) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\n at %sant:internal/call:21728:23%s", dim, reset);
	}
	}

	js->errmsg[js->errmsg_size - 1] = '\0';
	}

	static const char *get_error_type_name(js_err_type_t err_type) {
	switch (err_type) {
	case JS_ERR_TYPE: return "TypeError";
	case JS_ERR_SYNTAX: return "SyntaxError";
	case JS_ERR_REFERENCE: return "ReferenceError";
	case JS_ERR_RANGE: return "RangeError";
	case JS_ERR_EVAL: return "EvalError";
	case JS_ERR_URI: return "URIError";
	case JS_ERR_INTERNAL: return "InternalError";
	case JS_ERR_AGGREGATE: return "AggregateError";
	case JS_ERR_GENERIC: return "Error";
	default: return "Error";
	}
	}

	static inline js_err_type_t get_error_type(struct js *js) {
	if (!(js->flags & F_THROW)) return JS_ERR_GENERIC;
	jsval_t err_type = get_slot(js, js->thrown_value, SLOT_ERR_TYPE);
	if (vtype(err_type) != T_NUM) return JS_ERR_GENERIC;
	return (js_err_type_t)(int)js_getnum(err_type);
	}

	__attribute__((format(printf, 4, 5)))
	jsval_t js_create_error(struct js js, js_err_type_t err_type, jsval_t props, const char xx, ...) {
	va_list ap;
	int line = 0, col = 0;
	char error_line[256] = {0};
	int error_col = 0;
	char error_msg[256] = {0};

	bool no_stack = (err_type & JS_ERR_NO_STACK) != 0;
	err_type = (js_err_type_t)(err_type & ~JS_ERR_NO_STACK);

	if (!js->errmsg) {
	js->errmsg_size = 4096;
	js->errmsg = (char *)malloc(js->errmsg_size);
	if (!js->errmsg) return mkval(T_ERR, 0);
	}

	get_line_col(js->code, js->toff > 0 ? js->toff : js->pos, &line, &col);
	get_error_line(js->code, js->clen, js->toff > 0 ? js->toff : js->pos, error_line, sizeof(error_line), &error_col);

	va_start(ap, xx);
	vsnprintf(error_msg, sizeof(error_msg), xx, ap);
	va_end(ap);

	const char *err_name = get_error_type_name(err_type);
	size_t err_name_len = strlen(err_name);
	size_t msg_len = strlen(error_msg);

	jsval_t err_obj = js_mkobj(js);
	js_set(js, err_obj, "name", js_mkstr(js, err_name, err_name_len));
	js_set(js, err_obj, "message", js_mkstr(js, error_msg, msg_len));
	set_slot(js, err_obj, SLOT_ERR_TYPE, js_mknum((double)err_type));

	if (vtype(props) == T_OBJ) js_merge_obj(js, err_obj, props);
	jsval_t proto = js_get_ctor_proto(js, err_name, err_name_len);
	if (vtype(proto) == T_OBJ) js_set_proto(js, err_obj, proto);

	js->flags \|= F_THROW;
	js->thrown_value = err_obj;

	size_t n = 0;
	if (js->filename) {
	n = (size_t) snprintf(js->errmsg, js->errmsg_size, "%s:%d\n", js->filename, line);
	} else {
	n = (size_t) snprintf(js->errmsg, js->errmsg_size, "<eval>:%d\n", line);
	}

	size_t remaining = js->errmsg_size - n;
	if (remaining > 1) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\x1b[31m%s\x1b[0m: \x1b[1m%s\x1b[0m", err_name, error_msg);
	}

	if (!no_stack) {
	format_error_stack(js, &n, line, col, true, error_line, error_col);
	}

	js->pos = js->clen, js->tok = TOK_EOF, js->consumed = 0;
	return mkval(T_ERR, 0);
	}

	static jsval_t js_throw(struct js *js, jsval_t value) {
	int line = 0, col = 0;
	char error_line[256] = {0};
	int error_col = 0;

	get_line_col(js->code, js->toff > 0 ? js->toff : js->pos, &line, &col);
	get_error_line(js->code, js->clen, js->toff > 0 ? js->toff : js->pos, error_line, sizeof(error_line), &error_col);

	if (!js->errmsg) {
	js->errmsg_size = 4096;
	js->errmsg = (char *)malloc(js->errmsg_size);
	if (!js->errmsg) return mkval(T_ERR, 0);
	}

	size_t n = 0;
	if (js->filename) {
	n = (size_t) snprintf(js->errmsg, js->errmsg_size, "%s:%d\n", js->filename, line);
	} else {
	n = (size_t) snprintf(js->errmsg, js->errmsg_size, "<eval>:%d\n", line);
	}

	size_t remaining = js->errmsg_size - n;
	if (vtype(value) == T_STR) {
	jsoff_t slen, off = vstr(js, value, &slen);
	n += (size_t) snprintf(js->errmsg + n, remaining, "\x1b[31mError\x1b[0m: \x1b[1m%.s\x1b[0m", (int)slen, (char )&js->mem[off]);
	} else if (vtype(value) == T_OBJ) {
	jsoff_t name_off = lkp(js, value, "name", 4);
	jsoff_t msg_off = lkp(js, value, "message", 7);

	const char *name_str = NULL;
	const char *msg_str = NULL;
	jsoff_t name_len = 0, msg_len = 0;

	if (name_off > 0) {
	jsval_t name_val = resolveprop(js, mkval(T_PROP, name_off));
	if (vtype(name_val) == T_STR) {
	jsoff_t off = vstr(js, name_val, &name_len);
	name_str = (const char *)&js->mem[off];
	}
	}

	if (msg_off > 0) {
	jsval_t msg_val = resolveprop(js, mkval(T_PROP, msg_off));
	if (vtype(msg_val) == T_STR) {
	jsoff_t off = vstr(js, msg_val, &msg_len);
	msg_str = (const char *)&js->mem[off];
	}
	}

	if (name_str && msg_str) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\x1b[31m%.s\x1b[0m: \x1b[1m%.s\x1b[0m", (int)name_len, name_str, (int)msg_len, msg_str);
	} else if (name_str) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\x1b[31m%.*s\x1b[0m", (int)name_len, name_str);
	} else if (msg_str) {
	n += (size_t) snprintf(js->errmsg + n, remaining, "\x1b[31mError\x1b[0m: \x1b[1m%.*s\x1b[0m", (int)msg_len, msg_str);
	} else {
	const char *str = js_str(js, value);
	n += (size_t) snprintf(js->errmsg + n, remaining, "\x1b[31mError\x1b[0m: \x1b[1m%s\x1b[0m", str);
	}
	} else {
	const char *str = js_str(js, value);
	n += (size_t) snprintf(js->errmsg + n, remaining, "\x1b[31mError\x1b[0m: \x1b[1m%s\x1b[0m", str);
	}

	format_error_stack(js, &n, line, col, true, error_line, error_col);

	js->flags \|= F_THROW;
	js->thrown_value = value;
	js->pos = js->clen;
	js->tok = TOK_EOF;
	js->consumed = 0;
	return mkval(T_ERR, 0);
	}

	static size_t tostr(struct js js, jsval_t value, char buf, size_t len) {
	switch (vtype(value)) {
	case T_UNDEF: return ANT_COPY(buf, len, "undefined");
	case T_NULL: return ANT_COPY(buf, len, "null");

	case T_BOOL: {
	bool b = vdata(value) & 1;
	return b ? ANT_COPY(buf, len, "true") : ANT_COPY(buf, len, "false");
	}

	case T_ARR: return strarr(js, value, buf, len);
	case T_OBJ: return strobj(js, value, buf, len);
	case T_STR: return strstring(js, value, buf, len);
	case T_NUM: return strnum(value, buf, len);
	case T_BIGINT: return strbigint(js, value, buf, len);
	case T_PROMISE: return strpromise(js, value, buf, len);
	case T_FUNC: return strfunc(js, value, buf, len);

	case T_CFUNC: return ANT_COPY(buf, len, "[native code]");
	case T_FFI: return ANT_COPY(buf, len, "[native code (ffi)]");

	case T_SYMBOL: {
	const char *desc = js_sym_desc(js, value);
	if (desc) return (size_t) snprintf(buf, len, "Symbol(%s)", desc);
	return ANT_COPY(buf, len, "Symbol()");
	}

	case T_PROP: return (size_t) snprintf(buf, len, "PROP@%lu", (unsigned long) vdata(value));
	default: return (size_t) snprintf(buf, len, "VTYPE%d", vtype(value));
	}
	}

	static char tostr_alloc(struct js js, jsval_t value) {
	size_t cap = 64;
	char *buf = ant_calloc(cap);
	size_t n = tostr(js, value, buf, cap);
	if (n >= cap) {
	free(buf);
	buf = ant_calloc(n + 1);
	tostr(js, value, buf, n + 1);
	}
	return buf;
	}

	jsval_t js_tostring_val(struct js *js, jsval_t value) {
	uint8_t t = vtype(value);
	char *buf; size_t len, buflen;

	static const void *jump_table[] = {
	[T_OBJ] = &&L_OBJ, [T_PROP] = &&L_DEFAULT, [T_STR] = &&L_STR,
	[T_UNDEF] = &&L_UNDEF, [T_NULL] = &&L_NULL, [T_NUM] = &&L_NUM,
	[T_BOOL] = &&L_BOOL, [T_FUNC] = &&L_OBJ, [T_CODEREF] = &&L_DEFAULT,
	[T_CFUNC] = &&L_DEFAULT, [T_ERR] = &&L_DEFAULT, [T_ARR] = &&L_OBJ,
	[T_PROMISE] = &&L_DEFAULT, [T_TYPEDARRAY] = &&L_DEFAULT,
	[T_BIGINT] = &&L_BIGINT, [T_PROPREF] = &&L_DEFAULT,
	[T_SYMBOL] = &&L_DEFAULT, [T_GENERATOR] = &&L_DEFAULT, [T_FFI] = &&L_DEFAULT
	};

	if (t < sizeof(jump_table) / sizeof(jump_table[0])) goto *jump_table[t];
	goto L_DEFAULT;

	L_STR: return value;
	L_UNDEF: return js_mkstr(js, "undefined", 9);
	L_NULL: return js_mkstr(js, "null", 4);
	L_BOOL: return vdata(value) ? js_mkstr(js, "true", 4) : js_mkstr(js, "false", 5);
	L_OBJ: return js_call_toString(js, value);

	L_NUM: {
	buf = (char *)ant_calloc(32);
	len = strnum(value, buf, 32);
	jsval_t result = js_mkstr(js, buf, len);
	free(buf); return result;
	}

	L_BIGINT: {
	bigint_digits(js, value, &buflen);
	buf = (char *)ant_calloc(buflen + 2);
	len = strbigint(js, value, buf, buflen + 2);
	jsval_t result = js_mkstr(js, buf, len);
	free(buf); return result;
	}

	L_DEFAULT: {
	buf = (char *)ant_calloc(64);
	len = tostr(js, value, buf, 64);
	jsval_t result = js_mkstr(js, buf, len);
	free(buf); return result;
	}
	}

	const char js_str(struct js js, jsval_t value) {
	if (is_err(value)) return js->errmsg;

	multiref_count = 0;
	multiref_next_id = 0;
	stringify_depth = 0;
	scan_refs(js, value);

	size_t capacity = 4096;
	char buf = (char )ant_calloc(capacity);
	if (!buf) return "";

	size_t len;
	for (;;) {
	stringify_depth = 0;
	stringify_indent = 0;
	len = tostr(js, value, buf, capacity);

	if (len < capacity - 1) break;

	capacity *= 2;
	buf = (char *)ant_realloc(buf, capacity);
	if (!buf) return "";
	}

	jsval_t str = js_mkstr(js, buf, len);
	free(buf);

	if (is_err(str)) return "";
	return (const char *)&js->mem[vdata(str) + sizeof(jsoff_t)];
	}

	static bool js_try_grow_memory(struct js *js, size_t needed) {
	if (!js->owns_mem) return false;
	if (js->max_size == 0) return false;

	size_t current = (size_t)js->size;
	size_t required = current + needed;
	size_t new_mem_size = ((required + ARENA_GROW_INCREMENT - 1) / ARENA_GROW_INCREMENT) * ARENA_GROW_INCREMENT;

	if (new_mem_size > (size_t)js->max_size) new_mem_size = (size_t)js->max_size;
	if (new_mem_size <= current) return false;

	if (ant_arena_commit(js->mem, js->size, new_mem_size) != 0) return false;
	js->size = (jsoff_t)(new_mem_size / 8U * 8U);

	return true;
	}

	static jsoff_t js_alloc(struct js *js, size_t size) {
	size = align64((jsoff_t) size);

	jsoff_t ofs = js->brk;
	if (js->brk + size > js->size) {
	if (js_try_grow_memory(js, size)) {
	ofs = js->brk;
	if (js->brk + size > js->size) return ~(jsoff_t) 0;
	} else {
	// js_gc_compact(js);
	ofs = js->brk;
	if (js->brk + size > js->size) {
	if (js_try_grow_memory(js, size)) {
	ofs = js->brk;
	if (js->brk + size > js->size) return ~(jsoff_t) 0;
	} else return ~(jsoff_t) 0;
	}
	}
	}

	js->brk += (jsoff_t) size;
	return ofs;
	}

	static jsval_t mkentity(struct js js, jsoff_t b, const void buf, size_t len) {
	jsoff_t ofs = js_alloc(js, len + sizeof(b));
	if (ofs == (jsoff_t) ~0) return js_mkerr(js, "oom");
	memcpy(&js->mem[ofs], &b, sizeof(b));
	if (buf != NULL) {
	size_t copy_len = ((b & 3) == T_STR && len > 0) ? len - 1 : len;
	memmove(&js->mem[ofs + sizeof(b)], buf, copy_len);
	}
	if ((b & 3) == T_STR) js->mem[ofs + sizeof(b) + len - 1] = 0;
	return mkval(b & 3, ofs);
	}

	jsval_t js_mkstr(struct js js, const void ptr, size_t len) {
	jsoff_t n = (jsoff_t) (len + 1);
	return mkentity(js, (jsoff_t) ((n << 3) \| T_STR), ptr, n);
	}

	jsval_t js_mkbigint(struct js js, const char digits, size_t len, bool negative) {
	size_t total = len + 2;
	jsoff_t ofs = js_alloc(js, total + sizeof(jsoff_t));
	if (ofs == (jsoff_t) ~0) return js_mkerr(js, "oom");
	jsoff_t header = (jsoff_t) (total << 4);
	memcpy(&js->mem[ofs], &header, sizeof(header));
	js->mem[ofs + sizeof(header)] = negative ? 1 : 0;
	if (digits) memcpy(&js->mem[ofs + sizeof(header) + 1], digits, len);
	js->mem[ofs + sizeof(header) + 1 + len] = 0;
	return mkval(T_BIGINT, ofs);
	}

	static bool bigint_IsNegative(struct js *js, jsval_t v) {
	jsoff_t ofs = (jsoff_t) vdata(v);
	return js->mem[ofs + sizeof(jsoff_t)] == 1;
	}

	static const char bigint_digits(struct js js, jsval_t v, size_t *len) {
	jsoff_t ofs = (jsoff_t) vdata(v);
	jsoff_t header = loadoff(js, ofs);
	size_t total = (header >> 4) - 2;
	if (len) *len = total;
	return (const char *)&js->mem[ofs + sizeof(jsoff_t) + 1];
	}

	static int bigint_cmp_abs(const char a, size_t alen, const char b, size_t blen) {
	while (alen > 1 && a[0] == '0') { a++; alen--; }
	while (blen > 1 && b[0] == '0') { b++; blen--; }
	if (alen != blen) return alen > blen ? 1 : -1;
	for (size_t i = 0; i < alen; i++) {
	if (a[i] != b[i]) return a[i] > b[i] ? 1 : -1;
	}
	return 0;
	}

	static char bigint_add_abs(const char a, size_t alen, const char b, size_t blen, size_t rlen) {
	size_t maxlen = (alen > blen ? alen : blen) + 1;
	char result = (char )malloc(maxlen + 1);
	if (!result) return NULL;
	int carry = 0;
	size_t ri = 0;
	for (size_t i = 0; i < maxlen; i++) {
	int da = (i < alen) ? (a[alen - 1 - i] - '0') : 0;
	int db = (i < blen) ? (b[blen - 1 - i] - '0') : 0;
	int sum = da + db + carry;
	carry = sum / 10;
	result[ri++] = (char)('0' + (sum % 10));
	}
	while (ri > 1 && result[ri - 1] == '0') ri--;
	for (size_t i = 0; i < ri / 2; i++) {
	char tmp = result[i]; result[i] = result[ri - 1 - i]; result[ri - 1 - i] = tmp;
	}
	result[ri] = 0;
	*rlen = ri;
	return result;
	}

	static char bigint_sub_abs(const char a, size_t alen, const char b, size_t blen, size_t rlen) {
	char result = (char )malloc(alen + 1);
	if (!result) return NULL;
	int borrow = 0;
	size_t ri = 0;
	for (size_t i = 0; i < alen; i++) {
	int da = a[alen - 1 - i] - '0';
	int db = (i < blen) ? (b[blen - 1 - i] - '0') : 0;
	int diff = da - db - borrow;
	if (diff < 0) { diff += 10; borrow = 1; } else { borrow = 0; }
	result[ri++] = (char)('0' + diff);
	}
	while (ri > 1 && result[ri - 1] == '0') ri--;
	for (size_t i = 0; i < ri / 2; i++) {
	char tmp = result[i]; result[i] = result[ri - 1 - i]; result[ri - 1 - i] = tmp;
	}
	result[ri] = 0;
	*rlen = ri;
	return result;
	}

	static char bigint_mul_abs(const char a, size_t alen, const char b, size_t blen, size_t rlen) {
	size_t reslen = alen + blen;
	int temp = (int )calloc(reslen, sizeof(int));
	if (!temp) return NULL;
	for (size_t i = 0; i < alen; i++) {
	for (size_t j = 0; j < blen; j++) {
	temp[i + j] += (a[alen - 1 - i] - '0') * (b[blen - 1 - j] - '0');
	}
	}
	for (size_t i = 0; i < reslen - 1; i++) {
	temp[i + 1] += temp[i] / 10;
	temp[i] %= 10;
	}
	size_t start = reslen - 1;
	while (start > 0 && temp[start] == 0) start--;
	char result = (char )malloc(start + 2);
	if (!result) { free(temp); return NULL; }
	for (size_t i = 0; i <= start; i++) result[i] = (char)('0' + temp[start - i]);
	result[start + 1] = 0;
	*rlen = start + 1;
	free(temp);
	return result;
	}

	static char bigint_div_abs(const char a, size_t alen, const char b, size_t blen, size_t rlen, char *rem, size_t remlen) {
	if (blen == 1 && b[0] == '0') return NULL;
	if (bigint_cmp_abs(a, alen, b, blen) < 0) {
	char result = (char )malloc(2); result[0] = '0'; result[1] = 0; *rlen = 1;
	if (rem) { rem = (char )malloc(alen + 1); memcpy(rem, a, alen); (rem)[alen] = 0; *remlen = alen; }
	return result;
	}
	char current = (char )calloc(alen + 1, 1);
	char result = (char )calloc(alen + 1, 1);
	if (!current \|\| !result) { free(current); free(result); return NULL; }
	size_t curlen = 0, reslen = 0;
	for (size_t i = 0; i < alen; i++) {
	if (curlen == 1 && current[0] == '0') curlen = 0;
	current[curlen++] = a[i]; current[curlen] = 0;
	int count = 0;
	while (bigint_cmp_abs(current, curlen, b, blen) >= 0) {
	size_t sublen;
	char *sub = bigint_sub_abs(current, curlen, b, blen, &sublen);
	if (!sub) break;
	memcpy(current, sub, sublen + 1); curlen = sublen;
	free(sub); count++;
	}
	result[reslen++] = (char)('0' + count);
	}
	size_t start = 0;
	while (start < reslen - 1 && result[start] == '0') start++;
	memmove(result, result + start, reslen - start + 1);
	*rlen = reslen - start;
	if (rem) { rem = current; remlen = curlen; } else free(current);
	return result;
	}

	static jsval_t bigint_add(struct js *js, jsval_t a, jsval_t b) {
	bool aneg = bigint_IsNegative(js, a), bneg = bigint_IsNegative(js, b);
	size_t alen, blen;
	const char ad = bigint_digits(js, a, &alen), bd = bigint_digits(js, b, &blen);
	char *result; size_t rlen; bool rneg;
	if (aneg == bneg) {
	result = bigint_add_abs(ad, alen, bd, blen, &rlen); rneg = aneg;
	} else {
	int cmp = bigint_cmp_abs(ad, alen, bd, blen);
	if (cmp >= 0) { result = bigint_sub_abs(ad, alen, bd, blen, &rlen); rneg = aneg; }
	else { result = bigint_sub_abs(bd, blen, ad, alen, &rlen); rneg = bneg; }
	}
	if (!result) return js_mkerr(js, "oom");
	if (rlen == 1 && result[0] == '0') rneg = false;
	jsval_t r = js_mkbigint(js, result, rlen, rneg);
	free(result);
	return r;
	}

	static jsval_t bigint_sub(struct js *js, jsval_t a, jsval_t b) {
	bool aneg = bigint_IsNegative(js, a), bneg = bigint_IsNegative(js, b);
	size_t alen, blen;
	const char ad = bigint_digits(js, a, &alen), bd = bigint_digits(js, b, &blen);
	char *result; size_t rlen; bool rneg;
	if (aneg != bneg) {
	result = bigint_add_abs(ad, alen, bd, blen, &rlen); rneg = aneg;
	} else {
	int cmp = bigint_cmp_abs(ad, alen, bd, blen);
	if (cmp >= 0) { result = bigint_sub_abs(ad, alen, bd, blen, &rlen); rneg = aneg; }
	else { result = bigint_sub_abs(bd, blen, ad, alen, &rlen); rneg = !aneg; }
	}
	if (!result) return js_mkerr(js, "oom");
	if (rlen == 1 && result[0] == '0') rneg = false;
	jsval_t r = js_mkbigint(js, result, rlen, rneg);
	free(result);
	return r;
	}

	static jsval_t bigint_mul(struct js *js, jsval_t a, jsval_t b) {
	bool aneg = bigint_IsNegative(js, a), bneg = bigint_IsNegative(js, b);
	size_t alen, blen;
	const char ad = bigint_digits(js, a, &alen), bd = bigint_digits(js, b, &blen);
	size_t rlen;
	char *result = bigint_mul_abs(ad, alen, bd, blen, &rlen);
	if (!result) return js_mkerr(js, "oom");
	bool rneg = (aneg != bneg) && !(rlen == 1 && result[0] == '0');
	jsval_t r = js_mkbigint(js, result, rlen, rneg);
	free(result);
	return r;
	}

	static jsval_t bigint_div(struct js *js, jsval_t a, jsval_t b) {
	bool aneg = bigint_IsNegative(js, a), bneg = bigint_IsNegative(js, b);
	size_t alen, blen;
	const char ad = bigint_digits(js, a, &alen), bd = bigint_digits(js, b, &blen);
	if (blen == 1 && bd[0] == '0') return js_mkerr(js, "Division by zero");
	size_t rlen;
	char *result = bigint_div_abs(ad, alen, bd, blen, &rlen, NULL, NULL);
	if (!result) return js_mkerr(js, "oom");
	bool rneg = (aneg != bneg) && !(rlen == 1 && result[0] == '0');
	jsval_t r = js_mkbigint(js, result, rlen, rneg);
	free(result);
	return r;
	}

	static jsval_t bigint_mod(struct js *js, jsval_t a, jsval_t b) {
	bool aneg = bigint_IsNegative(js, a);
	size_t alen, blen;
	const char ad = bigint_digits(js, a, &alen), bd = bigint_digits(js, b, &blen);
	if (blen == 1 && bd[0] == '0') return js_mkerr(js, "Division by zero");
	size_t rlen, remlen; char *rem;
	char *result = bigint_div_abs(ad, alen, bd, blen, &rlen, &rem, &remlen);
	if (!result) return js_mkerr(js, "oom");
	free(result);
	bool rneg = aneg && !(remlen == 1 && rem[0] == '0');
	jsval_t r = js_mkbigint(js, rem, remlen, rneg);
	free(rem);
	return r;
	}

	static jsval_t bigint_neg(struct js *js, jsval_t a) {
	size_t len;
	const char *digits = bigint_digits(js, a, &len);
	bool neg = bigint_IsNegative(js, a);
	if (len == 1 && digits[0] == '0') return js_mkbigint(js, digits, len, false);
	return js_mkbigint(js, digits, len, !neg);
	}

	static jsval_t bigint_exp(struct js *js, jsval_t base, jsval_t exp) {
	if (bigint_IsNegative(js, exp)) return js_mkerr(js, "Exponent must be positive");
	size_t explen;
	const char *expd = bigint_digits(js, exp, &explen);
	if (explen == 1 && expd[0] == '0') return js_mkbigint(js, "1", 1, false);
	jsval_t result = js_mkbigint(js, "1", 1, false);
	jsval_t b = base;
	jsval_t e = exp;
	jsval_t two = js_mkbigint(js, "2", 1, false);
	while (true) {
	size_t elen;
	const char *ed = bigint_digits(js, e, &elen);
	if (elen == 1 && ed[0] == '0') break;
	int last_digit = ed[elen - 1] - '0';
	if (last_digit % 2 == 1) {
	result = bigint_mul(js, result, b);
	if (is_err(result)) return result;
	}
	b = bigint_mul(js, b, b);
	if (is_err(b)) return b;
	e = bigint_div(js, e, two);
	if (is_err(e)) return e;
	}
	return result;
	}

	static int bigint_compare(struct js *js, jsval_t a, jsval_t b) {
	bool aneg = bigint_IsNegative(js, a), bneg = bigint_IsNegative(js, b);
	size_t alen, blen;
	const char ad = bigint_digits(js, a, &alen), bd = bigint_digits(js, b, &blen);
	if (aneg && !bneg) return -1;
	if (!aneg && bneg) return 1;
	int cmp = bigint_cmp_abs(ad, alen, bd, blen);
	return aneg ? -cmp : cmp;
	}

	static bool bigint_is_zero(struct js *js, jsval_t v) {
	size_t len;
	const char *digits = bigint_digits(js, v, &len);
	return len == 1 && digits[0] == '0';
	}

	static size_t strbigint(struct js js, jsval_t value, char buf, size_t len) {
	bool neg = bigint_IsNegative(js, value);
	size_t dlen;
	const char *digits = bigint_digits(js, value, &dlen);
	size_t n = 0;
	if (neg) n += cpy(buf + n, len - n, "-", 1);
	n += cpy(buf + n, len - n, digits, dlen);
	return n;
	}

	static jsval_t builtin_BigInt(struct js js, jsval_t args, int nargs) {
	if (vtype(js->new_target) != T_UNDEF) return js_mkerr_typed(js, JS_ERR_TYPE, "BigInt is not a constructor");
	if (nargs < 1) return js_mkbigint(js, "0", 1, false);

	jsval_t arg = args[0];
	if (vtype(arg) == T_BIGINT) return arg;
	if (vtype(arg) == T_NUM) {
	double d = tod(arg);
	if (!isfinite(d)) return js_mkerr(js, "Cannot convert Infinity or NaN to BigInt");
	if (d != trunc(d)) return js_mkerr(js, "Cannot convert non-integer to BigInt");
	bool neg = d < 0;
	if (neg) d = -d;
	char buf[64];
	snprintf(buf, sizeof(buf), "%.0f", d);
	return js_mkbigint(js, buf, strlen(buf), neg);
	}
	if (vtype(arg) == T_STR) {
	jsoff_t slen, off = vstr(js, arg, &slen);
	const char str = (const char )&js->mem[off];
	bool neg = false;
	size_t i = 0;
	if (slen > 0 && str[0] == '-') { neg = true; i++; }
	else if (slen > 0 && str[0] == '+') { i++; }
	while (i < slen && str[i] == '0') i++;
	if (i >= slen) return js_mkbigint(js, "0", 1, false);
	for (size_t j = i; j < slen; j++) {
	if (!is_digit(str[j])) return js_mkerr(js, "Cannot convert string to BigInt");
	}
	return js_mkbigint(js, str + i, slen - i, neg);
	}
	if (vtype(arg) == T_BOOL) {
	return js_mkbigint(js, vdata(arg) ? "1" : "0", 1, false);
	}
	return js_mkerr(js, "Cannot convert to BigInt");
	}

	static jsval_t builtin_BigInt_asIntN(struct js js, jsval_t args, int nargs) {
	(void)js; (void)args; (void)nargs;
	return js_mkerr(js, "BigInt.asIntN not implemented");
	}

	static jsval_t builtin_BigInt_asUintN(struct js js, jsval_t args, int nargs) {
	(void)js; (void)args; (void)nargs;
	return js_mkerr(js, "BigInt.asUintN not implemented");
	}

	static jsval_t builtin_bigint_toString(struct js js, jsval_t args, int nargs) {
	jsval_t val = js->this_val;
	if (vtype(val) != T_BIGINT) return js_mkerr(js, "toString called on non-BigInt");

	int radix = 10;
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	radix = (int)tod(args[0]);
	if (radix < 2 \|\| radix > 36) {
	return js_mkerr(js, "radix must be between 2 and 36");
	}
	}

	bool neg = bigint_IsNegative(js, val);
	size_t dlen;
	const char *digits = bigint_digits(js, val, &dlen);

	if (radix == 10) {
	size_t buflen = dlen + 2;
	char buf = (char )ant_calloc(buflen);
	if (!buf) return js_mkerr(js, "oom");
	size_t n = 0;
	if (neg) buf[n++] = '-';
	memcpy(buf + n, digits, dlen);
	n += dlen;
	jsval_t ret = js_mkstr(js, buf, n);
	free(buf);
	return ret;
	}

	size_t result_cap = dlen * 4 + 16;
	char result = (char )ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");
	size_t rpos = result_cap - 1;
	result[rpos] = '\0';

	char num = (char )ant_calloc(dlen + 1);
	if (!num) { free(result); return js_mkerr(js, "oom"); }
	memcpy(num, digits, dlen);
	num[dlen] = '\0';
	size_t numlen = dlen;

	while (numlen > 0 && !(numlen == 1 && num[0] == '0')) {
	int remainder = 0;
	for (size_t i = 0; i < numlen; i++) {
	int d = remainder * 10 + (num[i] - '0');
	num[i] = (char)('0' + (d / radix));
	remainder = d % radix;
	}
	size_t start = 0;
	while (start < numlen - 1 && num[start] == '0') start++;
	memmove(num, num + start, numlen - start + 1);
	numlen -= start;
	if (numlen == 1 && num[0] == '0') numlen = 0;
	if (rpos == 0) {
	size_t new_cap = result_cap * 2;
	char new_result = (char )ant_calloc(new_cap);
	if (!new_result) { free(num); free(result); return js_mkerr(js, "oom"); }
	size_t used = result_cap - rpos;
	memcpy(new_result + new_cap - used, result + rpos, used);
	free(result);
	result = new_result;
	rpos = new_cap - used;
	result_cap = new_cap;
	}
	rpos--;
	result[rpos] = (char)(remainder < 10 ? '0' + remainder : 'a' + (remainder - 10));
	}

	free(num);

	if (rpos == result_cap - 1) {
	result[--rpos] = '0';
	}

	if (neg) result[--rpos] = '-';

	jsval_t ret = js_mkstr(js, result + rpos, result_cap - 1 - rpos);
	free(result);
	return ret;
	}

	static jsval_t mkobj(struct js *js, jsoff_t parent) {
	jsoff_t buf[2] = { parent, 0 };
	return mkentity(js, 0 \| T_OBJ, buf, sizeof(buf));
	}

	static jsval_t mkarr(struct js *js) {
	jsval_t arr = mkobj(js, 0);
	jsoff_t off = (jsoff_t) vdata(arr);
	jsoff_t header = loadoff(js, off);

	saveoff(js, off, header \| ARRMASK);
	jsval_t array_proto = get_ctor_proto(js, "Array", 5);
	if (vtype(array_proto) == T_OBJ) set_proto(js, arr, array_proto);

	jsval_t arr_val = mkval(T_ARR, vdata(arr));
	js_set_descriptor(js, arr_val, "length", 6, JS_DESC_W);

	return arr_val;
	}

	jsval_t js_mkarr(struct js *js) {
	return mkarr(js);
	}

	jsval_t js_newobj(struct js *js) {
	jsval_t obj = mkobj(js, 0);
	jsval_t proto = get_ctor_proto(js, "Object", 6);
	if (vtype(proto) == T_OBJ) set_proto(js, obj, proto);
	return obj;
	}

	static jsoff_t arr_length(struct js *js, jsval_t arr) {
	if (vtype(arr) != T_ARR) return 0;
	jsoff_t max_idx = 0;
	bool found_length_prop = false;
	jsoff_t length_prop_val = 0;
	jsoff_t scan = loadoff(js, (jsoff_t) vdata(arr)) & ~(3U \| FLAGMASK);
	while (scan < js->brk && scan != 0) {
	const char *key; jsoff_t klen;
	get_prop_key(js, scan, &key, &klen);
	if (streq(key, klen, "length", 6)) {
	jsval_t val = get_prop_val(js, scan);
	if (vtype(val) == T_NUM) {
	found_length_prop = true;
	length_prop_val = (jsoff_t) tod(val);
	}
	} else if (klen > 0 && key[0] >= '0' && key[0] <= '9') {
	char *endptr;
	unsigned long idx = strtoul(key, &endptr, 10);
	if (endptr == key + klen && idx + 1 > max_idx) max_idx = (jsoff_t)(idx + 1);
	}
	scan = loadoff(js, scan) & ~(3U \| FLAGMASK);
	}
	if (found_length_prop) return length_prop_val;
	return max_idx;
	}

	static jsval_t arr_get(struct js *js, jsval_t arr, jsoff_t idx) {
	if (vtype(arr) != T_ARR) return js_mkundef();
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsoff_t prop = loadoff(js, (jsoff_t) vdata(arr)) & ~(3U \| FLAGMASK);
	while (prop < js->brk && prop != 0) {
	const char *key; jsoff_t klen;
	get_prop_key(js, prop, &key, &klen);
	if (streq(key, klen, idxstr, idxlen)) return get_prop_val(js, prop);
	prop = loadoff(js, prop) & ~(3U \| FLAGMASK);
	}
	return js_mkundef();
	}

	static inline bool is_const_prop(struct js *js, jsoff_t propoff) {
	jsoff_t v = loadoff(js, propoff);
	return (v & CONSTMASK) != 0;
	}

	static inline bool is_nonconfig_prop(struct js *js, jsoff_t propoff) {
	jsoff_t v = loadoff(js, propoff);
	return (v & NONCONFIGMASK) != 0;
	}

	static void intern_init(void) {
	if (INTERN_LENGTH) return;
	INTERN_LENGTH = intern_string("length", 6);
	INTERN_BUFFER = intern_string("buffer", 6);
	INTERN_PROTOTYPE = intern_string("prototype", 9);
	INTERN_CONSTRUCTOR = intern_string("constructor", 11);
	INTERN_NAME = intern_string("name", 4);
	INTERN_MESSAGE = intern_string("message", 7);
	INTERN_VALUE = intern_string("value", 5);
	INTERN_GET = intern_string("get", 3);
	INTERN_SET = intern_string("set", 3);
	INTERN_ARGUMENTS = intern_string("arguments", 9);
	INTERN_CALLEE = intern_string("callee", 6);
	INTERN_IDX[0] = intern_string("0", 1);
	INTERN_IDX[1] = intern_string("1", 1);
	INTERN_IDX[2] = intern_string("2", 1);
	INTERN_IDX[3] = intern_string("3", 1);
	INTERN_IDX[4] = intern_string("4", 1);
	INTERN_IDX[5] = intern_string("5", 1);
	INTERN_IDX[6] = intern_string("6", 1);
	INTERN_IDX[7] = intern_string("7", 1);
	INTERN_IDX[8] = intern_string("8", 1);
	INTERN_IDX[9] = intern_string("9", 1);
	}

	static void invalidate_prop_cache(struct js *js, jsoff_t obj_off, jsoff_t prop_off) {
	jsoff_t koff = loadoff(js, prop_off + sizeof(jsoff_t));
	jsoff_t klen = (loadoff(js, koff) >> 3) - 1;

	const char key = (char )&js->mem[koff + sizeof(jsoff_t)];
	const char *interned = intern_string(key, klen);
	if (!interned) return;

	uint32_t cache_slot = (((uintptr_t)interned >> 3) ^ obj_off) & (ANT_LIMIT_SIZE_CACHE - 1);
	intern_prop_cache_entry_t *ce = &intern_prop_cache[cache_slot];

	if (ce->obj_off == obj_off && ce->intern_ptr == interned) {
	ce->obj_off = 0; ce->intern_ptr = NULL;
	ce->prop_off = 0; ce->tail = 0;
	}
	}

	static jsval_t mkprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v, jsoff_t flags) {
	jsoff_t koff = (jsoff_t) vdata(k);
	jsoff_t head = (jsoff_t) vdata(obj);
	char buf[sizeof(koff) + sizeof(v)];

	jsoff_t header = loadoff(js, head);
	jsoff_t first_prop = header & ~(3U \| FLAGMASK);
	jsoff_t tail = loadoff(js, head + sizeof(jsoff_t) + sizeof(jsoff_t));

	memcpy(buf, &koff, sizeof(koff));
	memcpy(buf + sizeof(koff), &v, sizeof(v));

	jsoff_t klen = (loadoff(js, koff) >> 3) - 1;
	const char p = (char ) &js->mem[koff + sizeof(koff)];
	(void)intern_string(p, klen);

	jsoff_t new_prop_off = js->brk;
	jsval_t prop = mkentity(js, 0 \| T_PROP \| flags, buf, sizeof(buf));
	if (is_err(prop)) return prop;

	if (first_prop == 0) {
	jsoff_t new_header = new_prop_off \| (header & (3U \| FLAGMASK));
	saveoff(js, head, new_header);
	} else {
	jsoff_t tail_header = loadoff(js, tail);
	jsoff_t new_tail_header = new_prop_off \| (tail_header & (3U \| FLAGMASK));
	saveoff(js, tail, new_tail_header);
	}
	saveoff(js, head + sizeof(jsoff_t) + sizeof(jsoff_t), new_prop_off);

	return prop;
	}

	static inline jsval_t mkprop_fast(struct js *js, jsval_t obj, jsval_t k, jsval_t v, jsoff_t flags) {
	jsoff_t koff = (jsoff_t) vdata(k);
	jsoff_t head = (jsoff_t) vdata(obj);
	char buf[sizeof(koff) + sizeof(v)];

	jsoff_t header = loadoff(js, head);
	jsoff_t first_prop = header & ~(3U \| FLAGMASK);
	jsoff_t tail = loadoff(js, head + sizeof(jsoff_t) + sizeof(jsoff_t));

	memcpy(buf, &koff, sizeof(koff));
	memcpy(buf + sizeof(koff), &v, sizeof(v));

	jsoff_t new_prop_off = js->brk;
	jsval_t prop = mkentity(js, 0 \| T_PROP \| flags, buf, sizeof(buf));
	if (is_err(prop)) return prop;

	if (first_prop == 0) {
	jsoff_t new_header = new_prop_off \| (header & (3U \| FLAGMASK));
	saveoff(js, head, new_header);
	} else {
	jsoff_t tail_header = loadoff(js, tail);
	jsoff_t new_tail_header = new_prop_off \| (tail_header & (3U \| FLAGMASK));
	saveoff(js, tail, new_tail_header);
	}
	saveoff(js, head + sizeof(jsoff_t) + sizeof(jsoff_t), new_prop_off);

	return prop;
	}

	jsval_t js_mkprop_fast(struct js js, jsval_t obj, const char key, size_t len, jsval_t v) {
	jsval_t k = js_mkstr(js, key, len);
	if (is_err(k)) return k;
	return mkprop_fast(js, obj, k, v, 0);
	}

	jsoff_t js_mkprop_fast_off(struct js js, jsval_t obj, const char key, size_t len, jsval_t v) {
	jsval_t k = js_mkstr(js, key, len);
	if (is_err(k)) return 0;
	jsoff_t prop_off = js->brk;
	mkprop_fast(js, obj, k, v, 0);
	return prop_off + sizeof(jsoff_t) * 2;
	}

	void js_saveval(struct js *js, jsoff_t off, jsval_t v) { saveval(js, off, v); }

	static jsval_t mkslot(struct js *js, jsval_t obj, internal_slot_t slot, jsval_t v) {
	jsoff_t head = (jsoff_t) vdata(obj);
	char buf[sizeof(jsoff_t) + sizeof(v)];

	jsoff_t header = loadoff(js, head);
	jsoff_t first_prop = header & ~(3U \| FLAGMASK);
	jsoff_t tail = loadoff(js, head + sizeof(jsoff_t) + sizeof(jsoff_t));

	jsoff_t slot_key = (jsoff_t)slot;
	memcpy(buf, &slot_key, sizeof(slot_key));
	memcpy(buf + sizeof(slot_key), &v, sizeof(v));

	jsoff_t new_prop_off = js->brk;
	jsval_t prop = mkentity(js, 0 \| T_PROP \| SLOTMASK, buf, sizeof(buf));
	if (is_err(prop)) return prop;

	if (first_prop == 0) {
	jsoff_t new_header = new_prop_off \| (header & (3U \| FLAGMASK));
	saveoff(js, head, new_header);
	} else {
	jsoff_t tail_header = loadoff(js, tail);
	jsoff_t new_tail_header = new_prop_off \| (tail_header & (3U \| FLAGMASK));
	saveoff(js, tail, new_tail_header);
	}
	saveoff(js, head + sizeof(jsoff_t) + sizeof(jsoff_t), new_prop_off);

	return prop;
	}

	static jsoff_t search_slot(struct js *js, jsval_t obj, internal_slot_t slot) {
	jsoff_t off = (jsoff_t) vdata(obj);
	if (off >= js->brk) return 0;
	jsoff_t next = loadoff(js, off) & ~(3U \| FLAGMASK);
	jsoff_t header, koff;

	check:
	if (next == 0 \|\| next >= js->brk) return 0;
	header = loadoff(js, next);
	if ((header & SLOTMASK) == 0) goto advance;
	koff = loadoff(js, next + sizeof(jsoff_t));
	if (koff == (jsoff_t)slot) return next;
	advance:
	next = header & ~(3U \| FLAGMASK);
	goto check;
	}

	static void set_slot(struct js *js, jsval_t obj, internal_slot_t slot, jsval_t val) {
	jsoff_t existing = search_slot(js, obj, slot);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, val);
	} else mkslot(js, obj, slot, val);
	}

	static jsval_t get_slot(struct js *js, jsval_t obj, internal_slot_t slot) {
	jsoff_t off = search_slot(js, obj, slot);
	if (off == 0) return js_mkundef();
	return loadval(js, off + sizeof(jsoff_t) * 2);
	}

	static void set_func_code_ptr(struct js js, jsval_t func_obj, const char code, size_t len) {
	set_slot(js, func_obj, SLOT_CODE, mkval(T_CFUNC, (size_t)code));
	set_slot(js, func_obj, SLOT_CODE_LEN, tov((double)len));
	}

	static void set_func_code(struct js js, jsval_t func_obj, const char code, size_t len) {
	const char *arena_code = code_arena_alloc(code, len);
	if (!arena_code) return;

	set_func_code_ptr(js, func_obj, arena_code, len);
	if (!code_has_function_decl(code, len)) set_slot(js, func_obj, SLOT_NO_FUNC_DECLS, js_mktrue());

	if (!memmem(code, len, "var", 3)) return;

	size_t vars_buf_len;
	char *vars = OXC_get_func_hoisted_vars(code, len, &vars_buf_len);

	if (vars) {
	set_slot(js, func_obj, SLOT_HOISTED_VARS, mkval(T_CFUNC, (size_t)vars));
	set_slot(js, func_obj, SLOT_HOISTED_VARS_LEN, tov((double)vars_buf_len));
	}
	}

	static const char get_func_code(struct js js, jsval_t func_obj, jsoff_t *len) {
	jsval_t code_val = get_slot(js, func_obj, SLOT_CODE);
	jsval_t len_val = get_slot(js, func_obj, SLOT_CODE_LEN);

	if (vtype(code_val) != T_CFUNC) {
	if (len) *len = 0;
	return NULL;
	}

	if (len) *len = (jsoff_t)tod(len_val);
	return (const char *)vdata(code_val);
	}

	static inline bool is_slot_prop(jsoff_t header) {
	return (header & SLOTMASK) != 0;
	}

	static inline jsoff_t next_prop(jsoff_t header) {
	return header & ~(3U \| FLAGMASK);
	}

	static double js_to_number(struct js *js, jsval_t arg) {
	if (vtype(arg) == T_NUM) return tod(arg);
	if (vtype(arg) == T_BOOL) return vdata(arg) ? 1.0 : 0.0;
	if (vtype(arg) == T_NULL) return 0.0;
	if (vtype(arg) == T_UNDEF) return JS_NAN;

	if (vtype(arg) == T_STR) {
	jsoff_t len, off = vstr(js, arg, &len);
	const char s = (char )&js->mem[off], *end;
	while (s == ' ' \|\| s == '\t' \|\| s == '\n' \|\| s == '\r') s++;
	if (!*s) return 0.0;
	double val = strtod(s, (char **)&end);
	while (end == ' ' \|\| end == '\t' \|\| end == '\n' \|\| end == '\r') end++;
	return (end == s \|\| *end) ? JS_NAN : val;
	}

	if (vtype(arg) == T_OBJ \|\| vtype(arg) == T_ARR) {
	if (vtype(arg) == T_OBJ) {
	jsval_t prim = js_call_valueOf(js, arg);
	uint8_t pt = vtype(prim);
	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC) return js_to_number(js, prim);
	}

	jsval_t str_val = js_tostring_val(js, arg);
	if (is_err(str_val) \|\| vtype(str_val) != T_STR) return JS_NAN;
	return js_to_number(js, str_val);
	}

	return JS_NAN;
	}

	static jsval_t setup_func_prototype(struct js *js, jsval_t func) {
	jsval_t proto_obj = mkobj(js, 0);
	if (is_err(proto_obj)) return proto_obj;

	jsval_t object_proto = get_ctor_proto(js, "Object", 6);
	if (vtype(object_proto) == T_OBJ) {
	set_proto(js, proto_obj, object_proto);
	}

	jsval_t constructor_key = js_mkstr(js, "constructor", 11);
	if (is_err(constructor_key)) return constructor_key;

	jsval_t res = mkprop(js, proto_obj, constructor_key, func, 0);
	if (is_err(res)) return res;
	js_set_descriptor(js, proto_obj, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	jsval_t prototype_key = js_mkstr(js, "prototype", 9);
	if (is_err(prototype_key)) return prototype_key;

	res = setprop(js, func, prototype_key, proto_obj);
	if (is_err(res)) return res;
	js_set_descriptor(js, func, "prototype", 9, JS_DESC_W);

	return js_mkundef();
	}

	static void infer_func_name(struct js js, jsval_t func, const char name, size_t len) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	if (vtype(get_slot(js, func_obj, SLOT_NAME)) != T_UNDEF) return;
	jsval_t name_val = js_mkstr(js, name, len);
	set_slot(js, func_obj, SLOT_NAME, name_val);
	setprop(js, func_obj, js_mkstr(js, "name", 4), name_val);
	}

	static jsval_t validate_array_length(struct js *js, jsval_t v) {
	if (vtype(v) != T_NUM) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid array length");
	}
	double d = tod(v);
	if (d < 0 \|\| d != (uint32_t)d \|\| d >= 4294967296.0) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid array length");
	}
	return js_mkundef();
	}

	jsval_t js_setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v) {
	jsoff_t koff = (jsoff_t) vdata(k);
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(jsoff_t)];

	if (vtype(obj) == T_ARR && streq(key, klen, "length", 6)) {
	jsval_t err = validate_array_length(js, v);
	if (is_err(err)) return err;
	}

	if (is_proxy(js, obj)) {
	jsval_t result = proxy_set(js, obj, key, klen, v);
	if (is_err(result)) return result;
	return v;
	}

	if (try_dynamic_setter(js, obj, key, klen, v)) {
	return v;
	}

	jsoff_t existing = lkp(js, obj, key, klen);

	{
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key, klen);

	if (!desc) goto no_descriptor;

	if (desc->has_setter) {
	jsval_t setter = desc->setter;
	uint8_t setter_type = vtype(setter);
	if (setter_type == T_FUNC \|\| setter_type == T_CFUNC) {
	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	uint8_t saved_flags = js->flags;
	jsoff_t saved_toff = js->toff;
	jsoff_t saved_tlen = js->tlen;

	jsval_t saved_this = js->this_val;
	js->this_val = obj;
	push_this(obj);
	jsval_t result = call_js_with_args(js, setter, &v, 1);
	pop_this();
	js->this_val = saved_this;

	JS_RESTORE_STATE(js, saved);
	js->flags = saved_flags;
	js->toff = saved_toff;
	js->tlen = saved_tlen;

	if (is_err(result)) return result;
	return v;
	}
	}

	if (desc->has_getter && !desc->has_setter) {
	if (js->flags & F_STRICT) return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot set property which has only a getter");
	return v;
	}

	if (existing <= 0) goto no_descriptor;

	if (!desc->writable) {
	if (js->flags & F_STRICT) return js_mkerr(js, "assignment to read-only property");
	return mkval(T_PROP, existing);
	}
	}

	no_descriptor:
	if (existing <= 0) goto create_new;

	if (is_const_prop(js, existing)) {
	if (js->flags & F_STRICT) return js_mkerr(js, "assignment to constant");
	return mkval(T_PROP, existing);
	}

	saveval(js, existing + sizeof(jsoff_t) * 2, v);
	if (vtype(obj) != T_ARR \|\| klen == 0 \|\| key[0] < '0' \|\| key[0] > '9') goto done_update;

	char *endptr;
	unsigned long update_idx = strtoul(key, &endptr, 10);
	if (endptr != key + klen) goto done_update;

	jsoff_t len_off = lkp_interned(js, obj, INTERN_LENGTH, 6);
	jsoff_t cur_len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) cur_len = (jsoff_t) tod(len_val);
	}
	if (update_idx < cur_len) goto done_update;

	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t new_len = tov((double)(update_idx + 1));
	if (len_off != 0) {
	saveval(js, len_off + sizeof(jsoff_t) * 2, new_len);
	} else mkprop(js, obj, len_key, new_len, 0);

	done_update:
	return mkval(T_PROP, existing);

	create_new:
	if (js_truthy(js, get_slot(js, obj, SLOT_FROZEN))) {
	if (js->flags & F_STRICT) return js_mkerr(js, "cannot add property to frozen object");
	return js_mkundef();
	}

	if (js_truthy(js, get_slot(js, obj, SLOT_SEALED))) {
	if (js->flags & F_STRICT) return js_mkerr(js, "cannot add property to sealed object");
	return js_mkundef();
	}

	jsval_t ext_slot = get_slot(js, obj, SLOT_EXTENSIBLE);
	if (vtype(ext_slot) != T_UNDEF && !js_truthy(js, ext_slot)) {
	if (js->flags & F_STRICT) return js_mkerr(js, "cannot add property to non-extensible object");
	return js_mkundef();
	}

	int need_length_update = 0;
	unsigned long idx = 0;

	if (vtype(obj) == T_ARR && klen > 0 && key[0] >= '0' && key[0] <= '9') {
	char *inner_endptr;
	idx = strtoul(key, &inner_endptr, 10);
	if (inner_endptr == key + klen) {
	jsoff_t inner_len_off = lkp_interned(js, obj, INTERN_LENGTH, 6);
	jsoff_t inner_cur_len = 0;
	if (inner_len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, inner_len_off));
	if (vtype(len_val) == T_NUM) inner_cur_len = (jsoff_t) tod(len_val);
	}
	if (idx >= inner_cur_len) need_length_update = 1;
	}
	}

	jsval_t result = mkprop(js, obj, k, v, 0);

	if (need_length_update) {
	jsoff_t inner_len_off = lkp_interned(js, obj, INTERN_LENGTH, 6);
	jsval_t inner_len_key = js_mkstr(js, "length", 6);
	jsval_t inner_new_len = tov((double)(idx + 1));
	if (inner_len_off != 0) {
	saveval(js, inner_len_off + sizeof(jsoff_t) * 2, inner_new_len);
	} else mkprop(js, obj, inner_len_key, inner_new_len, 0);
	}

	return result;
	}

	static inline jsval_t setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v) {
	return js_setprop(js, obj, k, v);
	}

	static inline jsval_t setprop_cstr(struct js js, jsval_t obj, const char key, size_t len, jsval_t v) {
	jsval_t k = js_mkstr(js, key, len);
	if (is_err(k)) return k;
	return mkprop(js, obj, k, v, 0);
	}

	static jsval_t setprop_interned(struct js js, jsval_t obj, const char key, size_t len, jsval_t v) {
	jsval_t k = js_mkstr(js, key, len);
	if (is_err(k)) return k;
	return js_setprop(js, obj, k, v);
	}

	jsval_t js_setprop_nonconfigurable(struct js js, jsval_t obj, const char key, size_t keylen, jsval_t v) {
	jsval_t k = js_mkstr(js, key, keylen);
	if (is_err(k)) return k;
	jsval_t result = setprop(js, obj, k, v);
	if (is_err(result)) return result;

	js_set_descriptor(js, obj, key, keylen, JS_DESC_W);
	return result;
	}

	jsval_t js_mksym(struct js js, const char desc) {
	uint64_t id = ++js->sym_counter;
	jsoff_t desc_off = 0;
	if (desc && *desc) {
	jsval_t desc_str = js_mkstr(js, desc, strlen(desc));
	desc_off = (jsoff_t)vdata(desc_str);
	}
	uint64_t payload = ((id & PROPREF_PAYLOAD) << PROPREF_KEY_SHIFT) \| (desc_off & PROPREF_PAYLOAD);
	return mkval(T_SYMBOL, payload);
	}

	static inline uint64_t sym_get_id(jsval_t v) {
	return (vdata(v) >> PROPREF_KEY_SHIFT) & PROPREF_PAYLOAD;
	}

	static inline jsoff_t sym_get_desc_off(jsval_t v) {
	return vdata(v) & PROPREF_PAYLOAD;
	}

	static const char sym_get_desc(struct js js, jsval_t v) {
	jsoff_t off = sym_get_desc_off(v);
	if (off == 0) return NULL;
	return (const char *)&js->mem[off + sizeof(jsoff_t)];
	}

	uint64_t inline js_sym_id(jsval_t sym) {
	return sym_get_id(sym);
	}

	jsval_t js_mksym_for(struct js js, const char key) {
	(void)js;
	const char *interned = intern_string(key, strlen(key));
	uint64_t id = (uint64_t)(uintptr_t)interned;
	return mkval(T_SYMBOL, id \| (1ULL << 47));
	}

	const char *js_sym_key(jsval_t sym) {
	if (vtype(sym) != T_SYMBOL) return NULL;
	uint64_t data = vdata(sym);
	if (!(data & (1ULL << 47))) return NULL;
	return (const char *)(uintptr_t)(data & ~(1ULL << 47));
	}

	const inline char js_sym_desc(struct js js, jsval_t sym) {
	return sym_get_desc(js, sym);
	}

	jsoff_t esize(jsoff_t w) {
	jsoff_t cleaned = w & ~FLAGMASK;
	switch (cleaned & 3U) {
	case T_OBJ: return (jsoff_t) (sizeof(jsoff_t) + sizeof(jsoff_t) + sizeof(jsoff_t));
	case T_PROP: return (jsoff_t) (sizeof(jsoff_t) + sizeof(jsoff_t) + sizeof(jsval_t));
	case T_STR: return (jsoff_t) (sizeof(jsoff_t) + align64(cleaned >> 3U));
	default: return (jsoff_t) ~0U;
	}
	}

	static int is_unicode_space(const unsigned char p, jsoff_t remaining, bool is_line_term) {
	if (is_line_term) *is_line_term = false;
	if (p[0] < 0x80) return 0;
	if (remaining >= 2 && p[0] == 0xC2 && p[1] == 0xA0) return 2;
	if (remaining >= 3 && p[0] == 0xE2 && p[1] == 0x80) {
	if (p[2] >= 0x80 && p[2] <= 0x8A) return 3;
	if (p[2] == 0xAF) return 3;
	if (p[2] == 0xA8) { if (is_line_term) *is_line_term = true; return 3; }
	if (p[2] == 0xA9) { if (is_line_term) *is_line_term = true; return 3; }
	}
	if (remaining >= 3 && p[0] == 0xE1 && p[1] == 0x9A && p[2] == 0x80) return 3;
	if (remaining >= 3 && p[0] == 0xE2 && p[1] == 0x81 && p[2] == 0x9F) return 3;
	if (remaining >= 3 && p[0] == 0xE3 && p[1] == 0x80 && p[2] == 0x80) return 3;
	if (remaining >= 3 && p[0] == 0xEF && p[1] == 0xBB && p[2] == 0xBF) return 3;
	return 0;
	}

	enum { C_0 = 0, C_SPC, C_NL, C_SL, C_HI };

	static const uint8_t cc[128] = {
	0,0,0,0,0,0,0,0,0,C_SPC,C_NL,C_SPC,C_SPC,C_SPC,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	C_SPC,0,0,0,0,0,0,0,0,0,0,0,0,0,0,C_SL,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	};

	static jsoff_t skiptonext(const char code, jsoff_t len, jsoff_t n, bool nl) {
	static const void *D[] = { &&L0, &&LS, &&LN, &&LSL, &&LH };
	bool saw_nl = false;
	unsigned char c;

	const char *p = code + n;
	const char *end = code + len;

	if (__builtin_expect(p == code && end - p >= 2 && p[0] == '#' && p[1] == '!', 0)) {
	for (p += 2; p < end && *p != '\n'; p++);
	if (p < end) { saw_nl = true; p++; }
	}

	if (__builtin_expect(p >= end, 0)) goto L0;
	c = (unsigned char)*p;
	goto *D[c & 0x80 ? C_HI : cc[c]];

	LS:
	p++;
	if (__builtin_expect(p >= end, 0)) goto L0;
	c = (unsigned char)*p;
	goto *D[c & 0x80 ? C_HI : cc[c]];

	LN:
	saw_nl = true;
	p++;
	if (__builtin_expect(p >= end, 0)) goto L0;
	c = (unsigned char)*p;
	goto *D[c & 0x80 ? C_HI : cc[c]];

	LSL:
	if (p + 1 >= end) goto L0;
	if (p[1] == '/') {
	for (p += 2; p < end && *p != '\n'; p++);
	if (p < end) { saw_nl = true; p++; }
	if (__builtin_expect(p >= end, 0)) goto L0;
	c = (unsigned char)*p;
	goto *D[c & 0x80 ? C_HI : cc[c]];
	}
	if (p[1] == '*') {
	for (p += 2; p + 1 < end; p++) {
	if (p == '' && p[1] == '/') { p += 2; break; }
	if (*p == '\n') saw_nl = true;
	}
	if (__builtin_expect(p >= end, 0)) goto L0;
	c = (unsigned char)*p;
	goto *D[c & 0x80 ? C_HI : cc[c]];
	}
	goto L0;

	LH: {
	bool lt;
	int u = is_unicode_space((const unsigned char *)p, (jsoff_t)(end - p), &lt);
	if (u > 0) {
	if (lt) saw_nl = true;
	p += u;
	if (__builtin_expect(p >= end, 0)) goto L0;
	c = (unsigned char)*p;
	goto *D[c & 0x80 ? C_HI : cc[c]];
	}
	}

	L0:
	if (nl) *nl = saw_nl;
	return (jsoff_t)(p - code);
	}

	#define K(s, t) if (len == sizeof(s)-1 && !memcmp(buf, s, sizeof(s)-1)) return t
	#define M(s) (len == sizeof(s)-1 && !memcmp(buf, s, sizeof(s)-1))

	static uint8_t parsekeyword(const char *buf, size_t len) {
	switch (buf[0]) {
	case 'a':
	K("as", TOK_AS);
	K("async", TOK_ASYNC);
	K("await", TOK_AWAIT);
	break;
	case 'b':
	K("break", TOK_BREAK);
	break;
	case 'c':
	K("case", TOK_CASE);
	K("catch", TOK_CATCH);
	K("class", TOK_CLASS);
	K("const", TOK_CONST);
	K("continue", TOK_CONTINUE);
	break;
	case 'd':
	K("do", TOK_DO);
	K("default", TOK_DEFAULT);
	K("delete", TOK_DELETE);
	K("debugger", TOK_DEBUGGER);
	break;
	case 'e':
	K("else", TOK_ELSE);
	K("export", TOK_EXPORT);
	break;
	case 'f':
	K("for", TOK_FOR);
	K("from", TOK_FROM);
	K("false", TOK_FALSE);
	K("finally", TOK_FINALLY);
	K("function", TOK_FUNC);
	break;
	case 'g':
	K("globalThis", TOK_GLOBAL_THIS);
	break;
	case 'i':
	K("if", TOK_IF);
	K("in", TOK_IN);
	K("import", TOK_IMPORT);
	K("instanceof", TOK_INSTANCEOF);
	break;
	case 'l':
	K("let", TOK_LET);
	break;
	case 'n':
	K("new", TOK_NEW);
	K("null", TOK_NULL);
	break;
	case 'o':
	K("of", TOK_OF);
	break;
	case 'r':
	K("return", TOK_RETURN);
	break;
	case 's':
	K("super", TOK_SUPER);
	K("static", TOK_STATIC);
	K("switch", TOK_SWITCH);
	break;
	case 't':
	K("try", TOK_TRY);
	K("this", TOK_THIS);
	K("true", TOK_TRUE);
	K("throw", TOK_THROW);
	K("typeof", TOK_TYPEOF);
	break;
	case 'u':
	K("undefined", TOK_UNDEF);
	break;
	case 'v':
	K("var", TOK_VAR);
	K("void", TOK_VOID);
	break;
	case 'w':
	K("while", TOK_WHILE);
	K("with", TOK_WITH);
	K("window", TOK_WINDOW);
	break;
	case 'y':
	K("yield", TOK_YIELD);
	break;
	}
	return TOK_IDENTIFIER;
	}

	static bool is_strict_reserved(const char *buf, size_t len) {
	switch (buf[0]) {
	case 'i':
	if M("interface") return true;
	if M("implements") return true;
	break;
	case 'l':
	if M("let") return true;
	break;
	case 'p':
	if M("private") return true;
	if M("package") return true;
	if M("public") return true;
	if M("protected") return true;
	break;
	case 's':
	if M("static") return true;
	break;
	case 'y':
	if M("yield") return true;
	break;
	}
	return false;
	}

	#undef K
	#undef M

	static inline bool streq(const char buf, size_t len, const char s, size_t n) {
	return len == n && !memcmp(buf, s, n);
	}

	static inline bool is_strict_restricted(const char *buf, size_t len) {
	if (len == 4) return streq(buf, len, "eval", 4);
	if (len == 9) return streq(buf, len, "arguments", 9);
	return false;
	}

	static int encode_utf8(uint32_t cp, char *out) {
	if (cp < 0x80) {
	out[0] = (char)cp;
	return 1;
	} else if (cp < 0x800) {
	out[0] = (char)(0xC0 \| (cp >> 6));
	out[1] = (char)(0x80 \| (cp & 0x3F));
	return 2;
	} else if (cp < 0x10000) {
	out[0] = (char)(0xE0 \| (cp >> 12));
	out[1] = (char)(0x80 \| ((cp >> 6) & 0x3F));
	out[2] = (char)(0x80 \| (cp & 0x3F));
	return 3;
	} else {
	out[0] = (char)(0xF0 \| (cp >> 18));
	out[1] = (char)(0x80 \| ((cp >> 12) & 0x3F));
	out[2] = (char)(0x80 \| ((cp >> 6) & 0x3F));
	out[3] = (char)(0x80 \| (cp & 0x3F));
	return 4;
	}
	}

	#define CHAR_DIGIT 0x01
	#define CHAR_XDIGIT 0x02
	#define CHAR_ALPHA 0x04
	#define CHAR_IDENT 0x08
	#define CHAR_IDENT1 0x10
	#define CHAR_WS 0x20
	#define CHAR_OCTAL 0x40

	static const uint8_t char_type[256] = {
	['\t'] = CHAR_WS, ['\n'] = CHAR_WS, ['\r'] = CHAR_WS, [' '] = CHAR_WS,
	['0'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['1'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['2'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['3'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['4'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['5'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['6'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['7'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT \| CHAR_OCTAL,
	['8'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT,
	['9'] = CHAR_DIGIT \| CHAR_XDIGIT \| CHAR_IDENT,
	['A'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['B'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['C'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['D'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['E'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['F'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['a'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['b'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['c'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['d'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['e'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['f'] = CHAR_XDIGIT \| CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['G'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['H'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['I'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['J'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['K'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['L'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['M'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['N'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['O'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['P'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['Q'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['R'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['S'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['T'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['U'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['V'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['W'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['X'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['Y'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['Z'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['g'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['h'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['i'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['j'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['k'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['l'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['m'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['n'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['o'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['p'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['q'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['r'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['s'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['t'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['u'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['v'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['w'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['x'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['y'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1, ['z'] = CHAR_ALPHA \| CHAR_IDENT \| CHAR_IDENT1,
	['_'] = CHAR_IDENT \| CHAR_IDENT1,
	['$'] = CHAR_IDENT \| CHAR_IDENT1,
	};

	#define IS_DIGIT(c) (char_type[(uint8_t)(c)] & CHAR_DIGIT)
	#define IS_XDIGIT(c) (char_type[(uint8_t)(c)] & CHAR_XDIGIT)
	#define IS_IDENT(c) (char_type[(uint8_t)(c)] & CHAR_IDENT)
	#define IS_IDENT1(c) (char_type[(uint8_t)(c)] & CHAR_IDENT1)
	#define IS_OCTAL(c) (char_type[(uint8_t)(c)] & CHAR_OCTAL)

	#define likely(x) __builtin_expect(!!(x), 1)
	#define unlikely(x) __builtin_expect(!!(x), 0)

	static inline bool is_function_keyword(const char *code, jsoff_t pos, jsoff_t end) {
	if (pos + 8 > end) return false;
	uint64_t word;
	memcpy(&word, code + pos, 8);

	if (word != 0x6e6f6974636e7566ULL) return false;
	return (pos + 8 >= end) \|\| !IS_IDENT(code[pos + 8]);
	}

	static inline bool is_async_function(const char *code, jsoff_t pos, jsoff_t end) {
	if (pos + 5 > end) return false;

	uint32_t word4;
	memcpy(&word4, code + pos, 4);

	if (word4 != 0x6e797361U \|\| code[pos + 4] != 'c') return false;
	if (pos + 5 < end && IS_IDENT(code[pos + 5])) return false;

	jsoff_t scan = pos + 5;
	while (scan < end && (
	code[scan] == ' ' \|\|
	code[scan] == '\t' \|\|
	code[scan] == '\n' \|\|
	code[scan] == '\r'
	)) scan++;

	return is_function_keyword(code, scan, end);
	}

	static bool code_has_function_decl(const char *code, size_t len) {
	if (!memmem(code, len, "function", 8)) return false;

	size_t pos = 0;

	int target_depth = 0;
	if (len > 0 && code[0] == '(') target_depth = 1;
	int depth = 0;

	while (pos < len) {
	uint8_t c = (uint8_t)code[pos];

	if (c == '"' \|\| c == '\'' \|\| c == '`') {
	uint8_t quote = c;
	pos++;
	while (pos < len && (uint8_t)code[pos] != quote) {
	if (code[pos] == '\\' && pos + 1 < len) pos++;
	pos++;
	}
	if (pos < len) pos++;
	continue;
	}

	if (c == '/' && pos + 1 < len) {
	if (code[pos + 1] == '/') {
	pos += 2;
	while (pos < len && code[pos] != '\n') pos++;
	continue;
	}
	if (code[pos + 1] == '*') {
	pos += 2;
	while (pos + 1 < len && !(code[pos] == '*' && code[pos + 1] == '/')) pos++;
	if (pos + 1 < len) pos += 2;
	continue;
	}
	}

	if (c == '{') { depth++; pos++; continue; }
	if (c == '}') {
	if (depth <= target_depth) break;
	depth--; pos++; continue;
	}

	if (depth == target_depth) {
	if (c == 'f' && is_function_keyword(code, (jsoff_t)pos, (jsoff_t)len)) return true;
	if (c == 'a' && is_async_function(code, (jsoff_t)pos, (jsoff_t)len)) return true;
	}

	pos++;
	}

	return false;
	}

	static const uint8_t single_char_tok[128] = {
	['('] = TOK_LPAREN,
	[')'] = TOK_RPAREN,
	['{'] = TOK_LBRACE,
	['}'] = TOK_RBRACE,
	['['] = TOK_LBRACKET,
	[']'] = TOK_RBRACKET,
	[';'] = TOK_SEMICOLON,
	[','] = TOK_COMMA,
	[':'] = TOK_COLON,
	['~'] = TOK_TILDA,
	['#'] = TOK_HASH,
	};

	static bool is_space(int c) {
	if (c < 0 \|\| c >= 256) return false;
	return (char_type[(uint8_t)c] & CHAR_WS) != 0;
	}

	static bool is_digit(int c) {
	if (c < 0 \|\| c >= 256) return false;
	return (char_type[(uint8_t)c] & CHAR_DIGIT) != 0;
	}

	static bool is_xdigit(int c) {
	if (c < 0 \|\| c >= 256) return false;
	return (char_type[(uint8_t)c] & CHAR_XDIGIT) != 0;
	}

	static bool is_alpha(int c) {
	if (c < 0 \|\| c >= 256) return false;
	return (char_type[(uint8_t)c] & CHAR_ALPHA) != 0;
	}

	static bool is_ident_begin(int c) {
	if (c < 0) return false;
	if (c < 128) return (char_type[(uint8_t)c] & CHAR_IDENT1) != 0;
	return (c & 0x80) != 0;
	}

	static bool is_ident_continue(int c) {
	if (c < 0) return false;
	if (c < 128) return (char_type[(uint8_t)c] & (CHAR_IDENT \| CHAR_IDENT1)) != 0;
	return (c & 0x80) != 0;
	}

	static int parse_unicode_escape(const char buf, jsoff_t len, jsoff_t pos, uint32_t codepoint) {
	if (pos + 5 >= len) return 0;
	if (buf[pos] != '\\' \|\| buf[pos + 1] != 'u') return 0;

	uint32_t cp = 0;
	for (int i = 0; i < 4; i++) {
	int c = (unsigned char)buf[pos + 2 + i];
	if (!is_xdigit(c)) return 0;
	cp <<= 4;
	cp \|= (c <= '9') ? (c - '0') : ((c \| 0x20) - 'a' + 10);
	}
	*codepoint = cp;
	return 6;
	}

	static bool is_unicode_ident_begin(uint32_t cp) {
	if (cp < 128) return (char_type[(uint8_t)cp] & CHAR_IDENT1) != 0;
	return true;
	}

	static bool is_unicode_ident_continue(uint32_t cp) {
	if (cp < 128) return (char_type[(uint8_t)cp] & (CHAR_IDENT \| CHAR_IDENT1)) != 0;
	return true;
	}

	static size_t decode_ident_escapes(const char src, size_t srclen, char dst, size_t dstlen) {
	size_t si = 0, di = 0;
	while (si < srclen && di + 4 < dstlen) {
	uint32_t cp;
	int el = parse_unicode_escape(src, (jsoff_t)srclen, (jsoff_t)si, &cp);
	if (el > 0) {
	di += encode_utf8(cp, dst + di);
	si += el;
	} else dst[di++] = src[si++];
	}
	dst[di] = '\0';
	return di;
	}

	static bool has_unicode_escape(const char *src, size_t len) {
	if (len < 6) return false;
	const char *end = src + len - 5;
	const char *p = src;
	while ((p = memchr(p, '\\', end - p)) != NULL) {
	if (p[1] == 'u') return true;
	p++;
	}
	return false;
	}

	static jsval_t js_mkstr_ident(struct js js, const char src, size_t srclen) {
	if (!has_unicode_escape(src, srclen)) {
	return js_mkstr(js, src, srclen);
	}
	char decoded[256];
	size_t decoded_len = decode_ident_escapes(src, srclen, decoded, sizeof(decoded));
	return js_mkstr(js, decoded, decoded_len);
	}


	static uint8_t parseident(const char buf, jsoff_t len, jsoff_t tlen) {
	if (len == 0) return TOK_ERR;

	unsigned char c = (unsigned char)buf[0];
	jsoff_t i = 0;

	if (c < 128 && c != '\\' && is_ident_begin(c)) {
	i = 1;
	while (i < len) {
	c = (unsigned char)buf[i];
	if (c >= 128 \|\| c == '\\') goto slow_path_continue;
	if (!is_ident_continue(c)) break;
	i++;
	}
	*tlen = i;
	return parsekeyword(buf, i);
	}

	if (c == '\\') {
	uint32_t first_cp;
	int esc_len = parse_unicode_escape(buf, len, 0, &first_cp);
	if (esc_len <= 0 \|\| !is_unicode_ident_begin(first_cp)) return TOK_ERR;
	*tlen = esc_len;
	goto slow_path_loop;
	}

	if (c >= 128) {
	if ((c & 0xC0) == 0x80) return TOK_ERR;
	int ws_len = is_unicode_space((const unsigned char *)buf, len, NULL);
	if (ws_len > 0) return TOK_ERR;
	i = 1;
	while (i < len && ((unsigned char)buf[i] & 0xC0) == 0x80) i++;
	*tlen = i;
	goto slow_path_loop;
	}

	return TOK_ERR;

	slow_path_continue:
	*tlen = i;

	slow_path_loop:;
	int has_escapes = (buf[0] == '\\');

	while (*tlen < len) {
	c = (unsigned char)buf[*tlen];

	if (c == '\\') {
	uint32_t cp;
	int el = parse_unicode_escape(buf, len, *tlen, &cp);
	if (el <= 0 \|\| !is_unicode_ident_continue(cp)) break;
	*tlen += el;
	has_escapes = 1;
	} else if (c < 128) {
	if (!is_ident_continue(c)) break;
	(*tlen)++;
	} else {
	if ((c & 0xC0) == 0x80) break;
	int ws_len = is_unicode_space((const unsigned char )&buf[tlen], len - *tlen, NULL);
	if (ws_len > 0) break;
	(*tlen)++;
	while (tlen < len && ((unsigned char)buf[tlen] & 0xC0) == 0x80) (*tlen)++;
	}
	}

	if (has_escapes) {
	char decoded[256];
	size_t decoded_len = decode_ident_escapes(buf, *tlen, decoded, sizeof(decoded));
	return parsekeyword(decoded, decoded_len);
	}

	return parsekeyword(buf, *tlen);
	}

	static inline jsoff_t parse_decimal(const char buf, jsoff_t maxlen, double out) {
	uint64_t int_part = 0, frac_part = 0;
	int frac_digits = 0;
	jsoff_t i = 0;

	while (i < maxlen && (IS_DIGIT(buf[i]) \|\| buf[i] == '_')) {
	if (buf[i] != '_') int_part = int_part * 10 + (buf[i] - '0');
	i++;
	}

	if (i < maxlen && buf[i] == '.') {
	i++;
	while (i < maxlen && (IS_DIGIT(buf[i]) \|\| buf[i] == '_')) {
	if (buf[i] != '_') { frac_part = frac_part * 10 + (buf[i] - '0'); frac_digits++; }
	i++;
	}
	}

	static const double neg_pow10[] = {
	1e0,1e-1,1e-2,1e-3,1e-4,1e-5,1e-6,1e-7,1e-8,1e-9,1e-10,
	1e-11,1e-12,1e-13,1e-14,1e-15,1e-16,1e-17,1e-18,1e-19,1e-20
	};

	static const double pos_pow10[] = {
	1e0,1e1,1e2,1e3,1e4,1e5,1e6,1e7,1e8,1e9,1e10,
	1e11,1e12,1e13,1e14,1e15,1e16,1e17,1e18,1e19,1e20
	};

	double val = (double)int_part;
	if (frac_digits > 0) {
	val += (frac_digits <= 20)
	? (double)frac_part * neg_pow10[frac_digits]
	: (double)frac_part * pow(10.0, -frac_digits);
	}

	if (i < maxlen && (buf[i] == 'e' \|\| buf[i] == 'E')) {
	i++;
	int exp_sign = 1, exp_val = 0;
	if (i < maxlen && (buf[i] == '+' \|\| buf[i] == '-')) {
	exp_sign = (buf[i] == '-') ? -1 : 1;
	i++;
	}
	while (i < maxlen && (IS_DIGIT(buf[i]) \|\| buf[i] == '_')) {
	if (buf[i] != '_') exp_val = exp_val * 10 + (buf[i] - '0');
	i++;
	}
	if (exp_val <= 20) {
	val = (exp_sign > 0) ? val * pos_pow10[exp_val] : val * neg_pow10[exp_val];
	} else val = pow(10.0, exp_sign exp_val);
	}

	*out = val;
	return i;
	}

	static inline jsoff_t parse_binary(const char buf, jsoff_t maxlen, double out) {
	double val = 0;
	jsoff_t i = 2;
	while (i < maxlen && (buf[i] == '0' \|\| buf[i] == '1' \|\| buf[i] == '_')) {
	if (buf[i] != '_') val = val * 2 + (buf[i] - '0');
	i++;
	}
	*out = val;
	return i;
	}

	static inline jsoff_t parse_octal(const char buf, jsoff_t maxlen, double out) {
	double val = 0;
	jsoff_t i = 2;
	while (i < maxlen && (IS_OCTAL(buf[i]) \|\| buf[i] == '_')) {
	if (buf[i] != '_') val = val * 8 + (buf[i] - '0');
	i++;
	}
	*out = val;
	return i;
	}

	static inline jsoff_t parse_legacy_octal(const char buf, jsoff_t maxlen, double out) {
	double val = 0;
	jsoff_t i = 1;
	while (i < maxlen && IS_OCTAL(buf[i])) {
	val = val * 8 + (buf[i] - '0');
	i++;
	}
	*out = val;
	return i;
	}

	static inline jsoff_t parse_hex(const char buf, jsoff_t maxlen, double out) {
	double val = 0;
	jsoff_t i = 2;
	while (i < maxlen && (IS_XDIGIT(buf[i]) \|\| buf[i] == '_')) {
	if (buf[i] != '_') {
	int d =
	(buf[i] >= 'a') ? (buf[i] - 'a' + 10) :
	(buf[i] >= 'A') ? (buf[i] - 'A' + 10) : (buf[i] - '0');
	val = val * 16 + d;
	} i++;
	}
	*out = val;
	return i;
	}

	static inline uint8_t parse_number(struct js js, const char buf, jsoff_t remaining) {
	double value = 0;
	jsoff_t numlen = 0;

	if (buf[0] == '0' && remaining > 1) {
	char c1 = buf[1] \| 0x20;
	if (c1 == 'b') {
	numlen = parse_binary(buf, remaining, &value);
	} else if (c1 == 'o') {
	numlen = parse_octal(buf, remaining, &value);
	} else if (c1 == 'x') {
	numlen = parse_hex(buf, remaining, &value);
	} else if (IS_OCTAL(buf[1])) {
	if (js->flags & F_STRICT) {
	js->tok = TOK_ERR;
	js->tlen = 1;
	return TOK_ERR;
	}
	numlen = parse_legacy_octal(buf, remaining, &value);
	} else numlen = parse_decimal(buf, remaining, &value);
	} else numlen = parse_decimal(buf, remaining, &value);

	js->tval = tov(value);
	if (numlen < remaining && buf[numlen] == 'n') {
	js->tok = TOK_BIGINT;
	js->tlen = numlen + 1;
	} else {
	js->tok = TOK_NUMBER;
	js->tlen = numlen;
	}

	return js->tok;
	}

	static inline uint8_t scan_string(struct js js, const char buf, jsoff_t rem, char quote) {
	jsoff_t i = 1;

	while (i < rem) {
	const char *p = buf + i;
	jsoff_t search_len = rem - i;

	const char *q = memchr(p, quote, search_len);
	const char *b = memchr(p, '\\', search_len);

	if (q == NULL) {
	js->tok = TOK_ERR;
	js->tlen = rem;
	return TOK_ERR;
	}

	if (b == NULL \|\| q < b) {
	i = (jsoff_t)((q - buf) + 1);
	js->tok = TOK_STRING;
	js->tlen = i;
	return TOK_STRING;
	}

	jsoff_t esc_pos = (jsoff_t)(b - buf);
	if (esc_pos + 1 >= rem) {
	js->tok = TOK_ERR;
	js->tlen = rem;
	return TOK_ERR;
	}

	char esc_char = buf[esc_pos + 1];
	jsoff_t skip = 2;

	if (esc_char == 'x') { skip = 4; } else if (esc_char == 'u') {
	skip = (esc_pos + 2 < rem && buf[esc_pos + 2] == '{') ? 0 : 6;
	if (skip == 0) {
	jsoff_t j = esc_pos + 3;
	while (j < rem && buf[j] != '}') j++;
	skip = (j < rem) ? (j - esc_pos + 1) : (rem - esc_pos);
	}
	}

	if (esc_pos + skip > rem) {
	js->tok = TOK_ERR;
	js->tlen = rem;
	return TOK_ERR;
	}

	i = esc_pos + skip;
	}

	js->tok = TOK_ERR;
	js->tlen = rem;
	return TOK_ERR;
	}

	static inline jsoff_t skip_string_literal(const char *buf, jsoff_t rem, jsoff_t start, char quote) {
	jsoff_t i = start + 1;
	while (i < rem) {
	if (buf[i] == '\\') { i += 2; continue; }
	if (buf[i] == quote) { return i + 1; } i++;
	}
	return rem;
	}

	static inline jsoff_t skip_line_comment(const char *buf, jsoff_t rem, jsoff_t start) {
	jsoff_t i = start + 2;
	while (i < rem && buf[i] != '\n') i++;
	return i;
	}

	static inline jsoff_t skip_block_comment(const char *buf, jsoff_t rem, jsoff_t start) {
	jsoff_t i = start + 2;
	while (i + 1 < rem && !(buf[i] == '*' && buf[i + 1] == '/')) i++;
	return (i + 1 < rem) ? (i + 2) : rem;
	}

	static jsoff_t skip_template_literal(const char *buf, jsoff_t rem, jsoff_t start) {
	jsoff_t i = start + 1;
	int expr_depth = 0;

	while (i < rem) {
	char c = buf[i];

	if (c == '\\') {
	i += 2;
	continue;
	}

	if (expr_depth == 0) {
	if (c == '`') return i + 1;
	if (c == '$' && i + 1 < rem && buf[i + 1] == '{') {
	expr_depth = 1;
	i += 2;
	continue;
	} i++; continue;
	}

	if (c == '\'' \|\| c == '"') {
	i = skip_string_literal(buf, rem, i, c);
	continue;
	}

	if (c == '`') {
	jsoff_t next = skip_template_literal(buf, rem, i);
	if (next <= i) return rem;
	i = next; continue;
	}

	if (c == '/' && i + 1 < rem) {
	if (buf[i + 1] == '/') { i = skip_line_comment(buf, rem, i); continue; }
	if (buf[i + 1] == '*') { i = skip_block_comment(buf, rem, i); continue; }
	}

	if (c == '{') { expr_depth++; i++; continue; }
	if (c == '}') { expr_depth--; i++; continue; }

	i++;
	}

	return rem;
	}

	static inline uint8_t scan_template(struct js js, const char buf, jsoff_t rem) {
	jsoff_t end = skip_template_literal(buf, rem, 0);
	if (end <= 1 \|\| end > rem) {
	js->tok = TOK_ERR;
	js->tlen = rem;
	return TOK_ERR;
	}

	js->tok = TOK_TEMPLATE;
	js->tlen = end;
	return TOK_TEMPLATE;
	}

	static inline uint8_t parse_operator(struct js js, const char buf, jsoff_t rem) {
	#define MATCH2(c1,c2) (rem >= 2 && buf[1] == (c2))
	#define MATCH3(c1,c2,c3) (rem >= 3 && buf[1] == (c2) && buf[2] == (c3))
	#define MATCH4(c1,c2,c3,c4) (rem >= 4 && buf[1]==(c2) && buf[2]==(c3) && buf[3]==(c4))

	switch (buf[0]) {
	case '?':
	if (MATCH3('?','?','=')) { js->tok = TOK_NULLISH_ASSIGN; js->tlen = 3; }
	else if (MATCH2('?','?')) { js->tok = TOK_NULLISH; js->tlen = 2; }
	else if (MATCH2('?','.')) { js->tok = TOK_OPTIONAL_CHAIN; js->tlen = 2; }
	else { js->tok = TOK_Q; js->tlen = 1; }
	break;

	case '!':
	if (MATCH3('!','=','=')) { js->tok = TOK_SNE; js->tlen = 3; }
	else if (MATCH2('!','=')) { js->tok = TOK_NE; js->tlen = 2; }
	else { js->tok = TOK_NOT; js->tlen = 1; }
	break;

	case '=':
	if (MATCH3('=','=','=')) { js->tok = TOK_SEQ; js->tlen = 3; }
	else if (MATCH2('=','=')) { js->tok = TOK_EQ; js->tlen = 2; }
	else if (MATCH2('=','>')) { js->tok = TOK_ARROW; js->tlen = 2; }
	else { js->tok = TOK_ASSIGN; js->tlen = 1; }
	break;

	case '<':
	if (MATCH3('<','<','=')) { js->tok = TOK_SHL_ASSIGN; js->tlen = 3; }
	else if (MATCH2('<','<')) { js->tok = TOK_SHL; js->tlen = 2; }
	else if (MATCH2('<','=')) { js->tok = TOK_LE; js->tlen = 2; }
	else { js->tok = TOK_LT; js->tlen = 1; }
	break;

	case '>':
	if (MATCH4('>','>','>','=')) { js->tok = TOK_ZSHR_ASSIGN; js->tlen = 4; }
	else if (MATCH3('>','>','>')) { js->tok = TOK_ZSHR; js->tlen = 3; }
	else if (MATCH3('>','>','=')) { js->tok = TOK_SHR_ASSIGN; js->tlen = 3; }
	else if (MATCH2('>','>')) { js->tok = TOK_SHR; js->tlen = 2; }
	else if (MATCH2('>','=')) { js->tok = TOK_GE; js->tlen = 2; }
	else { js->tok = TOK_GT; js->tlen = 1; }
	break;

	case '&':
	if (MATCH3('&','&','=')) { js->tok = TOK_LAND_ASSIGN; js->tlen = 3; }
	else if (MATCH2('&','&')) { js->tok = TOK_LAND; js->tlen = 2; }
	else if (MATCH2('&','=')) { js->tok = TOK_AND_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_AND; js->tlen = 1; }
	break;

	case '\|':
	if (MATCH3('\|','\|','=')) { js->tok = TOK_LOR_ASSIGN; js->tlen = 3; }
	else if (MATCH2('\|','\|')) { js->tok = TOK_LOR; js->tlen = 2; }
	else if (MATCH2('\|','=')) { js->tok = TOK_OR_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_OR; js->tlen = 1; }
	break;

	case '+':
	if (MATCH2('+','+')) { js->tok = TOK_POSTINC; js->tlen = 2; }
	else if (MATCH2('+','=')) { js->tok = TOK_PLUS_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_PLUS; js->tlen = 1; }
	break;

	case '-':
	if (MATCH2('-','-')) { js->tok = TOK_POSTDEC; js->tlen = 2; }
	else if (MATCH2('-','=')) { js->tok = TOK_MINUS_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_MINUS; js->tlen = 1; }
	break;

	case '*':
	if (MATCH2('','')) { js->tok = TOK_EXP; js->tlen = 2; }
	else if (MATCH2('*','=')) { js->tok = TOK_MUL_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_MUL; js->tlen = 1; }
	break;

	case '/':
	if (MATCH2('/','=')) { js->tok = TOK_DIV_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_DIV; js->tlen = 1; }
	break;

	case '%':
	if (MATCH2('%','=')) { js->tok = TOK_REM_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_REM; js->tlen = 1; }
	break;

	case '^':
	if (MATCH2('^','=')) { js->tok = TOK_XOR_ASSIGN; js->tlen = 2; }
	else { js->tok = TOK_XOR; js->tlen = 1; }
	break;

	case '.':
	if (MATCH3('.','.', '.')) { js->tok = TOK_REST; js->tlen = 3; }
	else if (rem > 1 && IS_DIGIT(buf[1])) {
	double val;
	js->tlen = parse_decimal(buf, rem, &val);
	js->tval = tov(val);
	js->tok = TOK_NUMBER;
	}
	else { js->tok = TOK_DOT; js->tlen = 1; }
	break;

	default:
	return 0;
	}

	#undef MATCH2
	#undef MATCH3
	#undef MATCH4

	return js->tok;
	}

	static uint8_t next(struct js *js) {
	if (likely(js->consumed == 0)) return js->tok;

	js->consumed = 0;
	js->tok = TOK_ERR;
	js->toff = js->pos = skiptonext(js->code, js->clen, js->pos, &js->had_newline);
	js->tlen = 0;

	if (unlikely(js->toff >= js->clen)) {
	js->tok = TOK_EOF;
	return TOK_EOF;
	}

	const char *buf = js->code + js->toff;
	jsoff_t rem = js->clen - js->toff;
	uint8_t c = (uint8_t)buf[0];

	if (likely(c < 128)) {
	uint8_t simple_tok = single_char_tok[c];
	if (simple_tok != 0) {
	js->tok = simple_tok;
	js->tlen = 1;
	js->pos = js->toff + 1;
	return simple_tok;
	}
	}

	if (likely(IS_IDENT1(c))) {
	js->tok = parseident(buf, rem, &js->tlen);
	js->pos = js->toff + js->tlen;
	return js->tok;
	}

	if (IS_DIGIT(c)) {
	parse_number(js, buf, rem);
	if (js->tlen == 0) js->tlen = 1;
	js->pos = js->toff + js->tlen;
	return js->tok;
	}

	if (c == '"' \|\| c == '\'') {
	scan_string(js, buf, rem, c);
	if (js->tlen == 0) js->tlen = 1;
	js->pos = js->toff + js->tlen;
	return js->tok;
	}

	if (c == '`') {
	scan_template(js, buf, rem);
	if (js->tlen == 0) js->tlen = 1;
	js->pos = js->toff + js->tlen;
	return js->tok;
	}

	if (parse_operator(js, buf, rem)) {
	if (js->tlen == 0) js->tlen = 1;
	js->pos = js->toff + js->tlen;
	return js->tok;
	}

	js->tok = parseident(buf, rem, &js->tlen);
	if (js->tlen == 0) js->tlen = 1;
	js->pos = js->toff + js->tlen;

	return js->tok;
	}

	static inline uint8_t lookahead(struct js *js) {
	uint8_t old = js->tok, tok = 0;
	uint8_t old_consumed = js->consumed;
	jsoff_t pos = js->pos;

	js->consumed = 1;
	tok = next(js);
	js->pos = pos;
	js->tok = old;
	js->consumed = old_consumed;

	return tok;
	}

	static bool is_typeof_bare_ident(struct js *js) {
	jsoff_t pos = js->pos, toff = js->toff, tlen = js->tlen;
	uint8_t tok = js->tok, consumed = js->consumed;
	bool had_newline = js->had_newline;

	int depth = 0;
	uint8_t t = next(js);
	while (t == TOK_LPAREN) { js->consumed = 1; t = next(js); depth++; }

	bool bare = (t == TOK_IDENTIFIER);
	if (bare) {
	js->consumed = 1;
	t = next(js);
	while (depth > 0 && t == TOK_RPAREN) { js->consumed = 1; t = next(js); depth--; }
	if (depth != 0 \|\| t == TOK_DOT \|\| t == TOK_LBRACKET \|\| t == TOK_LPAREN \|\| t == TOK_OPTIONAL_CHAIN) bare = false;
	}

	js->pos = pos; js->toff = toff; js->tlen = tlen;
	js->tok = tok; js->consumed = consumed; js->had_newline = had_newline;

	return bare;
	}

	jsval_t js_mkscope(struct js *js) {
	assert((js->flags & F_NOEXEC) == 0);
	if (global_scope_stack == NULL) utarray_new(global_scope_stack, &jsoff_icd);
	jsoff_t prev = (jsoff_t) vdata(js->scope);
	utarray_push_back(global_scope_stack, &prev);
	js->scope = mkobj(js, prev);
	return js->scope;
	}

	void js_delscope(struct js *js) {
	if (global_scope_stack && utarray_len(global_scope_stack) > 0) {
	jsoff_t prev = (jsoff_t )utarray_back(global_scope_stack);
	js->scope = mkval(T_OBJ, *prev);
	utarray_pop_back(global_scope_stack);
	} else js->scope = upper(js, js->scope);
	}

	static void mkscope(struct js *js) { (void)js_mkscope(js); }
	static void delscope(struct js *js) { (void)js_delscope(js); }

	static void for_let_push(struct js js, const char var_name, jsoff_t var_len, jsoff_t prop_off, jsval_t body_scope) {
	if (js->for_let_stack_len >= js->for_let_stack_cap) {
	int new_cap = js->for_let_stack_cap ? js->for_let_stack_cap * 2 : 4;
	js->for_let_stack = realloc(js->for_let_stack, new_cap * sizeof(struct for_let_ctx));
	js->for_let_stack_cap = new_cap;
	}
	js->for_let_stack[js->for_let_stack_len++] = (struct for_let_ctx){var_name, var_len, prop_off, body_scope};
	}

	static inline void for_let_set_body_scope(struct js *js, jsval_t body_scope) {
	if (js->for_let_stack_len > 0) js->for_let_stack[js->for_let_stack_len - 1].body_scope = body_scope;
	}

	static inline void for_let_pop(struct js *js) {
	if (js->for_let_stack_len > 0) js->for_let_stack_len--;
	}

	static inline struct for_let_ctx for_let_current(struct js js) {
	return js->for_let_stack_len > 0 ? &js->for_let_stack[js->for_let_stack_len - 1] : NULL;
	}

	static void for_let_swap_with_coro(struct js js, coroutine_t coro) {
	struct for_let_ctx *tmp_stack = js->for_let_stack;
	int tmp_len = js->for_let_stack_len;
	int tmp_cap = js->for_let_stack_cap;

	js->for_let_stack = coro->for_let_stack;
	js->for_let_stack_len = coro->for_let_stack_len;
	js->for_let_stack_cap = coro->for_let_stack_cap;

	coro->for_let_stack = tmp_stack;
	coro->for_let_stack_len = tmp_len;
	coro->for_let_stack_cap = tmp_cap;
	}

	static void copy_body_scope_props(struct js js, jsval_t body_scope, jsval_t closure_scope, const char skip_var, jsoff_t skip_len) {
	if (vtype(body_scope) != T_OBJ) return;
	jsoff_t prop_off = loadoff(js, (jsoff_t)vdata(body_scope)) & ~(3U \| FLAGMASK);

	while (prop_off < js->brk && prop_off != 0) {
	jsoff_t header = loadoff(js, prop_off);
	if (is_slot_prop(header)) { prop_off = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, prop_off + (jsoff_t)sizeof(prop_off));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char )&js->mem[koff + sizeof(koff)];
	jsval_t val = loadval(js, prop_off + (jsoff_t)(sizeof(prop_off) + sizeof(koff)));

	prop_off = next_prop(header);
	if (is_internal_prop(key, klen)) continue;
	if (skip_var && klen == skip_len && memcmp(key, skip_var, klen) == 0) continue;

	jsval_t key_str = js_mkstr(js, key, klen);
	mkprop(js, closure_scope, key_str, val, 0);
	}
	}

	static jsval_t for_let_capture_scope(struct js *js) {
	struct for_let_ctx *flc = for_let_current(js);
	if (!flc \|\| flc->prop_off == 0) return js->scope;

	jsval_t loop_var_val = resolveprop(js, mkval(T_PROP, flc->prop_off));
	jsval_t closure_scope = js_mkscope(js);
	if (is_err(closure_scope)) return closure_scope;

	jsval_t var_key = js_mkstr(js, flc->var_name, flc->var_len);
	mkprop(js, closure_scope, var_key, loop_var_val, 0);

	if (vtype(flc->body_scope) == T_OBJ) {
	copy_body_scope_props(js, flc->body_scope, closure_scope, flc->var_name, flc->var_len);
	}
	delscope(js);
	return closure_scope;
	}

	static void scope_clear_props(struct js *js, jsval_t scope) {
	jsoff_t off = (jsoff_t)vdata(scope);
	jsoff_t header = loadoff(js, off);
	jsoff_t parent = loadoff(js, off + sizeof(jsoff_t));

	saveoff(js, off, (header & FLAGMASK) \| T_OBJ);
	saveoff(js, off + sizeof(jsoff_t), parent);
	saveoff(js, off + sizeof(jsoff_t) + sizeof(jsoff_t), 0);
	}

	static bool block_needs_scope(struct js *js) {
	jsoff_t pos = js->pos, toff = js->toff, tlen = js->tlen;
	uint8_t tok = js->tok, consumed = js->consumed;
	bool had_newline = js->had_newline;

	bool needs = false;
	int depth = 1;
	js->consumed = 1;

	while (depth > 0) {
	uint8_t t = next(js);
	if (t == TOK_EOF) break;
	if (t == TOK_LBRACE) { depth++; js->consumed = 1; continue; }
	if (t == TOK_RBRACE) { depth--; js->consumed = 1; continue; }

	if (depth == 1 && (
	t == TOK_LET \|\|
	t == TOK_CONST \|\|
	t == TOK_CLASS \|\|
	t == TOK_FUNC
	)) { needs = true; break; }

	js->consumed = 1;
	}

	js->pos = pos; js->toff = toff; js->tlen = tlen;
	js->tok = tok; js->consumed = consumed; js->had_newline = had_newline;

	return needs;
	}

	static inline bool push_this(jsval_t this_value) {
	if (global_this_stack.depth >= global_this_stack.capacity) {
	int new_capacity = global_this_stack.capacity == 0 ? 16 : global_this_stack.capacity * 2;
	jsval_t new_stack = (jsval_t ) realloc(global_this_stack.stack, new_capacity * sizeof(jsval_t));
	if (!new_stack) return false;
	global_this_stack.stack = new_stack;
	global_this_stack.capacity = new_capacity;
	}
	global_this_stack.stack[global_this_stack.depth++] = this_value;
	return true;
	}

	static inline jsval_t pop_this() {
	if (global_this_stack.depth > 0) {
	return global_this_stack.stack[--global_this_stack.depth];
	}
	return js_mkundef();
	}

	static inline jsval_t peek_this() {
	if (global_this_stack.depth > 0) {
	return global_this_stack.stack[global_this_stack.depth - 1];
	}
	return js_mkundef();
	}

	static inline bool push_call_frame(const char filename, const char function_name, const char *code, uint32_t pos) {
	if (global_call_stack.depth >= global_call_stack.capacity) {
	int new_capacity = global_call_stack.capacity == 0 ? 32 : global_call_stack.capacity * 2;
	call_frame_t new_stack = (call_frame_t ) realloc(global_call_stack.frames, new_capacity * sizeof(call_frame_t));
	if (!new_stack) return false;
	global_call_stack.frames = new_stack;
	global_call_stack.capacity = new_capacity;
	}

	global_call_stack.frames[global_call_stack.depth].filename = filename;
	global_call_stack.frames[global_call_stack.depth].function_name = function_name;
	global_call_stack.frames[global_call_stack.depth].code = code;
	global_call_stack.frames[global_call_stack.depth].pos = pos;
	global_call_stack.frames[global_call_stack.depth].line = -1;
	global_call_stack.frames[global_call_stack.depth].col = -1;
	global_call_stack.depth++;

	return true;
	}

	static inline void pop_call_frame() {
	if (global_call_stack.depth > 0) {
	global_call_stack.depth--;
	}
	}

	static jsval_t js_func_decl(struct js *js);
	static jsval_t js_func_decl_async(struct js *js);

	static void hoist_function_declarations(struct js *js) {
	if (js->flags & F_NOEXEC) return;
	if (js->is_hoisting) return;

	if (js->skip_func_hoist) return;
	if (!code_has_function_decl(js->code + js->pos, js->clen - js->pos)) return;

	js->is_hoisting = true;
	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	jsval_t saved_scope = js->scope;

	int depth = 0;
	uint8_t tok, prev_tok = TOK_EOF;

	while ((tok = next(js)) != TOK_EOF && !(tok == TOK_RBRACE && depth == 0)) {
	if (tok == TOK_LBRACE) { depth++; prev_tok = tok; js->consumed = 1; continue; }
	if (tok == TOK_RBRACE) { depth--; prev_tok = tok; js->consumed = 1; continue; }
	if (depth > 0) { prev_tok = tok; js->consumed = 1; continue; }

	if (tok == TOK_EXPORT) {
	js->consumed = 1;
	uint8_t next_tok = next(js);
	if (next_tok != TOK_FUNC && next_tok != TOK_ASYNC && next_tok != TOK_DEFAULT)
	goto skip_export;

	int brace_depth = 0;
	while (next(js) != TOK_EOF) {
	if (js->tok == TOK_LBRACE) brace_depth++;
	else if (js->tok == TOK_RBRACE && --brace_depth <= 0) break;
	js->consumed = 1;
	}

	skip_export: {
	prev_tok = tok;
	continue;
	}
	}

	if (depth == 0 && tok == TOK_FUNC) {
	if (expr_context_tok[prev_tok]) {
	prev_tok = tok;
	js->consumed = 1;
	continue;
	}

	jsoff_t after_func = js->pos;
	js->consumed = 1;

	if (next(js) == TOK_IDENTIFIER) {
	js->pos = after_func;
	js->tok = TOK_FUNC;
	js->consumed = 1;
	js_func_decl(js);
	}

	prev_tok = tok;
	continue;
	}

	if (depth == 0 && tok == TOK_ASYNC) {
	if (expr_context_tok[prev_tok]) {
	prev_tok = tok;
	js->consumed = 1;
	continue;
	}

	js->consumed = 1;
	if (next(js) != TOK_FUNC) goto skip_async;
	jsoff_t func_pos = js->pos;
	js->consumed = 1;
	if (next(js) != TOK_IDENTIFIER) goto skip_async;
	js->pos = func_pos;
	js->tok = TOK_FUNC;
	js->consumed = 0;
	js_func_decl_async(js);

	skip_async: {
	prev_tok = tok;
	continue;
	}
	}

	prev_tok = tok;
	js->consumed = 1;
	}

	js->is_hoisting = false;
	JS_RESTORE_STATE(js, saved);
	js->scope = saved_scope;
	}

	static void declare_hoisted_vars(struct js js, jsval_t var_scope, const char var_names) {
	const char *ptr = var_names;
	while (*ptr) {
	size_t len = strlen(ptr);
	jsoff_t existing = lkp(js, var_scope, ptr, len);
	if (existing == 0) mkprop(js, var_scope, js_mkstr(js, ptr, len), js_mkundef(), 0);
	ptr += len + 1;
	}
	}

	static void hoist_var_declarations_from_slot(struct js *js, jsval_t var_scope, jsval_t func_obj) {
	jsval_t vars_val = get_slot(js, func_obj, SLOT_HOISTED_VARS);
	if (vtype(vars_val) != T_CFUNC) return;
	const char var_names = (const char )vdata(vars_val);
	if (!var_names) return;
	declare_hoisted_vars(js, var_scope, var_names);
	}

	static void hoist_var_declarations(struct js *js, jsval_t var_scope) {
	if (js->flags & F_NOEXEC) return;
	if (js->clen == 0) return;
	if (!memmem(js->code, js->clen, "var", 3)) return;

	size_t buf_len;
	char *var_names = OXC_get_hoisted_vars(js->code, (size_t)js->clen, &buf_len);
	if (!var_names) return;

	declare_hoisted_vars(js, var_scope, var_names);
	OXC_free_hoisted_vars(var_names, buf_len);
	}

	static jsval_t js_block(struct js *js, bool create_scope) {
	jsval_t res = js_mkundef();
	bool scope_created = false;

	if (create_scope && lookahead(js) != TOK_RBRACE && block_needs_scope(js)) {
	mkscope(js);
	scope_created = true;
	}

	js->consumed = 1;
	hoist_function_declarations(js);

	uint8_t peek;
	while ((peek = next(js)) != TOK_EOF && peek != TOK_RBRACE && !is_err(res)) {
	uint8_t t = js->tok;
	res = js_stmt(js);
	if (!is_err(res) && !is_block_tok(t) && !(js->had_newline \|\| is_asi_ok_tok(js->tok))) {
	res = js_mkerr_typed(js, JS_ERR_SYNTAX, "; expected"); break;
	}
	if (js->flags & (F_RETURN \| F_THROW)) break;
	}

	if (js->tok == TOK_RBRACE) js->consumed = 1;
	if (scope_created) delscope(js);

	return res;
	}

	static inline jsoff_t lkp_interned(struct js js, jsval_t obj, const char search_intern, size_t len) {
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	jsoff_t tail = loadoff(js, obj_off + sizeof(jsoff_t) * 2);

	uint32_t slot = (((uintptr_t)search_intern >> 3) ^ obj_off) & (ANT_LIMIT_SIZE_CACHE - 1);
	intern_prop_cache_entry_t *ce = &intern_prop_cache[slot];
	if (ce->obj_off == obj_off && ce->intern_ptr == search_intern && ce->tail == tail) return ce->prop_off;

	jsoff_t off = first_prop;
	jsoff_t result = 0;

	while (off < js->brk && off != 0) {
	jsoff_t header = loadoff(js, off);
	if (is_slot_prop(header)) { off = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, off + sizeof(jsoff_t));
	jsoff_t klen = (loadoff(js, koff) >> 3) - 1;

	if (klen == len) {
	const char p = (char )&js->mem[koff + sizeof(jsoff_t)];
	if (intern_string(p, klen) == search_intern) { result = off; break; }
	}
	off = next_prop(header);
	}

	ce->obj_off = obj_off;
	ce->intern_ptr = search_intern;
	ce->prop_off = result;
	ce->tail = tail;

	return result;
	}

	static inline jsoff_t lkp(struct js js, jsval_t obj, const char buf, size_t len) {
	const char *search_intern = intern_string(buf, len);
	if (!search_intern) return 0;
	return lkp_interned(js, obj, search_intern, len);
	}

	static jsval_t resolve_bound_args(struct js js, jsval_t func_obj, jsval_t args, int nargs, int out_nargs) {
	*out_nargs = nargs;

	jsval_t bound_arr = get_slot(js, func_obj, SLOT_BOUND_ARGS);
	int bound_argc = 0;

	if (vtype(bound_arr) == T_ARR) {
	jsoff_t len_off = lkp_interned(js, bound_arr, INTERN_LENGTH, 6);
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) bound_argc = (int) tod(len_val);
	}
	}

	if (bound_argc <= 0) return NULL;

	*out_nargs = bound_argc + nargs;
	jsval_t combined = (jsval_t )ant_calloc(sizeof(jsval_t) * (*out_nargs));
	if (!combined) return NULL;

	for (int i = 0; i < bound_argc; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	jsoff_t prop_off = lkp(js, bound_arr, idx, strlen(idx));
	combined[i] = (prop_off != 0) ? resolveprop(js, mkval(T_PROP, prop_off)) : js_mkundef();
	}
	for (int i = 0; i < nargs; i++) combined[bound_argc + i] = args[i];

	return combined;
	}

	static jsoff_t lkp_scope(struct js js, jsval_t scope, const char buf, size_t len) {
	const char *search_intern = intern_string(buf, len);
	if (!search_intern) return 0;

	jsoff_t scope_off = (jsoff_t)vdata(scope);
	jsoff_t off = loadoff(js, scope_off) & ~(3U \| FLAGMASK);

	while (off < js->brk && off != 0) {
	jsoff_t header = loadoff(js, off);
	if (is_slot_prop(header)) { off = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, (jsoff_t)(off + sizeof(off)));
	jsoff_t klen = (loadoff(js, koff) >> 3) - 1;
	if (klen == len) {
	const char p = (char )&js->mem[koff + sizeof(koff)];
	if (intern_string(p, klen) == search_intern) return off;
	}
	off = next_prop(header);
	}
	return 0;
	}

	static jsoff_t lkp_with_getter(struct js js, jsval_t obj, const char buf, size_t len, jsval_t getter_out, bool has_getter_out) {
	*has_getter_out = false;
	*getter_out = js_mkundef();

	jsval_t current = obj;
	while (vtype(current) == T_OBJ \|\| vtype(current) == T_FUNC) {
	jsoff_t current_off = (jsoff_t)vdata(current);
	descriptor_entry_t *desc = lookup_descriptor(current_off, buf, len);

	if (desc && desc->has_getter) {
	*getter_out = desc->getter;
	*has_getter_out = true;
	return current_off;
	}

	jsoff_t prop_off = lkp_interned(js, current, intern_string(buf, len), len);
	if (prop_off != 0) return prop_off;

	jsval_t proto = get_proto(js, current);
	if (vtype(proto) != T_OBJ && vtype(proto) != T_FUNC) break;
	current = proto;
	}

	return 0;
	}

	static jsoff_t lkp_with_setter(struct js js, jsval_t obj, const char buf, size_t len, jsval_t setter_out, bool has_setter_out) {
	*has_setter_out = false;
	*setter_out = js_mkundef();

	jsval_t current = obj;
	while (vtype(current) == T_OBJ \|\| vtype(current) == T_FUNC) {
	jsoff_t current_off = (jsoff_t)vdata(current);
	descriptor_entry_t *desc = lookup_descriptor(current_off, buf, len);

	if (desc && desc->has_setter) {
	*setter_out = desc->setter;
	*has_setter_out = true;
	return current_off;
	}

	jsoff_t prop_off = lkp_interned(js, current, intern_string(buf, len), len);
	if (prop_off != 0) return prop_off;

	jsval_t proto = get_proto(js, current);
	if (vtype(proto) != T_OBJ && vtype(proto) != T_FUNC) break;
	current = proto;
	}

	return 0;
	}

	static jsval_t call_proto_accessor(struct js js, jsval_t prim, jsval_t accessor, bool has_accessor, jsval_t arg, int arg_count, bool is_setter) {
	if (!has_accessor \|\| (vtype(accessor) != T_FUNC && vtype(accessor) != T_CFUNC)) return js_mkundef();

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	uint8_t saved_flags = js->flags;
	jsoff_t saved_toff = js->toff;
	jsoff_t saved_tlen = js->tlen;

	jsval_t saved_this = js->this_val;
	js->this_val = prim;
	push_this(prim);
	jsval_t result = call_js_with_args(js, accessor, arg, arg_count);
	pop_this();
	js->this_val = saved_this;

	JS_RESTORE_STATE(js, saved);
	js->flags = saved_flags;
	js->toff = saved_toff;
	js->tlen = saved_tlen;

	if (is_setter) return is_err(result) ? result : (arg ? *arg : js_mkundef());
	return result;
	}

	jsval_t js_get_proto(struct js *js, jsval_t obj) {
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC && t != T_PROMISE) return js_mknull();
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	jsval_t proto = get_slot(js, as_obj, SLOT_PROTO);
	uint8_t pt = vtype(proto);
	if (pt == T_OBJ \|\| pt == T_ARR \|\| pt == T_FUNC) return proto;

	if (t == T_FUNC \|\| t == T_ARR \|\| t == T_PROMISE) return get_prototype_for_type(js, t);
	return js_mknull();
	}

	static jsval_t get_proto(struct js *js, jsval_t obj) {
	return js_get_proto(js, obj);
	}

	void js_set_proto(struct js *js, jsval_t obj, jsval_t proto) {
	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return;

	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));
	set_slot(js, as_obj, SLOT_PROTO, proto);
	}

	static void set_proto(struct js *js, jsval_t obj, jsval_t proto) {
	js_set_proto(js, obj, proto);
	}

	jsval_t js_get_ctor_proto(struct js js, const char name, size_t len) {
	jsoff_t ctor_off = lkp_scope(js, js->scope, name, len);

	if (ctor_off == 0 && global_scope_stack) {
	unsigned int stack_len = utarray_len(global_scope_stack);
	for (int i = (int)stack_len - 1; i >= 0 && ctor_off == 0; i--) {
	jsoff_t scope_off = (jsoff_t )utarray_eltptr(global_scope_stack, (unsigned int)i);
	jsval_t scope = mkval(T_OBJ, *scope_off);
	ctor_off = lkp_scope(js, scope, name, len);
	}
	} else if (ctor_off == 0) {
	for (jsval_t scope = upper(js, js->scope); vdata(scope) != 0 && ctor_off == 0; scope = upper(js, scope)) {
	ctor_off = lkp_scope(js, scope, name, len);
	}
	}

	if (ctor_off == 0) return js_mknull();
	jsval_t ctor = resolveprop(js, mkval(T_PROP, ctor_off));
	if (vtype(ctor) != T_FUNC) return js_mknull();
	jsval_t ctor_obj = mkval(T_OBJ, vdata(ctor));
	jsoff_t proto_off = lkp_interned(js, ctor_obj, INTERN_PROTOTYPE, 9);

	if (proto_off == 0) return js_mknull();
	return resolveprop(js, mkval(T_PROP, proto_off));
	}

	static inline jsval_t get_ctor_proto(struct js js, const char name, size_t len) {
	return js_get_ctor_proto(js, name, len);
	}

	static jsval_t get_prototype_for_type(struct js *js, uint8_t type) {
	switch (type) {
	case T_STR: return get_ctor_proto(js, "String", 6);
	case T_NUM: return get_ctor_proto(js, "Number", 6);
	case T_BOOL: return get_ctor_proto(js, "Boolean", 7);
	case T_ARR: return get_ctor_proto(js, "Array", 5);
	case T_FUNC: return get_ctor_proto(js, "Function", 8);
	case T_PROMISE: return get_ctor_proto(js, "Promise", 7);
	case T_OBJ: return get_ctor_proto(js, "Object", 6);
	case T_BIGINT: return get_ctor_proto(js, "BigInt", 6);
	default: return js_mknull();
	}
	}

	static jsoff_t lkp_proto(struct js js, jsval_t obj, const char key, size_t len) {
	uint8_t t = vtype(obj);
	const char *key_intern = intern_string(key, len);

	if (!key_intern) return 0;
	if (len == STR_PROTO_LEN && memcmp(key, STR_PROTO, STR_PROTO_LEN) == 0) return 0;

	jsval_t cur = obj;
	int depth = 0;

	while (depth < 32) {
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC \|\| t == T_PROMISE) {
	jsval_t as_obj = mkval(T_OBJ, vdata(cur));
	jsoff_t off = lkp_interned(js, as_obj, key_intern, len);
	if (off != 0) return off;

	jsval_t proto = get_slot(js, as_obj, SLOT_PROTO);
	uint8_t pt = vtype(proto);
	if (pt == T_NULL) break;
	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC) {
	if (TYPE_FLAG(t) & T_NEEDS_PROTO_FALLBACK) {
	cur = get_prototype_for_type(js, t);
	t = vtype(cur);
	if (t == T_NULL \|\| t == T_UNDEF) break;
	depth++; continue;
	}
	break;
	}
	cur = proto;
	t = vtype(cur);
	if (t == T_NULL \|\| t == T_UNDEF) break;
	depth++;
	} else if (t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_BIGINT) {
	cur = get_prototype_for_type(js, t);
	t = vtype(cur);
	if (t == T_NULL \|\| t == T_UNDEF) break;
	depth++;
	} else if (t == T_CFUNC) {
	jsval_t func_proto = get_ctor_proto(js, "Function", 8);
	uint8_t ft = vtype(func_proto);
	if (ft == T_OBJ \|\| ft == T_ARR \|\| ft == T_FUNC) {
	jsoff_t off = lkp(js, mkval(T_OBJ, vdata(func_proto)), key, len);
	if (off != 0) return off;
	}
	break;
	} else {
	break;
	}
	}

	return 0;
	}

	static jsval_t try_dynamic_getter(struct js js, jsval_t obj, const char key, size_t key_len) {
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry \|\| !entry->getter) return js_mkundef();
	return entry->getter(js, obj, key, key_len);
	}

	static bool try_dynamic_setter(struct js js, jsval_t obj, const char key, size_t key_len, jsval_t value) {
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry \|\| !entry->setter) return false;
	return entry->setter(js, obj, key, key_len, value);
	}

	static jsval_t lookup(struct js js, const char buf, size_t len) {
	if (js->flags & F_NOEXEC) return 0;

	char decoded[256];
	const char *key_str = buf;
	size_t key_len = len;

	if (has_unicode_escape(buf, len)) {
	key_len = decode_ident_escapes(buf, len, decoded, sizeof(decoded));
	key_str = decoded;
	}

	if (key_len == STR_PROTO_LEN && memcmp(key_str, STR_PROTO, STR_PROTO_LEN) == 0) {
	jsval_t proto = get_slot(js, js->scope, SLOT_PROTO);
	if (vtype(proto) != T_UNDEF) return proto;
	return get_prototype_for_type(js, vtype(js->scope));
	}

	const char *key_intern = intern_string(key_str, key_len);

	jsval_t parent_scope = upper(js, js->scope);

	jsoff_t off = lkp_interned(js, js->scope, key_intern, key_len);
	if (off != 0) {
	return mkval(T_PROP, off);
	}

	jsval_t with_slot = get_slot(js, js->scope, SLOT_WITH);
	if (vtype(with_slot) != T_UNDEF) {
	jsval_t with_obj = (
	vtype(with_slot) == T_OBJ \|\|
	vtype(with_slot) == T_ARR \|\|
	vtype(with_slot) == T_FUNC) ?
	with_slot : mkval(T_OBJ, vdata(with_slot)
	);

	jsoff_t prop_off = lkp_interned(js, with_obj, key_intern, key_len);
	if (prop_off != 0) {
	jsval_t key = js_mkstr(js, key_str, key_len);
	if (is_err(key)) return key;
	return mkpropref((jsoff_t)vdata(with_obj), (jsoff_t)vdata(key));
	}
	}

	uint8_t depth = 1;
	for (jsval_t scope = parent_scope; depth < 255; depth++) {
	off = lkp_interned(js, scope, key_intern, key_len);
	if (off != 0) {
	return mkval(T_PROP, off);
	}

	jsval_t scope_with_slot = get_slot(js, scope, SLOT_WITH);
	if (vtype(scope_with_slot) != T_UNDEF) {
	jsval_t with_obj = (
	vtype(scope_with_slot) == T_OBJ \|\|
	vtype(scope_with_slot) == T_ARR \|\|
	vtype(scope_with_slot) == T_FUNC) ?
	scope_with_slot : mkval(T_OBJ, vdata(scope_with_slot)
	);

	jsoff_t prop_off = lkp_interned(js, with_obj, key_intern, key_len);
	if (prop_off != 0) {
	jsval_t key = js_mkstr(js, key_str, key_len);
	if (is_err(key)) return key;
	return mkpropref((jsoff_t)vdata(with_obj), (jsoff_t)vdata(key));
	}
	}

	if (vdata(scope) == 0) break;
	scope = upper(js, scope);
	}

	if (global_scope_stack && utarray_len(global_scope_stack) > 0) {
	jsoff_t root_off = (jsoff_t )utarray_eltptr(global_scope_stack, 0);
	if (root_off && *root_off != 0) {
	jsval_t root_scope = mkval(T_OBJ, *root_off);
	jsoff_t root_lkp_off = lkp(js, root_scope, key_str, key_len);
	if (root_lkp_off != 0) return mkval(T_PROP, root_lkp_off);
	}
	}

	return js_mkerr_typed(js, JS_ERR_REFERENCE, "'%.*s' is not defined", (int) key_len, key_str);
	}

	static bool try_accessor_getter(struct js js, jsval_t obj, const char key, size_t key_len, jsval_t *out) {
	jsval_t getter = js_mkundef();
	bool has_getter = false;
	lkp_with_getter(js, obj, key, key_len, &getter, &has_getter);

	jsval_t result = call_proto_accessor(js, obj, getter, has_getter, NULL, 0, false);
	if (vtype(result) != T_UNDEF) {
	*out = result;
	return true;
	}
	return false;
	}

	static jsval_t resolveprop(struct js *js, jsval_t v) {
	if (vtype(v) == T_PROPREF) {
	if (is_prim_propref(v)) {
	prim_propref_data_t *prim_data = prim_propref_get(v);
	if (!prim_data) return js_mkundef();

	jsval_t prim = prim_data->prim_val;
	jsval_t key = mkval(T_STR, prim_data->key_off);
	jsoff_t key_len;
	const char key_str = (const char )&js->mem[vstr(js, key, &key_len)];

	jsval_t proto = get_prototype_for_type(js, vtype(prim));
	if (vtype(proto) == T_OBJ) {
	jsval_t getter = js_mkundef();
	bool has_getter = false;
	lkp_with_getter(js, proto, key_str, key_len, &getter, &has_getter);
	jsval_t result = call_proto_accessor(js, prim, getter, has_getter, NULL, 0, false);
	if (vtype(result) != T_UNDEF) return result;

	jsoff_t off = lkp_proto(js, prim, key_str, key_len);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	}

	return js_mkundef();
	}

	jsoff_t obj_off = propref_obj(v);
	jsoff_t key_off = propref_key(v);
	jsval_t key = mkval(T_STR, key_off);
	jsoff_t len;
	const char key_str = (const char )&js->mem[vstr(js, key, &len)];

	if (is_arr_off(js, obj_off) && streq(key_str, len, "length", 6)) {
	jsval_t arr = mkval(T_ARR, obj_off);
	return tov(D(arr_length(js, arr)));
	}

	jsval_t obj = mkval(T_OBJ, obj_off);
	if (is_proxy(js, obj)) return proxy_get(js, obj, key_str, len);

	if (len == STR_PROTO_LEN && memcmp(key_str, STR_PROTO, STR_PROTO_LEN) == 0) {
	jsval_t proto = get_slot(js, obj, SLOT_PROTO);
	if (vtype(proto) != T_UNDEF) return proto;
	return get_prototype_for_type(js, vtype(obj));
	}

	jsoff_t prop_off = lkp(js, obj, key_str, len);
	if (prop_off != 0) return resolveprop(js, mkval(T_PROP, prop_off));

	jsoff_t proto_off = lkp_proto(js, obj, key_str, len);
	if (proto_off != 0) return resolveprop(js, mkval(T_PROP, proto_off));

	jsval_t accessor_result;
	if (try_accessor_getter(js, obj, key_str, len, &accessor_result)) {
	return accessor_result;
	}

	jsval_t dyn_result = try_dynamic_getter(js, obj, key_str, len);
	if (vtype(dyn_result) != T_UNDEF) return dyn_result;

	return js_mkundef();
	}
	if (vtype(v) != T_PROP) return v;
	return resolveprop(js, loadval(js, (jsoff_t) (vdata(v) + sizeof(jsoff_t) * 2)));
	}

	static bool try_accessor_setter(struct js js, jsval_t obj, const char key, size_t key_len, jsval_t val, jsval_t *out) {
	jsval_t setter = js_mkundef();
	bool has_setter = false;

	lkp_with_setter(js, obj, key, key_len, &setter, &has_setter);
	if (!has_setter) return false;

	jsval_t result = call_proto_accessor(js, obj, setter, has_setter, &val, 1, true);
	if (is_err(result)) {
	*out = result;
	return true;
	}

	*out = val;
	return true;
	}

	static jsval_t assign(struct js *js, jsval_t lhs, jsval_t val) {
	if (js->flags & F_NOEXEC) return val;
	if (vtype(lhs) == T_PROPREF) {
	if (is_prim_propref(lhs)) {
	prim_propref_data_t *prim_data = prim_propref_get(lhs);
	if (!prim_data) {
	if (js->flags & F_STRICT) return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot create property on primitive value");
	return val;
	}

	jsval_t prim = prim_data->prim_val;
	jsval_t key = mkval(T_STR, prim_data->key_off);
	jsoff_t key_len;
	const char key_str = (const char )&js->mem[vstr(js, key, &key_len)];

	jsval_t proto = get_prototype_for_type(js, vtype(prim));
	if (vtype(proto) == T_OBJ) {
	jsval_t setter = js_mkundef();
	bool has_setter = false;
	lkp_with_setter(js, proto, key_str, key_len, &setter, &has_setter);
	jsval_t result = call_proto_accessor(js, prim, setter, has_setter, &val, 1, true);
	if (vtype(result) != T_UNDEF) return result;
	}

	if (js->flags & F_STRICT) {
	return js_mkerr_typed(
	js, JS_ERR_TYPE, "Cannot create property '%.*s' on %s",
	(int)key_len, key_str, typestr(vtype(prim))
	);
	}
	return val;
	}

	jsoff_t obj_off = propref_obj(lhs);
	jsoff_t key_off = propref_key(lhs);
	jsval_t obj = mkval(is_arr_off(js, obj_off) ? T_ARR : T_OBJ, obj_off);
	jsval_t key = mkval(T_STR, key_off);

	jsoff_t key_len;
	const char key_str = (const char )&js->mem[vstr(js, key, &key_len)];

	jsval_t setter_result;
	if (try_accessor_setter(js, obj, key_str, key_len, val, &setter_result)) {
	return setter_result;
	}

	return setprop(js, obj, key, val);
	}

	if (vtype(lhs) != T_PROP) {
	if (js->flags & F_STRICT) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "Invalid left-hand side in assignment");
	}
	return val;
	}

	jsoff_t propoff = (jsoff_t) vdata(lhs);

	jsoff_t koff = loadoff(js, propoff + sizeof(jsoff_t));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char )&js->mem[koff + sizeof(jsoff_t)];

	if (is_const_prop(js, propoff)) {
	if (js->flags & F_STRICT) return js_mkerr(js, "assignment to constant");
	return mkval(T_PROP, propoff);
	}

	if ((klen == 9 && memcmp(key, "undefined", 9) == 0) \|\|
	(klen == 3 && memcmp(key, "NaN", 3) == 0) \|\|
	(klen == 8 && memcmp(key, "Infinity", 8) == 0)) {
	if (js->flags & F_STRICT) return js_mkerr(js, "Cannot assign to read only property");
	return lhs;
	}

	saveval(js, (jsoff_t) ((vdata(lhs) & ~3ULL) + sizeof(jsoff_t) * 2), val);
	return lhs;
	}

	static jsval_t do_assign_op(struct js *js, uint8_t op, jsval_t l, jsval_t r) {
	uint8_t m[] = {
	TOK_PLUS, TOK_MINUS, TOK_MUL, TOK_DIV, TOK_REM, TOK_SHL,
	TOK_SHR, TOK_ZSHR, TOK_AND, TOK_XOR, TOK_OR
	};

	jsval_t res = do_op(js, m[op - TOK_PLUS_ASSIGN], resolveprop(js, l), r);
	return assign(js, l, res);
	}

	typedef struct {
	char *buffer;
	size_t capacity;
	size_t size;
	bool is_dynamic;
	} string_builder_t;

	static void string_builder_init(string_builder_t sb, char static_buf, size_t static_cap) {
	sb->buffer = static_buf;
	sb->capacity = static_cap;
	sb->size = 0;
	sb->is_dynamic = false;
	}

	static bool string_builder_append(string_builder_t sb, const char data, size_t len) {
	if (sb->size + len > sb->capacity) {
	size_t new_capacity = sb->capacity ? sb->capacity * 2 : 256;
	while (new_capacity < sb->size + len) new_capacity *= 2;

	char new_buffer = (char )ant_calloc(new_capacity);
	if (!new_buffer) return false;

	if (sb->size > 0) memcpy(new_buffer, sb->buffer, sb->size);
	if (sb->is_dynamic) free(sb->buffer);

	sb->buffer = new_buffer;
	sb->capacity = new_capacity;
	sb->is_dynamic = true;
	}

	if (len > 0) {
	memcpy(sb->buffer + sb->size, data, len);
	sb->size += len;
	}

	return true;
	}

	static jsval_t string_builder_finalize(struct js js, string_builder_t sb) {
	jsval_t result = js_mkstr(js, sb->buffer, sb->size);
	if (sb->is_dynamic && sb->buffer) free(sb->buffer);
	return result;
	}

	static jsval_t do_string_op(struct js *js, uint8_t op, jsval_t l, jsval_t r) {
	jsoff_t n1, off1 = vstr(js, l, &n1);
	jsoff_t n2, off2 = vstr(js, r, &n2);

	if (op == TOK_PLUS) {
	string_builder_t sb;
	char static_buffer[512];
	string_builder_init(&sb, static_buffer, sizeof(static_buffer));

	if (!string_builder_append(&sb, (char *)&js->mem[off1], n1) \|\|
	!string_builder_append(&sb, (char *)&js->mem[off2], n2)) {
	return js_mkerr(js, "string concatenation failed");
	}

	return string_builder_finalize(js, &sb);
	} else if (op == TOK_EQ) {
	bool eq = n1 == n2 && memcmp(&js->mem[off1], &js->mem[off2], n1) == 0;
	return mkval(T_BOOL, eq ? 1 : 0);
	} else if (op == TOK_NE) {
	bool eq = n1 == n2 && memcmp(&js->mem[off1], &js->mem[off2], n1) == 0;
	return mkval(T_BOOL, eq ? 0 : 1);
	} else if (op == TOK_LT \|\| op == TOK_LE \|\| op == TOK_GT \|\| op == TOK_GE) {
	jsoff_t min_len = n1 < n2 ? n1 : n2;
	int cmp = memcmp(&js->mem[off1], &js->mem[off2], min_len);

	if (cmp == 0) {
	if (n1 == n2) {
	return mkval(T_BOOL, (op == TOK_LE \|\| op == TOK_GE) ? 1 : 0);
	} else {
	cmp = (n1 < n2) ? -1 : 1;
	}
	}

	switch (op) {
	case TOK_LT: return mkval(T_BOOL, cmp < 0 ? 1 : 0);
	case TOK_LE: return mkval(T_BOOL, cmp <= 0 ? 1 : 0);
	case TOK_GT: return mkval(T_BOOL, cmp > 0 ? 1 : 0);
	case TOK_GE: return mkval(T_BOOL, cmp >= 0 ? 1 : 0);
	default: return js_mkerr(js, "bad str op");
	}
	} else {
	return js_mkerr(js, "bad str op");
	}
	}

	static jsval_t do_bracket_op(struct js *js, jsval_t l, jsval_t r) {
	jsval_t obj = resolveprop(js, l);
	jsval_t key_val = resolveprop(js, r);
	char keybuf[64];
	const char *keystr;
	size_t keylen;
	if (vtype(key_val) == T_NUM) {
	double dv = tod(key_val);
	if (dv >= 0 && dv <= 0xFFFFFFFF && dv == (double)(uint32_t)dv) {
	keylen = uint_to_str(keybuf, sizeof(keybuf), (uint32_t)dv);
	} else {
	keylen = strnum(key_val, keybuf, sizeof(keybuf));
	}
	keystr = keybuf;
	} else if (vtype(key_val) == T_STR) {
	jsoff_t slen;
	jsoff_t off = vstr(js, key_val, &slen);
	keystr = (char *) &js->mem[off];
	keylen = slen;
	} else if (vtype(key_val) == T_SYMBOL) {
	snprintf(keybuf, sizeof(keybuf), "__sym_%llu__", (unsigned long long)sym_get_id(key_val));
	keystr = keybuf;
	keylen = strlen(keybuf);
	} else {
	jsval_t str_val = js_tostring_val(js, key_val);
	if (is_err(str_val)) return str_val;
	jsoff_t slen;
	jsoff_t off = vstr(js, str_val, &slen);
	keystr = (char *) &js->mem[off];
	keylen = slen;
	}
	if (streq(keystr, keylen, "length", 6)) {
	if (vtype(obj) == T_STR) {
	return tov(D(offtolen(loadoff(js, (jsoff_t) vdata(obj)))));
	}
	if (vtype(obj) == T_ARR) {
	jsoff_t len_off = lkp(js, obj, "length", 6);
	if (len_off != 0) {
	return mkval(T_PROP, len_off);
	}
	jsval_t key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov(D(arr_length(js, obj)));
	jsval_t prop = setprop(js, obj, key, len_val);
	return prop;
	}
	}
	if (vtype(obj) == T_STR) {
	double idx_d = JS_NAN;
	if (vtype(key_val) == T_NUM) {
	idx_d = tod(key_val);
	} else {
	char *endptr;
	char temp[64];
	size_t copy_len = keylen < sizeof(temp) - 1 ? keylen : sizeof(temp) - 1;
	memcpy(temp, keystr, copy_len);
	temp[copy_len] = '\0';
	idx_d = strtod(temp, &endptr);
	if (endptr == temp \|\| *endptr != '\0') idx_d = JS_NAN;
	}
	if (!isnan(idx_d) && idx_d >= 0 && idx_d == (double)(long)idx_d) {
	jsoff_t idx = (jsoff_t) idx_d;
	jsoff_t str_len = offtolen(loadoff(js, (jsoff_t) vdata(obj)));
	if (idx < str_len) {
	jsoff_t str_off = (jsoff_t) vdata(obj) + sizeof(jsoff_t);
	char ch[2] = {js->mem[str_off + idx], 0};
	return js_mkstr(js, ch, 1);
	}
	}
	jsoff_t off = lkp_proto(js, obj, keystr, keylen);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	return js_mkundef();
	}
	if (vtype(obj) == T_FUNC) {
	if ((js->flags & F_STRICT) && (streq(keystr, keylen, "caller", 6) \|\| streq(keystr, keylen, "arguments", 9))) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "'%.*s' not allowed on functions in strict mode", (int)keylen, keystr);
	}
	jsval_t func_obj = mkval(T_OBJ, vdata(obj));
	jsoff_t off = lkp_proto(js, obj, keystr, keylen);
	if (off != 0) {
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, keystr, keylen);
	if (desc) {
	jsval_t key = js_mkstr(js, keystr, keylen);
	return mkpropref(obj_off, (jsoff_t)vdata(key));
	}
	return mkval(T_PROP, off);
	}
	if (streq(keystr, keylen, "name", 4)) return js_mkstr(js, "", 0);
	jsval_t key = js_mkstr(js, keystr, keylen);
	jsval_t prop = setprop(js, func_obj, key, js_mkundef());
	return prop;
	}
	if (vtype(obj) == T_CFUNC) {
	if ((js->flags & F_STRICT) && (streq(keystr, keylen, "caller", 6) \|\| streq(keystr, keylen, "arguments", 9))) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "'%.*s' not allowed on functions in strict mode", (int)keylen, keystr);
	}
	jsoff_t off = lkp_proto(js, obj, keystr, keylen);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	if (streq(keystr, keylen, "name", 4)) return js_mkstr(js, "", 0);
	return js_mkundef();
	}
	if (vtype(obj) == T_NUM \|\| vtype(obj) == T_BOOL \|\| vtype(obj) == T_BIGINT) {
	jsval_t key = js_mkstr(js, keystr, keylen);
	return mkprim_propref(obj, (jsoff_t)vdata(key));
	}
	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR) {
	return js_mkundef();
	}
	if ((streq(keystr, keylen, "callee", 6) \|\| streq(keystr, keylen, "caller", 6)) &&
	vtype(get_slot(js, obj, SLOT_STRICT_ARGS)) != T_UNDEF) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "'%.*s' not allowed on strict arguments", (int)keylen, keystr);
	}

	jsval_t getter = js_mkundef();
	bool has_getter = false;
	jsoff_t prop_off = lkp_with_getter(js, obj, keystr, keylen, &getter, &has_getter);

	jsval_t setter = js_mkundef();
	bool has_setter = false;
	if (!has_getter) {
	lkp_with_setter(js, obj, keystr, keylen, &setter, &has_setter);
	}

	if (has_getter \|\| has_setter) {
	jsval_t key = js_mkstr(js, keystr, keylen);
	return mkpropref((jsoff_t)vdata(obj), (jsoff_t)vdata(key));
	}

	if (prop_off != 0) {
	return mkval(T_PROP, prop_off);
	}

	jsval_t dyn_result = try_dynamic_getter(js, obj, keystr, keylen);
	if (vtype(dyn_result) != T_UNDEF) {
	jsval_t key = js_mkstr(js, keystr, keylen);
	return mkpropref((jsoff_t)vdata(obj), (jsoff_t)vdata(key));
	}

	jsoff_t off = lkp_proto(js, obj, keystr, keylen);
	if (off == 0) {
	jsval_t key = js_mkstr(js, keystr, keylen);
	return mkpropref((jsoff_t)vdata(obj), (jsoff_t)vdata(key));
	}
	return mkval(T_PROP, off);
	}

	static jsval_t do_dot_op(struct js *js, jsval_t l, jsval_t r) {
	const char raw_ptr = (char ) &js->code[coderefoff(r)];
	size_t raw_len = codereflen(r);

	char decoded_buf[256];
	size_t plen = decode_ident_escapes(raw_ptr, raw_len, decoded_buf, sizeof(decoded_buf));
	const char *ptr = decoded_buf;

	if (vtype(r) != T_CODEREF) return js_mkerr_typed(js, JS_ERR_SYNTAX, "ident expected");
	uint8_t t = vtype(l);

	if (t == T_STR && streq(ptr, plen, "length", 6)) {
	return tov(D(offtolen(loadoff(js, (jsoff_t) vdata(l)))));
	}

	if (t == T_ARR && streq(ptr, plen, "length", 6)) {
	jsval_t key = js_mkstr(js, "length", 6);
	return mkpropref((jsoff_t)vdata(l), (jsoff_t)vdata(key));
	}

	if (t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_BIGINT) {
	jsval_t key = js_mkstr(js, ptr, plen);
	return mkprim_propref(l, (jsoff_t)vdata(key));
	}

	if (t == T_PROMISE) {
	jsoff_t off = lkp_proto(js, mkval(T_OBJ, vdata(l)), ptr, plen);
	if (off != 0) {
	return resolveprop(js, mkval(T_PROP, off));
	}
	jsval_t promise_proto = get_ctor_proto(js, "Promise", 7);
	if (vtype(promise_proto) != T_UNDEF && vtype(promise_proto) != T_NULL) {
	off = lkp_proto(js, promise_proto, ptr, plen);
	if (off != 0) {
	return resolveprop(js, mkval(T_PROP, off));
	}
	}
	return js_mkundef();
	}

	if (t == T_FUNC) {
	if ((js->flags & F_STRICT) && (streq(ptr, plen, "caller", 6) \|\| streq(ptr, plen, "arguments", 9))) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "'%.*s' not allowed on functions in strict mode", (int)plen, ptr);
	}
	if (plen == STR_PROTO_LEN && memcmp(ptr, STR_PROTO, STR_PROTO_LEN) == 0) {
	jsval_t proto = get_slot(js, mkval(T_OBJ, vdata(l)), SLOT_PROTO);
	if (vtype(proto) != T_UNDEF) return proto;
	return get_prototype_for_type(js, T_FUNC);
	}
	jsval_t func_obj = mkval(T_OBJ, vdata(l));
	jsoff_t off = lkp_proto(js, l, ptr, plen);
	if (off != 0) {
	jsoff_t obj_off = (jsoff_t)vdata(l);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, ptr, plen);
	if (desc) {
	jsval_t key = js_mkstr(js, ptr, plen);
	return mkpropref(obj_off, (jsoff_t)vdata(key));
	}
	return mkval(T_PROP, off);
	}
	if (streq(ptr, plen, "name", 4)) return js_mkstr(js, "", 0);
	jsval_t key = js_mkstr(js, ptr, plen);
	jsval_t prop = setprop(js, func_obj, key, js_mkundef());
	return prop;
	}

	if (t == T_CFUNC) {
	if ((js->flags & F_STRICT) && (streq(ptr, plen, "caller", 6) \|\| streq(ptr, plen, "arguments", 9))) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "'%.*s' not allowed on functions in strict mode", (int)plen, ptr);
	}
	jsoff_t off = lkp_proto(js, l, ptr, plen);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	if (streq(ptr, plen, "name", 4)) return js_mkstr(js, "", 0);
	return js_mkundef();
	}

	if (t == T_SYMBOL) {
	if (streq(ptr, plen, "description", 11)) {
	const char *desc = sym_get_desc(js, l);
	if (desc) return js_mkstr(js, desc, strlen(desc));
	return js_mkundef();
	}
	return js_mkundef();
	}

	if (t != T_OBJ && t != T_ARR) {
	jsoff_t saved_toff = js->toff;
	jsoff_t saved_tlen = js->tlen;

	js->toff = coderefoff(r);
	js->tlen = codereflen(r);

	jsval_t err = js_mkerr(
	js, "Cannot read properties of %s (reading '%.*s')",
	t == T_UNDEF ? "undefined" : t == T_NULL ? "null" : typestr(t),
	(int)plen, ptr
	);

	js->toff = saved_toff;
	js->tlen = saved_tlen;

	return err;
	}

	if ((streq(ptr, plen, "callee", 6) \|\| streq(ptr, plen, "caller", 6)) &&
	vtype(get_slot(js, l, SLOT_STRICT_ARGS)) != T_UNDEF) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "'%.*s' not allowed on strict arguments", (int)plen, ptr);
	}

	if (plen == STR_PROTO_LEN && memcmp(ptr, STR_PROTO, STR_PROTO_LEN) == 0) {
	jsval_t key = js_mkstr(js, ptr, plen);
	return mkpropref((jsoff_t)vdata(l), (jsoff_t)vdata(key));
	}

	jsoff_t own_off = lkp(js, l, ptr, plen);
	if (own_off != 0) {
	jsoff_t obj_off = (jsoff_t)vdata(l);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, ptr, plen);
	if (desc) {
	jsval_t key = js_mkstr(js, ptr, plen);
	return mkpropref((jsoff_t)vdata(l), (jsoff_t)vdata(key));
	}
	return mkval(T_PROP, own_off);
	}

	jsval_t result = try_dynamic_getter(js, l, ptr, plen);
	if (vtype(result) != T_UNDEF) {
	own_off = lkp(js, l, ptr, plen);
	if (own_off != 0) return mkval(T_PROP, own_off);
	}

	jsval_t key = js_mkstr(js, ptr, plen);
	return mkpropref((jsoff_t)vdata(l), (jsoff_t)vdata(key));
	}

	static jsval_t do_optional_chain_op(struct js *js, jsval_t l, jsval_t r) {
	if (vtype(l) == T_NULL \|\| vtype(l) == T_UNDEF) return js_mkundef();
	return do_dot_op(js, l, r);
	}

	static jsval_t js_call_params(struct js *js) {
	jsoff_t pos = js->pos;
	uint8_t flags = js->flags;
	js->flags \|= F_NOEXEC;
	js->consumed = 1;

	while (next(js) != TOK_EOF) {
	if (next(js) == TOK_RPAREN) break;
	if (next(js) == TOK_REST) js->consumed = 1;
	js_expr(js);
	if (next(js) == TOK_RPAREN) break;
	EXPECT(TOK_COMMA, js->flags = flags);
	}

	EXPECT(TOK_RPAREN, js->flags = flags);
	js->flags = flags;
	return mkcoderef(pos, js->pos - pos - js->tlen);
	}

	static void reverse(jsval_t *args, int nargs) {
	for (int i = 0; i < nargs / 2; i++) {
	jsval_t tmp = args[i];
	args[i] = args[nargs - i - 1], args[nargs - i - 1] = tmp;
	}
	}

	static int parse_call_args(struct js js, UT_array args, jsval_t *err_out) {
	while (js->pos < js->clen) {
	if (next(js) == TOK_RPAREN) break;
	bool is_spread = (next(js) == TOK_REST);
	if (is_spread) js->consumed = 1;
	jsval_t arg = resolveprop(js, js_expr(js));
	if (is_err(arg)) { *err_out = arg; return -1; }
	if (is_spread && vtype(arg) == T_ARR) {
	jsoff_t len = arr_length(js, arg);
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t elem = arr_get(js, arg, i);
	utarray_push_back(args, &elem);
	}
	} else utarray_push_back(args, &arg);
	if (next(js) == TOK_COMMA) js->consumed = 1;
	}

	return (int)utarray_len(args);
	}

	static jsval_t call_c(struct js js, jsval_t (fn)(struct js , jsval_t , int)) {
	UT_array *args;
	utarray_new(args, &jsval_icd);
	jsval_t err, res;

	int argc = parse_call_args(js, args, &err);
	if (argc < 0) { utarray_free(args); return err; }

	jsval_t argv = (jsval_t )utarray_front(args);
	jsval_t saved_this = js->this_val;
	js->this_val = peek_this();
	res = fn(js, argv, argc);
	js->this_val = saved_this;

	utarray_free(args);
	return res;
	}

	static jsoff_t extract_default_param_value(const char fn, jsoff_t fnlen, jsoff_t start_pos, jsoff_t out_start, jsoff_t *out_len) {
	jsoff_t after_ident = skiptonext(fn, fnlen, start_pos, NULL);
	if (after_ident >= fnlen \|\| fn[after_ident] != '=') {
	*out_start = 0;
	*out_len = 0;
	return after_ident;
	}

	jsoff_t default_start = skiptonext(fn, fnlen, after_ident + 1, NULL);
	jsoff_t default_len = 0;
	jsoff_t depth = 0;
	bool in_string = false;
	char string_char = 0;

	for (jsoff_t i = default_start; i < fnlen; i++) {
	if (in_string) {
	if (fn[i] == '\\' && i + 1 < fnlen) {
	default_len += 2;
	i++;
	continue;
	}
	if (fn[i] == string_char) {
	in_string = false;
	}
	default_len++;
	} else {
	if (fn[i] == '"' \|\| fn[i] == '\'' \|\| fn[i] == '`') {
	in_string = true;
	string_char = fn[i];
	default_len++;
	} else if (fn[i] == '(' \|\| fn[i] == '[' \|\| fn[i] == '{') {
	depth++;
	default_len++;
	} else if (fn[i] == ')' \|\| fn[i] == ']' \|\| fn[i] == '}') {
	if (depth == 0 && fn[i] == ')') break;
	depth--;
	default_len++;
	} else if (depth == 0 && fn[i] == ',') {
	break;
	} else {
	default_len++;
	}
	}
	}

	*out_start = default_start;
	*out_len = default_len;
	return skiptonext(fn, fnlen, default_start + default_len, NULL);
	}

	static jsoff_t skip_default_expr(const char *p, jsoff_t len, jsoff_t pos) {
	int depth = 0;
	while (pos < len) {
	char c = p[pos];
	if (c == '(' \|\| c == '[' \|\| c == '{') depth++;
	else if (c == ')' \|\| c == ']' \|\| c == '}') { if (depth == 0) break; depth--; }
	else if (c == ',' && depth == 0) break;
	pos++;
	}
	return pos;
	}

	static jsval_t bind_destruct_pattern(struct js js, const char p, jsoff_t len, jsval_t val, jsval_t scope) {
	jsoff_t pos = skiptonext(p, len, 0, NULL);
	if (pos >= len) return js_mkundef();

	bool is_arr = (p[pos] == '[');
	if (!is_arr && p[pos] != '{') return js_mkerr(js, "invalid destructuring pattern");

	pos++;
	int idx = 0;

	while (pos < len) {
	pos = skiptonext(p, len, pos, NULL);
	if (pos >= len) break;
	if ((is_arr && p[pos] == ']') \|\| (!is_arr && p[pos] == '}')) break;
	if (p[pos] == ',') { pos++; idx++; continue; }

	bool is_rest = (pos + 2 < len && p[pos] == '.' && p[pos+1] == '.' && p[pos+2] == '.');
	if (is_rest) { pos += 3; pos = skiptonext(p, len, pos, NULL); }

	jsoff_t name_len = 0;
	if (parseident(&p[pos], len - pos, &name_len) != TOK_IDENTIFIER) break;

	jsoff_t var_pos = pos, var_len = name_len;
	jsoff_t src_pos = pos, src_len = name_len;
	pos += name_len;
	pos = skiptonext(p, len, pos, NULL);

	if (!is_arr && !is_rest && pos < len && p[pos] == ':') {
	pos = skiptonext(p, len, pos + 1, NULL);
	jsoff_t rlen = 0;
	if (parseident(&p[pos], len - pos, &rlen) == TOK_IDENTIFIER) {
	var_pos = pos; var_len = rlen;
	pos += rlen;
	pos = skiptonext(p, len, pos, NULL);
	}
	}

	jsval_t prop_val;
	if (is_rest && is_arr) {
	jsval_t rest = js_mkarr(js);
	if (is_err(rest)) return rest;
	jsoff_t alen = arr_length(js, val);
	for (jsoff_t i = idx; i < alen; i++) js_arr_push(js, rest, arr_get(js, val, i));
	prop_val = rest;
	} else if (is_rest) {
	prop_val = mkobj(js, 0);
	} else if (is_arr) {
	prop_val = arr_get(js, val, idx);
	} else {
	jsoff_t off = lkp(js, val, &p[src_pos], src_len);
	prop_val = off > 0 ? resolveprop(js, mkval(T_PROP, off)) : js_mkundef();
	}

	if (is_rest) goto bind;
	if (pos >= len \|\| p[pos] != '=') goto bind;

	pos++;
	jsoff_t def_start = pos;
	pos = skip_default_expr(p, len, pos);
	if (vtype(prop_val) != T_UNDEF) goto bind;

	prop_val = js_eval_str(js, &p[def_start], pos - def_start);
	if (is_err(prop_val)) return prop_val;
	prop_val = resolveprop(js, prop_val);

	bind:;
	jsval_t vname = js_mkstr(js, &p[var_pos], var_len);
	if (is_err(vname)) return vname;
	jsval_t r = setprop(js, scope, vname, prop_val);
	if (is_err(r)) return r;

	idx++;
	pos = skiptonext(p, len, pos, NULL);
	if (pos < len && p[pos] == ',') pos++;
	}

	return js_mkundef();
	}

	static bool is_strict_function_body(const char *body, size_t len) {
	size_t i = 0;
	while (i < len && (body[i] == ' ' \|\| body[i] == '\t' \|\| body[i] == '\n' \|\| body[i] == '\r')) i++;
	if (i + 12 <= len && (body[i] == '\'' \|\| body[i] == '"')) {
	char q = body[i];
	if (memcmp(&body[i+1], "use strict", 10) == 0 && body[i+11] == q) return true;
	}
	return false;
	}

	static parsed_func_t get_or_parse_func(const char fn, jsoff_t fnlen) {
	uint64_t h = hash_key(fn, fnlen);
	parsed_func_t *cached = NULL;
	HASH_FIND(hh, func_parse_cache, &h, sizeof(h), cached);
	if (cached) return cached;

	parsed_func_t pf = (parsed_func_t )malloc(sizeof(parsed_func_t));
	if (!pf) return NULL;
	memset(pf, 0, sizeof(*pf));
	pf->code_hash = h;
	utarray_new(pf->params, &parsed_param_icd);

	jsoff_t fnpos = 1;

	while (fnpos < fnlen) {
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (fnpos < fnlen && fn[fnpos] == ')') break;

	bool is_rest = false;
	if (fnpos + 3 < fnlen && fn[fnpos] == '.' && fn[fnpos + 1] == '.' && fn[fnpos + 2] == '.') {
	is_rest = true;
	pf->has_rest = true;
	fnpos += 3;
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	}

	jsoff_t identlen = 0;

	uint8_t tok = parseident(&fn[fnpos], fnlen - fnpos, &identlen);
	bool is_valid_ident = (tok == TOK_IDENTIFIER \|\| is_contextual_keyword(tok));

	if (!is_valid_ident && (fn[fnpos] == '{' \|\| fn[fnpos] == '[')) {
	char bracket_open = fn[fnpos];
	char bracket_close = (bracket_open == '{') ? '}' : ']';

	jsoff_t pattern_start = fnpos;
	int depth = 1; fnpos++;

	while (fnpos < fnlen && depth > 0) {
	if (fn[fnpos] == bracket_open) depth++;
	else if (fn[fnpos] == bracket_close) depth--;
	fnpos++;
	}
	jsoff_t pattern_len = fnpos - pattern_start;

	{
	parsed_param_t pp = {0};
	pp.is_destruct = true;
	pp.pattern_off = pattern_start;
	pp.pattern_len = pattern_len;

	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (fnpos < fnlen && fn[fnpos] == '=') {
	fnpos = extract_default_param_value(fn, fnlen, fnpos, &pp.default_start, &pp.default_len);
	}
	utarray_push_back(pf->params, &pp);
	pf->param_count++;
	}

	if (fnpos < fnlen && fn[fnpos] == ',') fnpos++;
	continue;
	}

	if (!is_valid_ident) break;

	if (is_rest) {
	pf->rest_param_start = fnpos;
	pf->rest_param_len = identlen;
	fnpos = skiptonext(fn, fnlen, fnpos + identlen, NULL);
	break;
	}

	{
	parsed_param_t pp = {0};
	pp.name_off = fnpos;
	pp.name_len = identlen;
	pp.is_destruct = false;
	fnpos = extract_default_param_value(fn, fnlen, fnpos + identlen, &pp.default_start, &pp.default_len);
	utarray_push_back(pf->params, &pp);
	pf->param_count++;
	}

	if (fnpos < fnlen && fn[fnpos] == ',') fnpos++;
	}

	if (fnpos < fnlen && fn[fnpos] == ')') fnpos++;
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (fnpos < fnlen && fn[fnpos] == '{') fnpos++;

	pf->body_start = fnpos;
	pf->body_len = (fnlen > fnpos + 1) ? (fnlen - fnpos - 1) : 0;
	pf->is_strict = is_strict_function_body(&fn[fnpos], pf->body_len);

	HASH_ADD(hh, func_parse_cache, code_hash, sizeof(pf->code_hash), pf);
	return pf;
	}

	static bool is_eval_or_arguments(struct js *js, jsoff_t toff, jsoff_t tlen) {
	if (tlen == 4 && memcmp(&js->code[toff], "eval", 4) == 0) return true;
	if (tlen == 9 && memcmp(&js->code[toff], "arguments", 9) == 0) return true;
	return false;
	}

	static bool code_uses_arguments(const char *code, jsoff_t len) {
	if (len < 9) return false;
	for (jsoff_t i = 0; i + 8 < len; i++) {
	if (code[i] == 'a' && memcmp(&code[i], INTERN_ARGUMENTS, 9) == 0) {
	if (i > 0 && (is_alpha(code[i-1]) \|\| code[i-1] == '_' \|\| (code[i-1] >= '0' && code[i-1] <= '9'))) continue;
	if (i + 9 < len && (is_alpha(code[i+9]) \|\| code[i+9] == '_' \|\| (code[i+9] >= '0' && code[i+9] <= '9'))) continue;
	return true;
	}
	}
	return false;
	}

	static void setup_arguments(struct js js, jsval_t scope, jsval_t args, int nargs, bool strict) {
	if (vtype(js->current_func) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(js->current_func));
	if (vtype(get_slot(js, func_obj, SLOT_THIS)) != T_UNDEF) return;
	}

	jsval_t arguments_obj = mkobj(js, 0);
	for (int i = 0; i < nargs; i++) {
	if (i < 10) {
	setprop(js, arguments_obj, js_mkstr(js, INTERN_IDX[i], 1), args[i]);
	} else {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	setprop(js, arguments_obj, js_mkstr(js, idxstr, idxlen), args[i]);
	}
	}
	setprop_interned(js, arguments_obj, INTERN_LENGTH, 6, tov((double) nargs));
	if (strict) {
	set_slot(js, arguments_obj, SLOT_STRICT_ARGS, tov(1));
	} else if (vtype(js->current_func) == T_FUNC) {
	setprop_interned(js, arguments_obj, INTERN_CALLEE, 6, js->current_func);
	}

	const char *toStringTag_key = get_toStringTag_sym_key();
	if (toStringTag_key && toStringTag_key[0] != '\0') {
	setprop(js, arguments_obj, js_mkstr(js, toStringTag_key, strlen(toStringTag_key)), js_mkstr(js, "Arguments", 9));
	}

	arguments_obj = mkval(T_ARR, vdata(arguments_obj));
	setprop_interned(js, scope, INTERN_ARGUMENTS, 9, arguments_obj);

	if (!strict && vtype(js->current_func) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(js->current_func));
	setprop_interned(js, func_obj, INTERN_ARGUMENTS, 9, arguments_obj);
	}
	}

	static inline void restore_saved_scope(struct js *js) {
	if (saved_scope_stack && utarray_len(saved_scope_stack) >= 2) {
	jsval_t saved_this_ptr = (jsval_t )utarray_back(saved_scope_stack);
	js->this_val = *saved_this_ptr;
	utarray_pop_back(saved_scope_stack);

	jsval_t saved_scope_ptr = (jsval_t )utarray_back(saved_scope_stack);
	js->scope = *saved_scope_ptr;
	utarray_pop_back(saved_scope_stack);
	}
	}

	static jsval_t call_js_internal(
	struct js js, const char fn, jsoff_t fnlen,
	jsval_t closure_scope, jsval_t *bound_args, int bound_argc, jsval_t func_val
	) {
	if (saved_scope_stack == NULL) utarray_new(saved_scope_stack, &jsval_icd);
	utarray_push_back(saved_scope_stack, &js->scope);
	utarray_push_back(saved_scope_stack, &js->this_val);

	jsval_t target_this = peek_this();
	jsoff_t parent_scope_offset;

	if (vtype(closure_scope) == T_OBJ) {
	parent_scope_offset = (jsoff_t) vdata(closure_scope);
	} else {
	parent_scope_offset = (jsoff_t) vdata(js->scope);
	}

	if (global_scope_stack == NULL) utarray_new(global_scope_stack, &jsoff_icd);
	jsval_t function_scope = mkobj(js, parent_scope_offset);
	jsoff_t function_scope_offset = (jsoff_t)vdata(function_scope);
	utarray_push_back(global_scope_stack, &function_scope_offset);

	const char *caller_code = js->code;
	jsoff_t caller_clen = js->clen;
	jsoff_t caller_pos = js->pos;

	UT_array *args_arr;
	utarray_new(args_arr, &jsval_icd);

	for (int i = 0; i < bound_argc; i++) { utarray_push_back(args_arr, &bound_args[i]); }
	caller_pos = skiptonext(caller_code, caller_clen, caller_pos, NULL);

	while (caller_pos < caller_clen && caller_code[caller_pos] != ')') {
	bool is_spread = (
	caller_code[caller_pos] == '.' && caller_pos + 2 < caller_clen &&
	caller_code[caller_pos + 1] == '.' && caller_code[caller_pos + 2] == '.'
	);
	if (is_spread) caller_pos += 3;
	js->pos = caller_pos;
	js->consumed = 1;
	jsval_t arg = resolveprop(js, js_expr(js));
	caller_pos = js->pos;
	if (is_spread && vtype(arg) == T_ARR) {
	jsoff_t len = arr_length(js, arg);
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t elem = arr_get(js, arg, i);
	utarray_push_back(args_arr, &elem);
	}
	} else {
	utarray_push_back(args_arr, &arg);
	}
	caller_pos = skiptonext(caller_code, caller_clen, caller_pos, NULL);
	if (caller_pos < caller_clen && caller_code[caller_pos] == ',') caller_pos++;
	caller_pos = skiptonext(caller_code, caller_clen, caller_pos, NULL);
	}
	js->pos = caller_pos;

	jsval_t args = (jsval_t )utarray_front(args_arr);
	int argc = (int)utarray_len(args_arr);
	js->scope = function_scope;

	parsed_func_t *pf = get_or_parse_func(fn, fnlen);
	if (!pf) {
	utarray_free(args_arr);
	restore_saved_scope(js);
	if (global_scope_stack && utarray_len(global_scope_stack) > 0) utarray_pop_back(global_scope_stack);
	return js_mkerr(js, "failed to parse function");
	}

	int argi = 0;
	for (int i = 0; i < pf->param_count; i++) {
	parsed_param_t pp = (parsed_param_t )utarray_eltptr(pf->params, (unsigned int)i);

	if (pp->is_destruct) {
	jsval_t arg_val = (argi < argc) ? args[argi++] : js_mkundef();
	if (vtype(arg_val) == T_UNDEF && pp->default_len > 0) {
	arg_val = js_eval_str(js, &fn[pp->default_start], pp->default_len);
	}
	jsval_t r = bind_destruct_pattern(js, &fn[pp->pattern_off], pp->pattern_len, arg_val, function_scope);
	if (is_err(r)) {
	utarray_free(args_arr);
	restore_saved_scope(js);
	if (global_scope_stack && utarray_len(global_scope_stack) > 0) utarray_pop_back(global_scope_stack);
	return r;
	}
	} else {
	jsval_t v;
	if (argi < argc) {
	v = args[argi++];
	} else if (pp->default_len > 0) {
	v = js_eval_str(js, &fn[pp->default_start], pp->default_len);
	} else {
	v = js_mkundef();
	}
	jsval_t k = js_mkstr(js, &fn[pp->name_off], pp->name_len);
	if (!is_err(k)) mkprop_fast(js, function_scope, k, v, 0);
	}
	}

	if (pf->has_rest && pf->rest_param_len > 0) {
	jsval_t rest_array = mkarr(js);
	if (!is_err(rest_array)) {
	jsoff_t idx = 0;
	while (argi < argc) {
	jsval_t key;
	if (idx < 10 && INTERN_IDX[idx]) {
	key = js_mkstr(js, INTERN_IDX[idx], 1);
	} else {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	key = js_mkstr(js, idxstr, idxlen);
	}
	setprop(js, rest_array, key, args[argi++]);
	idx++;
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, rest_array, len_key, tov((double) idx));
	rest_array = mkval(T_ARR, vdata(rest_array));
	setprop(js, function_scope, js_mkstr(js, &fn[pf->rest_param_start], pf->rest_param_len), rest_array);
	}
	}

	bool needs_arguments = code_uses_arguments(&fn[pf->body_start], pf->body_len);
	bool func_strict = pf->is_strict;

	if (!func_strict && vtype(func_val) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func_val));
	jsval_t strict_slot = get_slot(js, func_obj, SLOT_STRICT);
	func_strict = (vtype(strict_slot) == T_BOOL && vdata(strict_slot) == 1);
	}

	if (needs_arguments) {
	setup_arguments(js, function_scope, args, argc, func_strict);
	}

	jsval_t slot_name = get_slot(js, func_val, SLOT_NAME);
	if (vtype(slot_name) == T_STR && vtype(func_val) == T_FUNC) {
	jsoff_t len;
	(void)vstr(js, slot_name, &len);
	if (len > 0) mkprop_fast(js, function_scope, slot_name, func_val, CONSTMASK);
	}

	if (vtype(func_val) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func_val));
	hoist_var_declarations_from_slot(js, function_scope, func_obj);
	jsval_t no_func_decls = get_slot(js, func_obj, SLOT_NO_FUNC_DECLS);
	js->skip_func_hoist = (vtype(no_func_decls) == T_BOOL && vdata(no_func_decls) == 1);
	} else js->skip_func_hoist = false;

	if (func_strict && (vtype(target_this) == T_UNDEF \|\| vtype(target_this) == T_NULL \|\|
	(vtype(target_this) == T_OBJ && vdata(target_this) == 0))) {
	js->this_val = js_mkundef();
	} else js->this_val = target_this;

	js->flags = F_CALL \| (func_strict ? F_STRICT : 0);
	jsval_t res = js_eval(js, &fn[pf->body_start], pf->body_len);
	js->skip_func_hoist = false;

	if (!is_err(res) && !(js->flags & F_RETURN)) res = js_mkundef();
	if (global_scope_stack && utarray_len(global_scope_stack) > 0) utarray_pop_back(global_scope_stack);

	utarray_free(args_arr);
	restore_saved_scope(js);

	return res;
	}

	static jsval_t call_js(struct js js, const char fn, jsoff_t fnlen, jsval_t closure_scope) {
	return call_js_internal(js, fn, fnlen, closure_scope, NULL, 0, js_mkundef());
	}

	static jsval_t call_js_with_args(struct js js, jsval_t func, jsval_t args, int nargs) {
	if (vtype(func) == T_CFUNC) {
	jsval_t (fn)(struct js , jsval_t , int) = (jsval_t()(struct js , jsval_t , int)) vdata(func);
	return fn(js, args, nargs);
	}

	if (vtype(func) != T_FUNC) return js_mkerr(js, "not a function");
	jsval_t func_obj = mkval(T_OBJ, vdata(func));

	jsval_t *combined_args = NULL;
	int combined_nargs = nargs;
	int bound_argc = 0;

	jsval_t bound_arr = get_slot(js, func_obj, SLOT_BOUND_ARGS);
	if (vtype(bound_arr) == T_ARR) {
	jsoff_t len_off = lkp_interned(js, bound_arr, INTERN_LENGTH, 6);
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) {
	bound_argc = (int) tod(len_val);
	}
	}

	if (bound_argc > 0) {
	combined_nargs = bound_argc + nargs;
	combined_args = (jsval_t )ant_calloc(sizeof(jsval_t) combined_nargs);
	if (combined_args) {
	for (int i = 0; i < bound_argc; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	jsoff_t prop_off = lkp(js, bound_arr, idx, strlen(idx));
	combined_args[i] = (prop_off != 0) ? resolveprop(js, mkval(T_PROP, prop_off)) : js_mkundef();
	}
	for (int i = 0; i < nargs; i++) {
	combined_args[bound_argc + i] = args[i];
	}
	args = combined_args;
	nargs = combined_nargs;
	}
	}
	}

	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);
	if (vtype(cfunc_slot) == T_CFUNC) {
	jsval_t bound_this = get_slot(js, func_obj, SLOT_BOUND_THIS);

	jsval_t saved_this = js->this_val;
	if (vtype(bound_this) != JS_UNDEF) {
	push_this(bound_this);
	js->this_val = bound_this;
	}

	jsval_t saved_func = js->current_func;
	js->current_func = func;

	jsval_t (fn)(struct js , jsval_t , int) = (jsval_t()(struct js , jsval_t , int)) vdata(cfunc_slot);
	jsval_t result = fn(js, args, nargs);

	js->current_func = saved_func;
	if (vtype(bound_this) != JS_UNDEF) {
	pop_this();
	js->this_val = saved_this;
	}

	if (combined_args) free(combined_args);
	return result;
	}

	jsoff_t fnlen;
	const char *fn = get_func_code(js, func_obj, &fnlen);
	if (!fn) {
	if (combined_args) free(combined_args);
	return js_mkerr(js, "function has no code");
	}

	jsval_t closure_scope = get_slot(js, func_obj, SLOT_SCOPE);
	jsval_t saved_super = js->super_val;

	jsval_t func_super = get_slot(js, func_obj, SLOT_SUPER);
	if (vtype(func_super) != T_UNDEF) js->super_val = func_super;

	jsval_t captured_this = get_slot(js, func_obj, SLOT_THIS);
	if (vtype(captured_this) != T_UNDEF) {
	pop_this();
	push_this(captured_this);
	}

	jsval_t bound_this = get_slot(js, func_obj, SLOT_BOUND_THIS);
	if (vtype(bound_this) != T_UNDEF) {
	pop_this();
	push_this(bound_this);
	}

	jsval_t result = call_js_code_with_args(js, fn, fnlen, closure_scope, args, nargs, func);
	js->super_val = saved_super;
	if (combined_args) free(combined_args);

	return result;
	}

	static jsval_t call_js_code_with_args(struct js js, const char fn, jsoff_t fnlen, jsval_t closure_scope, jsval_t *args, int nargs, jsval_t func_val) {
	jsoff_t parent_scope_offset;
	if (vtype(closure_scope) == T_OBJ) {
	parent_scope_offset = (jsoff_t) vdata(closure_scope);
	} else parent_scope_offset = (jsoff_t) vdata(js->scope);

	jsval_t saved_scope = js->scope;
	if (global_scope_stack == NULL) utarray_new(global_scope_stack, &jsoff_icd);
	utarray_push_back(global_scope_stack, &parent_scope_offset);
	jsval_t function_scope = mkobj(js, parent_scope_offset);
	js->scope = function_scope;

	jsval_t slot_name = get_slot(js, func_val, SLOT_NAME);
	if (vtype(slot_name) == T_STR && vtype(func_val) == T_FUNC) {
	jsoff_t len; vstr(js, slot_name, &len);
	if (len > 0) mkprop(js, function_scope, slot_name, func_val, CONSTMASK);
	}

	jsval_t func_obj = mkval(T_OBJ, vdata(func_val));
	hoist_var_declarations_from_slot(js, function_scope, func_obj);

	jsoff_t fnpos = 1;
	int arg_idx = 0;
	bool has_rest = false;
	jsoff_t rest_param_start = 0, rest_param_len = 0;

	while (fnpos < fnlen) {
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (fnpos < fnlen && fn[fnpos] == ')') break;

	bool is_rest = false;
	if (fnpos + 3 < fnlen && fn[fnpos] == '.' && fn[fnpos + 1] == '.' && fn[fnpos + 2] == '.') {
	is_rest = true;
	has_rest = true;
	fnpos += 3;
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	}

	jsoff_t identlen = 0;
	uint8_t tok = parseident(&fn[fnpos], fnlen - fnpos, &identlen);

	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (tok != TOK_IDENTIFIER && fnpos < fnlen && (fn[fnpos] == '{' \|\| fn[fnpos] == '[')) {
	char bracket_open = fn[fnpos];
	char bracket_close = (bracket_open == '{') ? '}' : ']';
	jsoff_t pattern_start = fnpos;
	int depth = 1;
	fnpos++;
	while (fnpos < fnlen && depth > 0) {
	if (fn[fnpos] == bracket_open) depth++;
	else if (fn[fnpos] == bracket_close) depth--;
	fnpos++;
	}
	jsoff_t pattern_len = fnpos - pattern_start;

	jsval_t arg_val = (arg_idx < nargs) ? args[arg_idx] : js_mkundef();
	jsval_t r = bind_destruct_pattern(js, &fn[pattern_start], pattern_len, arg_val, function_scope);
	if (is_err(r)) return r;

	arg_idx++;
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (fnpos < fnlen && fn[fnpos] == ',') fnpos++;
	continue;
	}

	if (tok != TOK_IDENTIFIER) break;

	if (is_rest) {
	rest_param_start = fnpos;
	rest_param_len = identlen;
	fnpos = skiptonext(fn, fnlen, fnpos + identlen, NULL);
	break;
	}

	jsoff_t param_name_pos = fnpos;
	jsoff_t default_start = 0, default_len = 0;
	fnpos = extract_default_param_value(fn, fnlen, fnpos + identlen, &default_start, &default_len);

	jsval_t v;
	if (arg_idx < nargs) {
	v = args[arg_idx];
	} else if (default_len > 0) {
	v = js_eval_str(js, &fn[default_start], default_len);
	} else {
	v = js_mkundef();
	}
	setprop(js, function_scope, js_mkstr(js, &fn[param_name_pos], identlen), v);
	arg_idx++;
	if (fnpos < fnlen && fn[fnpos] == ',') fnpos++;
	}

	if (has_rest && rest_param_len > 0) {
	jsval_t rest_array = mkarr(js);
	if (!is_err(rest_array)) {
	jsoff_t idx = 0;
	while (arg_idx < nargs) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, rest_array, key, args[arg_idx]);
	idx++;
	arg_idx++;
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, rest_array, len_key, tov((double) idx));
	rest_array = mkval(T_ARR, vdata(rest_array));
	setprop(js, function_scope, js_mkstr(js, &fn[rest_param_start], rest_param_len), rest_array);
	}
	}

	if (fnpos < fnlen && fn[fnpos] == ')') fnpos++;
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (fnpos >= fnlen) return js_mkerr(js, "unexpected end of function");
	if (fn[fnpos] == '{') fnpos++;
	jsoff_t body_len = fnlen - fnpos - 1;

	bool func_strict = is_strict_function_body(&fn[fnpos], body_len);
	if (code_uses_arguments(&fn[fnpos], body_len)) {
	setup_arguments(js, function_scope, args, nargs, func_strict);
	}

	jsval_t saved_this = js->this_val;
	jsval_t target_this = peek_this();

	if (func_strict && (vtype(target_this) == T_UNDEF \|\| vtype(target_this) == T_NULL \|\|
	(vtype(target_this) == T_OBJ && vdata(target_this) == 0))) {
	js->this_val = js_mkundef();
	} else {
	js->this_val = target_this;
	}
	js->flags = F_CALL \| (func_strict ? F_STRICT : 0);

	jsval_t res = js_eval(js, &fn[fnpos], body_len);
	if (!is_err(res) && !(js->flags & F_RETURN)) res = js_mkundef();

	js->this_val = saved_this;
	if (global_scope_stack && utarray_len(global_scope_stack) > 0) utarray_pop_back(global_scope_stack);

	js->scope = saved_scope;
	return res;
	}

	static jsval_t call_ffi(struct js *js, unsigned int func_index) {
	UT_array *args;
	utarray_new(args, &jsval_icd);
	jsval_t err, res;

	int argc = parse_call_args(js, args, &err);
	if (argc < 0) { utarray_free(args); return err; }

	jsval_t argv = (jsval_t )utarray_front(args);
	res = ffi_call_by_index(js, func_index, argv, argc);

	utarray_free(args);
	return res;
	}

	static jsval_t do_call_op(struct js *js, jsval_t func, jsval_t args) {
	if (js_stack_overflow(js)) return js_mkerr_typed(js, JS_ERR_RANGE \| JS_ERR_NO_STACK, "stack overflow");

	if (vtype(args) != T_CODEREF) return js_mkerr(js, "bad call");
	if (vtype(func) != T_FUNC && vtype(func) != T_CFUNC && vtype(func) != T_FFI) return js_mkerr(js, "calling non-function");

	if (vtype(func) == T_FFI) {
	const char *code = js->code;
	jsoff_t clen = js->clen, pos = js->pos;
	uint8_t tok = js->tok, flags = js->flags;

	js->code = &js->code[coderefoff(args)];
	js->clen = codereflen(args);
	js->pos = skiptonext(js->code, js->clen, 0, NULL);

	jsval_t res = call_ffi(js, (unsigned int)vdata(func));

	js->code = code; js->clen = clen; js->pos = pos;
	js->flags = (flags & ~F_THROW) \| (js->flags & F_THROW);
	js->tok = tok;
	js->consumed = 1;
	return res;
	}

	jsval_t target_this = peek_this();
	jsval_t target_proto = (vtype(target_this) == T_OBJ) ? get_slot(js, target_this, SLOT_PROTO) : js_mkundef();

	if (vtype(func) == T_FUNC && vtype(target_this) == T_OBJ) {
	if (vtype(target_proto) == T_UNDEF) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func));

	jsval_t target_func = get_slot(js, func_obj, SLOT_TARGET_FUNC);
	jsval_t proto_source = func_obj;
	if (vtype(target_func) == T_FUNC) {
	proto_source = mkval(T_OBJ, vdata(target_func));
	}

	jsoff_t proto_off = lkp_interned(js, proto_source, INTERN_PROTOTYPE, 9);
	if (proto_off != 0) {
	jsval_t proto = resolveprop(js, mkval(T_PROP, proto_off));
	if (vtype(proto) == T_OBJ) set_proto(js, target_this, proto);
	}
	}
	}

	const char *code = js->code;
	jsoff_t clen = js->clen, pos = js->pos;

	js->code = &js->code[coderefoff(args)];
	js->clen = codereflen(args);
	js->pos = skiptonext(js->code, js->clen, 0, NULL);

	uint8_t tok = js->tok, flags = js->flags;
	jsval_t res = js_mkundef();

	if (vtype(func) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);
	if (vtype(cfunc_slot) == T_CFUNC) {
	jsval_t bound_this_slot = get_slot(js, func_obj, SLOT_BOUND_THIS);
	bool has_bound_this = vtype(bound_this_slot) != T_UNDEF;

	if (has_bound_this) {
	pop_this();
	push_this(bound_this_slot);
	}

	jsval_t saved_func = js->current_func;
	js->current_func = func;

	int bound_argc;
	jsval_t *bound_args = resolve_bound_args(js, func_obj, NULL, 0, &bound_argc);

	if (!bound_args) {
	res = call_c(js, (jsval_t()(struct js , jsval_t *, int)) vdata(cfunc_slot));
	} else {
	UT_array *args_arr;
	utarray_new(args_arr, &jsval_icd);
	for (int i = 0; i < bound_argc; i++) utarray_push_back(args_arr, &bound_args[i]);
	free(bound_args);

	jsval_t err;
	int call_argc = parse_call_args(js, args_arr, &err);
	if (call_argc < 0) {
	utarray_free(args_arr);
	js->current_func = saved_func;
	if (has_bound_this) pop_this();
	return err;
	}

	jsval_t argv = (jsval_t )utarray_front(args_arr);
	int total_argc = (int)utarray_len(args_arr);
	jsval_t saved_this = js->this_val;
	js->this_val = peek_this();
	res = ((jsval_t()(struct js , jsval_t *, int)) vdata(cfunc_slot))(js, argv, total_argc);
	js->this_val = saved_this;
	utarray_free(args_arr);
	}

	js->current_func = saved_func;

	if (has_bound_this) {
	pop_this();
	push_this(target_this);
	}
	} else {
	jsval_t builtin_slot = get_slot(js, func_obj, SLOT_BUILTIN);
	if (vtype(builtin_slot) == T_NUM && (int)tod(builtin_slot) == BUILTIN_OBJECT) res = call_c(js, builtin_Object); else {
	jsoff_t fnlen;

	const char *code_str = get_func_code(js, func_obj, &fnlen);
	if (!code_str) return js_mkerr(js, "function has no code");

	jsval_t closure_scope = get_slot(js, func_obj, SLOT_SCOPE);
	jsval_t async_slot = get_slot(js, func_obj, SLOT_ASYNC);
	bool is_async = vtype(async_slot) == T_BOOL && vdata(async_slot) == 1;

	jsval_t captured_this = js_mkundef();
	bool is_arrow = false;
	bool is_bound = false;

	jsval_t this_slot = get_slot(js, func_obj, SLOT_THIS);
	if (vtype(this_slot) != T_UNDEF) {
	captured_this = this_slot; is_arrow = true;
	}

	jsval_t bound_this_slot = get_slot(js, func_obj, SLOT_BOUND_THIS);
	if (vtype(bound_this_slot) != T_UNDEF && vtype(js->new_target) == T_UNDEF) {
	captured_this = bound_this_slot; is_bound = true;
	}

	int bound_argc;
	jsval_t *bound_args = resolve_bound_args(js, func_obj, NULL, 0, &bound_argc);

	jsval_t nfe_name_val = js_mkundef();
	jsval_t slot_name = get_slot(js, func_obj, SLOT_NAME);

	if (vtype(slot_name) == T_STR) nfe_name_val = slot_name; else {
	jsoff_t nfe_name_off = lkp(js, func_obj, "name", 4);
	if (nfe_name_off != 0) nfe_name_val = resolveprop(js, mkval(T_PROP, nfe_name_off));
	}

	static char full_func_name[256];
	const char *func_name = NULL;
	const char *this_name = NULL;

	if (vtype(nfe_name_val) == T_STR) {
	jsoff_t name_len, name_offset = vstr(js, nfe_name_val, &name_len);
	func_name = (const char *)&js->mem[name_offset];
	}

	if (vtype(target_this) != T_OBJ) goto skip_constructor_name;

	jsoff_t ctor_off = lkp_interned(js, target_this, INTERN_CONSTRUCTOR, 11);
	if (ctor_off == 0) goto default_object_name;

	jsval_t ctor_val = resolveprop(js, mkval(T_PROP, ctor_off));
	if (vtype(ctor_val) != T_FUNC) goto default_object_name;

	jsval_t ctor_obj = mkval(T_OBJ, vdata(ctor_val));
	jsoff_t ctor_name_off = lkp(js, ctor_obj, "name", 4);
	if (ctor_name_off == 0) goto default_object_name;

	jsval_t ctor_name_val = resolveprop(js, mkval(T_PROP, ctor_name_off));
	if (vtype(ctor_name_val) != T_STR) goto default_object_name;

	jsoff_t ctor_name_len, ctor_name_offset = vstr(js, ctor_name_val, &ctor_name_len);
	this_name = (const char *)&js->mem[ctor_name_offset];
	if (this_name && strlen(this_name) > 0) goto skip_constructor_name;

	default_object_name:
	this_name = "Object";

	skip_constructor_name:

	const char *final_name;
	if (this_name && func_name) {
	snprintf(full_func_name, sizeof(full_func_name), "%s.%s", this_name, func_name);
	final_name = full_func_name;
	} else if (func_name) {
	final_name = func_name;
	} else if (this_name) {
	snprintf(full_func_name, sizeof(full_func_name), "%s.<anonymous>", this_name);
	final_name = full_func_name;
	} else {
	final_name = "<anonymous>";
	}

	push_call_frame(
	js->filename,
	final_name,
	code, (uint32_t) pos
	);

	jsval_t saved_func = js->current_func;
	js->current_func = func;

	jsval_t saved_super = js->super_val;
	jsval_t func_super = get_slot(js, func_obj, SLOT_SUPER);
	if (vtype(func_super) != T_UNDEF) js->super_val = func_super;

	if (is_arrow \|\| is_bound) {
	pop_this();
	push_this(captured_this);
	}

	if (is_true(get_slot(js, func_obj, SLOT_DEFAULT_CTOR))) {
	jsval_t super_ctor = js->super_val;
	uint8_t st = vtype(super_ctor);
	if (st == T_FUNC \|\| st == T_CFUNC) {
	js->code = code; js->clen = clen; js->pos = pos;
	res = do_call_op(js, super_ctor, args);
	js->super_val = saved_super;
	js->current_func = saved_func;
	pop_call_frame(); goto restore_state;
	}
	}

	jsval_t count_val = get_slot(js, func_obj, SLOT_FIELD_COUNT);
	if (vtype(count_val) != T_NUM \|\| vtype(target_this) != T_OBJ) goto skip_fields;

	int field_count = (int)tod(count_val);
	jsval_t src_val = get_slot(js, func_obj, SLOT_SOURCE);
	jsval_t fields_meta = get_slot(js, func_obj, SLOT_FIELDS);
	if (vtype(src_val) == T_UNDEF \|\| vtype(fields_meta) == T_UNDEF) goto skip_fields;

	if (vtype(src_val) != T_CFUNC) goto skip_fields;
	const char source = (const char )vdata(src_val);

	jsoff_t meta_len, meta_ptr_off = vstr(js, fields_meta, &meta_len);
	const jsoff_t metadata = (const jsoff_t )(&js->mem[meta_ptr_off]);

	for (int i = 0; i < field_count; i++) {
	jsoff_t name_off = metadata[i * 4 + 0];
	jsoff_t name_len = metadata[i * 4 + 1];
	jsoff_t init_start = metadata[i * 4 + 2];
	jsoff_t init_end = metadata[i * 4 + 3];

	jsval_t fname = js_mkstr(js, &source[name_off], name_len);
	if (is_err(fname)) {
	js->current_func = saved_func;
	pop_call_frame();
	return fname;
	}

	jsval_t field_val = js_mkundef();
	if (init_start > 0 && init_end > init_start) {
	field_val = js_eval_str(js, &source[init_start], init_end - init_start);
	field_val = resolveprop(js, field_val);
	}

	jsval_t set_res = setprop(js, target_this, fname, field_val);
	if (is_err(set_res)) {
	js->current_func = saved_func;
	pop_call_frame();
	return set_res;
	}
	}
	skip_fields:
	if (is_async) {
	UT_array *call_args;
	utarray_new(call_args, &jsval_icd);
	for (int i = 0; i < bound_argc; i++) utarray_push_back(call_args, &bound_args[i]);
	jsval_t err;
	int call_argc = parse_call_args(js, call_args, &err);
	if (call_argc < 0) {
	utarray_free(call_args);
	pop_call_frame();
	if (bound_args) free(bound_args);
	js->super_val = saved_super;
	js->current_func = saved_func;
	return err;
	}
	jsval_t argv = (jsval_t )utarray_front(call_args);
	int argc = (int)utarray_len(call_args);
	res = start_async_in_coroutine(js, code_str, fnlen, closure_scope, argv, argc);
	utarray_free(call_args);
	} else res = call_js_internal(js, code_str, fnlen, closure_scope, bound_args, bound_argc, func);
	pop_call_frame();
	if (bound_args) free(bound_args);
	js->super_val = saved_super;
	js->current_func = saved_func;
	}
	}
	} else {
	res = call_c(js, (jsval_t()(struct js , jsval_t *, int)) vdata(func));
	}

	restore_state:
	js->code = code, js->clen = clen, js->pos = pos;
	js->flags = (flags & ~F_THROW) \| (js->flags & F_THROW);
	js->tok = tok;
	js->consumed = 1;

	return res;
	}

	static jsval_t js_call_toString(struct js *js, jsval_t value) {
	jsoff_t ts_off = lkp(js, value, "toString", 8);
	if (ts_off == 0) ts_off = lkp_proto(js, value, "toString", 8);
	if (ts_off == 0) goto fallback;

	jsval_t ts_func = resolveprop(js, mkval(T_PROP, ts_off));
	uint8_t ft = vtype(ts_func);
	if (ft != T_FUNC && ft != T_CFUNC) goto fallback;

	jsval_t saved_this = js->this_val;
	js->this_val = value;
	jsval_t result;

	if (ft == T_CFUNC) {
	result = ((jsval_t ()(struct js , jsval_t *, int))vdata(ts_func))(js, NULL, 0);
	} else {
	jsval_t func_obj = mkval(T_OBJ, vdata(ts_func));
	jsoff_t fnlen;
	const char *code_str = get_func_code(js, func_obj, &fnlen);
	if (!code_str) goto restore_fallback;

	jsval_t closure_scope = get_slot(js, func_obj, SLOT_SCOPE);
	if (vtype(closure_scope) == T_UNDEF) closure_scope = js->scope;

	result = call_js(js, code_str, fnlen, closure_scope);
	}

	js->this_val = saved_this;
	if (vtype(result) == T_STR) return result;

	uint8_t rtype = vtype(result);
	if (rtype != T_OBJ && rtype != T_ARR && rtype != T_FUNC) {
	char buf[256];
	size_t len = tostr(js, result, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	restore_fallback:
	js->this_val = saved_this;
	fallback:;
	char buf[4096];
	size_t len = tostr(js, value, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	static jsval_t js_call_valueOf(struct js *js, jsval_t value) {
	jsoff_t off = lkp(js, value, "valueOf", 7);
	if (off == 0) off = lkp_proto(js, value, "valueOf", 7);
	if (off == 0) return value;

	jsval_t fn = resolveprop(js, mkval(T_PROP, off));
	uint8_t ft = vtype(fn);
	if (ft != T_FUNC && ft != T_CFUNC) return value;

	jsval_t saved = js->this_val;
	js->this_val = value;
	jsval_t result;

	if (ft == T_CFUNC) {
	result = ((jsval_t ()(struct js , jsval_t *, int))vdata(fn))(js, NULL, 0);
	} else {
	jsval_t func_obj = mkval(T_OBJ, vdata(fn));
	jsoff_t fnlen;
	const char *code_str = get_func_code(js, func_obj, &fnlen);
	if (!code_str) { js->this_val = saved; return value; }

	jsval_t closure_scope = get_slot(js, func_obj, SLOT_SCOPE);
	if (vtype(closure_scope) == T_UNDEF) closure_scope = js->scope;

	result = call_js(js, code_str, fnlen, closure_scope);
	}

	js->this_val = saved;
	return result;
	}

	static inline bool strict_eq_values(struct js *js, jsval_t l, jsval_t r) {
	uint8_t t = vtype(l);
	if (t != vtype(r)) return false;
	if (t == T_STR) {
	jsoff_t n1, n2, off1 = vstr(js, l, &n1), off2 = vstr(js, r, &n2);
	return n1 == n2 && memcmp(&js->mem[off1], &js->mem[off2], n1) == 0;
	}
	if (t == T_NUM) return tod(l) == tod(r);
	if (t == T_BIGINT) return bigint_compare(js, l, r) == 0;
	return vdata(l) == vdata(r);
	}

	static inline jsval_t coerce_to_str(struct js *js, jsval_t v) {
	if (vtype(v) == T_STR) return v;
	if (vtype(v) == T_ARR) {
	char buf[1024];
	size_t len = array_to_string(js, v, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}
	return js_tostring_val(js, v);
	}

	static jsval_t do_op(struct js *js, uint8_t op, jsval_t lhs, jsval_t rhs) {
	if (js->flags & F_NOEXEC) return 0;

	jsval_t l = is_assign(op) ? lhs : resolveprop(js, lhs);
	jsval_t r = resolveprop(js, rhs);

	if (is_err(l)) return l;
	if (is_err(r)) return r;

	if (is_assign(op) && vtype(lhs) != T_PROP && vtype(lhs) != T_PROPREF) {
	if (!(js->flags & F_STRICT) && vtype(lhs) == T_UNDEF) return r;
	if (!(js->flags & F_STRICT) && vtype(lhs) == T_CODEREF && op == TOK_ASSIGN) {
	jsoff_t id_off = coderefoff(lhs), id_len = codereflen(lhs);
	jsval_t global_scope = js->scope;
	while (vdata(upper(js, global_scope)) != 0) global_scope = upper(js, global_scope);
	jsval_t key = js_mkstr(js, &js->code[id_off], id_len);
	if (is_err(key)) return key;
	jsval_t prop = setprop(js, global_scope, key, r);
	return is_err(prop) ? prop : r;
	}
	return js_mkerr_typed(js, (js->flags & F_STRICT) && vtype(lhs) == T_UNDEF ? JS_ERR_TYPE : JS_ERR_SYNTAX,
	(js->flags & F_STRICT) && vtype(lhs) == T_UNDEF ? "Cannot create property on primitive value" : "Invalid left-hand side in assignment");
	}

	#define L(tok) [tok] = &&L_##tok
	static const void *dispatch[TOK_MAX] = {
	L(TOK_TYPEOF), L(TOK_VOID), L(TOK_INSTANCEOF), L(TOK_IN),
	L(TOK_CALL), L(TOK_BRACKET), L(TOK_ASSIGN), L(TOK_DOT),
	L(TOK_OPTIONAL_CHAIN), L(TOK_POSTINC), L(TOK_POSTDEC),
	L(TOK_NOT), L(TOK_UMINUS), L(TOK_UPLUS), L(TOK_SEQ),
	L(TOK_SNE), L(TOK_EQ), L(TOK_NE), L(TOK_PLUS),
	L(TOK_MINUS), L(TOK_MUL), L(TOK_DIV), L(TOK_REM),
	L(TOK_EXP), L(TOK_LT), L(TOK_LE), L(TOK_GT), L(TOK_GE),
	L(TOK_XOR), L(TOK_AND), L(TOK_OR), L(TOK_TILDA),
	L(TOK_SHL), L(TOK_SHR), L(TOK_ZSHR),
	};
	#undef L

	if (op < TOK_MAX && dispatch[op]) goto *dispatch[op];
	goto L_default;

	L_TOK_TYPEOF: {
	const char *ts = typestr(vtype(r));
	return js_mkstr(js, ts, strlen(ts));
	}
	L_TOK_VOID: return js_mkundef();
	L_TOK_INSTANCEOF: return do_instanceof(js, l, r);
	L_TOK_IN: return do_in(js, l, r);
	L_TOK_CALL: return do_call_op(js, l, r);
	L_TOK_BRACKET: return do_bracket_op(js, l, rhs);
	L_TOK_ASSIGN: return assign(js, lhs, r);
	L_TOK_DOT: return do_dot_op(js, l, r);
	L_TOK_OPTIONAL_CHAIN: return do_optional_chain_op(js, l, r);

	L_TOK_POSTINC:
	L_TOK_POSTDEC: {
	uint8_t lhs_type = vtype(lhs);
	if (lhs_type != T_PROP && lhs_type != T_PROPREF)
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "Invalid left-hand side expression in postfix operation");
	do_assign_op(js, op == TOK_POSTINC ? TOK_PLUS_ASSIGN : TOK_MINUS_ASSIGN, lhs, tov(1));
	return l;
	}

	L_TOK_NOT: return mkval(T_BOOL, !js_truthy(js, r));

	L_TOK_UMINUS:
	if (vtype(r) == T_BIGINT) return bigint_neg(js, r);
	return tov(-js_to_number(js, r));

	L_TOK_UPLUS:
	if (vtype(r) == T_BIGINT) return js_mkerr(js, "Cannot convert a BigInt value to a number");
	return tov(js_to_number(js, r));

	L_TOK_TILDA: return tov((double)(~js_to_int32(js_to_number(js, r))));

	L_TOK_SEQ:
	L_TOK_SNE: {
	bool eq = strict_eq_values(js, l, r);
	return mkval(T_BOOL, op == TOK_SEQ ? eq : !eq);
	}

	L_TOK_EQ:
	L_TOK_NE: {
	bool eq = false;
	uint8_t lt = vtype(l), rtype = vtype(r);

	if ((lt == T_NULL && rtype == T_NULL) \|\| (lt == T_UNDEF && rtype == T_UNDEF) \|\|
	(lt == T_UNDEF && rtype == T_NULL) \|\| (lt == T_NULL && rtype == T_UNDEF)) {
	eq = true;
	} else if (lt == T_NULL \|\| rtype == T_NULL \|\| lt == T_UNDEF \|\| rtype == T_UNDEF) {
	eq = false;
	} else if (lt == rtype) {
	eq = strict_eq_values(js, l, r);
	} else if ((lt == T_BIGINT && rtype == T_NUM) \|\| (lt == T_NUM && rtype == T_BIGINT)) {
	double num_val = lt == T_NUM ? tod(l) : tod(r);
	jsval_t bigint_val = lt == T_BIGINT ? l : r;
	if (isfinite(num_val) && num_val == trunc(num_val)) {
	bool neg = num_val < 0;
	if (neg) num_val = -num_val;
	char buf[64];
	snprintf(buf, sizeof(buf), "%.0f", num_val);
	eq = bigint_compare(js, bigint_val, js_mkbigint(js, buf, strlen(buf), neg)) == 0;
	}
	} else if (lt == T_BOOL) {
	return do_op(js, op, tov(vdata(l) ? 1.0 : 0.0), r);
	} else if (rtype == T_BOOL) {
	return do_op(js, op, l, tov(vdata(r) ? 1.0 : 0.0));
	} else if ((lt == T_NUM && rtype == T_STR) \|\| (lt == T_STR && rtype == T_NUM)) {
	eq = js_to_number(js, l) == js_to_number(js, r);
	} else if (lt == T_ARR \|\| lt == T_OBJ) {
	jsval_t l_prim = js_tostring_val(js, l);
	if (!is_err(l_prim)) return do_op(js, op, l_prim, r);
	} else if (rtype == T_ARR \|\| rtype == T_OBJ) {
	jsval_t r_prim = js_tostring_val(js, r);
	if (!is_err(r_prim)) return do_op(js, op, l, r_prim);
	}
	return mkval(T_BOOL, op == TOK_EQ ? eq : !eq);
	}

	L_TOK_PLUS: {
	if (vtype(l) == T_NUM && vtype(r) == T_NUM) return tov(tod(l) + tod(r));
	jsval_t lu = unwrap_primitive(js, l);
	jsval_t ru = unwrap_primitive(js, r);
	if (vtype(lu) == T_BIGINT && vtype(ru) == T_BIGINT) return bigint_add(js, lu, ru);
	if (vtype(lu) == T_BIGINT \|\| vtype(ru) == T_BIGINT) return js_mkerr(js, "Cannot mix BigInt value and other types");
	if (is_non_numeric(lu) \|\| is_non_numeric(ru) \|\| (vtype(lu) == T_STR && vtype(ru) == T_STR)) {
	jsval_t l_str = coerce_to_str(js, l);
	if (is_err(l_str)) return l_str;
	jsval_t r_str = coerce_to_str(js, r);
	if (is_err(r_str)) return r_str;
	return do_string_op(js, op, l_str, r_str);
	}
	return tov(js_to_number(js, l) + js_to_number(js, r));
	}

	L_TOK_MINUS:
	L_TOK_MUL:
	L_TOK_DIV:
	L_TOK_REM:
	L_TOK_EXP: {
	uint8_t lt = vtype(l), rtype = vtype(r);
	if (lt == T_NUM && rtype == T_NUM) {
	double a = tod(l), b = tod(r);
	switch (op) {
	case TOK_MINUS: return tov(a - b);
	case TOK_MUL: return tov(a * b);
	case TOK_DIV: return tov(a / b);
	case TOK_REM: return tov(a - b * ((double)(long)(a / b)));
	case TOK_EXP: return tov(pow(a, b));
	}
	}
	if (lt == T_BIGINT && rtype == T_BIGINT) {
	switch (op) {
	case TOK_MINUS: return bigint_sub(js, l, r);
	case TOK_MUL: return bigint_mul(js, l, r);
	case TOK_DIV: return bigint_div(js, l, r);
	case TOK_REM: return bigint_mod(js, l, r);
	case TOK_EXP: return bigint_exp(js, l, r);
	}
	}
	if (lt == T_BIGINT \|\| rtype == T_BIGINT)
	return js_mkerr(js, "Cannot mix BigInt value and other types");
	double a = js_to_number(js, l), b = js_to_number(js, r);
	switch (op) {
	case TOK_MINUS: return tov(a - b);
	case TOK_MUL: return tov(a * b);
	case TOK_DIV: return tov(a / b);
	case TOK_REM: return tov(a - b * ((double)(long)(a / b)));
	case TOK_EXP: return tov(pow(a, b));
	}
	}

	L_TOK_LT:
	L_TOK_LE:
	L_TOK_GT:
	L_TOK_GE: {
	uint8_t lt = vtype(l), rtype = vtype(r);
	if (lt == T_NUM && rtype == T_NUM) {
	double a = tod(l), b = tod(r);
	switch (op) {
	case TOK_LT: return mkval(T_BOOL, a < b);
	case TOK_LE: return mkval(T_BOOL, a <= b);
	case TOK_GT: return mkval(T_BOOL, a > b);
	case TOK_GE: return mkval(T_BOOL, a >= b);
	}
	}
	if (lt == T_BIGINT && rtype == T_BIGINT) {
	int cmp = bigint_compare(js, l, r);
	switch (op) {
	case TOK_LT: return mkval(T_BOOL, cmp < 0);
	case TOK_LE: return mkval(T_BOOL, cmp <= 0);
	case TOK_GT: return mkval(T_BOOL, cmp > 0);
	case TOK_GE: return mkval(T_BOOL, cmp >= 0);
	}
	}
	if (lt == T_BIGINT \|\| rtype == T_BIGINT)
	return js_mkerr(js, "Cannot mix BigInt value and other types");
	if (lt == T_STR && rtype == T_STR)
	return do_string_op(js, op, l, r);
	double a = js_to_number(js, l), b = js_to_number(js, r);
	switch (op) {
	case TOK_LT: return mkval(T_BOOL, a < b);
	case TOK_LE: return mkval(T_BOOL, a <= b);
	case TOK_GT: return mkval(T_BOOL, a > b);
	case TOK_GE: return mkval(T_BOOL, a >= b);
	}
	}

	L_TOK_XOR:
	L_TOK_AND:
	L_TOK_OR:
	L_TOK_SHL:
	L_TOK_SHR:
	L_TOK_ZSHR: {
	uint8_t lt = vtype(l), rtype = vtype(r);
	if (lt == T_BIGINT \|\| rtype == T_BIGINT)
	return js_mkerr(js, "Cannot mix BigInt value and other types");
	int32_t ai = (lt == T_NUM) ? js_to_int32(tod(l)) : js_to_int32(js_to_number(js, l));
	uint32_t bi = (rtype == T_NUM) ? js_to_uint32(tod(r)) : js_to_uint32(js_to_number(js, r));
	switch (op) {
	case TOK_XOR: return tov((double)(ai ^ (int32_t)bi));
	case TOK_AND: return tov((double)(ai & (int32_t)bi));
	case TOK_OR: return tov((double)(ai \| (int32_t)bi));
	case TOK_SHL: return tov((double)(ai << (bi & 0x1f)));
	case TOK_SHR: return tov((double)(ai >> (bi & 0x1f)));
	case TOK_ZSHR: return tov((double)((uint32_t)ai >> (bi & 0x1f)));
	}
	}

	L_default:
	if (is_assign(op)) return do_assign_op(js, op, lhs, r);
	return js_mkerr(js, "unknown op %d", (int)op);
	}

	static jsval_t js_template_literal(struct js *js) {
	uint8_t in = (uint8_t ) &js->code[js->toff];
	size_t template_len = js->tlen;

	size_t n = 1;
	jsval_t parts[64];
	int part_count = 0;

	while (n < template_len - 1 && part_count < 64) {
	size_t part_start = n;
	while (n < template_len - 1) {
	if (in[n] == '\\' && n + 1 < template_len - 1) {
	n += 2;
	continue;
	}
	if (in[n] == '$' && n + 1 < template_len - 1 && in[n + 1] == '{') {
	break;
	}
	n++;
	}
	if (n > part_start \|\| (n == part_start && (n >= template_len - 1 \|\| in[n] != '$'))) {
	size_t part_len = n - part_start;
	size_t needed = sizeof(jsoff_t) + part_len;
	if (js->brk + needed > js->size) {
	if (!js_try_grow_memory(js, needed)) return js_mkerr(js, "oom");
	}
	uint8_t *out = &js->mem[js->brk + sizeof(jsoff_t)];
	size_t out_len = 0;

	for (size_t i = part_start; i < n; i++) {
	if (in[i] == '\\' && i + 1 < n) {
	i++;
	if (in[i] == 'n') out[out_len++] = '\n';
	else if (in[i] == 't') out[out_len++] = '\t';
	else if (in[i] == 'r') out[out_len++] = '\r';
	else if (in[i] == '\\') out[out_len++] = '\\';
	else if (in[i] == '`') out[out_len++] = '`';
	else out[out_len++] = in[i];
	} else {
	out[out_len++] = in[i];
	}
	}

	parts[part_count++] = js_mkstr(js, NULL, out_len);
	}

	if (n < template_len - 1 && in[n] == '$' && in[n + 1] == '{') {
	n += 2;
	size_t expr_start = n;
	int brace_count = 1;

	while (n < template_len - 1 && brace_count > 0) {
	if (in[n] == '{') brace_count++;
	else if (in[n] == '}') brace_count--;
	if (brace_count > 0) n++;
	}

	if (brace_count != 0) return js_mkerr_typed(js, JS_ERR_SYNTAX, "unclosed ${");

	jsval_t expr_result = js_eval_str(js, (const char *)&in[expr_start], (jsoff_t)(n - expr_start));
	if (is_err(expr_result)) return expr_result;
	expr_result = resolveprop(js, expr_result);

	if (vtype(expr_result) != T_STR) {
	const char *str = js_str(js, expr_result);
	expr_result = js_mkstr(js, str, strlen(str));
	}

	parts[part_count++] = expr_result;
	n++;
	}
	}

	if (part_count == 0) return js_mkstr(js, "", 0);
	if (part_count == 1) return parts[0];

	size_t total_len = 0;
	for (int i = 0; i < part_count; i++) {
	if (vtype(parts[i]) == T_STR) {
	total_len += vstrlen(js, parts[i]);
	}
	}

	jsval_t result = js_mkstr(js, NULL, total_len);
	if (is_err(result)) return result;

	jsoff_t result_len, result_off = vstr(js, result, &result_len);
	size_t pos = 0;

	for (int i = 0; i < part_count; i++) {
	if (vtype(parts[i]) == T_STR) {
	jsoff_t part_len, part_off = vstr(js, parts[i], &part_len);
	memmove(&js->mem[result_off + pos], &js->mem[part_off], part_len);
	pos += part_len;
	}
	}

	return result;
	}

	static jsval_t js_tagged_template(struct js *js, jsval_t tag_func) {
	if (js->flags & F_NOEXEC) return js_mkundef();

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);

	uint8_t in = (uint8_t ) &js->code[js->toff];
	size_t template_len = js->tlen;
	jsval_t strings[64], values[64];
	int string_count = 0, value_count = 0;
	size_t n = 1;

	while (n < template_len - 1) {
	size_t part_start = n;

	while (n < template_len - 1 && !(in[n] == '$' && n + 1 < template_len - 1 && in[n + 1] == '{')) {
	if (in[n] == '\\' && n + 1 < template_len - 1) n += 2;
	else n++;
	}

	size_t out_len = 0;
	size_t needed = sizeof(jsoff_t) + (n - part_start);
	if (js->brk + needed > js->size) {
	if (!js_try_grow_memory(js, needed)) {
	return js_mkerr(js, "oom");
	}
	}
	uint8_t *out = &js->mem[js->brk + sizeof(jsoff_t)];

	for (size_t i = part_start; i < n; i++) {
	if (in[i] == '\\' && i + 1 < n) {
	i++;
	if (in[i] == 'n') out[out_len++] = '\n';
	else if (in[i] == 't') out[out_len++] = '\t';
	else if (in[i] == 'r') out[out_len++] = '\r';
	else if (in[i] == '\\') out[out_len++] = '\\';
	else if (in[i] == '`') out[out_len++] = '`';
	else out[out_len++] = in[i];
	} else {
	out[out_len++] = in[i];
	}
	}
	strings[string_count++] = js_mkstr(js, NULL, out_len);

	if (n >= template_len - 1 \|\| in[n] != '$') break;

	n += 2;
	int brace_count = 1;
	size_t expr_start = n;
	while (n < template_len - 1 && brace_count > 0) {
	if (in[n] == '{') brace_count++;
	else if (in[n] == '}') brace_count--;
	if (brace_count > 0) n++;
	}
	if (brace_count != 0) return js_mkerr_typed(js, JS_ERR_SYNTAX, "unclosed ${");

	jsval_t expr_result = js_eval_str(js, (const char *)&in[expr_start], (jsoff_t)(n - expr_start));
	if (is_err(expr_result)) return expr_result;
	expr_result = resolveprop(js, expr_result);
	values[value_count++] = expr_result;
	n++;
	}

	jsval_t strings_arr = mkarr(js);
	for (int i = 0; i < string_count; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	setprop(js, strings_arr, js_mkstr(js, idx, strlen(idx)), strings[i]);
	}
	setprop(js, strings_arr, js_mkstr(js, "length", 6), tov((double)string_count));
	strings_arr = mkval(T_ARR, vdata(strings_arr));

	jsval_t args[65];
	args[0] = strings_arr;
	for (int i = 0; i < value_count; i++) {
	args[i + 1] = values[i];
	}

	uint8_t saved_flags = js->flags;
	jsval_t result = call_js_with_args(js, tag_func, args, 1 + value_count);

	JS_RESTORE_STATE(js, saved);
	js->flags = saved_flags;
	js->consumed = 1;

	return result;
	}

	static jsval_t js_str_literal(struct js *js) {
	uint8_t in = (uint8_t ) &js->code[js->toff];
	size_t n1 = 0, n2 = 0;
	size_t needed = sizeof(jsoff_t) + js->tlen;
	if (js->brk + needed > js->size) {
	if (!js_try_grow_memory(js, needed)) return js_mkerr(js, "oom");
	}
	uint8_t *out = &js->mem[js->brk + sizeof(jsoff_t)];
	while (n2++ + 2 < js->tlen) {
	if (in[n2] == '\\') {
	if (in[n2 + 1] == in[0]) {
	out[n1++] = in[0];
	} else if (in[n2 + 1] == 'n') {
	out[n1++] = '\n';
	} else if (in[n2 + 1] == 't') {
	out[n1++] = '\t';
	} else if (in[n2 + 1] == 'r') {
	out[n1++] = '\r';
	} else if (in[n2 + 1] == '0' && !(in[n2 + 2] >= '0' && in[n2 + 2] <= '7')) {
	out[n1++] = '\0';
	} else if (in[n2 + 1] >= '0' && in[n2 + 1] <= '7') {
	if (js->flags & F_STRICT) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "octal escape sequences are not allowed in strict mode");
	}
	int val = in[n2 + 1] - '0';
	int extra = 0;
	if (in[n2 + 2] >= '0' && in[n2 + 2] <= '7') {
	val = val * 8 + (in[n2 + 2] - '0');
	extra++;
	if (in[n2 + 3] >= '0' && in[n2 + 3] <= '7' && val * 8 + (in[n2 + 3] - '0') <= 255) {
	val = val * 8 + (in[n2 + 3] - '0');
	extra++;
	}
	}
	n2 += extra;
	out[n1++] = (uint8_t)val;
	} else if (in[n2 + 1] == 'v') {
	out[n1++] = '\v';
	} else if (in[n2 + 1] == 'f') {
	out[n1++] = '\f';
	} else if (in[n2 + 1] == 'b') {
	out[n1++] = '\b';
	} else if (in[n2 + 1] == 'x' && is_xdigit(in[n2 + 2]) &&
	is_xdigit(in[n2 + 3])) {
	out[n1++] = (uint8_t) ((unhex(in[n2 + 2]) << 4U) \| unhex(in[n2 + 3]));
	n2 += 2;
	} else if (in[n2 + 1] == 'u' && in[n2 + 2] == '{') {
	uint32_t cp = 0;
	size_t i = n2 + 3;
	while (i < js->tlen && is_xdigit(in[i])) {
	cp = (cp << 4) \| unhex(in[i]);
	i++;
	}
	if (in[i] == '}') {
	if (cp < 0x80) {
	out[n1++] = (uint8_t) cp;
	} else if (cp < 0x800) {
	out[n1++] = (uint8_t) (0xC0 \| (cp >> 6));
	out[n1++] = (uint8_t) (0x80 \| (cp & 0x3F));
	} else if (cp < 0x10000) {
	out[n1++] = (uint8_t) (0xE0 \| (cp >> 12));
	out[n1++] = (uint8_t) (0x80 \| ((cp >> 6) & 0x3F));
	out[n1++] = (uint8_t) (0x80 \| (cp & 0x3F));
	} else {
	out[n1++] = (uint8_t) (0xF0 \| (cp >> 18));
	out[n1++] = (uint8_t) (0x80 \| ((cp >> 12) & 0x3F));
	out[n1++] = (uint8_t) (0x80 \| ((cp >> 6) & 0x3F));
	out[n1++] = (uint8_t) (0x80 \| (cp & 0x3F));
	}
	n2 = i;
	} else {
	out[n1++] = in[n2 + 1];
	}
	} else if (in[n2 + 1] == 'u' && is_xdigit(in[n2 + 2]) &&
	is_xdigit(in[n2 + 3]) && is_xdigit(in[n2 + 4]) &&
	is_xdigit(in[n2 + 5])) {
	uint32_t cp = (unhex(in[n2 + 2]) << 12U) \| (unhex(in[n2 + 3]) << 8U) \|
	(unhex(in[n2 + 4]) << 4U) \| unhex(in[n2 + 5]);
	if (cp < 0x80) {
	out[n1++] = (uint8_t) cp;
	} else if (cp < 0x800) {
	out[n1++] = (uint8_t) (0xC0 \| (cp >> 6));
	out[n1++] = (uint8_t) (0x80 \| (cp & 0x3F));
	} else {
	out[n1++] = (uint8_t) (0xE0 \| (cp >> 12));
	out[n1++] = (uint8_t) (0x80 \| ((cp >> 6) & 0x3F));
	out[n1++] = (uint8_t) (0x80 \| (cp & 0x3F));
	}
	n2 += 4;
	} else if (in[n2 + 1] == '\\') {
	out[n1++] = '\\';
	} else {
	out[n1++] = in[n2 + 1];
	}
	n2++;
	} else {
	out[n1++] = ((uint8_t *) js->code)[js->toff + n2];
	}
	}
	return js_mkstr(js, NULL, n1);
	}

	static jsval_t js_bigint_literal(struct js *js) {
	const char *start = &js->code[js->toff];
	size_t len = js->tlen - 1;
	while (len > 1 && start[0] == '0') { start++; len--; }
	bool neg = false;
	if (len > 0 && start[0] == '-') { neg = true; start++; len--; }
	return js_mkbigint(js, start, len, neg);
	}

	static jsval_t js_arr_destruct_assign(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	js->consumed = 1;

	js_parse_state_t pattern_state;
	JS_SAVE_STATE(js, pattern_state);

	int depth = 1;
	while (depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LBRACKET) depth++;
	else if (js->tok == TOK_RBRACKET) depth--;
	if (depth > 0) js->consumed = 1;
	}
	js->consumed = 1;

	if (next(js) != TOK_ASSIGN) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "array destructuring requires assignment");
	}
	js->consumed = 1;

	jsval_t v = js_expr(js);
	if (is_err(v)) return v;

	jsval_t arr = js_mkundef();
	if (exe) {
	arr = resolveprop(js, v);
	if (vtype(arr) != T_ARR && vtype(arr) != T_STR) {
	return js_mkerr(js, "cannot array destructure non-iterable");
	}
	}

	js_parse_state_t end_state;
	JS_SAVE_STATE(js, end_state);
	JS_RESTORE_STATE(js, pattern_state);

	int index = 0;
	while (next(js) != TOK_RBRACKET && next(js) != TOK_EOF) {
	if (next(js) == TOK_COMMA) {
	js->consumed = 1;
	index++;
	continue;
	}

	bool is_rest = false;
	if (next(js) == TOK_REST) {
	is_rest = true;
	js->consumed = 1;
	}

	if (next(js) != TOK_IDENTIFIER) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected in array destructuring");
	}
	jsoff_t var_off = js->toff, var_len = js->tlen;
	js->consumed = 1;

	jsoff_t default_off = 0, default_len = 0;
	if (!is_rest && next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	default_off = js->pos;
	uint8_t sf = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t r = js_expr(js);
	js->flags = sf;
	if (is_err(r)) return r;
	default_len = js->pos - default_off;
	}

	if (exe) {
	const char *var_name = &js->code[var_off];

	jsval_t prop_val;
	if (is_rest) {
	jsval_t rest_arr = js_mkarr(js);
	if (is_err(rest_arr)) return rest_arr;
	jsoff_t total_len = vtype(arr) == T_STR ? 0 : arr_length(js, arr);
	if (vtype(arr) == T_STR) {
	jsoff_t slen;
	vstr(js, arr, &slen);
	total_len = slen;
	}
	for (jsoff_t i = index; i < total_len; i++) {
	jsval_t elem;
	if (vtype(arr) == T_STR) {
	jsoff_t slen, soff = vstr(js, arr, &slen);
	elem = js_mkstr(js, (char *)&js->mem[soff + i], 1);
	} else {
	elem = arr_get(js, arr, i);
	}
	js_arr_push(js, rest_arr, elem);
	}
	prop_val = rest_arr;
	} else {
	if (vtype(arr) == T_STR) {
	jsoff_t slen, soff = vstr(js, arr, &slen);
	if ((jsoff_t)index < slen) {
	prop_val = js_mkstr(js, (char *)&js->mem[soff + index], 1);
	} else {
	prop_val = js_mkundef();
	}
	} else {
	prop_val = arr_get(js, arr, index);
	}

	if (vtype(prop_val) == T_UNDEF && default_len > 0) {
	prop_val = js_eval_slice(js, default_off, default_len);
	if (is_err(prop_val)) return prop_val;
	prop_val = resolveprop(js, prop_val);
	}
	}

	jsoff_t existing = lkp_scope(js, js->scope, var_name, var_len);
	if (existing != 0) {
	jsval_t res = setprop(js, js->scope, js_mkstr(js, var_name, var_len), prop_val);
	if (is_err(res)) return res;
	} else {
	jsval_t global_scope = js->scope;
	while (vdata(upper(js, global_scope)) != 0) {
	global_scope = upper(js, global_scope);
	}
	jsval_t res = setprop(js, global_scope, js_mkstr(js, var_name, var_len), prop_val);
	if (is_err(res)) return res;
	}
	}

	index++;
	if (next(js) == TOK_RBRACKET) break;
	EXPECT(TOK_COMMA);
	}

	JS_RESTORE_STATE(js, end_state);
	return v;
	}

	static jsval_t js_arr_literal(struct js *js);

	static jsval_t js_arr_or_destruct(struct js *js) {
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;
	uint8_t saved_flags = js->flags;

	js->flags \|= F_NOEXEC;
	js->consumed = 1;
	int depth = 1;
	while (depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LBRACKET) depth++;
	else if (js->tok == TOK_RBRACKET) depth--;
	if (depth > 0) js->consumed = 1;
	}
	js->consumed = 1;
	bool is_destruct = (next(js) == TOK_ASSIGN);

	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	js->flags = saved_flags;

	if (is_destruct) {
	return js_arr_destruct_assign(js);
	}
	return js_arr_literal(js);
	}

	static jsval_t js_arr_literal(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	jsval_t arr = exe ? mkarr(js) : js_mkundef();
	if (is_err(arr)) return arr;

	js->consumed = 1;
	jsoff_t idx = 0;
	while (next(js) != TOK_RBRACKET) {
	if (next(js) == TOK_COMMA) {
	idx++;
	js->consumed = 1;
	continue;
	}

	bool is_spread = (next(js) == TOK_REST);
	if (is_spread) js->consumed = 1;

	jsval_t val = js_expr(js);
	if (!exe) goto next_elem;
	if (is_err(val)) return val;

	jsval_t resolved = resolveprop(js, val);
	if (!is_spread) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t res = setprop(js, arr, key, resolved);
	if (is_err(res)) return res;
	idx++;
	goto next_elem;
	}

	uint8_t t = vtype(resolved);
	if (t != T_ARR && t != T_STR) goto next_elem;

	if (t == T_STR) {
	jsoff_t slen, soff = vstr(js, resolved, &slen);
	for (jsoff_t i = 0; i < slen; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t ch = js_mkstr(js, (char *)&js->mem[soff + i], 1);
	setprop(js, arr, key, ch);
	idx++;
	}
	goto next_elem;
	}

	jsoff_t len = arr_length(js, resolved);
	for (jsoff_t i = 0; i < len; i++) {
	char src_idx[16], dst_idx[16];
	snprintf(src_idx, sizeof(src_idx), "%u", (unsigned)i);
	snprintf(dst_idx, sizeof(dst_idx), "%u", (unsigned)idx);
	jsval_t key = js_mkstr(js, src_idx, strlen(src_idx));
	jsoff_t prop_off = lkp(js, resolved, (char *)&js->mem[(jsoff_t)vdata(key) + sizeof(jsoff_t)], strlen(src_idx));
	jsval_t elem = (prop_off != 0) ? resolveprop(js, mkval(T_PROP, prop_off)) : js_mkundef();
	setprop(js, arr, js_mkstr(js, dst_idx, strlen(dst_idx)), elem);
	idx++;
	}

	next_elem:
	if (next(js) == TOK_RBRACKET) break;
	EXPECT(TOK_COMMA);
	}

	EXPECT(TOK_RBRACKET);
	if (exe) {
	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double)idx);
	jsval_t res = setprop(js, arr, len_key, len_val);
	if (is_err(res)) return res;
	arr = mkval(T_ARR, vdata(arr));
	}
	return arr;
	}

	static jsval_t js_regex_literal(struct js *js) {
	jsoff_t start = js->pos;
	jsoff_t pattern_start = start;
	bool in_class = false;

	while (js->pos < js->clen) {
	char c = js->code[js->pos];
	if (c == '\\' && js->pos + 1 < js->clen) {
	js->pos += 2;
	continue;
	}
	if (c == '[') in_class = true;
	else if (c == ']') in_class = false;
	else if (c == '/' && !in_class) break;
	js->pos++;
	}

	if (js->pos >= js->clen \|\| js->code[js->pos] != '/') {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "unterminated regex");
	}

	jsoff_t pattern_end = js->pos;
	js->pos++;

	jsoff_t flags_start = js->pos;
	while (js->pos < js->clen) {
	char c = js->code[js->pos];
	if (c == 'g' \|\| c == 'i' \|\| c == 'm' \|\| c == 's' \|\| c == 'u' \|\| c == 'y') {
	js->pos++;
	} else {
	break;
	}
	}
	jsoff_t flags_end = js->pos;

	if (js->flags & F_NOEXEC) return js_mkundef();

	jsval_t pattern = js_mkstr(js, &js->code[pattern_start], pattern_end - pattern_start);
	jsval_t flags = js_mkstr(js, &js->code[flags_start], flags_end - flags_start);

	jsval_t regexp_obj = mkobj(js, 0);
	jsval_t regexp_proto = get_ctor_proto(js, "RegExp", 6);
	if (vtype(regexp_proto) == T_OBJ) set_proto(js, regexp_obj, regexp_proto);

	setprop(js, regexp_obj, js_mkstr(js, "source", 6), pattern);
	setprop(js, regexp_obj, js_mkstr(js, "flags", 5), flags);

	jsoff_t flen = flags_end - flags_start;
	const char *fstr = &js->code[flags_start];
	bool global = false, ignoreCase = false, multiline = false, dotAll = false, sticky = false;
	for (jsoff_t i = 0; i < flen; i++) {
	if (fstr[i] == 'g') global = true;
	if (fstr[i] == 'i') ignoreCase = true;
	if (fstr[i] == 'm') multiline = true;
	if (fstr[i] == 's') dotAll = true;
	if (fstr[i] == 'y') sticky = true;
	}

	setprop(js, regexp_obj, js_mkstr(js, "global", 6), mkval(T_BOOL, global ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "ignoreCase", 10), mkval(T_BOOL, ignoreCase ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "multiline", 9), mkval(T_BOOL, multiline ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "dotAll", 6), mkval(T_BOOL, dotAll ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "sticky", 6), mkval(T_BOOL, sticky ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "lastIndex", 9), tov(0));

	return regexp_obj;
	}

	static jsval_t set_obj_property(struct js js, jsval_t obj, jsval_t key, jsval_t val, bool is_computed, bool proto_set) {
	bool is_proto = false;
	if (!is_computed && vtype(key) == T_STR) {
	jsoff_t klen;
	const char kstr = (char )&js->mem[vstr(js, key, &klen)];
	is_proto = (klen == STR_PROTO_LEN && memcmp(kstr, STR_PROTO, STR_PROTO_LEN) == 0);
	}

	if (is_proto) {
	if (*proto_set) return js_mkerr_typed(js, JS_ERR_SYNTAX, "Duplicate __proto__ fields are not allowed in object literals");
	*proto_set = true;
	uint8_t pt = vtype(val);
	if (pt == T_OBJ \|\| pt == T_ARR \|\| pt == T_FUNC \|\| pt == T_NULL) {
	set_proto(js, obj, pt == T_NULL ? js_mknull() : val);
	}
	return js_mkundef();
	}

	if (vtype(val) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(val));
	if (lkp(js, func_obj, "name", 4) == 0) {
	jsval_t name_key = js_mkstr(js, "name", 4);
	if (!is_err(name_key)) setprop(js, func_obj, name_key, key);
	}
	}

	return setprop(js, obj, key, val);
	}

	static jsval_t js_obj_literal(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	jsval_t obj = exe ? mkobj(js, 0) : js_mkundef();
	if (is_err(obj)) return obj;
	if (exe) {
	jsval_t object_proto = get_ctor_proto(js, "Object", 6);
	if (vtype(object_proto) == T_OBJ) set_proto(js, obj, object_proto);
	}
	js->consumed = 1;
	bool proto_set_in_literal = false;

	while (next(js) != TOK_RBRACE) {
	jsval_t key = 0;
	jsoff_t id_off = 0, id_len = 0;
	bool is_computed = false;

	if (js->tok == TOK_REST) {
	js->consumed = 1;
	jsval_t spread_expr = js_expr(js);
	if (is_err(spread_expr)) return spread_expr;
	if (!exe) goto spread_next;

	jsval_t spread_obj = resolveprop(js, spread_expr);
	uint8_t st = vtype(spread_obj);
	if (st != T_OBJ && st != T_ARR && st != T_FUNC) goto spread_next;

	jsval_t src_obj = (st == T_OBJ) ? spread_obj : mkval(T_OBJ, vdata(spread_obj));
	jsoff_t next_prop_off = loadoff(js, (jsoff_t) vdata(src_obj)) & ~(3U \| FLAGMASK);

	while (next_prop_off < js->brk && next_prop_off != 0) {
	jsoff_t header = loadoff(js, next_prop_off);
	if (is_slot_prop(header)) { next_prop_off = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next_prop_off + (jsoff_t) sizeof(next_prop_off));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char prop_key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t prop_val = loadval(js, next_prop_off + (jsoff_t) (sizeof(next_prop_off) + sizeof(koff)));

	next_prop_off = next_prop(header);
	if (is_internal_prop(prop_key, klen)) continue;

	jsval_t key_str = js_mkstr(js, prop_key, klen);
	setprop(js, obj, key_str, prop_val);
	}

	spread_next:
	if (next(js) == TOK_RBRACE) break;
	EXPECT(TOK_COMMA);
	continue;
	}

	bool is_getter = false, is_setter = false;
	if (js->tok == TOK_IDENTIFIER) {
	bool is_get = (js->tlen == 3 && memcmp(js->code + js->toff, "get", 3) == 0);
	bool is_set = (js->tlen == 3 && memcmp(js->code + js->toff, "set", 3) == 0);

	if (is_get \|\| is_set) {
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;
	jsoff_t saved_toff = js->toff;
	jsoff_t saved_tlen = js->tlen;

	js->consumed = 1;
	uint8_t peek = next(js);

	if (peek == TOK_IDENTIFIER \|\| peek == TOK_STRING \|\| peek == TOK_NUMBER \|\| peek == TOK_LBRACKET) {
	is_getter = is_get;
	is_setter = is_set;

	if (peek == TOK_IDENTIFIER) {
	id_off = js->toff;
	id_len = js->tlen;
	if (exe) key = js_mkstr_ident(js, js->code + js->toff, js->tlen);
	} else if (peek == TOK_STRING) {
	id_off = js->toff;
	id_len = js->tlen;
	if (exe) key = js_str_literal(js);
	} else if (peek == TOK_NUMBER) {
	id_off = js->toff;
	id_len = js->tlen;
	if (exe) {
	double num = strtod(js->code + js->toff, NULL);
	char buf[64];
	size_t n = strnum(tov(num), buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}
	} else if (peek == TOK_LBRACKET) {
	is_computed = true;
	js->consumed = 1;
	jsval_t key_expr = js_expr(js);
	if (is_err(key_expr)) return key_expr;

	if (exe) {
	jsval_t resolved_key = resolveprop(js, key_expr);
	if (vtype(resolved_key) == T_STR) {
	key = resolved_key;
	} else {
	char buf[64];
	size_t n = tostr(js, resolved_key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}
	if (is_err(key)) return key;
	}

	if (next(js) != TOK_RBRACKET) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "] expected after computed property name");
	}
	}
	} else {
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	js->toff = saved_toff;
	js->tlen = saved_tlen;

	id_off = saved_toff;
	id_len = saved_tlen;
	if (exe) key = js_mkstr_ident(js, js->code + saved_toff, saved_tlen);
	}
	} else {
	id_off = js->toff;
	id_len = js->tlen;
	if (exe) key = js_mkstr_ident(js, js->code + js->toff, js->tlen);
	}
	} else if (js->tok == TOK_STRING) {
	if (exe) key = js_str_literal(js);
	} else if (js->tok == TOK_NUMBER) {
	if (exe) {
	double num = strtod(js->code + js->toff, NULL);
	char buf[64];
	size_t n = strnum(tov(num), buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}
	} else if (js->tok == TOK_LBRACKET) {
	is_computed = true;
	js->consumed = 1;
	jsval_t key_expr = js_expr(js);
	if (is_err(key_expr)) return key_expr;

	if (exe) {
	jsval_t resolved_key = resolveprop(js, key_expr);
	if (vtype(resolved_key) == T_STR) {
	key = resolved_key;
	} else if (vtype(resolved_key) == T_SYMBOL) {
	char buf[64];
	snprintf(buf, sizeof(buf), "__sym_%llu__", (unsigned long long)sym_get_id(resolved_key));
	key = js_mkstr(js, buf, strlen(buf));
	} else {
	char buf[64];
	size_t n = tostr(js, resolved_key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}
	if (is_err(key)) return key;
	}

	if (next(js) != TOK_RBRACKET) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "] expected after computed property name");
	}
	} else if (is_keyword_propname(js->tok)) {
	id_off = js->toff;
	id_len = js->tlen;
	if (exe) key = js_mkstr(js, js->code + js->toff, js->tlen);
	} else {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "parse error");
	}
	js->consumed = 1;

	if (!is_computed && id_len > 0 && (next(js) == TOK_COMMA \|\| next(js) == TOK_RBRACE)) {
	jsval_t val = lookup(js, js->code + id_off, id_len);
	if (exe) {
	if (is_err(val)) return val;
	if (is_err(key)) return key;
	jsval_t res = setprop(js, obj, key, resolveprop(js, val));
	if (is_err(res)) return res;
	}
	} else if (
	(is_getter \|\| is_setter) \|\|
	(!is_computed && id_len > 0 && next(js) == TOK_LPAREN) \|\|
	(is_computed && next(js) == TOK_LPAREN)
	) {
	uint8_t flags = js->flags;
	jsoff_t pos = js->pos - 1;
	js->consumed = 1;
	if (!parse_func_params(js, &flags, NULL)) {
	js->flags = flags;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "invalid parameters");
	}
	EXPECT(TOK_RPAREN, js->flags = flags);
	EXPECT(TOK_LBRACE, js->flags = flags);
	js->consumed = 0;
	js->flags \|= F_NOEXEC;
	jsval_t block_res = js_block(js, false);
	if (is_err(block_res)) {
	js->flags = flags;
	return block_res;
	}
	js->flags = flags;
	js->consumed = 1;

	if (exe) {
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	set_func_code(js, func_obj, &js->code[pos], js->pos - pos);
	jsval_t name_key = js_mkstr(js, "name", 4);
	setprop(js, func_obj, name_key, key);

	jsval_t closure_scope = for_let_capture_scope(js);
	if (is_err(closure_scope)) return closure_scope;
	set_slot(js, func_obj, SLOT_SCOPE, closure_scope);

	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, func_obj, func_proto);
	jsval_t val = mkval(T_FUNC, (unsigned long) vdata(func_obj));

	if (is_getter \|\| is_setter) {
	jsoff_t key_len;
	const char *key_str = NULL;
	if (vtype(key) == T_STR) {
	jsoff_t key_off = vstr(js, key, &key_len);
	key_str = (char *)&js->mem[key_off];
	}

	if (key_str) {
	if (is_getter) {
	js_set_getter_desc(js, obj, key_str, key_len, val, JS_DESC_E \| JS_DESC_C);
	} else js_set_setter_desc(js, obj, key_str, key_len, val, JS_DESC_E \| JS_DESC_C);
	}
	} else {
	jsval_t res = setprop(js, obj, key, val);
	if (is_err(res)) return res;
	}
	}
	} else {
	EXPECT(TOK_COLON);
	jsval_t val = js_expr(js);
	if (exe) {
	if (is_err(val)) return val;
	if (is_err(key)) return key;
	jsval_t res = set_obj_property(
	js, obj, key, resolveprop(js, val),
	is_computed, &proto_set_in_literal
	);
	if (is_err(res)) return res;
	}
	}

	if (next(js) == TOK_RBRACE) break;
	EXPECT(TOK_COMMA);
	}

	EXPECT(TOK_RBRACE);
	return obj;
	}

	static void skip_default_value(struct js *js) {
	int depth = 0;
	while (next(js) != TOK_EOF) {
	uint8_t tok = next(js);
	if (depth == 0 && (tok == TOK_RPAREN \|\| tok == TOK_COMMA)) break;
	js->consumed = 1;
	if (tok == TOK_LPAREN \|\| tok == TOK_LBRACKET \|\| tok == TOK_LBRACE) depth++;
	else if (tok == TOK_RPAREN \|\| tok == TOK_RBRACKET \|\| tok == TOK_RBRACE) depth--;
	}
	}

	static void skip_destructuring_pattern(struct js *js) {
	uint8_t open_tok = js->tok;
	uint8_t close_tok = (open_tok == TOK_LBRACE) ? TOK_RBRACE : TOK_RBRACKET;
	int depth = 1;
	js->consumed = 1;
	while (depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == open_tok) depth++;
	else if (js->tok == close_tok) depth--;
	if (depth > 0) js->consumed = 1;
	}
	js->consumed = 1;
	}

	typedef struct { const char *name; size_t len; } param_entry_t;
	static const UT_icd param_entry_icd = { sizeof(param_entry_t), NULL, NULL, NULL };

	static bool parse_func_params(struct js js, uint8_t flags, int *out_count) {
	UT_array *params;
	utarray_new(params, &param_entry_icd);

	#define FAIL(msg, ...) do { \
	if (flags) js->flags = *flags; \
	js_mkerr_typed(js, JS_ERR_SYNTAX, msg, ##__VA_ARGS__); \
	utarray_free(params); \
	return false; \
	} while(0)

	while (next(js) != TOK_EOF && next(js) != TOK_RPAREN) {
	bool is_rest = (next(js) == TOK_REST);
	if (is_rest) { js->consumed = 1; next(js); }

	if (next(js) == TOK_LBRACE \|\| next(js) == TOK_LBRACKET) {
	skip_destructuring_pattern(js);
	param_entry_t entry = {NULL, 0};
	utarray_push_back(params, &entry);
	if (next(js) == TOK_ASSIGN) { js->consumed = 1; skip_default_value(js); }
	} else if (is_valid_param_name(next(js))) {
	const char *name = &js->code[js->toff];
	size_t len = js->tlen;

	if ((js->flags & F_STRICT) && is_strict_restricted(name, len))
	FAIL("cannot use '%.*s' as parameter name in strict mode", (int)len, name);

	if (js->flags & F_STRICT) {
	param_entry_t *p = NULL;
	while ((p = (param_entry_t *)utarray_next(params, p))) {
	if (p->len == len && p->name && memcmp(p->name, name, len) == 0)
	FAIL("duplicate parameter name '%.*s' in strict mode", (int)len, name);
	}
	}

	param_entry_t entry = {name, len};
	utarray_push_back(params, &entry);
	js->consumed = 1;
	if (next(js) == TOK_ASSIGN) { js->consumed = 1; skip_default_value(js); }
	} else {
	FAIL("identifier expected");
	}

	if (is_rest && next(js) != TOK_RPAREN) FAIL("rest parameter must be last");
	if (next(js) == TOK_RPAREN) break;
	if (next(js) != TOK_COMMA) FAIL("parse error");
	js->consumed = 1;
	}

	#undef FAIL

	if (out_count) *out_count = (int)utarray_len(params);
	utarray_free(params);
	return true;
	}

	static jsval_t js_func_literal(struct js *js, bool is_async) {
	uint8_t flags = js->flags;
	js->consumed = 1;
	jsoff_t name_off = 0, name_len = 0;
	if (next(js) == TOK_IDENTIFIER) {
	name_off = js->toff;
	name_len = js->tlen;
	js->consumed = 1;
	}

	EXPECT(TOK_LPAREN, js->flags = flags);
	jsoff_t pos = js->pos - 1;
	int param_count = 0;
	if (!parse_func_params(js, &flags, &param_count)) {
	js->flags = flags;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "invalid parameters");
	}

	EXPECT(TOK_RPAREN, js->flags = flags);
	EXPECT(TOK_LBRACE, js->flags = flags);
	js->consumed = 0;
	js->flags \|= F_NOEXEC;

	jsval_t res = js_block(js, false);
	if (is_err(res)) {
	js->flags = flags;
	return res;
	}
	js->flags = flags;
	js->consumed = 1;
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	set_func_code(js, func_obj, &js->code[pos], js->pos - pos);

	jsval_t len_key = js_mkstr(js, "length", 6);
	if (is_err(len_key)) return len_key;
	jsval_t res_len = setprop(js, func_obj, len_key, tov(param_count));
	if (is_err(res_len)) return res_len;
	js_set_descriptor(js, func_obj, "length", 6, JS_DESC_C);

	if (is_async) {
	set_slot(js, func_obj, SLOT_ASYNC, js_mktrue());
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);
	} else {
	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, func_obj, func_proto);
	}

	if (name_len > 0) {
	jsval_t name_val = js_mkstr(js, &js->code[name_off], name_len);
	if (is_err(name_val)) return name_val;
	set_slot(js, func_obj, SLOT_NAME, name_val);
	jsval_t name_key = js_mkstr(js, "name", 4);
	if (is_err(name_key)) return name_key;
	jsval_t res3 = setprop(js, func_obj, name_key, name_val);
	if (is_err(res3)) return res3;
	}

	if (!(flags & F_NOEXEC)) {
	jsval_t closure_scope = for_let_capture_scope(js);
	if (is_err(closure_scope)) return closure_scope;
	set_slot(js, func_obj, SLOT_SCOPE, closure_scope);
	if (flags & F_STRICT) set_slot(js, func_obj, SLOT_STRICT, js_mktrue());
	}

	jsval_t func = mkval(T_FUNC, (unsigned long) vdata(func_obj));

	jsval_t proto_setup = setup_func_prototype(js, func);
	if (is_err(proto_setup)) return proto_setup;

	return func;
	}

	#define RTL_BINOP(_f1, _f2, _cond) \
	jsval_t res = _f1(js); \
	while (!is_err(res) && (_cond)) { \
	uint8_t op = js->tok; \
	js->consumed = 1; \
	jsval_t rhs = _f2(js); \
	if (is_err(rhs)) return rhs; \
	res = do_op(js, op, res, rhs); \
	} \
	return res;

	#define LTR_BINOP(_f, _cond) \
	jsval_t res = _f(js); \
	while (!is_err(res) && (_cond)) { \
	uint8_t op = js->tok; \
	js->consumed = 1; \
	jsval_t rhs = _f(js); \
	if (is_err(rhs)) return rhs; \
	res = do_op(js, op, res, rhs); \
	} \
	return res;

	static jsval_t js_class_expr(struct js *js, bool is_expression);

	static jsval_t js_literal(struct js *js) {
	next(js);
	js->consumed = 1;

	switch (js->tok) {
	case TOK_ERR:
	if ((js->flags & F_STRICT) && js->toff < js->clen && js->code[js->toff] == '0' &&
	js->toff + 1 < js->clen && is_digit(js->code[js->toff + 1])) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "octal literals are not allowed in strict mode");
	}
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "parse error");
	case TOK_NUMBER: return js->tval;
	case TOK_BIGINT: return js_bigint_literal(js);
	case TOK_STRING: return js_str_literal(js);
	case TOK_TEMPLATE: return js_template_literal(js);
	case TOK_LBRACE: return js_obj_literal(js);
	case TOK_LBRACKET: return js_arr_or_destruct(js);
	case TOK_DIV: return js_regex_literal(js);
	case TOK_CLASS: return js_class_expr(js, true);
	case TOK_FUNC: {
	uint8_t la = lookahead(js);
	if (la != TOK_LPAREN && la != TOK_IDENTIFIER) {
	return mkcoderef((jsoff_t) js->toff, (jsoff_t) js->tlen);
	}
	return js_func_literal(js, false);
	}
	case TOK_ASYNC: {
	jsoff_t async_off = js->toff, async_len = js->tlen;
	js->consumed = 1;
	uint8_t next_tok = next(js);
	if (next_tok == TOK_FUNC) {
	return js_func_literal(js, true);
	} else if (next_tok == TOK_LPAREN) {
	return js_async_arrow_paren(js);
	} else if (next_tok == TOK_IDENTIFIER) {
	jsoff_t id_start = js->toff;
	jsoff_t id_len = js->tlen;
	js->consumed = 1;
	if (next(js) == TOK_ARROW) {
	js->consumed = 1;
	char param_buf[256];
	if (id_len + 3 > sizeof(param_buf)) return js_mkerr(js, "param too long");
	param_buf[0] = '(';
	memcpy(param_buf + 1, &js->code[id_start], id_len);
	param_buf[id_len + 1] = ')';
	param_buf[id_len + 2] = '\0';
	uint8_t flags = js->flags;
	bool is_expr = next(js) != TOK_LBRACE;
	jsoff_t body_start = is_expr ? js->toff : js->pos;
	jsoff_t body_end = 0;
	jsval_t body_result;
	if (is_expr) {
	js->flags \|= F_NOEXEC;
	body_result = js_assignment(js);
	if (is_err(body_result)) { js->flags = flags; return body_result; }
	uint8_t tok = next(js);
	body_end = is_body_end_tok(tok) ? js->toff : js->pos;
	} else {
	body_start = js->toff;
	js->flags \|= F_NOEXEC;
	js->consumed = 1;
	body_result = js_block(js, false);
	if (is_err(body_result)) { js->flags = flags; return body_result; }
	if (js->tok == TOK_RBRACE && js->consumed) {
	body_end = js->pos;
	} else if (next(js) == TOK_RBRACE) {
	body_end = js->pos;
	js->consumed = 1;
	} else body_end = js->pos;
	}
	js->flags = flags;
	size_t fn_size = id_len + (body_end - body_start) + 64;
	char fn_str = (char ) malloc(fn_size);
	if (!fn_str) return js_mkerr(js, "oom");
	jsoff_t fn_pos = 0;
	memcpy(fn_str + fn_pos, param_buf, id_len + 2);
	fn_pos += id_len + 2;
	if (is_expr) {
	fn_str[fn_pos++] = '{';
	memcpy(fn_str + fn_pos, "return ", 7);
	fn_pos += 7;
	size_t body_len = body_end - body_start;
	memcpy(fn_str + fn_pos, &js->code[body_start], body_len);
	fn_pos += body_len;
	fn_str[fn_pos++] = '}';
	} else {
	size_t body_len = body_end - body_start;
	memcpy(fn_str + fn_pos, &js->code[body_start], body_len);
	fn_pos += body_len;
	}
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) { free(fn_str); return func_obj; }
	set_func_code(js, func_obj, fn_str, fn_pos);
	free(fn_str);
	set_slot(js, func_obj, SLOT_ASYNC, js_mktrue());
	set_slot(js, func_obj, SLOT_ARROW, tov(1));
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);
	if (!(flags & F_NOEXEC)) {
	jsval_t closure_scope = for_let_capture_scope(js);
	if (is_err(closure_scope)) return closure_scope;
	set_slot(js, func_obj, SLOT_SCOPE, closure_scope);
	set_slot(js, func_obj, SLOT_THIS, js->this_val);
	}
	return mkval(T_FUNC, (unsigned long) vdata(func_obj));
	}
	return mkcoderef((jsoff_t) id_start, (jsoff_t) id_len);
	}
	return mkcoderef(async_off, async_len);
	}

	case TOK_SUPER: {
	jsval_t super_ctor = js->super_val;
	uint8_t la = lookahead(js);
	if ((la == TOK_DOT \|\| la == TOK_LBRACKET) && vtype(super_ctor) == T_FUNC) {
	jsval_t ctor_obj = mkval(T_OBJ, vdata(super_ctor));
	jsoff_t proto_off = lkp_interned(js, ctor_obj, INTERN_PROTOTYPE, 9);
	if (proto_off == 0) return js_mkundef();
	jsval_t proto = resolveprop(js, mkval(T_PROP, proto_off));

	next(js); js->consumed = 1;
	const char *prop; jsoff_t prop_len;
	if (la == TOK_DOT) {
	if (next(js) != TOK_IDENTIFIER && !is_keyword_propname(js->tok))
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected");
	prop = &js->code[js->toff]; prop_len = js->tlen;
	js->consumed = 1;
	} else {
	jsval_t idx = js_expr(js);
	if (is_err(idx)) return idx;
	if (next(js) != TOK_RBRACKET) return js_mkerr_typed(js, JS_ERR_SYNTAX, "] expected");
	js->consumed = 1;
	idx = resolveprop(js, idx);
	if (vtype(idx) == T_STR) {
	prop_len = 0; prop = (const char *)&js->mem[vstr(js, idx, &prop_len)];
	} else {
	char buf[32]; prop_len = (jsoff_t)tostr(js, idx, buf, sizeof(buf));
	prop = buf;
	}
	}

	jsoff_t off = lkp(js, proto, prop, prop_len);
	if (off == 0) off = lkp_proto(js, proto, prop, prop_len);
	if (off == 0) return js_mkundef();

	jsval_t method = resolveprop(js, mkval(T_PROP, off));
	if (vtype(method) != T_FUNC) return method;

	jsval_t bound = mkobj(js, 0);
	jsval_t method_obj = mkval(T_OBJ, vdata(method));

	set_slot(js, bound, SLOT_CODE, get_slot(js, method_obj, SLOT_CODE));
	set_slot(js, bound, SLOT_CODE_LEN, get_slot(js, method_obj, SLOT_CODE_LEN));
	set_slot(js, bound, SLOT_SCOPE, get_slot(js, method_obj, SLOT_SCOPE));
	set_slot(js, bound, SLOT_BOUND_THIS, js->this_val);

	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, bound, func_proto);

	return mkval(T_FUNC, vdata(bound));
	}
	return super_ctor;
	}

	case TOK_NULL: return js_mknull();
	case TOK_UNDEF: return js_mkundef();
	case TOK_TRUE: return js_mktrue();
	case TOK_FALSE: return js_mkfalse();
	case TOK_THIS: return js->this_val;

	default:
	if (is_identifier_like(js->tok)) return mkcoderef((jsoff_t) js->toff, (jsoff_t) js->tlen);
	size_t tok_len = js->tlen > 20 ? 20 : js->tlen;
	if (tok_len == 0) return js_mkerr_typed(js, JS_ERR_SYNTAX, "Unexpected token 'EOF'");
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "Unexpected token '%.*s'", (int)tok_len, &js->code[js->toff]);
	}
	}

	static jsval_t js_arrow_func(struct js *js, jsoff_t params_start, jsoff_t params_end, bool is_async) {
	uint8_t flags = js->flags;
	bool is_expr = next(js) != TOK_LBRACE;
	jsoff_t body_start, body_end_actual;
	jsval_t body_result;

	if (is_expr) {
	body_start = js->toff;
	js->flags \|= F_NOEXEC;
	body_result = js_assignment(js);
	if (is_err(body_result)) {
	js->flags = flags;
	return body_result;
	}
	uint8_t tok = next(js);
	body_end_actual = is_body_end_tok(tok) ? js->toff : js->pos;
	} else {
	body_start = js->toff;
	js->flags \|= F_NOEXEC;
	js->consumed = 1;
	body_result = js_block(js, false);
	if (is_err(body_result)) {
	js->flags = flags;
	return body_result;
	}
	if (js->tok == TOK_RBRACE && js->consumed) {
	body_end_actual = js->pos;
	} else if (next(js) == TOK_RBRACE) {
	body_end_actual = js->pos;
	js->consumed = 1;
	} else {
	body_end_actual = js->pos;
	}
	}

	js->flags = flags;

	size_t fn_size = (params_end - params_start) + (body_end_actual - body_start) + 32;
	char fn_str = (char ) malloc(fn_size);
	if (!fn_str) return js_mkerr(js, "oom");

	jsoff_t fn_pos = 0;

	size_t param_len = params_end - params_start;
	memcpy(fn_str + fn_pos, &js->code[params_start], param_len);
	fn_pos += param_len;

	if (is_expr) {
	fn_str[fn_pos++] = '{';
	memcpy(fn_str + fn_pos, "return ", 7);
	fn_pos += 7;
	size_t body_len = body_end_actual - body_start;
	memcpy(fn_str + fn_pos, &js->code[body_start], body_len);
	fn_pos += body_len;
	fn_str[fn_pos++] = '}';
	} else {
	size_t body_len = body_end_actual - body_start;
	memcpy(fn_str + fn_pos, &js->code[body_start], body_len);
	fn_pos += body_len;
	}

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) { free(fn_str); return func_obj; }

	set_func_code(js, func_obj, fn_str, fn_pos);
	free(fn_str);

	if (is_async) {
	set_slot(js, func_obj, SLOT_ASYNC, js_mktrue());
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);
	} else {
	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, func_obj, func_proto);
	}

	if (!(flags & F_NOEXEC)) {
	jsval_t closure_scope = for_let_capture_scope(js);
	if (is_err(closure_scope)) return closure_scope;
	set_slot(js, func_obj, SLOT_SCOPE, closure_scope);
	set_slot(js, func_obj, SLOT_THIS, js->this_val);
	}

	set_slot(js, func_obj, SLOT_ARROW, tov(1));
	return mkval(T_FUNC, (unsigned long) vdata(func_obj));
	}

	static jsval_t js_async_arrow_paren(struct js *js) {
	jsoff_t paren_start = js->pos - 1;
	js->consumed = 1;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;
	uint8_t saved_flags = js->flags;
	int paren_depth = 1;
	js->flags \|= F_NOEXEC;
	while (paren_depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LPAREN) paren_depth++;
	else if (js->tok == TOK_RPAREN) paren_depth--;
	js->consumed = 1;
	}
	jsoff_t paren_end = js->pos;
	bool is_arrow = lookahead(js) == TOK_ARROW;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	js->flags = saved_flags;
	if (is_arrow) {
	js->flags \|= F_NOEXEC;
	while (next(js) != TOK_RPAREN && next(js) != TOK_EOF) {
	js->consumed = 1;
	}
	if (next(js) != TOK_RPAREN) return js_mkerr_typed(js, JS_ERR_SYNTAX, ") expected");
	js->consumed = 1;
	js->flags = saved_flags;
	if (next(js) != TOK_ARROW) return js_mkerr_typed(js, JS_ERR_SYNTAX, "=> expected");
	js->consumed = 1;
	return js_arrow_func(js, paren_start, paren_end, true);
	}
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "async ( must be arrow function");
	}

	static jsval_t js_group(struct js *js) {
	if (next(js) == TOK_LPAREN) {
	if (++js->parse_depth > JS_MAX_PARSE_DEPTH) {
	js->parse_depth--;
	return js_mkerr_typed(js, JS_ERR_RANGE \| JS_ERR_NO_STACK, "Maximum call stack size exceeded");
	}
	jsoff_t paren_start = js->pos - 1;
	js->consumed = 1;

	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;
	uint8_t saved_flags = js->flags;

	int paren_depth = 1;
	bool could_be_arrow = true;
	js->flags \|= F_NOEXEC;

	while (paren_depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LPAREN) paren_depth++;
	else if (js->tok == TOK_RPAREN) paren_depth--;
	if (paren_depth > 0 && !is_valid_arrow_param_tok(js->tok)) could_be_arrow = false;
	js->consumed = 1;
	}

	jsoff_t paren_end = js->pos;
	bool is_arrow = could_be_arrow && lookahead(js) == TOK_ARROW;

	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	js->flags = saved_flags;

	if (is_arrow) {
	js->flags \|= F_NOEXEC;
	int skip_paren_depth = 1;
	while (skip_paren_depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LPAREN) skip_paren_depth++;
	else if (js->tok == TOK_RPAREN) skip_paren_depth--;
	if (skip_paren_depth > 0) js->consumed = 1;
	}

	if (next(js) != TOK_RPAREN) {
	js->parse_depth--;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, ") expected");
	}

	js->consumed = 1;
	js->flags = saved_flags;

	if (next(js) != TOK_ARROW) {
	js->parse_depth--;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "=> expected");
	}

	js->consumed = 1;
	js->parse_depth--;

	return js_arrow_func(js, paren_start, paren_end, false);
	} else {
	if (next(js) == TOK_RPAREN) {
	js->parse_depth--;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "Parenthesized expression cannot be empty");
	}

	jsval_t v = js_expr(js);
	if (is_err(v)) { js->parse_depth--; return v; }

	while (next(js) == TOK_COMMA) {
	js->consumed = 1;
	v = js_expr(js);
	if (is_err(v)) { js->parse_depth--; return v; }
	}

	if (next(js) != TOK_RPAREN) {
	js->parse_depth--;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, ") expected");
	}

	js->consumed = 1;
	js->parse_depth--;

	return v;
	}
	} else return js_literal(js);
	}

	static jsval_t js_call_dot(struct js *js) {
	jsval_t res = js_group(js);
	jsval_t obj = js_mkundef();
	if (is_err(res)) return res;
	if (vtype(res) == T_CODEREF) {
	if (lookahead(js) == TOK_ARROW) return res;
	if (lookahead(js) == TOK_TEMPLATE) {
	jsval_t tag_func = lookup(js, &js->code[coderefoff(res)], codereflen(res));
	if (is_err(tag_func)) return tag_func;
	if (!(js->flags & F_NOEXEC) && !is_err(tag_func)) tag_func = resolveprop(js, tag_func);
	js->consumed = 1;
	next(js);
	js->consumed = 1;
	res = js_tagged_template(js, tag_func);
	if (is_err(res)) return res;
	goto js_call_dot_loop;
	}
	if ((js->flags & F_STRICT) && is_eval_or_arguments(js, coderefoff(res), codereflen(res))) {
	uint8_t la = lookahead(js);
	if (la == TOK_ASSIGN \|\| la == TOK_PLUS_ASSIGN \|\| la == TOK_MINUS_ASSIGN \|\|
	la == TOK_MUL_ASSIGN \|\| la == TOK_DIV_ASSIGN \|\| la == TOK_REM_ASSIGN \|\|
	la == TOK_SHL_ASSIGN \|\| la == TOK_SHR_ASSIGN \|\| la == TOK_ZSHR_ASSIGN \|\|
	la == TOK_AND_ASSIGN \|\| la == TOK_XOR_ASSIGN \|\| la == TOK_OR_ASSIGN \|\|
	la == TOK_POSTINC \|\| la == TOK_POSTDEC) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot modify eval or arguments in strict mode");
	}
	}
	jsoff_t id_off = coderefoff(res);
	jsoff_t id_len = codereflen(res);
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;
	res = lookup(js, &js->code[id_off], id_len);
	if (is_err(res)) {
	if (!(js->flags & F_STRICT) && !(js->flags & F_NOEXEC)) {
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	uint8_t next_tok = next(js);
	if (next_tok == TOK_ASSIGN) {
	js->flags &= (uint8_t)~F_THROW;
	js->thrown_value = js_mkundef();
	if (js->errmsg) js->errmsg[0] = '\0';
	return mkcoderef(id_off, id_len);
	}
	}
	if (is_err(res)) return res;
	}
	}
	js_call_dot_loop:
	while (next(js) == TOK_LPAREN \|\| next(js) == TOK_DOT \|\| next(js) == TOK_OPTIONAL_CHAIN \|\| next(js) == TOK_LBRACKET \|\| next(js) == TOK_TEMPLATE) {
	if (js->tok == TOK_TEMPLATE) {
	if (vtype(res) == T_PROP) res = resolveprop(js, res);
	if (is_err(res)) return res;
	js->consumed = 1;
	res = js_tagged_template(js, res);
	if (is_err(res)) return res;
	} else if (js->tok == TOK_DOT \|\| js->tok == TOK_OPTIONAL_CHAIN) {
	uint8_t op = js->tok;
	js->consumed = 1;
	if (vtype(res) != T_PROP && vtype(res) != T_PROPREF) {
	obj = res;
	} else obj = resolveprop(js, res);
	jsval_t prop_name;
	uint8_t nxt = next(js);
	if (nxt == TOK_HASH) {
	js->consumed = 1;
	if (next(js) != TOK_IDENTIFIER) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "private field name expected");
	}
	js->consumed = 1;
	prop_name = mkcoderef((jsoff_t) js->toff, (jsoff_t) js->tlen);
	} else if (nxt == TOK_IDENTIFIER \|\| is_keyword_propname(nxt)) {
	js->consumed = 1;
	prop_name = mkcoderef((jsoff_t) js->toff, (jsoff_t) js->tlen);
	} else if (nxt == TOK_LBRACKET) {
	js->consumed = 1;
	jsval_t idx = js_expr(js);
	if (is_err(idx)) return idx;
	if (next(js) != TOK_RBRACKET) return js_mkerr_typed(js, JS_ERR_SYNTAX, "] expected");
	js->consumed = 1;
	if (op == TOK_OPTIONAL_CHAIN && (vtype(obj) == T_NULL \|\| vtype(obj) == T_UNDEF)) {
	res = js_mkundef();
	} else {
	res = do_op(js, TOK_BRACKET, res, idx);
	}
	continue;
	} else {
	prop_name = js_group(js);
	}
	if (op == TOK_OPTIONAL_CHAIN && (vtype(obj) == T_NULL \|\| vtype(obj) == T_UNDEF)) {
	res = js_mkundef();
	} else {
	res = do_op(js, op, res, prop_name);
	}
	} else if (js->tok == TOK_LBRACKET) {
	js->consumed = 1;
	if (vtype(res) != T_PROP && vtype(res) != T_PROPREF) {
	obj = res;
	} else {
	obj = resolveprop(js, res);
	}
	jsval_t idx = js_expr(js);
	if (is_err(idx)) return idx;
	if (next(js) != TOK_RBRACKET) return js_mkerr_typed(js, JS_ERR_SYNTAX, "] expected");
	js->consumed = 1;
	res = do_op(js, TOK_BRACKET, res, idx);
	} else {
	jsval_t func_this = obj;
	bool is_super_call = (vtype(js->super_val) != T_UNDEF && res == js->super_val);
	if (vtype(obj) == T_UNDEF) {
	if (vtype(res) == T_PROPREF) {
	jsoff_t obj_off = propref_obj(res);
	func_this = mkval(T_OBJ, obj_off);
	} else func_this = js->this_val;
	}
	push_this(func_this);
	jsval_t params = js_call_params(js);
	if (is_err(params)) {
	pop_this();
	return params;
	}
	res = do_op(js, TOK_CALL, res, params);
	pop_this();
	if (is_super_call && !is_err(res) && is_object_type(res)) {
	jsoff_t proto_off = lkp_interned(js, mkval(T_OBJ, vdata(js->current_func)), INTERN_PROTOTYPE, 9);
	if (proto_off) set_proto(js, res, resolveprop(js, mkval(T_PROP, proto_off)));
	js->this_val = res;
	if (global_this_stack.depth > 0) global_this_stack.stack[global_this_stack.depth - 1] = res;
	}
	obj = js_mkundef();
	}
	}
	return res;
	}

	static jsval_t js_postfix(struct js *js) {
	jsval_t res = js_call_dot(js);
	if (is_err(res)) return res;
	next(js);
	if ((js->tok == TOK_POSTINC \|\| js->tok == TOK_POSTDEC) && !js->had_newline) {
	js->consumed = 1;
	res = do_op(js, js->tok, res, 0);
	}
	return res;
	}

	static inline jsval_t resolve_coderef(struct js *js, jsval_t v) {
	if (vtype(v) == T_CODEREF) return lookup(js, &js->code[coderefoff(v)], codereflen(v));
	return v;
	}

	static void unlink_prop(struct js *js, jsoff_t obj_off, jsoff_t prop_off, jsoff_t prev_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~FLAGMASK;
	jsoff_t target = prev_off ? prev_off : obj_off;
	jsoff_t current = loadoff(js, target);

	saveoff(js, target, (deleted_next & ~3ULL) \| (current & (FLAGMASK \| 3ULL)));
	jsoff_t tail = loadoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t));

	if (tail == prop_off) {
	saveoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t), prev_off);
	}

	invalidate_prop_cache(js, obj_off, prop_off);
	js->needs_gc = true;
	}

	static jsval_t check_frozen_sealed(struct js js, jsval_t obj, const char action) {
	if (js_truthy(js, get_slot(js, obj, SLOT_FROZEN))) {
	if (js->flags & F_STRICT) return js_mkerr(js, "cannot %s property of frozen object", action);
	return js_mkfalse();
	}
	if (js_truthy(js, get_slot(js, obj, SLOT_SEALED))) {
	if (js->flags & F_STRICT) return js_mkerr(js, "cannot %s property of sealed object", action);
	return js_mkfalse();
	}
	return js_mkundef();
	}

	static jsval_t js_unary(struct js *js) {
	uint8_t tok = next(js);

	static const void *dispatch[] = {
	[TOK_NEW] = &&do_new,
	[TOK_DELETE] = &&do_delete,
	[TOK_AWAIT] = &&do_await,
	[TOK_POSTINC] = &&do_prefix_inc,
	[TOK_POSTDEC] = &&do_prefix_inc,
	[TOK_NOT] = &&do_unary_op,
	[TOK_TILDA] = &&do_unary_op,
	[TOK_TYPEOF] = &&do_typeof,
	[TOK_VOID] = &&do_unary_op,
	[TOK_MINUS] = &&do_unary_op,
	[TOK_PLUS] = &&do_unary_op,
	};

	if (tok < sizeof(dispatch)/sizeof(dispatch[0]) && dispatch[tok]) {
	goto *dispatch[tok];
	}
	return js_postfix(js);

	do_new: {
	js->consumed = 1;
	jsval_t obj = mkobj(js, 0);
	jsval_t saved_this = js->this_val;
	jsval_t saved_new_target = js->new_target;
	js->this_val = obj;

	jsval_t ctor = js_group(js);
	if (is_err(ctor)) { js->this_val = saved_this; return ctor; }

	while (next(js) == TOK_DOT \|\| next(js) == TOK_LBRACKET) {
	ctor = resolve_coderef(js, ctor);
	if (is_err(ctor)) { js->this_val = saved_this; return ctor; }

	if (js->tok == TOK_DOT) {
	js->consumed = 1;
	if (next(js) != TOK_IDENTIFIER && !is_keyword_propname(js->tok)) {
	js->this_val = saved_this;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected");
	}
	js->consumed = 1;
	ctor = do_op(js, TOK_DOT, ctor, mkcoderef((jsoff_t)js->toff, (jsoff_t)js->tlen));
	} else {
	js->consumed = 1;
	jsval_t idx = js_expr(js);
	if (is_err(idx)) { js->this_val = saved_this; return idx; }
	if (next(js) != TOK_RBRACKET) { js->this_val = saved_this; return js_mkerr_typed(js, JS_ERR_SYNTAX, "] expected"); }
	js->consumed = 1;
	ctor = do_op(js, TOK_BRACKET, ctor, idx);
	}
	}

	ctor = resolve_coderef(js, ctor);
	if (is_err(ctor)) { js->this_val = saved_this; return ctor; }
	if (vtype(ctor) == T_PROP \|\| vtype(ctor) == T_PROPREF) ctor = resolveprop(js, ctor);

	js->new_target = ctor;

	jsval_t result;
	push_this(obj);
	if (next(js) == TOK_LPAREN) {
	jsval_t params = js_call_params(js);
	if (is_err(params)) {
	pop_this(); js->this_val = saved_this;
	js->new_target = saved_new_target; return params;
	}
	result = do_op(js, TOK_CALL, ctor, params);
	} else {
	result = do_op(js, TOK_CALL, ctor, mkcoderef(0, 0));
	js->consumed = 0;
	}

	jsval_t constructed_obj = peek_this();
	pop_this();

	js->this_val = saved_this;
	js->new_target = saved_new_target;

	if (is_err(result)) return result;

	uint8_t rtype = vtype(result);
	jsval_t new_result = (
	rtype == T_OBJ \|\| rtype == T_ARR \|\|
	rtype == T_PROMISE \|\| rtype == T_FUNC
	) ? result : constructed_obj;

	if (vtype(new_result) == T_OBJ && (vtype(ctor) == T_FUNC \|\| vtype(ctor) == T_CFUNC)) {
	set_slot(js, new_result, SLOT_CTOR, ctor);
	}

	jsval_t call_obj = js_mkundef();
	while (next(js) == TOK_DOT \|\| next(js) == TOK_LBRACKET \|\| next(js) == TOK_OPTIONAL_CHAIN \|\| next(js) == TOK_LPAREN) {
	uint8_t op = js->tok;
	if (op == TOK_DOT \|\| op == TOK_OPTIONAL_CHAIN) {
	js->consumed = 1;
	call_obj = new_result;
	if (op == TOK_OPTIONAL_CHAIN && (vtype(call_obj) == T_NULL \|\| vtype(call_obj) == T_UNDEF)) {
	new_result = call_obj = js_mkundef();
	} else {
	if (next(js) != TOK_IDENTIFIER && !is_keyword_propname(js->tok)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected");
	}
	js->consumed = 1;
	new_result = do_op(js, op, new_result, mkcoderef((jsoff_t)js->toff, (jsoff_t)js->tlen));
	}
	} else if (op == TOK_LBRACKET) {
	js->consumed = 1;
	call_obj = new_result;
	jsval_t idx = js_expr(js);
	if (is_err(idx)) return idx;
	if (next(js) != TOK_RBRACKET) return js_mkerr_typed(js, JS_ERR_SYNTAX, "] expected");
	js->consumed = 1;
	new_result = do_op(js, TOK_BRACKET, new_result, idx);
	} else {
	jsval_t func_this = vtype(call_obj) == T_UNDEF ? js->this_val : call_obj;
	push_this(func_this);
	jsval_t params = js_call_params(js);
	if (is_err(params)) { pop_this(); return params; }
	new_result = do_op(js, TOK_CALL, new_result, params);
	pop_this();
	call_obj = js_mkundef();
	}
	}
	return new_result;
	}

	do_delete: {
	js->consumed = 1;

	if ((js->flags & F_STRICT) && next(js) == TOK_IDENTIFIER) {
	jsoff_t id_pos = js->pos;
	uint8_t id_tok = js->tok;
	jsoff_t id_toff = js->toff, id_tlen = js->tlen;
	js->consumed = 1;
	uint8_t after = next(js);
	if (after != TOK_DOT && after != TOK_LBRACKET && after != TOK_OPTIONAL_CHAIN) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot delete unqualified identifier in strict mode");
	}
	js->pos = id_pos; js->tok = id_tok; js->toff = id_toff; js->tlen = id_tlen; js->consumed = 0;
	}

	js_parse_state_t saved_state;
	JS_SAVE_STATE(js, saved_state);
	uint8_t saved_flags = js->flags;
	jsval_t operand = js_postfix(js);

	if (is_err(operand)) {
	JS_RESTORE_STATE(js, saved_state);
	js->flags = (saved_flags & ~F_THROW) \| F_NOEXEC;
	js_postfix(js);
	js->flags = saved_flags;
	return js_mktrue();
	}
	if (js->flags & F_NOEXEC) return js_mktrue();

	if (vtype(operand) == T_PROPREF) {
	jsoff_t obj_off = propref_obj(operand);
	jsoff_t key_off = propref_key(operand);
	jsval_t obj = mkval(T_OBJ, obj_off);
	jsval_t key = mkval(T_STR, key_off);
	jsoff_t len;
	const char key_str = (const char )&js->mem[vstr(js, key, &len)];

	if (is_proxy(js, obj)) {
	jsval_t result = proxy_delete(js, obj, key_str, len);
	return is_err(result) ? result : (js_truthy(js, result) ? js_mktrue() : js_mkfalse());
	}

	jsval_t err = check_frozen_sealed(js, obj, "delete");
	if (vtype(err) != T_UNDEF) return err;

	jsoff_t prop_off = lkp(js, obj, key_str, len);
	if (prop_off == 0) return js_mktrue();

	if (is_nonconfig_prop(js, prop_off)) {
	if (js->flags & F_STRICT) return js_mkerr_typed(js, JS_ERR_TYPE, "cannot delete non-configurable property");
	return js_mkfalse();
	}

	descriptor_entry_t *desc = lookup_descriptor(obj_off, key_str, len);
	if (desc && !desc->configurable) {
	if (js->flags & F_STRICT) return js_mkerr_typed(js, JS_ERR_TYPE, "cannot delete non-configurable property");
	return js_mkfalse();
	}

	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	if (first_prop == prop_off) {
	unlink_prop(js, obj_off, prop_off, 0);
	return js_mktrue();
	}
	for (jsoff_t prev = first_prop; prev != 0; ) {
	jsoff_t next_prop = loadoff(js, prev) & ~(3U \| FLAGMASK);
	if (next_prop == prop_off) {
	unlink_prop(js, obj_off, prop_off, prev);
	return js_mktrue();
	}
	prev = next_prop;
	}
	return js_mktrue();
	}

	if (vtype(operand) != T_PROP) return js_mktrue();

	jsoff_t prop_off = (jsoff_t)vdata(operand);
	if (is_nonconfig_prop(js, prop_off)) {
	if (js->flags & F_STRICT) return js_mkerr(js, "cannot delete non-configurable property");
	return js_mkfalse();
	}

	jsoff_t owner_obj_off = 0, prev_prop_off = 0;
	bool is_first_prop = false;
	for (jsoff_t off = 0; off < js->brk; ) {
	jsoff_t v = loadoff(js, off);
	jsoff_t cleaned = v & ~FLAGMASK;
	jsoff_t n = esize(cleaned);
	if ((cleaned & 3) == T_OBJ) {
	jsoff_t first_prop = cleaned & ~3ULL;
	if (first_prop == prop_off) { owner_obj_off = off; is_first_prop = true; break; }
	for (jsoff_t cur = first_prop; cur != 0 && cur < js->brk; ) {
	jsoff_t nx = loadoff(js, cur) & ~(3U \| FLAGMASK);
	if (nx == prop_off) { owner_obj_off = off; prev_prop_off = cur; break; }
	cur = nx;
	}
	if (owner_obj_off) break;
	}
	off += n;
	}

	if (owner_obj_off) {
	jsval_t owner_obj = mkval(T_OBJ, owner_obj_off);
	jsval_t err = check_frozen_sealed(js, owner_obj, "delete");
	if (vtype(err) != T_UNDEF) return err;

	jsoff_t key_str_off = loadoff(js, (jsoff_t)(prop_off + sizeof(jsoff_t)));
	jsoff_t key_len = (loadoff(js, key_str_off) >> 3) - 1;
	const char key_str = (char )&js->mem[key_str_off + sizeof(jsoff_t)];
	descriptor_entry_t *desc = lookup_descriptor(owner_obj_off, key_str, key_len);
	if (desc && !desc->configurable) {
	if (js->flags & F_STRICT) return js_mkerr_typed(js, JS_ERR_TYPE, "cannot delete non-configurable property");
	return js_mkfalse();
	}
	unlink_prop(js, owner_obj_off, prop_off, is_first_prop ? 0 : prev_prop_off);
	}
	return js_mktrue();
	}

	do_await: {
	js->consumed = 1;
	jsval_t expr = js_unary(js);
	if (is_err(expr)) return expr;
	if (js->flags & F_NOEXEC) return expr;

	jsval_t resolved = resolveprop(js, expr);
	if (vtype(resolved) != T_PROMISE) return resolved;

	uint32_t pid = get_promise_id(js, resolved);
	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (!pd) return js_mkerr(js, "invalid promise state");

	if (pd->state == 1) return pd->value;
	if (pd->state == 2) return js_throw(js, pd->value);

	mco_coro *current_mco = mco_running();
	if (!current_mco) return js_mkerr(js, "await can only be used inside async functions");

	async_exec_context_t ctx = (async_exec_context_t )mco_get_user_data(current_mco);
	if (!ctx \|\| !ctx->coro) return js_mkerr(js, "invalid async context");

	coroutine_t *coro = ctx->coro;
	coro->awaited_promise = resolved;
	coro->is_settled = coro->is_ready = false;

	jsval_t resume_obj = mkobj(js, 0);
	set_slot(js, resume_obj, SLOT_CFUNC, js_mkfun(resume_coroutine_wrapper));
	set_slot(js, resume_obj, SLOT_CORO, tov((double)(uintptr_t)coro));

	jsval_t reject_obj = mkobj(js, 0);
	set_slot(js, reject_obj, SLOT_CFUNC, js_mkfun(reject_coroutine_wrapper));
	set_slot(js, reject_obj, SLOT_CORO, tov((double)(uintptr_t)coro));

	jsval_t then_args[] = { mkval(T_FUNC, vdata(resume_obj)), mkval(T_FUNC, vdata(reject_obj)) };
	jsval_t saved_this = js->this_val;
	js->this_val = resolved;
	(void)builtin_promise_then(js, then_args, 2);
	js->this_val = saved_this;

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	uint8_t saved_flags = js->flags;
	mco_result mco_res = mco_yield(current_mco);

	JS_RESTORE_STATE(js, saved);
	js->flags = saved_flags;

	if (mco_res != MCO_SUCCESS) return js_mkerr(js, "failed to yield coroutine");

	jsval_t result = coro->result;
	bool is_error = coro->is_error;
	coro->is_settled = false;
	coro->awaited_promise = js_mkundef();

	return is_error ? js_throw(js, result) : result;
	}

	do_prefix_inc: {
	uint8_t op = js->tok;
	js->consumed = 1;
	if ((js->flags & F_STRICT) && next(js) == TOK_IDENTIFIER && is_eval_or_arguments(js, js->toff, js->tlen)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot modify eval or arguments in strict mode");
	}
	jsval_t operand = js_unary(js);
	if (is_err(operand)) return operand;
	if (js->flags & F_NOEXEC) return operand;
	jsval_t resolved = resolveprop(js, operand);
	if (vtype(operand) == T_PROP \|\| vtype(operand) == T_PROPREF) {
	do_assign_op(js, op == TOK_POSTINC ? TOK_PLUS_ASSIGN : TOK_MINUS_ASSIGN, operand, tov(1));
	} else {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "Invalid left-hand side in assignment");
	}
	return do_op(js, op == TOK_POSTINC ? TOK_PLUS : TOK_MINUS, resolved, tov(1));
	}

	do_typeof: {
	js->consumed = 1;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok, saved_consumed = js->consumed, saved_flags = js->flags;
	bool bare = is_typeof_bare_ident(js);
	jsval_t operand = js_unary(js);
	if (is_err(operand)) {
	if (!bare \|\| get_error_type(js) != JS_ERR_REFERENCE) return operand;
	js->pos = saved_pos; js->tok = saved_tok; js->consumed = saved_consumed;
	js->flags = (saved_flags & ~F_THROW) \| F_NOEXEC;
	js_unary(js);
	js->flags = saved_flags & ~F_THROW;
	operand = js_mkundef();
	}
	return do_op(js, TOK_TYPEOF, js_mkundef(), operand);
	}

	do_unary_op: {
	uint8_t t = js->tok;
	if (t == TOK_MINUS) t = TOK_UMINUS;
	if (t == TOK_PLUS) t = TOK_UPLUS;
	js->consumed = 1;
	jsval_t operand = js_unary(js);
	if (is_err(operand)) return operand;
	if (next(js) == TOK_EXP) {
	return js_mkerr_typed(
	js, JS_ERR_SYNTAX,
	"Unary operator used immediately before exponentiation expression. Parenthesis must be used to disambiguate operator precedence"
	);
	}
	return do_op(js, t, js_mkundef(), operand);
	}
	}

	static jsval_t js_expr_bp(struct js *js, uint8_t min_bp) {
	jsval_t lhs = js_unary(js);
	if (is_err(lhs)) return lhs;

	loop: {
	uint8_t tok = next(js);
	if (tok >= TOK_MAX) return lhs;
	uint8_t bp = prec_table[tok];
	if (bp == 0 \|\| bp < min_bp) return lhs;

	js->consumed = 1;

	static const void *dispatch[] = {
	[TOK_LOR] = &&do_lor,
	[TOK_LAND] = &&do_land,
	[TOK_NULLISH] = &&do_nullish,
	[TOK_EXP] = &&do_exp,
	[TOK_OR] = &&do_binop,
	[TOK_XOR] = &&do_binop,
	[TOK_AND] = &&do_binop,
	[TOK_EQ] = &&do_binop,
	[TOK_NE] = &&do_binop,
	[TOK_SEQ] = &&do_binop,
	[TOK_SNE] = &&do_binop,
	[TOK_LT] = &&do_binop,
	[TOK_LE] = &&do_binop,
	[TOK_GT] = &&do_binop,
	[TOK_GE] = &&do_binop,
	[TOK_INSTANCEOF] = &&do_binop,
	[TOK_IN] = &&do_binop,
	[TOK_SHL] = &&do_binop,
	[TOK_SHR] = &&do_binop,
	[TOK_ZSHR] = &&do_binop,
	[TOK_PLUS] = &&do_binop,
	[TOK_MINUS] = &&do_binop,
	[TOK_MUL] = &&do_binop,
	[TOK_DIV] = &&do_binop,
	[TOK_REM] = &&do_binop,
	};

	goto *dispatch[tok];

	do_binop: {
	jsval_t rhs = js_expr_bp(js, bp + 1);
	if (is_err(rhs)) return rhs;
	lhs = do_op(js, tok, lhs, rhs);
	goto loop;
	}

	do_exp: {
	jsval_t rhs = js_expr_bp(js, bp);
	if (is_err(rhs)) return rhs;
	lhs = do_op(js, TOK_EXP, lhs, rhs);
	goto loop;
	}

	do_lor: {
	uint8_t flags = js->flags;
	lhs = resolveprop(js, lhs);
	if (js_truthy(js, lhs)) js->flags \|= F_NOEXEC;
	jsval_t rhs = js_expr_bp(js, bp);
	if (!(flags & F_NOEXEC) && !js_truthy(js, lhs)) lhs = rhs;
	js->flags = flags;
	if (is_err(rhs)) return rhs;
	goto loop;
	}

	do_land: {
	uint8_t flags = js->flags;
	lhs = resolveprop(js, lhs);
	if (!js_truthy(js, lhs)) js->flags \|= F_NOEXEC;
	jsval_t rhs = js_expr_bp(js, bp);
	if (!(flags & F_NOEXEC) && js_truthy(js, lhs)) lhs = rhs;
	js->flags = flags;
	if (is_err(rhs)) return rhs;
	goto loop;
	}

	do_nullish: {
	uint8_t flags = js->flags;
	lhs = resolveprop(js, lhs);
	uint8_t lhs_type = vtype(lhs);
	if (lhs_type != T_NULL && lhs_type != T_UNDEF) js->flags \|= F_NOEXEC;
	jsval_t rhs = js_expr_bp(js, bp);
	if (!(flags & F_NOEXEC) && (lhs_type == T_NULL \|\| lhs_type == T_UNDEF)) lhs = rhs;
	js->flags = flags;
	if (is_err(rhs)) return rhs;
	goto loop;
	}
	}
	}

	static jsval_t js_ternary(struct js *js) {
	jsval_t res = js_expr_bp(js, 1);
	if (next(js) == TOK_Q) {
	uint8_t flags = js->flags;
	js->consumed = 1;
	if (js_truthy(js, resolveprop(js, res))) {
	res = js_ternary(js);
	js->flags \|= F_NOEXEC;
	EXPECT(TOK_COLON, js->flags = flags);
	js_ternary(js);
	js->flags = flags;
	} else {
	js->flags \|= F_NOEXEC;
	js_ternary(js);
	EXPECT(TOK_COLON, js->flags = flags);
	js->flags = flags;
	res = js_ternary(js);
	}
	}
	return res;
	}

	static jsval_t js_assignment(struct js *js) {
	jsval_t res = js_ternary(js);

	if (!is_err(res) && vtype(res) == T_CODEREF && next(js) == TOK_ARROW) {
	jsoff_t param_start = coderefoff(res);
	jsoff_t param_len = codereflen(res);
	js->consumed = 1;

	char param_buf[256];
	if (param_len + 3 > sizeof(param_buf)) return js_mkerr(js, "param too long");
	param_buf[0] = '(';
	memcpy(param_buf + 1, &js->code[param_start], param_len);
	param_buf[param_len + 1] = ')';
	param_buf[param_len + 2] = '\0';

	uint8_t flags = js->flags;
	bool is_expr = next(js) != TOK_LBRACE;
	jsoff_t body_start = js->pos;
	if (is_expr && js->tok != TOK_EOF) {
	body_start = js->toff;
	}
	jsval_t body_result;

	if (is_expr) {
	js->flags \|= F_NOEXEC;
	body_result = js_assignment(js);
	if (is_err(body_result)) {
	js->flags = flags;
	return body_result;
	}
	} else {
	body_start = js->toff;
	js->flags \|= F_NOEXEC;
	js->consumed = 1;
	body_result = js_block(js, false);
	if (is_err(body_result)) {
	js->flags = flags;
	return body_result;
	}
	if (js->tok == TOK_RBRACE && js->consumed) {
	} else if (next(js) == TOK_RBRACE) {
	js->consumed = 1;
	}
	}

	js->flags = flags;
	jsoff_t body_end;
	if (is_expr) {
	uint8_t tok = next(js);
	body_end = is_body_end_tok(tok) ? js->toff : js->pos;
	} else body_end = js->pos;

	size_t fn_size = param_len + (body_end - body_start) + 64;
	char fn_str = (char ) malloc(fn_size);
	if (!fn_str) return js_mkerr(js, "oom");

	jsoff_t fn_pos = 0;
	memcpy(fn_str + fn_pos, param_buf, param_len + 2);
	fn_pos += param_len + 2;

	if (is_expr) {
	fn_str[fn_pos++] = '{';
	memcpy(fn_str + fn_pos, "return ", 7);
	fn_pos += 7;
	size_t body_len = body_end - body_start;
	memcpy(fn_str + fn_pos, &js->code[body_start], body_len);
	fn_pos += body_len;
	fn_str[fn_pos++] = '}';
	} else {
	size_t body_len = body_end - body_start;
	memcpy(fn_str + fn_pos, &js->code[body_start], body_len);
	fn_pos += body_len;
	}

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) { free(fn_str); return func_obj; }
	set_func_code(js, func_obj, fn_str, fn_pos);
	free(fn_str);

	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, func_obj, func_proto);

	if (!(flags & F_NOEXEC)) {
	jsval_t closure_scope = for_let_capture_scope(js);
	if (is_err(closure_scope)) return closure_scope;
	set_slot(js, func_obj, SLOT_SCOPE, closure_scope);
	set_slot(js, func_obj, SLOT_THIS, js->this_val);
	}

	return mkval(T_FUNC, (unsigned long) vdata(func_obj));
	}

	while (
	!is_err(res) && (next(js) == TOK_ASSIGN \|\| js->tok == TOK_PLUS_ASSIGN \|\|
	js->tok == TOK_MINUS_ASSIGN \|\| js->tok == TOK_MUL_ASSIGN \|\|
	js->tok == TOK_DIV_ASSIGN \|\| js->tok == TOK_REM_ASSIGN \|\|
	js->tok == TOK_SHL_ASSIGN \|\| js->tok == TOK_SHR_ASSIGN \|\|
	js->tok == TOK_ZSHR_ASSIGN \|\| js->tok == TOK_AND_ASSIGN \|\|
	js->tok == TOK_XOR_ASSIGN \|\| js->tok == TOK_OR_ASSIGN \|\|
	js->tok == TOK_LOR_ASSIGN \|\| js->tok == TOK_LAND_ASSIGN \|\|
	js->tok == TOK_NULLISH_ASSIGN)
	) {
	uint8_t op = js->tok;
	js->consumed = 1;

	if (op == TOK_LOR_ASSIGN \|\| op == TOK_LAND_ASSIGN \|\| op == TOK_NULLISH_ASSIGN) {
	jsval_t lhs_val = js_mkundef();
	bool should_assign = true;

	if (!(js->flags & F_NOEXEC)) {
	lhs_val = resolveprop(js, res);
	if (is_err(lhs_val)) return lhs_val;

	if (op == TOK_LOR_ASSIGN) {
	should_assign = !js_truthy(js, lhs_val);
	} else if (op == TOK_LAND_ASSIGN) {
	should_assign = js_truthy(js, lhs_val);
	} else should_assign = is_null(lhs_val) \|\| is_undefined(lhs_val);
	}

	if (should_assign \|\| (js->flags & F_NOEXEC)) {
	jsval_t rhs = js_assignment(js);
	if (is_err(rhs)) return rhs;

	if (!(js->flags & F_NOEXEC) && should_assign) {
	jsval_t rhs_resolved = resolveprop(js, rhs);
	if (is_err(rhs_resolved)) return rhs_resolved;
	res = assign(js, res, rhs_resolved);
	}
	} else {
	uint8_t saved_flags = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t rhs = js_assignment(js);
	js->flags = saved_flags;
	if (is_err(rhs)) return rhs;
	res = lhs_val;
	}
	continue;
	}

	jsval_t lhs_val = js_mkundef();
	if (op != TOK_ASSIGN && !(js->flags & F_NOEXEC)) {
	lhs_val = resolveprop(js, res);
	if (is_err(lhs_val)) return lhs_val;
	}

	jsval_t rhs = js_assignment(js);
	if (is_err(rhs)) return rhs;

	if (op == TOK_ASSIGN) {
	res = do_op(js, op, res, rhs);
	} else {
	jsval_t rhs_resolved = resolveprop(js, rhs);
	if (is_err(rhs_resolved)) return rhs_resolved;

	uint8_t m[] = {
	TOK_PLUS, TOK_MINUS, TOK_MUL, TOK_DIV, TOK_REM, TOK_SHL,
	TOK_SHR, TOK_ZSHR, TOK_AND, TOK_XOR, TOK_OR
	};
	uint8_t binary_op = m[op - TOK_PLUS_ASSIGN];

	jsval_t op_result = do_op(js, binary_op, lhs_val, rhs_resolved);
	if (is_err(op_result)) return op_result;
	res = assign(js, res, op_result);
	}
	}

	return res;
	}

	static jsval_t js_decl(struct js *js, bool is_const) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	js->consumed = 1;
	for (;;) {
	if (next(js) == TOK_LBRACE) {
	js->consumed = 1;

	js_parse_state_t pattern_state;
	JS_SAVE_STATE(js, pattern_state);

	int depth = 1;
	while (depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LBRACE) depth++;
	else if (js->tok == TOK_RBRACE) depth--;
	if (depth > 0) js->consumed = 1;
	}
	js->consumed = 1;

	if (next(js) != TOK_ASSIGN) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "destructuring requires assignment");
	}
	js->consumed = 1;

	jsval_t v = js_expr(js);
	if (is_err(v)) return v;

	jsval_t obj = js_mkundef();
	if (exe) {
	obj = resolveprop(js, v);
	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR) {
	return js_mkerr(js, "cannot destructure non-object");
	}
	}

	js_parse_state_t end_state;
	JS_SAVE_STATE(js, end_state);
	JS_RESTORE_STATE(js, pattern_state);

	jsval_t picked_keys = exe ? js_mkarr(js) : js_mkundef();
	if (exe && is_err(picked_keys)) return picked_keys;

	while (next(js) != TOK_RBRACE && next(js) != TOK_EOF) {
	bool is_rest = false;
	if (next(js) == TOK_REST) {
	is_rest = true;
	js->consumed = 1;
	}

	if (next(js) != TOK_IDENTIFIER) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected in object destructuring");
	}
	jsoff_t src_off = js->toff, src_len = js->tlen;
	jsoff_t var_off = src_off, var_len = src_len;
	js->consumed = 1;

	bool is_nested_obj = false;
	bool is_nested_arr = false;
	jsoff_t nested_pattern_start = 0;

	if (!is_rest && next(js) == TOK_COLON) {
	js->consumed = 1;
	if (next(js) == TOK_LBRACE) {
	is_nested_obj = true;
	nested_pattern_start = js->toff;
	int inner_depth = 1;
	js->consumed = 1;
	while (inner_depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LBRACE) inner_depth++;
	else if (js->tok == TOK_RBRACE) inner_depth--;
	if (inner_depth > 0) js->consumed = 1;
	}
	js->consumed = 1;
	} else if (next(js) == TOK_LBRACKET) {
	is_nested_arr = true;
	nested_pattern_start = js->toff;
	int inner_depth = 1;
	js->consumed = 1;
	while (inner_depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LBRACKET) inner_depth++;
	else if (js->tok == TOK_RBRACKET) inner_depth--;
	if (inner_depth > 0) js->consumed = 1;
	}
	js->consumed = 1;
	} else {
	EXPECT_IDENT();
	var_off = js->toff;
	var_len = js->tlen;
	js->consumed = 1;
	}
	}

	jsoff_t default_off = 0, default_len = 0;
	if (!is_rest && !is_nested_obj && !is_nested_arr && next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	default_off = js->pos;
	uint8_t sf = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t r = js_expr(js);
	js->flags = sf;
	if (is_err(r)) return r;
	default_len = js->pos - default_off;
	}

	if (!exe) goto obj_destruct_next;

	if (is_rest) goto obj_destruct_rest;
	if (is_nested_obj \|\| is_nested_arr) goto obj_destruct_nested;
	goto obj_destruct_simple;

	obj_destruct_rest:;
	jsval_t rest_obj = mkobj(js, 0);
	if (is_err(rest_obj)) return rest_obj;
	jsoff_t scan = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	while (scan < js->brk && scan != 0) {
	jsoff_t header = loadoff(js, scan);
	if (is_slot_prop(header)) { scan = next_prop(header); continue; }

	const char *key; jsoff_t klen;
	get_prop_key(js, scan, &key, &klen);
	bool is_picked = false;
	jsoff_t picked_len = arr_length(js, picked_keys);
	for (jsoff_t i = 0; i < picked_len; i++) {
	jsval_t pk = arr_get(js, picked_keys, i);
	if (vtype(pk) != T_STR) continue;
	jsoff_t pklen, pkoff = vstr(js, pk, &pklen);
	if (klen == pklen && memcmp(key, &js->mem[pkoff], klen) == 0) { is_picked = true; break; }
	}
	if (!is_picked && !(klen == STR_PROTO_LEN && memcmp(key, STR_PROTO, STR_PROTO_LEN) == 0)) {
	jsval_t val = get_prop_val(js, scan);
	jsval_t key_str = js_mkstr(js, key, klen);
	if (is_err(key_str)) return key_str;
	jsval_t res = setprop(js, rest_obj, key_str, val);
	if (is_err(res)) return res;
	}
	scan = next_prop(header);
	}
	{
	const char *vn = &js->code[var_off];
	if (lkp_scope(js, js->scope, vn, var_len) > 0) return js_mkerr(js, "'%.*s' already declared", (int)var_len, vn);
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, vn, var_len), rest_obj, is_const ? CONSTMASK : 0);
	if (is_err(x)) return x;
	}
	goto obj_destruct_next;

	obj_destruct_nested:;
	{
	jsval_t sk = js_mkstr(js, &js->code[src_off], src_len);
	if (is_err(sk)) return sk;
	js_arr_push(js, picked_keys, sk);

	jsoff_t poff = lkp(js, obj, &js->code[src_off], src_len);
	jsval_t nobj = poff > 0 ? resolveprop(js, mkval(T_PROP, poff)) : js_mkundef();

	jsoff_t pattern_end = js->pos;
	js->pos = nested_pattern_start;
	js->consumed = 1;

	jsval_t saved_obj = obj;
	obj = nobj;

	if (!is_nested_obj) goto nested_done;
	if (next(js) != TOK_LBRACE) return js_mkerr_typed(js, JS_ERR_SYNTAX, "expected '{' in nested destructuring");
	js->consumed = 1;

	while (next(js) != TOK_RBRACE && next(js) != TOK_EOF) {
	if (next(js) != TOK_IDENTIFIER) return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected in nested destructuring");
	jsoff_t isoff = js->toff, islen = js->tlen;
	jsoff_t ivoff = isoff, ivlen = islen;
	js->consumed = 1;

	if (next(js) == TOK_COLON) {
	js->consumed = 1;
	EXPECT_IDENT();
	ivoff = js->toff; ivlen = js->tlen;
	js->consumed = 1;
	}

	const char *ivn = &js->code[ivoff];
	if (lkp_scope(js, js->scope, ivn, ivlen) > 0) return js_mkerr(js, "'%.*s' already declared", (int)ivlen, ivn);

	jsoff_t ipoff = lkp(js, nobj, &js->code[isoff], islen);
	jsval_t ival = ipoff > 0 ? resolveprop(js, mkval(T_PROP, ipoff)) : js_mkundef();
	jsval_t ix = mkprop(js, js->scope, js_mkstr(js, ivn, ivlen), ival, is_const ? CONSTMASK : 0);
	if (is_err(ix)) return ix;

	if (next(js) == TOK_RBRACE) break;
	EXPECT(TOK_COMMA);
	}
	js->consumed = 1;

	nested_done:
	obj = saved_obj;
	js->pos = pattern_end;
	js->consumed = 1;
	}
	goto obj_destruct_next;

	obj_destruct_simple:;
	{
	const char *vn = &js->code[var_off];
	if (lkp_scope(js, js->scope, vn, var_len) > 0) return js_mkerr(js, "'%.*s' already declared", (int)var_len, vn);

	jsval_t sk = js_mkstr(js, &js->code[src_off], src_len);
	if (is_err(sk)) return sk;
	js_arr_push(js, picked_keys, sk);

	jsoff_t poff = lkp(js, obj, &js->code[src_off], src_len);
	jsval_t pval = poff > 0 ? resolveprop(js, mkval(T_PROP, poff)) : js_mkundef();

	if (vtype(pval) == T_UNDEF && default_len > 0) {
	pval = js_eval_slice(js, default_off, default_len);
	if (is_err(pval)) return pval;
	pval = resolveprop(js, pval);
	}

	jsval_t x = mkprop(js, js->scope, js_mkstr(js, vn, var_len), pval, is_const ? CONSTMASK : 0);
	if (is_err(x)) return x;
	}

	obj_destruct_next:

	if (next(js) == TOK_RBRACE) break;
	EXPECT(TOK_COMMA);
	}

	JS_RESTORE_STATE(js, end_state);
	} else if (next(js) == TOK_LBRACKET) {
	js->consumed = 1;

	js_parse_state_t pattern_state;
	JS_SAVE_STATE(js, pattern_state);

	int depth = 1;
	while (depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == TOK_LBRACKET) depth++;
	else if (js->tok == TOK_RBRACKET) depth--;
	if (depth > 0) js->consumed = 1;
	}
	js->consumed = 1;

	if (next(js) != TOK_ASSIGN) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "array destructuring requires assignment");
	}
	js->consumed = 1;

	jsval_t v = js_expr(js);
	if (is_err(v)) return v;

	jsval_t arr = js_mkundef();
	if (exe) {
	arr = resolveprop(js, v);
	if (vtype(arr) != T_ARR && vtype(arr) != T_STR) {
	return js_mkerr(js, "cannot array destructure non-iterable");
	}
	}

	js_parse_state_t end_state;
	JS_SAVE_STATE(js, end_state);
	JS_RESTORE_STATE(js, pattern_state);

	int index = 0;
	while (next(js) != TOK_RBRACKET && next(js) != TOK_EOF) {
	if (next(js) == TOK_COMMA) {
	js->consumed = 1;
	index++;
	continue;
	}

	bool is_rest = false;
	if (next(js) == TOK_REST) {
	is_rest = true;
	js->consumed = 1;
	}

	if (next(js) != TOK_IDENTIFIER) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected in array destructuring");
	}
	jsoff_t var_off = js->toff, var_len = js->tlen;
	js->consumed = 1;

	jsoff_t default_off = 0, default_len = 0;
	if (!is_rest && next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	default_off = js->pos;
	uint8_t sf = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t r = js_expr(js);
	js->flags = sf;
	if (is_err(r)) return r;
	default_len = js->pos - default_off;
	}

	if (exe) {
	const char *var_name = &js->code[var_off];
	if (lkp_scope(js, js->scope, var_name, var_len) > 0) {
	return js_mkerr(js, "'%.*s' already declared", (int)var_len, var_name);
	}

	jsval_t prop_val;
	if (is_rest) {
	jsval_t rest_arr = js_mkarr(js);
	if (is_err(rest_arr)) return rest_arr;
	jsoff_t total_len = vtype(arr) == T_STR ? 0 : arr_length(js, arr);
	if (vtype(arr) == T_STR) {
	jsoff_t slen;
	vstr(js, arr, &slen);
	total_len = slen;
	}
	for (jsoff_t i = index; i < total_len; i++) {
	jsval_t elem;
	if (vtype(arr) == T_STR) {
	jsoff_t slen, soff = vstr(js, arr, &slen);
	elem = js_mkstr(js, (char *)&js->mem[soff + i], 1);
	} else {
	elem = arr_get(js, arr, i);
	}
	js_arr_push(js, rest_arr, elem);
	}
	prop_val = rest_arr;
	} else {
	if (vtype(arr) == T_STR) {
	jsoff_t slen, soff = vstr(js, arr, &slen);
	if ((jsoff_t)index < slen) {
	prop_val = js_mkstr(js, (char *)&js->mem[soff + index], 1);
	} else {
	prop_val = js_mkundef();
	}
	} else {
	prop_val = arr_get(js, arr, index);
	}

	if (vtype(prop_val) == T_UNDEF && default_len > 0) {
	prop_val = js_eval_slice(js, default_off, default_len);
	if (is_err(prop_val)) return prop_val;
	prop_val = resolveprop(js, prop_val);
	}
	}

	jsval_t x = mkprop(js, js->scope, js_mkstr(js, var_name, var_len), prop_val, is_const ? CONSTMASK : 0);
	if (is_err(x)) return x;
	}

	index++;
	if (next(js) == TOK_RBRACKET) break;
	EXPECT(TOK_COMMA);
	}

	JS_RESTORE_STATE(js, end_state);
	} else {
	EXPECT_IDENT();
	js->consumed = 0;
	jsoff_t noff = js->toff, nlen = js->tlen;
	char name = (char ) &js->code[noff];

	if ((js->flags & F_STRICT) && is_strict_restricted(name, nlen)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot use '%.*s' as variable name in strict mode", (int) nlen, name);
	}

	if ((js->flags & F_STRICT) && is_strict_reserved(name, nlen)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "'%.*s' is reserved in strict mode", (int) nlen, name);
	}

	jsval_t v = js_mkundef();
	js->consumed = 1;
	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	v = js_expr(js);
	if (is_err(v)) return v;
	} else if (is_const) return js_mkerr_typed(js, JS_ERR_SYNTAX, "Missing initializer in const declaration");
	if (exe) {
	char decoded_name[256];
	size_t decoded_len = decode_ident_escapes(name, nlen, decoded_name, sizeof(decoded_name));

	jsval_t resolved = resolveprop(js, v);
	if (vtype(resolved) == T_FUNC) infer_func_name(js, resolved, decoded_name, decoded_len);

	if (lkp_scope(js, js->scope, decoded_name, decoded_len) > 0) return js_mkerr(js, "'%.*s' already declared", (int) decoded_len, decoded_name);
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, decoded_name, decoded_len), resolved, is_const ? CONSTMASK : 0);

	if (is_err(x)) return x;
	}
	}

	uint8_t decl_next = next(js);
	bool asi = js->had_newline \|\| decl_next == TOK_EOF \|\| decl_next == TOK_RBRACE;
	if (decl_next == TOK_SEMICOLON \|\| asi) break;
	EXPECT(TOK_COMMA);
	}
	return js_mkundef();
	}

	static jsval_t js_expr(struct js *js) {
	return js_assignment(js);
	}

	static jsval_t js_expr_comma(struct js *js) {
	jsval_t res = js_assignment(js);
	if (is_err(res)) return res;
	while (next(js) == TOK_COMMA) {
	js->consumed = 1;
	res = js_assignment(js);
	if (is_err(res)) return res;
	}
	return res;
	}

	static jsval_t js_eval_slice(struct js *js, jsoff_t off, jsoff_t len) {
	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);

	js->code = saved.code + off;
	js->clen = len;
	js->pos = 0;
	js->consumed = 1;

	jsval_t result = js_expr(js);

	JS_RESTORE_STATE(js, saved);
	return result;
	}

	static jsval_t js_eval_str(struct js js, const char code, jsoff_t len) {
	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);

	js->code = code;
	js->clen = len;
	js->pos = 0;
	js->consumed = 1;

	jsval_t result = js_expr(js);

	JS_RESTORE_STATE(js, saved);
	return result;
	}

	static jsval_t js_let(struct js *js) {
	return js_decl(js, false);
	}

	static jsval_t js_const(struct js *js) {
	return js_decl(js, true);
	}

	static jsval_t js_func_decl(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	uint8_t saved_flags = js->flags;
	js->consumed = 1;
	EXPECT_IDENT();
	js->consumed = 0;
	jsoff_t noff = js->toff, nlen = js->tlen;
	char name = (char ) &js->code[noff];
	js->consumed = 1;
	EXPECT(TOK_LPAREN);
	jsoff_t pos = js->pos - 1;
	int param_count = 0;
	if (!parse_func_params(js, &saved_flags, &param_count)) {
	js->flags = saved_flags;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "invalid parameters");
	}
	EXPECT(TOK_RPAREN);
	EXPECT(TOK_LBRACE);
	js->consumed = 0;
	uint8_t flags = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t res = js_block(js, false);
	if (is_err(res)) {
	js->flags = flags;
	return res;
	}
	js->flags = flags;
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	set_func_code(js, func_obj, &js->code[pos], js->pos - pos);

	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, func_obj, func_proto);

	jsval_t len_key = js_mkstr(js, "length", 6);
	if (is_err(len_key)) return len_key;
	jsval_t res_len = setprop(js, func_obj, len_key, tov(param_count));
	if (is_err(res_len)) return res_len;
	js_set_descriptor(js, func_obj, "length", 6, JS_DESC_C);
	jsval_t name_key = js_mkstr(js, "name", 4);
	if (is_err(name_key)) return name_key;
	jsval_t name_val = js_mkstr(js, name, nlen);
	if (is_err(name_val)) return name_val;
	set_slot(js, func_obj, SLOT_NAME, name_val);
	jsval_t res3 = setprop(js, func_obj, name_key, name_val);
	if (is_err(res3)) return res3;
	if (exe) {
	jsval_t closure_scope = for_let_capture_scope(js);
	if (is_err(closure_scope)) return closure_scope;
	set_slot(js, func_obj, SLOT_SCOPE, closure_scope);
	if (flags & F_STRICT) {
	set_slot(js, func_obj, SLOT_STRICT, js_mktrue());
	}
	}

	jsval_t func = mkval(T_FUNC, (unsigned long) vdata(func_obj));
	jsval_t proto_setup = setup_func_prototype(js, func);
	if (is_err(proto_setup)) return proto_setup;

	if (exe) {
	jsoff_t existing = lkp_scope(js, js->scope, name, nlen);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, func);
	} else {
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, name, nlen), func, 0);
	if (is_err(x)) return x;
	}
	}

	return js_mkundef();
	}

	static jsval_t js_func_decl_async(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	js->consumed = 1;
	EXPECT_IDENT();
	js->consumed = 0;
	jsoff_t noff = js->toff, nlen = js->tlen;
	char name = (char ) &js->code[noff];
	js->consumed = 1;
	EXPECT(TOK_LPAREN);
	jsoff_t pos = js->pos - 1;
	if (!parse_func_params(js, NULL, NULL)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "invalid parameters");
	}
	EXPECT(TOK_RPAREN);
	EXPECT(TOK_LBRACE);
	js->consumed = 0;
	uint8_t flags = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t res = js_block(js, false);
	if (is_err(res)) {
	js->flags = flags;
	return res;
	}
	js->flags = flags;
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	set_func_code(js, func_obj, &js->code[pos], js->pos - pos);
	set_slot(js, func_obj, SLOT_ASYNC, js_mktrue());
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);
	jsval_t len_key = js_mkstr(js, "length", 6);
	if (is_err(len_key)) return len_key;
	jsval_t res_len = setprop(js, func_obj, len_key, tov(0));
	if (is_err(res_len)) return res_len;
	js_set_descriptor(js, func_obj, "length", 6, JS_DESC_C);
	jsval_t name_key = js_mkstr(js, "name", 4);
	if (is_err(name_key)) return name_key;
	jsval_t name_val = js_mkstr(js, name, nlen);
	if (is_err(name_val)) return name_val;
	set_slot(js, func_obj, SLOT_NAME, name_val);
	jsval_t res3 = setprop(js, func_obj, name_key, name_val);
	if (is_err(res3)) return res3;
	if (exe) {
	jsval_t closure_scope = for_let_capture_scope(js);
	if (is_err(closure_scope)) return closure_scope;
	set_slot(js, func_obj, SLOT_SCOPE, closure_scope);
	if (flags & F_STRICT) set_slot(js, func_obj, SLOT_STRICT, js_mktrue());
	}
	jsval_t func = mkval(T_FUNC, (unsigned long) vdata(func_obj));

	jsval_t proto_setup = setup_func_prototype(js, func);
	if (is_err(proto_setup)) return proto_setup;

	if (exe) {
	jsoff_t existing = lkp_scope(js, js->scope, name, nlen);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, func);
	} else {
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, name, nlen), func, 0);
	if (is_err(x)) return x;
	}
	}

	return js_mkundef();
	}

	static jsval_t js_block_or_stmt(struct js *js) {
	if (next(js) == TOK_LBRACE) return js_block(js, !(js->flags & F_NOEXEC));
	uint8_t stmt_tok = js->tok;
	jsval_t res = resolveprop(js, js_stmt(js));
	bool is_block_stmt = (
	stmt_tok == TOK_FUNC \|\| stmt_tok == TOK_CLASS \|\|
	stmt_tok == TOK_IF \|\| stmt_tok == TOK_WHILE \|\|
	stmt_tok == TOK_DO \|\| stmt_tok == TOK_FOR \|\|
	stmt_tok == TOK_SWITCH \|\| stmt_tok == TOK_TRY \|\|
	stmt_tok == TOK_LBRACE \|\| stmt_tok == TOK_ASYNC
	);
	if (!is_block_stmt) js->consumed = 0;
	return res;
	}

	typedef struct {
	bool is_block;
	bool needs_scope;
	jsval_t loop_scope;
	} loop_block_ctx_t;

	static void loop_block_init(struct js js, loop_block_ctx_t ctx) {
	ctx->is_block = (lookahead(js) == TOK_LBRACE);
	ctx->needs_scope = false;
	ctx->loop_scope = js_mkundef();

	if (ctx->is_block && !(js->flags & F_NOEXEC)) {
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;

	js->consumed = 1;
	next(js);
	ctx->needs_scope = block_needs_scope(js);

	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;

	if (ctx->needs_scope) ctx->loop_scope = js_mkscope(js);
	}
	}

	static inline jsval_t loop_block_exec(struct js js, loop_block_ctx_t ctx) {
	if (ctx->is_block) {
	next(js);
	return js_block(js, false);
	}

	return js_block_or_stmt(js);
	}

	static inline void loop_block_sync_scope(struct js js, loop_block_ctx_t ctx) {
	struct for_let_ctx *flc = for_let_current(js);
	if (flc && vtype(flc->body_scope) == T_OBJ) ctx->loop_scope = flc->body_scope;
	}

	#define loop_block_clear(js, ctx) if ((ctx)->needs_scope) scope_clear_props(js, (ctx)->loop_scope)
	#define loop_block_cleanup(js, ctx) if ((ctx)->needs_scope) delscope(js)

	static jsval_t js_if(struct js *js) {
	js->consumed = 1;
	EXPECT(TOK_LPAREN);

	jsval_t res = js_mkundef(), cond_expr = js_expr(js);
	if (is_err(cond_expr)) return cond_expr;
	jsval_t cond = resolveprop(js, cond_expr);
	if (is_err(cond)) return cond;

	EXPECT(TOK_RPAREN);

	bool cond_true = js_truthy(js, cond), exe = !(js->flags & F_NOEXEC);
	if (!cond_true) js->flags \|= F_NOEXEC;
	jsval_t blk = js_block_or_stmt(js);
	if (cond_true) res = blk;
	if (exe && !cond_true) js->flags &= (uint8_t) ~F_NOEXEC;

	if (lookahead(js) == TOK_ELSE) {
	js->consumed = 1;
	next(js);
	js->consumed = 1;
	if (cond_true) js->flags \|= F_NOEXEC;
	blk = js_block_or_stmt(js);
	if (!cond_true) res = blk;
	if (cond_true && exe) js->flags &= (uint8_t) ~F_NOEXEC;
	}

	return res;
	}

	static inline bool expect(struct js js, uint8_t tok, jsval_t res) {
	if (next(js) != tok) {
	*res = js_mkerr_typed(js, JS_ERR_SYNTAX, "parse error");
	return false;
	} else { js->consumed = 1; return true; }
	}

	static inline bool is_err2(jsval_t v, jsval_t res) {
	bool r = is_err(*v);
	if (r) { res = v; } return r;
	}

	typedef struct {
	jsoff_t body_start;
	jsoff_t body_end;
	jsoff_t var_name_off;
	jsoff_t var_name_len;
	bool is_const_var;
	uint8_t flags;
	bool has_destructure;
	jsoff_t destructure_off;
	jsoff_t destructure_len;
	int marker_index;
	loop_block_ctx_t loop_ctx;
	} for_iter_ctx_t;

	static jsval_t for_iter_bind_var(struct js js, for_iter_ctx_t ctx, jsval_t value) {
	loop_block_clear(js, &ctx->loop_ctx);
	if (ctx->has_destructure) {
	return bind_destruct_pattern(js, &js->code[ctx->destructure_off], ctx->destructure_len, value, js->scope);
	}
	const char *var_name = &js->code[ctx->var_name_off];
	jsoff_t existing = lkp_scope(js, js->scope, var_name, ctx->var_name_len);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, value);
	return js_mkundef();
	}
	return mkprop(js, js->scope, js_mkstr(js, var_name, ctx->var_name_len), value, ctx->is_const_var ? CONSTMASK : 0);
	}

	static jsval_t for_iter_exec_body(struct js js, for_iter_ctx_t ctx) {
	js->pos = ctx->body_start;
	js->consumed = 1;
	js->flags = (ctx->flags & ~F_NOEXEC) \| F_LOOP;
	return loop_block_exec(js, &ctx->loop_ctx);
	}

	static inline bool for_iter_handle_continue(struct js js, for_iter_ctx_t ctx) {
	if (!(label_flags & F_CONTINUE_LABEL)) return false;
	if (is_this_loop_continue_target(ctx->marker_index)) {
	clear_continue_label();
	js->flags &= ~(F_BREAK \| F_NOEXEC);
	return false;
	}
	js->flags \|= F_BREAK;
	return true;
	}

	static int for_iter_step(struct js js, for_iter_ctx_t ctx, jsval_t key_str, jsval_t *out) {
	jsval_t err = for_iter_bind_var(js, ctx, key_str);
	if (is_err(err)) { *out = err; return 2; }

	jsval_t v = for_iter_exec_body(js, ctx);
	if (is_err(v)) { *out = v; return 2; }
	if (for_iter_handle_continue(js, ctx)) return 1;
	if (js->flags & F_BREAK) return 1;
	if (js->flags & F_RETURN) { *out = v; return 2; }

	return 0;
	}

	static jsval_t for_iter_string_indices(struct js js, for_iter_ctx_t ctx, jsval_t str) {
	jsoff_t slen = vstrlen(js, str);
	for (jsoff_t i = 0; i < slen; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%u", (unsigned)i);
	jsval_t key_str = js_mkstr(js, idx, strlen(idx));

	jsval_t out;
	int rc = for_iter_step(js, ctx, key_str, &out);
	if (rc) return (rc == 2) ? out : js_mkundef();
	}
	return js_mkundef();
	}

	static jsval_t for_in_iter_object(struct js js, for_iter_ctx_t ctx, jsval_t obj) {
	uint8_t obj_type = vtype(obj);
	if (obj_type == T_NULL \|\| obj_type == T_UNDEF) return js_mkundef();
	if (obj_type == T_STR) return for_iter_string_indices(js, ctx, obj);
	if (obj_type != T_OBJ && obj_type != T_ARR && obj_type != T_FUNC)
	return js_mkerr(js, "for-in requires object");

	jsval_t iter_obj = (obj_type == T_FUNC) ? mkval(T_OBJ, vdata(obj)) : obj;
	jsoff_t iter_obj_off = (jsoff_t)vdata(iter_obj);
	jsoff_t prop_off = loadoff(js, iter_obj_off) & ~(3U \| FLAGMASK);

	jsval_t prim = get_slot(js, obj, SLOT_PRIMITIVE);
	if (vtype(prim) == T_STR) return for_iter_string_indices(js, ctx, prim);

	const char *tag_sym_key = get_toStringTag_sym_key();
	size_t tag_sym_len = tag_sym_key ? strlen(tag_sym_key) : 0;

	while (prop_off < js->brk && prop_off != 0) {
	jsoff_t header = loadoff(js, prop_off);
	if (is_slot_prop(header)) { prop_off = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, prop_off + (jsoff_t)sizeof(prop_off));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char )&js->mem[koff + sizeof(koff)];

	bool skip = streq(key, klen, STR_PROTO, STR_PROTO_LEN);
	if (!skip && tag_sym_key) skip = streq(key, klen, tag_sym_key, tag_sym_len);

	if (!skip) {
	descriptor_entry_t *desc = lookup_descriptor(iter_obj_off, key, klen);
	if (desc && !desc->enumerable) skip = true;
	}

	if (!skip) {
	jsval_t out;
	int rc = for_iter_step(js, ctx, js_mkstr(js, key, klen), &out);
	if (rc) return (rc == 2) ? out : js_mkundef();
	}

	prop_off = next_prop(header);
	}

	return js_mkundef();
	}

	static jsval_t for_of_iter_array(struct js js, for_iter_ctx_t ctx, jsval_t iterable) {
	jsoff_t next_prop_off = loadoff(js, (jsoff_t) vdata(iterable)) & ~(3U \| FLAGMASK);
	jsoff_t length = 0, scan = next_prop_off;

	while (scan < js->brk && scan != 0) {
	jsoff_t header = loadoff(js, scan);
	if (is_slot_prop(header)) { scan = next_prop(header); continue; }
	const char *key; jsoff_t klen;
	get_prop_key(js, scan, &key, &klen);
	if (streq(key, klen, "length", 6)) {
	jsval_t val = get_prop_val(js, scan);
	if (vtype(val) == T_NUM) length = (jsoff_t) tod(val);
	break;
	}
	scan = next_prop(header);
	}

	for (jsoff_t i = 0; i < length; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%u", (unsigned) i);
	jsoff_t idxlen = (jsoff_t) strlen(idx);
	jsoff_t prop = next_prop_off;
	jsval_t val = js_mkundef();

	while (prop < js->brk && prop != 0) {
	jsoff_t header = loadoff(js, prop);
	if (is_slot_prop(header)) { prop = next_prop(header); continue; }
	const char *key; jsoff_t klen;
	get_prop_key(js, prop, &key, &klen);
	if (streq(key, klen, idx, idxlen)) { val = get_prop_val(js, prop); break; }
	prop = next_prop(header);
	}

	jsval_t err = for_iter_bind_var(js, ctx, val);
	if (is_err(err)) return err;

	jsval_t v = for_iter_exec_body(js, ctx);
	if (is_err(v)) return v;
	if (for_iter_handle_continue(js, ctx)) break;
	if (js->flags & F_BREAK) break;
	if (js->flags & F_RETURN) return v;
	}

	return js_mkundef();
	}

	static jsval_t for_of_iter_string(struct js js, for_iter_ctx_t ctx, jsval_t iterable) {
	jsoff_t slen, soff = vstr(js, iterable, &slen);
	const char str = (char ) &js->mem[soff];

	for (jsoff_t i = 0; i < slen; i++) {
	jsval_t char_str = js_mkstr(js, &str[i], 1);

	jsval_t err = for_iter_bind_var(js, ctx, char_str);
	if (is_err(err)) return err;

	jsval_t v = for_iter_exec_body(js, ctx);
	if (is_err(v)) return v;
	if (for_iter_handle_continue(js, ctx)) break;
	if (js->flags & F_BREAK) break;
	if (js->flags & F_RETURN) return v;
	}

	return js_mkundef();
	}

	typedef enum { ITER_CONTINUE, ITER_BREAK, ITER_ERROR } iter_action_t;
	typedef iter_action_t (iter_callback_t)(struct js js, jsval_t value, void ctx, jsval_t out);

	static jsval_t iter_foreach(struct js js, jsval_t iterable, iter_callback_t cb, void ctx) {
	const char *iter_key = get_iterator_sym_key();
	jsoff_t iter_prop = iter_key ? lkp_proto(js, iterable, iter_key, strlen(iter_key)) : 0;
	if (iter_prop == 0) return js_mkerr(js, "not iterable");

	js_parse_state_t saved_state;
	JS_SAVE_STATE(js, saved_state);
	uint8_t saved_flags = js->flags;

	jsval_t iter_method = loadval(js, iter_prop + sizeof(jsoff_t) * 2);
	push_this(iterable);
	jsval_t iterator = call_js_with_args(js, iter_method, NULL, 0);
	pop_this();
	JS_RESTORE_STATE(js, saved_state);
	js->flags = saved_flags;

	if (is_err(iterator)) return iterator;

	jsval_t out = js_mkundef();
	while (true) {
	jsoff_t next_off = lkp_proto(js, iterator, "next", 4);
	if (next_off == 0) return js_mkerr(js, "iterator.next is not a function");

	jsval_t next_method = loadval(js, next_off + sizeof(jsoff_t) * 2);
	if (vtype(next_method) != T_FUNC && vtype(next_method) != T_CFUNC)
	return js_mkerr(js, "iterator.next is not a function");

	push_this(iterator);
	jsval_t result = call_js_with_args(js, next_method, NULL, 0);
	pop_this();
	JS_RESTORE_STATE(js, saved_state);
	js->flags = saved_flags;

	if (is_err(result)) return result;

	jsoff_t done_off = lkp(js, result, "done", 4);
	jsval_t done_val = done_off ? loadval(js, done_off + sizeof(jsoff_t) * 2) : js_mkundef();
	if (js_truthy(js, done_val)) break;

	jsoff_t value_off = lkp(js, result, "value", 5);
	jsval_t value = value_off ? loadval(js, value_off + sizeof(jsoff_t) * 2) : js_mkundef();

	iter_action_t action = cb(js, value, ctx, &out);
	if (action == ITER_BREAK) break;
	if (action == ITER_ERROR) return out;
	}

	return out;
	}

	static iter_action_t for_of_iter_cb(struct js js, jsval_t value, void ctx, jsval_t *out) {
	for_iter_ctx_t fctx = (for_iter_ctx_t )ctx;

	jsval_t err = for_iter_bind_var(js, fctx, value);
	if (is_err(err)) { *out = err; return ITER_ERROR; }

	jsval_t v = for_iter_exec_body(js, fctx);
	if (is_err(v)) { *out = v; return ITER_ERROR; }
	if (for_iter_handle_continue(js, fctx)) return ITER_BREAK;
	if (js->flags & F_BREAK) return ITER_BREAK;
	if (js->flags & F_RETURN) { *out = v; return ITER_BREAK; }

	return ITER_CONTINUE;
	}

	static jsval_t for_of_iter_object(struct js js, for_iter_ctx_t ctx, jsval_t iterable) {
	jsval_t result = iter_foreach(js, iterable, for_of_iter_cb, ctx);
	if (is_err(result) && strcmp(js->errmsg, "not iterable") == 0) {
	return js_mkerr(js, "for-of requires iterable");
	}
	return result;
	}

	static jsval_t js_for(struct js *js) {
	uint8_t flags = js->flags, exe = !(flags & F_NOEXEC);
	jsval_t v, res = js_mkundef();
	jsoff_t pos1 = 0, pos2 = 0, pos3 = 0, pos4 = 0;

	bool use_label_stack = label_stack && utarray_len(label_stack) > 0;
	int marker_index = 0;
	if (use_label_stack) {
	label_entry_t marker = { .name = NULL, .name_len = 0, .is_loop = true, .is_block = false };
	utarray_push_back(label_stack, &marker);
	marker_index = utarray_len(label_stack) - 1;
	}

	if (exe) mkscope(js);
	if (!expect(js, TOK_FOR, &res)) goto done;
	if (!expect(js, TOK_LPAREN, &res)) goto done;

	bool is_for_in = false;
	bool is_for_of = false;

	bool is_var_decl = false;
	bool is_const_var = false;
	bool is_let_loop = false;

	jsoff_t var_name_off = 0;
	jsoff_t var_name_len = 0;
	jsoff_t let_var_off = 0;
	jsoff_t let_var_len = 0;

	bool has_destructure = false;
	jsoff_t destructure_off = 0;
	jsoff_t destructure_len = 0;

	if (next(js) == TOK_LET \|\| next(js) == TOK_CONST \|\| next(js) == TOK_VAR) {
	if (js->tok == TOK_VAR) {
	is_var_decl = true;
	if ((js->flags & F_STRICT) && !js->var_warning_shown) {
	fprintf(stderr, "Warning: 'var' is deprecated, use 'let' or 'const' instead\n");
	js->var_warning_shown = true;
	}
	} else if (js->tok == TOK_LET) {
	is_let_loop = true;
	}
	is_const_var = (js->tok == TOK_CONST);
	js->consumed = 1;

	if (next(js) == TOK_LBRACKET \|\| next(js) == TOK_LBRACE) {
	has_destructure = true;
	destructure_off = js->toff;
	uint8_t open_tok = js->tok;
	uint8_t close_tok = (open_tok == TOK_LBRACKET) ? TOK_RBRACKET : TOK_RBRACE;
	int depth = 1;
	js->consumed = 1;
	while (depth > 0 && next(js) != TOK_EOF) {
	if (js->tok == open_tok) depth++;
	else if (js->tok == close_tok) depth--;
	js->consumed = 1;
	}
	destructure_len = js->pos - destructure_off;
	if (next(js) == TOK_IN) {
	is_for_in = true;
	js->consumed = 1;
	} else if (next(js) == TOK_OF) {
	is_for_of = true;
	js->consumed = 1;
	} else {
	res = js_mkerr_typed(js, JS_ERR_SYNTAX, "expected 'in' or 'of' after destructuring pattern");
	goto done;
	}
	} else if (next(js) == TOK_IDENTIFIER) {
	var_name_off = js->toff;
	var_name_len = js->tlen;
	if (is_let_loop) {
	let_var_off = var_name_off;
	let_var_len = var_name_len;
	}
	js->consumed = 1;
	if (next(js) == TOK_IN) {
	is_for_in = true;
	js->consumed = 1;
	} else if (next(js) == TOK_OF) {
	is_for_of = true;
	js->consumed = 1;
	} else {
	js->pos = var_name_off;
	js->consumed = 1;
	if (is_const_var) {
	v = js_const(js);
	} else if (is_var_decl) {
	v = js_var_decl(js);
	} else {
	v = js_let(js);
	}
	if (is_err2(&v, &res)) goto done;
	}
	}
	} else if (next(js) == TOK_IDENTIFIER) {
	var_name_off = js->toff;
	var_name_len = js->tlen;
	js->consumed = 1;
	if (next(js) == TOK_IN) {
	is_for_in = true;
	js->consumed = 1;
	} else if (next(js) == TOK_OF) {
	is_for_of = true;
	js->consumed = 1;
	} else {
	js->pos = var_name_off;
	js->consumed = 1;
	v = js_expr_comma(js);
	if (is_err2(&v, &res)) goto done;
	}
	} else if (next(js) == TOK_SEMICOLON) {
	} else {
	v = js_expr_comma(js);
	if (is_err2(&v, &res)) goto done;
	}

	if (is_for_in) {
	jsval_t obj_expr = js_expr(js);
	if (is_err2(&obj_expr, &res)) goto done;
	if (!expect(js, TOK_RPAREN, &res)) goto done;

	jsoff_t body_start = js->pos;
	loop_block_ctx_t forin_loop_ctx = {0};
	if (exe) loop_block_init(js, &forin_loop_ctx);
	js->flags \|= F_NOEXEC;
	v = js_block_or_stmt(js);
	if (is_err2(&v, &res)) goto done;
	jsoff_t body_end = js->pos;

	if (exe) {
	jsval_t obj = resolveprop(js, obj_expr);
	for_iter_ctx_t ctx = {
	body_start, body_end,
	var_name_off, var_name_len,
	is_const_var, flags,
	has_destructure, destructure_off,
	destructure_len, marker_index,
	forin_loop_ctx
	};
	res = for_in_iter_object(js, &ctx, obj);
	loop_block_cleanup(js, &forin_loop_ctx);
	if (is_err(res)) goto done;
	if (js->flags & F_RETURN) goto done;
	}

	js->pos = body_end;
	js->tok = TOK_SEMICOLON;
	js->consumed = 0;
	goto done;
	}

	if (is_for_of) {
	jsval_t iter_expr = js_expr(js);
	if (is_err2(&iter_expr, &res)) goto done;
	if (!expect(js, TOK_RPAREN, &res)) goto done;

	jsoff_t body_start = js->pos;
	loop_block_ctx_t forof_loop_ctx = {0};
	if (exe) loop_block_init(js, &forof_loop_ctx);
	js->flags \|= F_NOEXEC;
	v = js_block_or_stmt(js);
	if (is_err2(&v, &res)) goto done;
	jsoff_t body_end = js->pos;

	if (exe) {
	jsval_t iterable = resolveprop(js, iter_expr);
	uint8_t itype = vtype(iterable);
	for_iter_ctx_t ctx = {
	body_start, body_end,
	var_name_off, var_name_len,
	is_const_var, flags,
	has_destructure, destructure_off,
	destructure_len, marker_index,
	forof_loop_ctx
	};

	if (itype == T_ARR) res = for_of_iter_array(js, &ctx, iterable);
	else if (itype == T_STR) res = for_of_iter_string(js, &ctx, iterable);
	else if (itype == T_OBJ) res = for_of_iter_object(js, &ctx, iterable);
	else res = js_mkerr(js, "for-of requires iterable");

	loop_block_cleanup(js, &forof_loop_ctx);
	if (is_err(res)) goto done;
	if (js->flags & F_RETURN) goto done;
	}

	js->pos = body_end;
	js->tok = TOK_SEMICOLON;
	js->consumed = 0;
	goto done;
	}

	if (!expect(js, TOK_SEMICOLON, &res)) goto done;
	js->flags \|= F_NOEXEC;
	pos1 = js->pos;
	if (next(js) != TOK_SEMICOLON) {
	v = js_expr(js);
	if (is_err2(&v, &res)) goto done;
	}
	if (!expect(js, TOK_SEMICOLON, &res)) goto done;
	pos2 = js->pos;
	if (next(js) != TOK_RPAREN) {
	v = js_expr_comma(js);
	if (is_err2(&v, &res)) goto done;
	}
	if (!expect(js, TOK_RPAREN, &res)) goto done;
	pos3 = js->pos;

	jsoff_t iter_var_prop_off = 0;
	if (is_let_loop && let_var_len > 0 && exe) {
	js->flags = flags;
	mkscope(js);
	jsval_t let_var_key = js_mkstr(js, &js->code[let_var_off], let_var_len);
	jsoff_t outer_off = lkp_scope(js, upper(js, js->scope), &js->code[let_var_off], let_var_len);
	jsval_t init_val = outer_off ? resolveprop(js, mkval(T_PROP, outer_off)) : js_mkundef();
	mkprop(js, js->scope, let_var_key, init_val, 0);
	iter_var_prop_off = lkp(js, js->scope, &js->code[let_var_off], let_var_len);
	const char *var_interned = intern_string(&js->code[let_var_off], let_var_len);
	for_let_push(js, var_interned, let_var_len, iter_var_prop_off, js_mkundef());
	}

	loop_block_ctx_t loop_ctx = {0};
	if (exe) {
	loop_block_init(js, &loop_ctx);
	if (is_let_loop && let_var_len > 0 && loop_ctx.needs_scope) for_let_set_body_scope(js, loop_ctx.loop_scope);
	}

	js->flags \|= F_NOEXEC;
	v = js_block_or_stmt(js);
	if (exe) js->flags = flags;
	if (is_err2(&v, &res)) goto done;
	pos4 = js->pos;

	while (!(flags & F_NOEXEC)) {
	js->flags = flags, js->pos = pos1, js->consumed = 1;
	if (next(js) != TOK_SEMICOLON) {
	v = resolveprop(js, js_expr(js));
	if (is_err2(&v, &res)) goto done;
	if (!js_truthy(js, v)) break;
	}

	js->flags \|= F_LOOP;
	js->pos = pos3;
	js->consumed = 1;

	if (is_let_loop && let_var_len > 0 && loop_ctx.needs_scope) {
	loop_block_sync_scope(js, &loop_ctx);
	}

	loop_block_clear(js, &loop_ctx);
	v = loop_block_exec(js, &loop_ctx);
	if (is_err2(&v, &res)) {
	loop_block_cleanup(js, &loop_ctx);
	if (is_let_loop && let_var_len > 0) {
	for_let_pop(js); delscope(js);
	}
	goto done;
	}

	if (label_flags & F_CONTINUE_LABEL) {
	if (is_this_loop_continue_target(marker_index)) {
	clear_continue_label();
	js->flags &= ~(F_BREAK \| F_NOEXEC);
	js->flags = flags;
	js->pos = pos2, js->consumed = 1;
	if (next(js) != TOK_RPAREN) {
	v = js_expr_comma(js);
	if (is_err2(&v, &res)) goto done;
	} continue;
	}
	}

	if (js->flags & F_BREAK) break;
	if (js->flags & F_RETURN) { res = v; break; }

	js->flags = flags, js->pos = pos2, js->consumed = 1;
	if (next(js) != TOK_RPAREN) {
	v = js_expr_comma(js);
	if (is_err2(&v, &res)) goto done;
	}
	}
	if (exe) loop_block_cleanup(js, &loop_ctx);
	if (is_let_loop && let_var_len > 0 && exe) {
	for_let_pop(js); delscope(js);
	}
	js->pos = pos4, js->tok = TOK_SEMICOLON, js->consumed = 0;
	done:
	if (use_label_stack && label_stack && utarray_len(label_stack) > 0) {
	utarray_pop_back(label_stack);
	}

	if (exe) delscope(js);
	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| F_NOEXEC);
	}
	if ((js->flags & F_BREAK) && (label_flags & F_BREAK_LABEL)) {
	preserve \|= (js->flags & (F_BREAK \| F_NOEXEC));
	}
	if (label_flags & F_CONTINUE_LABEL) {
	preserve \|= F_BREAK \| F_NOEXEC;
	}
	js->flags = flags \| preserve;
	return res;
	}

	static jsval_t js_while(struct js *js) {
	uint8_t flags = js->flags, exe = !(flags & F_NOEXEC);
	jsval_t res = js_mkundef(), v;
	loop_block_ctx_t loop_ctx = {0};

	bool use_label_stack = label_stack && utarray_len(label_stack) > 0;
	int marker_index = 0;
	if (use_label_stack) {
	label_entry_t marker = { .name = NULL, .name_len = 0, .is_loop = true, .is_block = false };
	utarray_push_back(label_stack, &marker);
	marker_index = utarray_len(label_stack) - 1;
	}

	js->consumed = 1;
	if (!expect(js, TOK_LPAREN, &res)) goto done;

	jsoff_t cond_start = js->pos;
	js->flags \|= F_NOEXEC;
	v = js_expr(js);
	if (is_err(v)) { res = v; goto done; }

	if (!expect(js, TOK_RPAREN, &res)) goto done;

	jsoff_t body_start = js->pos;
	if (exe) {
	js->flags = flags;
	loop_block_init(js, &loop_ctx);
	js->flags \|= F_NOEXEC;
	}

	v = js_block_or_stmt(js);
	if (is_err(v)) { res = v; goto done; }
	jsoff_t body_end = js->pos;

	if (exe) {
	while (true) {
	js->flags = flags;
	js->pos = cond_start;
	js->consumed = 1;

	v = resolveprop(js, js_expr(js));
	if (is_err(v)) { res = v; break; }

	if (!js_truthy(js, v)) break;

	js->pos = body_start;
	js->consumed = 1;
	js->flags = (flags & ~F_NOEXEC) \| F_LOOP;

	loop_block_clear(js, &loop_ctx);
	v = loop_block_exec(js, &loop_ctx);
	if (is_err(v)) { res = v; break; }

	if (label_flags & F_CONTINUE_LABEL) {
	if (is_this_loop_continue_target(marker_index)) {
	clear_continue_label();
	js->flags &= ~(F_BREAK \| F_NOEXEC);
	continue;
	}
	}

	if (js->flags & F_BREAK) break;
	if (js->flags & F_RETURN) { res = v; break; }
	}
	loop_block_cleanup(js, &loop_ctx);
	}

	js->pos = body_end;
	js->tok = TOK_SEMICOLON;
	js->consumed = 0;

	done:
	if (use_label_stack && label_stack && utarray_len(label_stack) > 0) {
	utarray_pop_back(label_stack);
	}

	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| F_NOEXEC);
	}
	if ((js->flags & F_BREAK) && (label_flags & F_BREAK_LABEL)) {
	preserve \|= (js->flags & (F_BREAK \| F_NOEXEC));
	}
	if (label_flags & F_CONTINUE_LABEL) {
	preserve \|= F_BREAK \| F_NOEXEC;
	}
	js->flags = flags \| preserve;

	return res;
	}

	static jsval_t js_do_while(struct js *js) {
	uint8_t flags = js->flags, exe = !(flags & F_NOEXEC);
	jsval_t res = js_mkundef(), v;
	loop_block_ctx_t loop_ctx = {0};

	bool use_label_stack = label_stack && utarray_len(label_stack) > 0;
	int marker_index = 0;
	if (use_label_stack) {
	label_entry_t marker = { .name = NULL, .name_len = 0, .is_loop = true, .is_block = false };
	utarray_push_back(label_stack, &marker);
	marker_index = utarray_len(label_stack) - 1;
	}

	js->consumed = 1;

	jsoff_t body_start = js->pos;
	bool is_block = (next(js) == TOK_LBRACE);
	if (exe) loop_block_init(js, &loop_ctx);

	js->flags \|= F_NOEXEC;
	v = js_block_or_stmt(js);
	if (is_err(v)) { res = v; goto done; }

	if (is_block && next(js) == TOK_RBRACE) {
	js->consumed = 1;
	}
	(void) js->pos;

	if (!expect(js, TOK_WHILE, &res)) goto done;
	if (!expect(js, TOK_LPAREN, &res)) goto done;

	jsoff_t cond_start = js->pos;
	v = js_expr(js);
	if (is_err(v)) { res = v; goto done; }

	if (!expect(js, TOK_RPAREN, &res)) goto done;
	jsoff_t cond_end = js->pos;

	if (exe) {
	do {
	js->pos = body_start;
	js->consumed = 1;
	js->flags = (flags & ~F_NOEXEC) \| F_LOOP;

	loop_block_clear(js, &loop_ctx);
	v = loop_block_exec(js, &loop_ctx);
	if (is_err(v)) {
	res = v; break;
	}

	if (label_flags & F_CONTINUE_LABEL) {
	if (is_this_loop_continue_target(marker_index)) {
	clear_continue_label();
	js->flags &= ~(F_BREAK \| F_NOEXEC);
	} else { break; }
	}

	if (js->flags & F_BREAK) {
	break;
	}

	if (js->flags & F_RETURN) {
	res = v;
	break;
	}

	js->flags = flags;
	js->pos = cond_start;
	js->consumed = 1;

	v = resolveprop(js, js_expr(js));
	if (is_err(v)) {
	res = v;
	break;
	}
	} while (js_truthy(js, v));
	loop_block_cleanup(js, &loop_ctx);
	}

	js->pos = cond_end;
	js->consumed = 1;

	done:
	if (use_label_stack && label_stack && utarray_len(label_stack) > 0) {
	utarray_pop_back(label_stack);
	}

	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| F_NOEXEC);
	}
	if ((js->flags & F_BREAK) && (label_flags & F_BREAK_LABEL)) {
	preserve \|= (js->flags & (F_BREAK \| F_NOEXEC));
	}
	if (label_flags & F_CONTINUE_LABEL) {
	preserve \|= F_BREAK \| F_NOEXEC;
	}
	js->flags = flags \| preserve;

	return res;
	}

	static jsval_t js_try(struct js *js) {
	uint8_t flags = js->flags, exe = !(flags & F_NOEXEC);
	jsval_t res = js_mkundef();
	jsval_t try_result = js_mkundef();
	jsval_t catch_result = js_mkundef();
	jsval_t finally_result = js_mkundef();

	bool had_exception = false;
	char saved_errmsg[256] = {0};
	jsval_t exception_value = js_mkundef();

	js->consumed = 1;

	if (next(js) != TOK_LBRACE) {
	return js_mkerr(js, "{ expected after try");
	}

	jsoff_t try_start = js->pos;
	js->flags \|= F_NOEXEC;
	js->consumed = 1;

	while (next(js) != TOK_EOF && next(js) != TOK_RBRACE) {
	jsval_t v = js_stmt(js);
	if (is_err(v)) break;
	}
	if (next(js) == TOK_RBRACE) js->consumed = 1;
	jsoff_t try_end = js->pos;

	bool has_catch = false;
	bool has_finally = false;
	jsoff_t catch_start = 0, catch_end = 0;
	jsoff_t finally_start = 0, finally_end = 0;
	jsoff_t catch_param_off = 0, catch_param_len = 0;

	if (lookahead(js) == TOK_CATCH) {
	has_catch = true;
	js->consumed = 1;
	next(js);
	js->consumed = 1;

	if (next(js) == TOK_LPAREN) {
	js->consumed = 1;
	if (next(js) == TOK_IDENTIFIER) {
	catch_param_off = js->toff;
	catch_param_len = js->tlen;
	if ((js->flags & F_STRICT) && is_strict_restricted(&js->code[catch_param_off], catch_param_len)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot use '%.*s' as catch parameter in strict mode", (int) catch_param_len, &js->code[catch_param_off]);
	}
	js->consumed = 1;
	}
	if (next(js) != TOK_RPAREN) return js_mkerr(js, ") expected in catch");
	js->consumed = 1;
	}

	if (next(js) != TOK_LBRACE) {
	return js_mkerr(js, "{ expected after catch");
	}

	catch_start = js->pos;
	js->consumed = 1;

	while (next(js) != TOK_EOF && next(js) != TOK_RBRACE) {
	jsval_t v = js_stmt(js);
	if (is_err(v)) break;
	}
	if (next(js) == TOK_RBRACE) js->consumed = 1;
	catch_end = js->pos;
	}

	if (lookahead(js) == TOK_FINALLY) {
	has_finally = true;
	js->consumed = 1;
	next(js);
	js->consumed = 1;

	if (next(js) != TOK_LBRACE) {
	return js_mkerr(js, "{ expected after finally");
	}

	finally_start = js->pos;
	js->consumed = 1;

	while (next(js) != TOK_EOF && next(js) != TOK_RBRACE) {
	jsval_t v = js_stmt(js);
	if (is_err(v)) break;
	}
	if (next(js) == TOK_RBRACE) js->consumed = 1;
	finally_end = js->pos;
	}

	if (!has_catch && !has_finally) {
	return js_mkerr(js, "try requires catch or finally");
	}

	jsoff_t end_pos = has_finally ? finally_end : (has_catch ? catch_end : try_end);

	if (exe) {
	bool try_returned = false;
	jsval_t try_return_value = js_mkundef();

	js->flags = flags & (uint8_t)~F_NOEXEC;
	js->pos = try_start;
	js->consumed = 1;

	while (next(js) != TOK_EOF && next(js) != TOK_RBRACE && !(js->flags & (F_RETURN \| F_THROW \| F_BREAK))) {
	try_result = js_stmt(js);
	if (is_err(try_result)) {
	had_exception = true;
	break;
	}
	}

	if (js->flags & F_RETURN) {
	try_returned = true;
	try_return_value = try_result;
	js->flags &= (uint8_t)~(F_RETURN \| F_NOEXEC);
	}

	if (js->flags & F_THROW) {
	had_exception = true;
	js->flags &= (uint8_t)~F_THROW;
	strncpy(saved_errmsg, js->errmsg, sizeof(saved_errmsg) - 1);
	saved_errmsg[sizeof(saved_errmsg) - 1] = '\0';

	exception_value = js->thrown_value;
	js->thrown_value = js_mkundef();
	js->errmsg[0] = '\0';
	}

	if (next(js) == TOK_RBRACE) js->consumed = 1;

	bool exception_handled = false;
	bool catch_returned = false;
	jsval_t catch_return_value = js_mkundef();

	if (had_exception && has_catch) {
	exception_handled = true;
	mkscope(js);

	if (catch_param_len > 0) {
	jsval_t key = js_mkstr(js, &js->code[catch_param_off], catch_param_len);
	mkprop(js, js->scope, key, exception_value, 0);
	}

	js->flags = flags & (uint8_t)~F_NOEXEC;
	js->pos = catch_start;
	js->consumed = 1;

	while (next(js) != TOK_EOF && next(js) != TOK_RBRACE && !(js->flags & (F_RETURN \| F_THROW \| F_BREAK))) {
	catch_result = js_stmt(js);
	if (is_err(catch_result)) break;
	}

	if (js->flags & F_RETURN) {
	catch_returned = true;
	catch_return_value = catch_result;
	js->flags &= (uint8_t)~(F_RETURN \| F_NOEXEC);
	}

	if (next(js) == TOK_RBRACE) js->consumed = 1;
	delscope(js);

	if (js->flags & F_THROW) {
	exception_handled = false;
	strncpy(saved_errmsg, js->errmsg, sizeof(saved_errmsg) - 1);
	saved_errmsg[sizeof(saved_errmsg) - 1] = '\0';
	exception_value = js->thrown_value;
	js->thrown_value = js_mkundef();
	js->flags &= (uint8_t)~F_THROW;
	js->errmsg[0] = '\0';
	} else {
	res = catch_result;
	}
	}

	if (has_finally) {
	uint8_t pre_finally_flags = js->flags;
	bool had_pre_finally_exception = (js->flags & F_THROW) != 0;
	char pre_finally_errmsg[256] = {0};
	if (had_pre_finally_exception) {
	strncpy(pre_finally_errmsg, js->errmsg, sizeof(pre_finally_errmsg) - 1);
	js->flags &= (uint8_t)~F_THROW;
	js->errmsg[0] = '\0';
	}

	js->flags = flags & (uint8_t)~F_NOEXEC;
	js->pos = finally_start;
	js->consumed = 1;

	while (next(js) != TOK_EOF && next(js) != TOK_RBRACE && !(js->flags & (F_RETURN \| F_THROW \| F_BREAK))) {
	finally_result = js_stmt(js);
	if (is_err(finally_result)) break;
	}

	if (next(js) == TOK_RBRACE) js->consumed = 1;

	if (!(js->flags & (F_RETURN \| F_THROW))) {
	if (had_pre_finally_exception) {
	js->flags = pre_finally_flags;
	strncpy(js->errmsg, pre_finally_errmsg, sizeof(js->errmsg) - 1);
	} else if (had_exception && !exception_handled) {
	js->flags \|= F_THROW;
	strncpy(js->errmsg, saved_errmsg, sizeof(js->errmsg) - 1);
	js->thrown_value = exception_value;
	} else if (catch_returned) {
	js->flags \|= F_RETURN;
	res = catch_return_value;
	} else if (try_returned) {
	js->flags \|= F_RETURN;
	res = try_return_value;
	}
	}
	} else if (had_exception && !exception_handled) {
	js->flags \|= F_THROW;
	strncpy(js->errmsg, saved_errmsg, sizeof(js->errmsg) - 1);
	js->thrown_value = exception_value;
	res = mkval(T_ERR, 0);
	} else if (catch_returned) {
	js->flags \|= F_RETURN;
	res = catch_return_value;
	} else if (try_returned) {
	js->flags \|= F_RETURN;
	res = try_return_value;
	}

	if (!had_exception && !try_returned && !(js->flags & (F_RETURN \| F_THROW))) {
	res = try_result;
	}
	}

	js->pos = end_pos;
	js->tok = TOK_SEMICOLON;
	js->consumed = 0;

	return res;
	}

	static bool label_exists(const char *name, jsoff_t len, bool check_loop) {
	if (!label_stack) return false;
	unsigned int depth = utarray_len(label_stack);
	for (int i = (int)depth - 1; i >= 0; i--) {
	label_entry_t entry = (label_entry_t )utarray_eltptr(label_stack, (unsigned int)i);
	if (entry && entry->name_len == len &&
	memcmp(entry->name, name, len) == 0) {
	if (check_loop && !entry->is_loop) {
	return false;
	}
	return true;
	}
	}
	return false;
	}

	static bool is_this_loop_continue_target(int marker_index) {
	if (!(label_flags & F_CONTINUE_LABEL)) return false;
	if (!label_stack \|\| !continue_target_label) return false;
	if (marker_index <= 0) return false;

	label_entry_t entry = (label_entry_t )utarray_eltptr(label_stack, (unsigned int)(marker_index - 1));
	if (!entry) return false;
	if (entry->name == NULL) return false;
	if (!entry->is_loop) return false;

	if (entry->name_len == continue_target_label_len &&
	memcmp(entry->name, continue_target_label, continue_target_label_len) == 0) {
	return true;
	}
	return false;
	}

	static jsval_t js_break(struct js *js) {
	js->consumed = 1;

	uint8_t nxt = next(js);
	if (nxt == TOK_IDENTIFIER && !js->had_newline) {
	const char *label = &js->code[js->toff];
	jsoff_t label_len = js->tlen;
	js->consumed = 1;

	if (js->flags & F_NOEXEC) {
	return js_mkundef();
	}

	if (!label_exists(label, label_len, false)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "undefined label '%.*s'", (int)label_len, label);
	}

	break_target_label = label;
	break_target_label_len = label_len;
	label_flags \|= F_BREAK_LABEL;
	js->flags \|= F_BREAK \| F_NOEXEC;
	return js_mkundef();
	}

	if (js->flags & F_NOEXEC) {
	return js_mkundef();
	}

	if (!(js->flags & (F_LOOP \| F_SWITCH))) {
	bool in_labeled_block = false;
	if (label_stack) {
	unsigned int depth = utarray_len(label_stack);
	for (int i = (int)depth - 1; i >= 0; i--) {
	label_entry_t entry = (label_entry_t )utarray_eltptr(label_stack, (unsigned int)i);
	if (entry && entry->is_block) {
	in_labeled_block = true;
	break;
	}
	}
	}
	if (!in_labeled_block) {
	return js_mkerr(js, "not in loop or switch");
	}
	}

	js->flags \|= F_BREAK \| F_NOEXEC;
	return js_mkundef();
	}

	static jsval_t js_continue(struct js *js) {
	js->consumed = 1;

	uint8_t nxt = next(js);
	if (nxt == TOK_IDENTIFIER && !js->had_newline) {
	const char *label = &js->code[js->toff];
	jsoff_t label_len = js->tlen;
	js->consumed = 1;

	if (js->flags & F_NOEXEC) {
	return js_mkundef();
	}

	if (!label_exists(label, label_len, true)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "undefined label '%.*s' or not a loop", (int)label_len, label);
	}

	continue_target_label = label;
	continue_target_label_len = label_len;
	label_flags \|= F_CONTINUE_LABEL;
	js->flags \|= F_BREAK \| F_NOEXEC;
	return js_mkundef();
	}

	if (js->flags & F_NOEXEC) {
	return js_mkundef();
	}

	if (!(js->flags & F_LOOP)) {
	return js_mkerr(js, "not in loop");
	}

	js->flags \|= F_NOEXEC;
	return js_mkundef();
	}

	static jsval_t js_return(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	uint8_t in_func = js->flags & F_CALL;
	js->consumed = 1;
	jsval_t res = js_mkundef();

	uint8_t nxt = next(js);
	if (nxt != TOK_SEMICOLON && nxt != TOK_RBRACE && nxt != TOK_EOF && !js->had_newline) {
	res = resolveprop(js, js_expr_comma(js));
	}

	if (exe && !in_func) return js_mkundef();

	if (exe) {
	js->pos = js->clen;
	js->flags \|= F_RETURN \| F_NOEXEC;
	}

	return res;
	}

	static jsval_t js_switch(struct js *js) {
	uint8_t flags = js->flags, exe = !(flags & F_NOEXEC);
	jsval_t res = js_mkundef();

	js->consumed = 1;
	if (!expect(js, TOK_LPAREN, &res)) return res;

	jsoff_t switch_expr_start = js->pos;
	uint8_t saved_flags = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t switch_expr = js_expr(js);
	js->flags = saved_flags;

	if (is_err(switch_expr)) return switch_expr;

	if (!expect(js, TOK_RPAREN, &res)) return res;
	if (!expect(js, TOK_LBRACE, &res)) return res;

	typedef struct {
	jsoff_t case_expr_start;
	jsoff_t case_expr_end;
	jsoff_t body_start;
	bool is_default;
	} CaseInfo;

	CaseInfo cases[64];
	int case_count = 0;

	js->flags \|= F_NOEXEC;

	while (next(js) != TOK_RBRACE && next(js) != TOK_EOF && case_count < 64) {
	if (next(js) == TOK_CASE) {
	js->consumed = 1;

	cases[case_count].is_default = false;
	cases[case_count].case_expr_start = js->pos;

	jsval_t case_val = js_expr(js);
	if (is_err(case_val)) {
	js->flags = flags;
	return case_val;
	}

	cases[case_count].case_expr_end = js->pos;

	if (!expect(js, TOK_COLON, &res)) {
	js->flags = flags;
	return res;
	}

	cases[case_count].body_start = js->pos;
	case_count++;

	while (next(js) != TOK_EOF && next(js) != TOK_CASE && next(js) != TOK_DEFAULT && next(js) != TOK_RBRACE) {
	jsval_t stmt = js_stmt(js);
	if (is_err(stmt)) {
	js->flags = flags;
	return stmt;
	}
	}

	} else if (next(js) == TOK_DEFAULT) {
	js->consumed = 1;

	cases[case_count].is_default = true;
	cases[case_count].case_expr_start = 0;
	cases[case_count].case_expr_end = 0;

	if (!expect(js, TOK_COLON, &res)) {
	js->flags = flags;
	return res;
	}

	cases[case_count].body_start = js->pos;
	case_count++;

	while (next(js) != TOK_EOF && next(js) != TOK_CASE && next(js) != TOK_DEFAULT && next(js) != TOK_RBRACE) {
	jsval_t stmt = js_stmt(js);
	if (is_err(stmt)) {
	js->flags = flags;
	return stmt;
	}
	}

	} else {
	break;
	}
	}

	if (!expect(js, TOK_RBRACE, &res)) {
	js->flags = flags;
	return res;
	}

	jsoff_t end_pos = js->pos;

	if (exe) {
	js->pos = switch_expr_start;
	js->consumed = 1;
	js->flags = flags;
	jsval_t switch_val = resolveprop(js, js_expr(js));

	if (is_err(switch_val)) {
	js->pos = end_pos;
	js->flags = flags;
	return switch_val;
	}

	int matching_case = -1;
	int default_case = -1;

	for (int i = 0; i < case_count; i++) {
	if (cases[i].is_default) {
	default_case = i;
	continue;
	}

	js->pos = cases[i].case_expr_start;
	js->consumed = 1;
	js->flags = flags;
	jsval_t case_val = resolveprop(js, js_expr(js));

	if (is_err(case_val)) {
	js->pos = end_pos;
	js->flags = flags;
	return case_val;
	}

	bool matches = false;
	if (vtype(switch_val) == vtype(case_val)) {
	if (vtype(switch_val) == T_NUM) {
	matches = tod(switch_val) == tod(case_val);
	} else if (vtype(switch_val) == T_STR) {
	jsoff_t n1, off1 = vstr(js, switch_val, &n1);
	jsoff_t n2, off2 = vstr(js, case_val, &n2);
	matches = n1 == n2 && memcmp(&js->mem[off1], &js->mem[off2], n1) == 0;
	} else if (vtype(switch_val) == T_BOOL) {
	matches = vdata(switch_val) == vdata(case_val);
	} else {
	matches = vdata(switch_val) == vdata(case_val);
	}
	}

	if (matches) {
	matching_case = i;
	break;
	}
	}

	if (matching_case < 0 && default_case >= 0) matching_case = default_case;

	if (matching_case >= 0) {
	js->flags = (flags & ~F_NOEXEC) \| F_SWITCH;

	for (int i = matching_case; i < case_count; i++) {
	js->pos = cases[i].body_start;
	js->consumed = 1;

	while (next(js) != TOK_EOF && next(js) != TOK_CASE &&
	next(js) != TOK_DEFAULT && next(js) != TOK_RBRACE &&
	!(js->flags & (F_BREAK \| F_RETURN \| F_THROW))) {
	res = js_stmt(js);
	if (is_err(res)) {
	js->pos = end_pos;
	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| F_NOEXEC);
	}
	if (js->flags & F_THROW) {
	preserve = js->flags & (F_THROW \| F_NOEXEC);
	}
	js->flags = flags \| preserve;
	return res;
	}
	}

	if (js->flags & F_BREAK) { js->flags &= ~F_BREAK; break; }
	if (js->flags & (F_RETURN \| F_THROW)) break;
	}
	}
	}

	js->pos = end_pos;
	js->tok = TOK_SEMICOLON;
	js->consumed = 0;

	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| F_NOEXEC);
	}
	if (js->flags & F_THROW) {
	preserve = js->flags & (F_THROW \| F_NOEXEC);
	}
	js->flags = (flags & ~F_SWITCH) \| preserve;

	return res;
	}

	static jsval_t js_with(struct js *js) {
	uint8_t flags = js->flags, exe = !(flags & F_NOEXEC);
	jsval_t res = js_mkundef();

	if (flags & F_STRICT) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "with statement not allowed in strict mode");
	}

	js->consumed = 1;
	if (!expect(js, TOK_LPAREN, &res)) return res;

	jsval_t obj_expr = js_expr(js);
	if (is_err(obj_expr)) return obj_expr;

	if (!expect(js, TOK_RPAREN, &res)) return res;

	if (exe) {
	jsval_t obj = resolveprop(js, obj_expr);
	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR && vtype(obj) != T_FUNC) {
	return js_mkerr(js, "with requires object");
	}

	jsval_t with_obj = obj;
	if (vtype(obj) == T_FUNC) {
	with_obj = mkval(T_OBJ, vdata(obj));
	}

	jsoff_t parent_scope_offset = (jsoff_t) vdata(js->scope);
	if (global_scope_stack == NULL) utarray_new(global_scope_stack, &jsoff_icd);
	utarray_push_back(global_scope_stack, &parent_scope_offset);

	jsval_t with_scope = mkobj(js, parent_scope_offset);
	set_slot(js, with_scope, SLOT_WITH, with_obj);

	jsval_t saved_scope = js->scope;
	js->scope = with_scope;

	res = js_block_or_stmt(js);
	if (global_scope_stack && utarray_len(global_scope_stack) > 0) utarray_pop_back(global_scope_stack);
	js->scope = saved_scope;
	} else res = js_block_or_stmt(js);

	js->flags = flags;
	return res;
	}

	static jsval_t js_class_expr(struct js *js, bool is_expression);
	static jsval_t js_class_decl(struct js *js) { return js_class_expr(js, false); }

	static jsval_t js_class_expr(struct js *js, bool is_expression) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	js->consumed = 1;

	jsoff_t class_name_off = 0, class_name_len = 0;
	char *class_name = NULL;

	if (next(js) == TOK_IDENTIFIER) {
	if (!(js->tlen == 7 && streq(&js->code[js->toff], js->tlen, "extends", 7))) {
	class_name_off = js->toff;
	class_name_len = js->tlen;
	class_name = (char *) &js->code[class_name_off];
	js->consumed = 1;
	}
	} else if (!is_expression) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "class name expected");
	}

	jsoff_t super_off = 0, super_len = 0;
	if (next(js) == TOK_IDENTIFIER && js->tlen == 7 &&
	streq(&js->code[js->toff], js->tlen, "extends", 7)) {
	js->consumed = 1;
	EXPECT_IDENT();
	super_off = js->toff;
	super_len = js->tlen;
	js->consumed = 1;
	}

	EXPECT(TOK_LBRACE);
	jsoff_t constructor_params_start = 0;
	jsoff_t constructor_body_start = 0, constructor_body_end = 0;
	uint8_t save_flags = js->flags;
	js->flags \|= F_NOEXEC;

	typedef struct {
	jsoff_t name_off, name_len, fn_start, fn_end;
	bool is_async;
	bool is_static;
	bool is_field;
	bool is_private;
	bool is_getter;
	bool is_setter;
	jsoff_t field_start, field_end;
	jsoff_t param_start;
	} MethodInfo;

	static const UT_icd method_info_icd = {
	.sz = sizeof(MethodInfo),
	.init = NULL,
	.copy = NULL,
	.dtor = NULL,
	};

	UT_array *methods = NULL;
	utarray_new(methods, &method_info_icd);

	uint8_t class_tok;
	while ((class_tok = next(js)) != TOK_RBRACE && class_tok != TOK_EOF) {
	bool is_async_method = false;
	bool is_static_member = false;
	bool is_getter_method = false;
	bool is_setter_method = false;

	if (next(js) == TOK_STATIC) {
	is_static_member = true;
	js->consumed = 1;
	}
	if (next(js) == TOK_ASYNC) {
	is_async_method = true;
	js->consumed = 1;
	}

	bool is_private_member = false;
	if (next(js) == TOK_HASH) {
	js->consumed = 1;
	if (next(js) == TOK_IDENTIFIER) { is_private_member = true; } else {
	js->flags = save_flags;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "private field name expected");
	}
	}

	if (next(js) == TOK_IDENTIFIER) {
	bool is_get = (js->tlen == 3 && memcmp(&js->code[js->toff], "get", 3) == 0);
	bool is_set = (js->tlen == 3 && memcmp(&js->code[js->toff], "set", 3) == 0);
	if (!is_private_member && (is_get \|\| is_set)) {
	jsoff_t saved_pos = js->pos;
	jsoff_t saved_toff = js->toff;
	jsoff_t saved_tlen = js->tlen;
	uint8_t saved_tok = js->tok;
	js->consumed = 1;
	if (next(js) == TOK_IDENTIFIER) {
	is_getter_method = is_get;
	is_setter_method = is_set;
	} else {
	js->pos = saved_pos;
	js->toff = saved_toff;
	js->tlen = saved_tlen;
	js->tok = saved_tok;
	js->consumed = 0;
	}
	}
	}

	if (next(js) != TOK_IDENTIFIER && (next(js) < TOK_ASYNC \|\| next(js) > TOK_STATIC)) {
	js->flags = save_flags;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "method name expected");
	}
	jsoff_t method_name_off = js->toff, method_name_len = js->tlen;
	js->consumed = 1;

	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	jsoff_t field_start = js->pos;
	int depth = 0;
	bool done = false;
	while (!done && next(js) != TOK_EOF) {
	uint8_t tok = next(js);
	if (depth == 0 && (tok == TOK_SEMICOLON \|\| tok == TOK_RBRACE \|\|
	(tok == TOK_IDENTIFIER && js->pos > field_start + 1))) {
	if (tok != TOK_SEMICOLON && tok != TOK_RBRACE) {
	js->consumed = 0;
	}
	done = true;
	} else if (tok == TOK_LPAREN \|\| tok == TOK_LBRACKET \|\| tok == TOK_LBRACE) {
	depth++;
	js->consumed = 1;
	} else if (tok == TOK_RPAREN \|\| tok == TOK_RBRACKET \|\| tok == TOK_RBRACE) {
	if (depth == 0) {
	done = true;
	} else {
	depth--;
	js->consumed = 1;
	}
	} else {
	js->consumed = 1;
	}
	}
	jsoff_t field_end = js->pos;
	if (next(js) == TOK_SEMICOLON) js->consumed = 1;

	MethodInfo field_method = {
	.name_off = method_name_off,
	.name_len = method_name_len,
	.is_static = is_static_member,
	.is_async = false,
	.is_field = true,
	.is_private = is_private_member,
	.field_start = field_start,
	.field_end = field_end,
	.fn_start = 0,
	.fn_end = 0,
	};
	utarray_push_back(methods, &field_method);
	continue;
	}

	if (next(js) == TOK_SEMICOLON \|\| (next(js) != TOK_LPAREN && next(js) == TOK_IDENTIFIER)) {
	if (next(js) == TOK_SEMICOLON) js->consumed = 1;
	MethodInfo bare_method = {
	.name_off = method_name_off,
	.name_len = method_name_len,
	.is_static = is_static_member,
	.is_async = false,
	.is_field = true,
	.is_private = is_private_member,
	.field_start = 0,
	.field_end = 0,
	.fn_start = 0,
	.fn_end = 0,
	};
	utarray_push_back(methods, &bare_method);
	continue;
	}

	EXPECT(TOK_LPAREN, js->flags = save_flags);
	jsoff_t method_params_start = js->pos - 1;
	if (!parse_func_params(js, &save_flags, NULL)) {
	js->flags = save_flags;
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "invalid method parameters");
	}
	EXPECT(TOK_RPAREN, js->flags = save_flags);
	EXPECT(TOK_LBRACE, js->flags = save_flags);
	jsoff_t method_body_start = js->pos - 1;
	js->consumed = 0;
	jsval_t blk = js_block(js, false);
	if (is_err(blk)) {
	js->flags = save_flags;
	return blk;
	}
	jsoff_t method_body_end = js->pos;
	if (streq(&js->code[method_name_off], method_name_len, "constructor", 11)) {
	constructor_params_start = method_params_start;
	constructor_body_start = method_body_start + 1;
	constructor_body_end = method_body_end;
	} else {
	MethodInfo func_method = {
	.name_off = method_name_off,
	.name_len = method_name_len,
	.fn_start = method_params_start,
	.fn_end = method_body_end,
	.param_start = method_params_start,
	.is_async = is_async_method,
	.is_static = is_static_member,
	.is_field = false,
	.is_private = is_private_member,
	.is_getter = is_getter_method,
	.is_setter = is_setter_method,
	.field_start = 0,
	.field_end = 0,
	};
	utarray_push_back(methods, &func_method);
	}
	js->consumed = 1;
	}

	EXPECT(TOK_RBRACE, js->flags = save_flags);
	js->flags = save_flags;

	if (exe) {
	jsval_t super_constructor = js_mkundef();
	jsval_t super_proto = js_mknull();
	if (super_len > 0) {
	jsval_t super_val = lookup(js, &js->code[super_off], super_len);
	if (is_err(super_val)) return super_val;
	super_constructor = resolveprop(js, super_val);
	if (vtype(super_constructor) != T_FUNC && vtype(super_constructor) != T_CFUNC) {
	return js_mkerr(js, "super class must be a constructor");
	}
	jsval_t super_obj = mkval(T_OBJ, vdata(super_constructor));
	jsoff_t super_proto_off = lkp_interned(js, super_obj, INTERN_PROTOTYPE, 9);
	if (super_proto_off != 0) {
	super_proto = resolveprop(js, mkval(T_PROP, super_proto_off));
	}
	}

	jsval_t proto = js_mkobj(js);
	if (is_err(proto)) return proto;

	if (vtype(super_proto) == T_OBJ) {
	set_proto(js, proto, super_proto);
	} else {
	jsval_t object_proto = get_ctor_proto(js, "Object", 6);
	if (vtype(object_proto) == T_OBJ) set_proto(js, proto, object_proto);
	}

	jsval_t func_scope = mkobj(js, (jsoff_t) vdata(js->scope));

	for (unsigned int i = 0; i < utarray_len(methods); i++) {
	MethodInfo m = (MethodInfo )utarray_eltptr(methods, i);
	if (m->is_static) continue;
	if (m->is_field) continue;

	jsval_t method_name = js_mkstr(js, &js->code[m->name_off], m->name_len);
	if (is_err(method_name)) return method_name;

	jsoff_t mlen = m->fn_end - m->fn_start;

	jsval_t method_obj = mkobj(js, 0);
	if (is_err(method_obj)) return method_obj;

	set_func_code(js, method_obj, &js->code[m->fn_start], mlen);
	set_slot(js, method_obj, SLOT_SCOPE, func_scope);

	if (m->is_async) {
	set_slot(js, method_obj, SLOT_ASYNC, js_mktrue());
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, method_obj, async_proto);
	} else {
	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, method_obj, func_proto);
	}

	if (super_len > 0) set_slot(js, method_obj, SLOT_SUPER, super_constructor);
	jsval_t method_func = mkval(T_FUNC, (unsigned long) vdata(method_obj));

	if (m->is_getter \|\| m->is_setter) {
	jsoff_t name_len;
	const char name_str = (const char )&js->mem[vstr(js, method_name, &name_len)];

	if (m->is_getter) {
	js_set_getter_desc(js, proto, name_str, name_len, method_func, JS_DESC_C);
	} else {
	js_set_setter_desc(js, proto, name_str, name_len, method_func, JS_DESC_C);
	}
	} else {
	jsval_t set_res = setprop(js, proto, method_name, method_func);
	if (is_err(set_res)) return set_res;
	}
	}

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	if (constructor_params_start > 0 && constructor_body_start > 0) {
	jsoff_t code_len = constructor_body_end - constructor_params_start;
	set_func_code(js, func_obj, &js->code[constructor_params_start], code_len);
	} else {
	set_func_code_ptr(js, func_obj, "(){}", 4);
	if (super_len > 0) set_slot(js, func_obj, SLOT_DEFAULT_CTOR, js_mktrue());
	}

	int instance_field_count = 0;
	for (unsigned int i = 0; i < utarray_len(methods); i++) {
	MethodInfo m = (MethodInfo )utarray_eltptr(methods, i);
	if (m->is_static) continue;
	if (!m->is_field) continue;
	instance_field_count++;
	}

	if (instance_field_count > 0) {
	size_t metadata_size = instance_field_count * sizeof(jsoff_t) * 4;
	jsoff_t meta_len = (jsoff_t) (metadata_size + 1);
	jsoff_t meta_header = (jsoff_t) ((meta_len << 3) \| T_STR);
	jsoff_t meta_off = js_alloc(js, meta_len + sizeof(meta_header));
	if (meta_off == (jsoff_t) ~0) return js_mkerr(js, "oom");

	memcpy(&js->mem[meta_off], &meta_header, sizeof(meta_header));
	jsoff_t metadata = (jsoff_t )(&js->mem[meta_off + sizeof(meta_header)]);

	int meta_idx = 0;
	for (unsigned int i = 0; i < utarray_len(methods); i++) {
	MethodInfo m = (MethodInfo )utarray_eltptr(methods, i);
	if (m->is_static) continue;
	if (!m->is_field) continue;

	metadata[meta_idx * 4 + 0] = m->name_off;
	metadata[meta_idx * 4 + 1] = m->name_len;
	metadata[meta_idx * 4 + 2] = m->field_start;
	metadata[meta_idx * 4 + 3] = m->field_end;
	meta_idx++;
	}

	js->mem[meta_off + sizeof(meta_header) + metadata_size] = 0;
	jsval_t fields_meta = mkval(T_STR, meta_off);

	set_slot(js, func_obj, SLOT_FIELD_COUNT, tov((double)instance_field_count));
	set_slot(js, func_obj, SLOT_FIELDS, fields_meta);

	const char *arena_src = code_arena_alloc(js->code, js->clen);
	if (arena_src) set_slot(js, func_obj, SLOT_SOURCE, mkval(T_CFUNC, (size_t)arena_src));
	}

	set_slot(js, func_obj, SLOT_SCOPE, func_scope);
	if (super_len > 0) set_slot(js, func_obj, SLOT_SUPER, super_constructor);

	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, func_obj, func_proto);

	jsval_t name_key = js_mkstr(js, "name", 4);
	if (is_err(name_key)) return name_key;
	jsval_t name_val = class_name_len > 0 ? js_mkstr(js, class_name, class_name_len) : js_mkstr(js, "", 0);
	if (is_err(name_val)) return name_val;
	jsval_t res_name = setprop(js, func_obj, name_key, name_val);
	if (is_err(res_name)) return res_name;

	jsval_t proto_key = js_mkstr(js, "prototype", 9);
	if (is_err(proto_key)) return proto_key;
	jsval_t proto_res = setprop(js, func_obj, proto_key, proto);
	if (is_err(proto_res)) return proto_res;

	jsval_t constructor = mkval(T_FUNC, (unsigned long) vdata(func_obj));

	jsval_t ctor_key = js_mkstr(js, "constructor", 11);
	if (is_err(ctor_key)) return ctor_key;
	jsval_t ctor_res = setprop(js, proto, ctor_key, constructor);
	if (is_err(ctor_res)) return ctor_res;
	js_set_descriptor(js, proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	if (class_name_len > 0) {
	if (lkp_scope(js, js->scope, class_name, class_name_len) > 0) {
	return js_mkerr(js, "'%.*s' already declared", (int) class_name_len, class_name);
	}
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, class_name, class_name_len), constructor, 0);
	if (is_err(x)) return x;
	}

	for (unsigned int i = 0; i < utarray_len(methods); i++) {
	MethodInfo m = (MethodInfo )utarray_eltptr(methods, i);
	if (!m->is_static) continue;

	jsval_t member_name = js_mkstr(js, &js->code[m->name_off], m->name_len);
	if (is_err(member_name)) return member_name;

	if (m->is_field) {
	jsval_t field_val = js_mkundef();
	if (m->field_start > 0 && m->field_end > m->field_start) {
	field_val = js_eval_slice(js, m->field_start, m->field_end - m->field_start);
	field_val = resolveprop(js, field_val);
	}
	jsval_t set_res = setprop(js, func_obj, member_name, field_val);
	if (is_err(set_res)) return set_res;
	} else {
	jsoff_t mlen = m->fn_end - m->fn_start;

	jsval_t method_obj = mkobj(js, 0);
	if (is_err(method_obj)) return method_obj;

	set_func_code(js, method_obj, &js->code[m->fn_start], mlen);
	set_slot(js, method_obj, SLOT_SCOPE, func_scope);
	if (super_len > 0) set_slot(js, method_obj, SLOT_SUPER, super_constructor);

	jsval_t method_func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(method_func_proto) == T_FUNC) set_proto(js, method_obj, method_func_proto);

	jsval_t method_func = mkval(T_FUNC, (unsigned long) vdata(method_obj));
	jsval_t set_res = setprop(js, func_obj, member_name, method_func);
	if (is_err(set_res)) return set_res;
	}
	}

	utarray_free(methods);
	return constructor;
	}

	utarray_free(methods);
	return js_mkundef();
	}

	static void js_throw_handle(struct js js, jsval_t res) {
	js->consumed = 1;
	jsval_t throw_val = js_expr(js);
	if (js->flags & F_NOEXEC) *res = js_mkundef(); else {
	throw_val = resolveprop(js, throw_val);
	if (is_err(throw_val)) *res = throw_val;
	else *res = js_throw(js, throw_val);
	}
	}

	static jsval_t find_var_scope(struct js *js) {
	jsval_t scope = js->scope;

	jsval_t eval_marker = get_slot(js, scope, SLOT_STRICT_EVAL_SCOPE);
	if (vtype(eval_marker) != T_UNDEF) return scope;

	jsval_t module_marker = get_slot(js, scope, SLOT_MODULE_SCOPE);
	if (vtype(module_marker) != T_UNDEF) return scope;

	if ((js->flags & F_CALL) && global_scope_stack && utarray_len(global_scope_stack) > 0) {
	jsoff_t scope_off = (jsoff_t )utarray_back(global_scope_stack);
	if (scope_off && scope_off != 0) return mkval(T_OBJ, scope_off);
	}

	while (vdata(upper(js, scope)) != 0) {
	jsval_t parent = upper(js, scope);

	jsval_t parent_eval_marker = get_slot(js, parent, SLOT_STRICT_EVAL_SCOPE);
	if (vtype(parent_eval_marker) != T_UNDEF) return scope;

	jsval_t parent_module_marker = get_slot(js, parent, SLOT_MODULE_SCOPE);
	if (vtype(parent_module_marker) != T_UNDEF) return scope;

	scope = parent;
	}

	return scope;
	}

	static jsval_t js_var_decl(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	jsval_t var_scope = find_var_scope(js);

	js->consumed = 1;
	for (;;) {
	EXPECT_IDENT();
	js->consumed = 0;
	jsoff_t noff = js->toff, nlen = js->tlen;
	char name = (char ) &js->code[noff];

	if (exe && (js->flags & F_STRICT) && is_strict_restricted(name, nlen)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot use '%.*s' as variable name in strict mode", (int) nlen, name);
	}

	if (exe && (js->flags & F_STRICT) && is_strict_reserved(name, nlen)) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "'%.*s' is reserved in strict mode", (int) nlen, name);
	}

	jsval_t v = js_mkundef();
	bool has_initializer = false;
	js->consumed = 1;
	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	v = js_expr(js);
	if (is_err(v)) return v;
	has_initializer = true;
	}

	if (exe) {
	char decoded_name[256];
	size_t decoded_len = decode_ident_escapes(name, nlen, decoded_name, sizeof(decoded_name));

	jsoff_t existing_off = lkp(js, var_scope, decoded_name, decoded_len);
	if (existing_off > 0) {
	if (has_initializer && !is_err(v)) {
	jsval_t key_val = js_mkstr(js, decoded_name, decoded_len);
	setprop(js, var_scope, key_val, resolveprop(js, v));
	}
	} else {
	jsval_t x = mkprop(js, var_scope, js_mkstr(js, decoded_name, decoded_len), resolveprop(js, v), 0);
	if (is_err(x)) return x;
	}
	}

	uint8_t var_next = next(js);
	if (var_next == TOK_SEMICOLON \|\| var_next == TOK_EOF \|\| var_next == TOK_RBRACE \|\| js->had_newline) break;
	EXPECT(TOK_COMMA);
	}
	return js_mkundef();
	}

	static void js_var(struct js js, jsval_t res) {
	if ((js->flags & F_STRICT) && !js->var_warning_shown) {
	fprintf(stderr, "Warning: 'var' is deprecated, use 'let' or 'const' instead\n");
	js->var_warning_shown = true;
	}

	*res = js_var_decl(js);
	}

	static void js_async(struct js js, jsval_t res) {
	js->consumed = 1;
	uint8_t next_tok = next(js);
	if (next_tok == TOK_FUNC) {
	*res = js_func_decl_async(js);
	return;
	}
	if (next_tok == TOK_LPAREN) {
	*res = js_async_arrow_paren(js);
	return;
	}
	*res = js_mkerr_typed(js, JS_ERR_SYNTAX, "async must be followed by function");
	}

	static jsval_t js_stmt(struct js *js);

	static bool is_break_target(const char *name, jsoff_t len) {
	if (!(label_flags & F_BREAK_LABEL)) return false;
	if (break_target_label_len != len) return false;
	return memcmp(break_target_label, name, len) == 0;
	}

	static bool is_continue_target(const char *name, jsoff_t len) {
	if (!(label_flags & F_CONTINUE_LABEL)) return false;
	if (continue_target_label_len != len) return false;
	return memcmp(continue_target_label, name, len) == 0;
	}

	static jsval_t js_labeled_stmt(struct js js, const char label, jsoff_t label_len) {
	uint8_t flags = js->flags;
	jsval_t res = js_mkundef();

	if (!label_stack) {
	utarray_new(label_stack, &label_entry_icd);
	}

	uint8_t next_tok = next(js);
	bool is_loop = (next_tok == TOK_WHILE \|\| next_tok == TOK_DO \|\| next_tok == TOK_FOR);
	bool is_block = (next_tok == TOK_LBRACE);

	label_entry_t entry = {
	.name = label,
	.name_len = label_len,
	.is_loop = is_loop,
	.is_block = is_block \|\| !is_loop
	};
	utarray_push_back(label_stack, &entry);

	if (is_loop && !(flags & F_NOEXEC)) {
	res = js_stmt_impl(js);

	if ((js->flags & F_BREAK) && is_break_target(label, label_len)) {
	js->flags &= ~(F_BREAK \| F_NOEXEC);
	clear_break_label();
	res = js_mkundef();
	}

	if ((label_flags & F_CONTINUE_LABEL) && is_continue_target(label, label_len)) {
	clear_continue_label();
	}
	} else if (is_loop && (flags & F_NOEXEC)) {
	res = js_stmt_impl(js);
	} else {
	res = js_stmt_impl(js);

	if ((js->flags & F_BREAK) && is_break_target(label, label_len)) {
	js->flags &= ~(F_BREAK \| F_NOEXEC);
	js->flags \|= (flags & F_NOEXEC);
	clear_break_label();
	res = js_mkundef();
	}
	}

	if (label_stack && utarray_len(label_stack) > 0) {
	utarray_pop_back(label_stack);
	}

	return res;
	}

	static jsval_t js_stmt_impl(struct js *js) {
	jsval_t res;
	uint8_t stmt_tok = next(js);

	switch (stmt_tok) {
	case TOK_SEMICOLON:
	res = js_mkundef();
	break;
	case TOK_CASE: case TOK_CATCH:
	case TOK_DEFAULT: case TOK_FINALLY:
	res = js_mkerr(js, "SyntaxError '%.*s'", (int) js->tlen, js->code + js->toff);
	break;
	case TOK_YIELD:
	res = js_mkerr(js, " '%.*s' not implemented", (int) js->tlen, js->code + js->toff);
	break;
	case TOK_IMPORT: res = js_import_stmt(js); break;
	case TOK_EXPORT: res = js_export_stmt(js); break;
	case TOK_THROW: js_throw_handle(js, &res); break;
	case TOK_VAR: js_var(js, &res); break;
	case TOK_ASYNC: js_async(js, &res); break;
	case TOK_WITH: res = js_with(js); break;
	case TOK_SWITCH: res = js_switch(js); break;
	case TOK_WHILE: res = js_while(js); break;
	case TOK_DO: res = js_do_while(js); break;
	case TOK_DEBUGGER: js->consumed = 1; res = js_mkundef(); break;
	case TOK_CONTINUE: res = js_continue(js); break;
	case TOK_BREAK: res = js_break(js); break;
	case TOK_LET: res = js_let(js); break;
	case TOK_CONST: res = js_const(js); break;
	case TOK_FUNC: res = js_func_decl(js); break;
	case TOK_CLASS: res = js_class_decl(js); break;
	case TOK_IF: res = js_if(js); break;
	case TOK_LBRACE: res = js_block(js, !(js->flags & F_NOEXEC)); break;
	case TOK_FOR: res = js_for(js); break;
	case TOK_RETURN: res = js_return(js); break;
	case TOK_TRY: res = js_try(js); break;
	default:
	res = resolveprop(js, js_expr(js));
	while (next(js) == TOK_COMMA) {
	js->consumed = 1;
	res = resolveprop(js, js_expr(js));
	}
	break;
	}

	bool is_block_statement = (
	stmt_tok == TOK_FUNC \|\| stmt_tok == TOK_CLASS \|\|
	stmt_tok == TOK_EXPORT \|\| stmt_tok == TOK_IMPORT \|\|
	stmt_tok == TOK_IF \|\| stmt_tok == TOK_WHILE \|\|
	stmt_tok == TOK_DO \|\| stmt_tok == TOK_FOR \|\|
	stmt_tok == TOK_SWITCH \|\| stmt_tok == TOK_TRY \|\|
	stmt_tok == TOK_LBRACE \|\| stmt_tok == TOK_ASYNC
	);

	if (is_err(res)) return res;

	if (!is_block_statement) {
	int next_tok = next(js);
	bool asi_applies = js->had_newline \|\| next_tok == TOK_EOF \|\| next_tok == TOK_RBRACE;
	bool missing_semicolon = next_tok != TOK_SEMICOLON && !asi_applies;
	if (missing_semicolon) return js_mkerr_typed(js, JS_ERR_SYNTAX, "; expected");
	if (next_tok == TOK_SEMICOLON) js->consumed = 1;
	}

	return res;
	}

	static jsval_t js_stmt(struct js *js) {
	uint8_t tok = next(js);

	if (tok == TOK_IDENTIFIER) {
	js_parse_state_t saved_state;
	JS_SAVE_STATE(js, saved_state);
	jsoff_t saved_toff = js->toff;
	jsoff_t saved_tlen = js->tlen;

	const char *potential_label = &js->code[js->toff];
	jsoff_t potential_label_len = js->tlen;

	js->consumed = 1;

	if (next(js) == TOK_COLON) {
	js->consumed = 1;
	return js_labeled_stmt(js, potential_label, potential_label_len);
	}

	JS_RESTORE_STATE(js, saved_state);
	js->toff = saved_toff;
	js->tlen = saved_tlen;
	}

	return js_stmt_impl(js);
	}

	static jsval_t builtin_String(struct js js, jsval_t args, int nargs) {
	jsval_t sval;
	if (nargs == 0) {
	sval = js_mkstr(js, "", 0);
	} else {
	jsval_t arg = args[0];
	if (vtype(arg) == T_STR) {
	sval = arg;
	} else {
	const char *str = js_str(js, arg);
	sval = js_mkstr(js, str, strlen(str));
	}
	}
	jsval_t string_proto = js_get_ctor_proto(js, "String", 6);
	if (is_unboxed_obj(js, js->this_val, string_proto)) {
	set_slot(js, js->this_val, SLOT_PRIMITIVE, sval);
	jsoff_t slen;
	vstr(js, sval, &slen);
	setprop(js, js->this_val, js_mkstr(js, "length", 6), tov((double)slen));
	js_set_descriptor(js, js->this_val, "length", 6, 0);
	}
	return sval;
	}

	static jsval_t builtin_Number_isNaN(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t arg = args[0];

	if (vtype(arg) != T_NUM) return mkval(T_BOOL, 0);

	double val = tod(arg);
	return mkval(T_BOOL, isnan(val) ? 1 : 0);
	}

	static jsval_t builtin_Number_isFinite(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t arg = args[0];

	if (vtype(arg) != T_NUM) return mkval(T_BOOL, 0);

	double val = tod(arg);
	return mkval(T_BOOL, isfinite(val) ? 1 : 0);
	}

	static jsval_t builtin_global_isNaN(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 1);
	double val = js_to_number(js, args[0]);
	return mkval(T_BOOL, isnan(val) ? 1 : 0);
	}

	static jsval_t builtin_global_isFinite(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 0);
	double val = js_to_number(js, args[0]);
	return mkval(T_BOOL, isfinite(val) ? 1 : 0);
	}

	static jsval_t builtin_Number_isInteger(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t arg = args[0];

	if (vtype(arg) != T_NUM) return mkval(T_BOOL, 0);

	double val = tod(arg);
	if (!isfinite(val)) return mkval(T_BOOL, 0);
	return mkval(T_BOOL, (val == floor(val)) ? 1 : 0);
	}

	static jsval_t builtin_Number_isSafeInteger(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t arg = args[0];

	if (vtype(arg) != T_NUM) return mkval(T_BOOL, 0);

	double val = tod(arg);
	if (!isfinite(val)) return mkval(T_BOOL, 0);
	if (val != floor(val)) return mkval(T_BOOL, 0);

	return mkval(T_BOOL, (val >= -9007199254740991.0 && val <= 9007199254740991.0) ? 1 : 0);
	}

	static jsval_t builtin_Number(struct js js, jsval_t args, int nargs) {
	jsval_t nval = tov(nargs > 0 ? js_to_number(js, args[0]) : 0.0);
	jsval_t number_proto = js_get_ctor_proto(js, "Number", 6);
	if (is_unboxed_obj(js, js->this_val, number_proto)) {
	set_slot(js, js->this_val, SLOT_PRIMITIVE, nval);
	}
	return nval;
	}

	static jsval_t builtin_Boolean(struct js js, jsval_t args, int nargs) {
	jsval_t bval = mkval(T_BOOL, nargs > 0 && js_truthy(js, args[0]) ? 1 : 0);
	jsval_t boolean_proto = js_get_ctor_proto(js, "Boolean", 7);
	if (is_unboxed_obj(js, js->this_val, boolean_proto)) {
	set_slot(js, js->this_val, SLOT_PRIMITIVE, bval);
	}
	return bval;
	}

	static jsval_t builtin_Object(struct js js, jsval_t args, int nargs) {
	if (nargs == 0 \|\| vtype(args[0]) == T_NULL \|\| vtype(args[0]) == T_UNDEF) {
	jsval_t obj_proto = js_get_ctor_proto(js, "Object", 6);
	if (is_unboxed_obj(js, js->this_val, obj_proto)) return js->this_val;
	return js_mkobj(js);
	}

	jsval_t arg = args[0];
	uint8_t t = vtype(arg);

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) return arg;
	if (t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_BIGINT) {
	jsval_t wrapper = js_mkobj(js);
	if (is_err(wrapper)) return wrapper;
	set_slot(js, wrapper, SLOT_PRIMITIVE, arg);
	jsval_t proto = get_prototype_for_type(js, t);
	if (vtype(proto) == T_OBJ) set_proto(js, wrapper, proto);
	return wrapper;
	}

	return arg;
	}

	static jsval_t js_eval_inherit_strict(struct js js, const char buf, size_t len, bool inherit_strict);

	static jsval_t builtin_eval(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkundef();

	jsval_t code_arg = args[0];
	if (vtype(code_arg) != T_STR) return code_arg;

	jsoff_t code_len, code_off = vstr(js, code_arg, &code_len);
	const char code_str = (const char )&js->mem[code_off];

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	uint8_t saved_flags = js->flags;
	bool caller_strict = (js->flags & F_STRICT) != 0;

	jsval_t result = js_eval_inherit_strict(js, code_str, code_len, caller_strict);
	bool had_throw = (js->flags & F_THROW) != 0;

	JS_RESTORE_STATE(js, saved);
	js->flags = saved_flags;

	if (is_err(result) \|\| had_throw) {
	js->flags \|= F_THROW;
	}

	return result;
	}

	static jsval_t builtin_Function(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) {
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	set_func_code_ptr(js, func_obj, "(){}", 4);
	set_slot(js, func_obj, SLOT_SCOPE, js_glob(js));

	jsval_t func = mkval(T_FUNC, (unsigned long) vdata(func_obj));

	jsval_t proto_setup = setup_func_prototype(js, func);
	if (is_err(proto_setup)) return proto_setup;

	return func;
	}

	size_t total_len = 1;

	for (int i = 0; i < nargs - 1; i++) {
	if (vtype(args[i]) != T_STR) {
	const char *str = js_str(js, args[i]);
	args[i] = js_mkstr(js, str, strlen(str));
	if (is_err(args[i])) return args[i];
	}
	total_len += vstrlen(js, args[i]);
	if (i < nargs - 2) total_len += 1;
	}

	total_len += 2;

	jsval_t body = args[nargs - 1];
	if (vtype(body) != T_STR) {
	const char *str = js_str(js, body);
	body = js_mkstr(js, str, strlen(str));
	if (is_err(body)) return body;
	}
	total_len += vstrlen(js, body);
	total_len += 1;

	char code_buf = (char )malloc(total_len + 1);
	if (!code_buf) return js_mkerr(js, "oom");
	size_t pos = 0;

	code_buf[pos++] = '(';

	for (int i = 0; i < nargs - 1; i++) {
	jsoff_t param_len, param_off = vstr(js, args[i], &param_len);
	memcpy(code_buf + pos, &js->mem[param_off], param_len);
	pos += param_len;
	if (i < nargs - 2) {
	code_buf[pos++] = ',';
	}
	}

	code_buf[pos++] = ')';
	code_buf[pos++] = '{';

	jsoff_t body_len, body_off = vstr(js, body, &body_len);
	memcpy(code_buf + pos, &js->mem[body_off], body_len);
	pos += body_len;

	code_buf[pos++] = '}';
	code_buf[pos] = '\0';

	bool is_strict_body = is_strict_function_body((const char *)&js->mem[body_off], body_len);
	if (is_strict_body && nargs > 1) {
	int i = 0, j;
	jsoff_t param_len_i, param_off_i;
	const char *param_i;

	check_param:
	if (i >= nargs - 1) goto params_done;

	param_off_i = vstr(js, args[i], &param_len_i);
	param_i = (const char *)&js->mem[param_off_i];

	if (is_strict_restricted(param_i, param_len_i)) {
	free(code_buf);
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot use '%.*s' as parameter name in strict mode", (int)param_len_i, param_i);
	}

	j = i + 1;

	check_dup:
	if (j >= nargs - 1) { i++; goto check_param; }

	jsoff_t param_len_j, param_off_j = vstr(js, args[j], &param_len_j);
	const char param_j = (const char )&js->mem[param_off_j];

	if (param_len_i == param_len_j && memcmp(param_i, param_j, param_len_i) == 0) {
	free(code_buf);
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "duplicate parameter name '%.*s' in strict mode", (int)param_len_i, param_i);
	}

	j++;
	goto check_dup;

	params_done:;
	}

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) { free(code_buf); return func_obj; }

	set_func_code(js, func_obj, code_buf, pos);
	free(code_buf);
	set_slot(js, func_obj, SLOT_SCOPE, js_glob(js));

	jsval_t func = mkval(T_FUNC, (unsigned long) vdata(func_obj));
	jsval_t proto_setup = setup_func_prototype(js, func);
	if (is_err(proto_setup)) return proto_setup;

	return func;
	}

	static jsval_t builtin_AsyncFunction(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) {
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	set_func_code_ptr(js, func_obj, "(){}", 4);
	set_slot(js, func_obj, SLOT_SCOPE, js_glob(js));
	set_slot(js, func_obj, SLOT_ASYNC, js_mktrue());

	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);

	jsval_t func = mkval(T_FUNC, (unsigned long)vdata(func_obj));
	jsval_t proto_setup = setup_func_prototype(js, func);

	if (is_err(proto_setup)) return proto_setup;
	return func;
	}

	size_t total_len = 1;

	for (int i = 0; i < nargs - 1; i++) {
	if (vtype(args[i]) != T_STR) {
	const char *str = js_str(js, args[i]);
	args[i] = js_mkstr(js, str, strlen(str));
	if (is_err(args[i])) return args[i];
	}
	total_len += vstrlen(js, args[i]);
	if (i < nargs - 2) total_len += 1;
	}

	total_len += 2;

	jsval_t body = args[nargs - 1];
	if (vtype(body) != T_STR) {
	const char *str = js_str(js, body);
	body = js_mkstr(js, str, strlen(str));
	if (is_err(body)) return body;
	}
	total_len += vstrlen(js, body);
	total_len += 1;

	char code_buf = (char )malloc(total_len + 1);
	if (!code_buf) return js_mkerr(js, "oom");
	size_t pos = 0;

	code_buf[pos++] = '(';

	for (int i = 0; i < nargs - 1; i++) {
	jsoff_t param_len, param_off = vstr(js, args[i], &param_len);
	memcpy(code_buf + pos, &js->mem[param_off], param_len);
	pos += param_len;
	if (i < nargs - 2) code_buf[pos++] = ',';
	}

	code_buf[pos++] = ')';
	code_buf[pos++] = '{';

	jsoff_t body_len, body_off = vstr(js, body, &body_len);
	memcpy(code_buf + pos, &js->mem[body_off], body_len);
	pos += body_len;
	code_buf[pos++] = '}';
	code_buf[pos] = '\0';

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) { free(code_buf); return func_obj; }

	set_func_code(js, func_obj, code_buf, pos);
	free(code_buf);
	set_slot(js, func_obj, SLOT_SCOPE, js_glob(js));
	set_slot(js, func_obj, SLOT_ASYNC, js_mktrue());

	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);

	jsval_t func = mkval(T_FUNC, (unsigned long) vdata(func_obj));
	jsval_t proto_setup = setup_func_prototype(js, func);

	if (is_err(proto_setup)) return proto_setup;
	return func;
	}

	static jsval_t builtin_function_empty(struct js js, jsval_t args, int nargs) {
	(void)js; (void)args; (void)nargs;
	return js_mkundef();
	}

	static jsval_t builtin_function_call(struct js js, jsval_t args, int nargs) {
	jsval_t func = js->this_val;
	if (vtype(func) != T_FUNC && vtype(func) != T_CFUNC) {
	return js_mkerr(js, "call requires a function");
	}

	jsval_t this_arg = (nargs > 0) ? args[0] : js_mkundef();

	jsval_t *call_args = NULL;
	int call_nargs = (nargs > 1) ? nargs - 1 : 0;
	if (call_nargs > 0) {
	call_args = &args[1];
	}

	jsval_t saved_this = js->this_val;
	push_this(this_arg);
	js->this_val = this_arg;

	jsval_t result = call_js_with_args(js, func, call_args, call_nargs);

	pop_this();
	js->this_val = saved_this;

	return result;
	}

	static int extract_array_args(struct js js, jsval_t arr, jsval_t *out_args) {
	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	if (len_off == 0) return 0;

	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) != T_NUM) return 0;

	int len = (int) tod(len_val);
	if (len <= 0) return 0;

	jsval_t args_out = (jsval_t )ant_calloc(sizeof(jsval_t) * len);
	if (!args_out) return 0;

	for (int i = 0; i < len; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	jsoff_t prop_off = lkp(js, arr, idx, strlen(idx));
	args_out[i] = (prop_off != 0) ? resolveprop(js, mkval(T_PROP, prop_off)) : js_mkundef();
	}

	*out_args = args_out;
	return len;
	}

	static jsval_t builtin_function_toString(struct js js, jsval_t args, int nargs) {
	jsval_t func = js->this_val;
	uint8_t t = vtype(func);

	if (t != T_FUNC && t != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Function.prototype.toString requires that 'this' be a Function");
	}

	if (t == T_CFUNC) return ANT_STRING("function() { [native code] }");

	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsval_t code_val = get_slot(js, func_obj, SLOT_CODE);
	jsval_t len_val = get_slot(js, func_obj, SLOT_CODE_LEN);

	if (vtype(code_val) == T_CFUNC && vtype(len_val) == T_NUM) {
	const char code = (const char )(uintptr_t)vdata(code_val);
	size_t code_len = (size_t)tod(len_val);

	if (code && code_len > 0) {
	jsval_t async_slot = get_slot(js, func_obj, SLOT_ASYNC);
	bool is_async = is_true(async_slot);
	bool is_arrow = vtype(get_slot(js, func_obj, SLOT_ARROW)) != T_UNDEF;

	if (is_arrow) {
	const char *brace = memchr(code, '{', code_len);
	if (!brace) goto fallback_arrow;

	size_t params_len = brace - code;
	const char *body_start = brace + 1;
	size_t body_len = code_len - params_len - 1;
	bool is_expr = (body_len >= 7 && memcmp(body_start, "return ", 7) == 0);

	size_t total = (is_async ? 6 : 0) + params_len + 4 + body_len + 2;
	char *buf = ant_calloc(total + 1);
	size_t n = 0;

	if (is_async) n += cpy(buf + n, total - n, "async ", 6);
	n += cpy(buf + n, total - n, code, params_len);
	n += cpy(buf + n, total - n, " => ", 4);

	if (is_expr) {
	const char *expr = body_start + 7;
	size_t expr_len = body_len - 7;
	while (expr_len > 0 && (expr[expr_len-1] == ' ' \|\| expr[expr_len-1] == '}' \|\| expr[expr_len-1] == ')')) expr_len--;
	n += cpy(buf + n, total - n, expr, expr_len);
	} else {
	size_t block_len = code_len - params_len;
	while (block_len > 0 && brace[block_len-1] == ')') block_len--;
	n += cpy(buf + n, total - n, brace, block_len);
	}

	jsval_t result = js_mkstr(js, buf, n);
	free(buf);
	return result;
	fallback_arrow:;
	}

	jsoff_t name_len = 0;
	const char *name = get_func_name(js, func, &name_len);
	size_t total = (is_async ? 6 : 0) + 9 + name_len + code_len + 1;
	char *buf = ant_calloc(total + 1);
	size_t n = 0;

	if (is_async) n += cpy(buf + n, total - n, "async ", 6);
	n += cpy(buf + n, total - n, "function ", 9);
	if (name && name_len > 0) n += cpy(buf + n, total - n, name, name_len);
	n += cpy(buf + n, total - n, code, code_len);
	n += cpy(buf + n, total - n, "}", 1);

	jsval_t result = js_mkstr(js, buf, n);
	free(buf);

	return result;
	}
	}

	char buf[256];
	size_t len = strfunc(js, func, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	static jsval_t builtin_function_apply(struct js js, jsval_t args, int nargs) {
	jsval_t func = js->this_val;
	if (vtype(func) != T_FUNC && vtype(func) != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Function.prototype.apply requires that 'this' be a Function");
	}

	jsval_t this_arg = (nargs > 0) ? args[0] : js_mkundef();
	jsval_t *call_args = NULL;
	int call_nargs = 0;

	if (nargs > 1) {
	jsval_t arg_array = args[1];
	uint8_t t = vtype(arg_array);
	if (t == T_ARR \|\| t == T_OBJ) {
	call_nargs = extract_array_args(js, arg_array, &call_args);
	} else if (t != T_UNDEF && t != T_NULL) {}
	}

	jsval_t saved_this = js->this_val;
	push_this(this_arg);

	js->this_val = this_arg;
	jsval_t result = call_js_with_args(js, func, call_args, call_nargs);

	pop_this();
	js->this_val = saved_this;

	if (call_args) free(call_args);

	return result;
	}

	static jsval_t builtin_function_bind(struct js js, jsval_t args, int nargs) {
	jsval_t func = js->this_val;

	if (vtype(func) != T_FUNC && vtype(func) != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "bind requires a function");
	}

	jsval_t this_arg = (nargs > 0) ? args[0] : js_mkundef();

	int bound_argc = (nargs > 1) ? nargs - 1 : 0;
	jsval_t *bound_args = (bound_argc > 0) ? &args[1] : NULL;

	int orig_length = 0;
	jsval_t target_func_obj;
	if (vtype(func) == T_CFUNC) {
	orig_length = 0;
	} else {
	target_func_obj = mkval(T_OBJ, vdata(func));
	jsoff_t len_off = lkp_interned(js, target_func_obj, INTERN_LENGTH, 6);
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) {
	orig_length = (int) tod(len_val);
	}
	}
	}

	int bound_length = orig_length - bound_argc;
	if (bound_length < 0) bound_length = 0;

	if (vtype(func) == T_CFUNC) {
	jsval_t bound_func = mkobj(js, 0);
	if (is_err(bound_func)) return bound_func;

	set_slot(js, bound_func, SLOT_CFUNC, func);
	set_slot(js, bound_func, SLOT_BOUND_THIS, this_arg);

	if (bound_argc > 0) {
	jsval_t bound_arr = mkarr(js);
	for (int i = 0; i < bound_argc; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	setprop(js, bound_arr, js_mkstr(js, idx, strlen(idx)), bound_args[i]);
	}
	setprop(js, bound_arr, js_mkstr(js, "length", 6), tov((double) bound_argc));
	set_slot(js, bound_func, SLOT_BOUND_ARGS, bound_arr);
	}

	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, bound_func, func_proto);

	jsval_t bound = mkval(T_FUNC, (unsigned long) vdata(bound_func));
	setprop(js, bound_func, js_mkstr(js, "length", 6), tov((double) bound_length));

	jsval_t proto_setup = setup_func_prototype(js, bound);
	if (is_err(proto_setup)) return proto_setup;

	return bound;
	}

	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsval_t bound_func = mkobj(js, 0);
	if (is_err(bound_func)) return bound_func;

	jsval_t code_val = get_slot(js, func_obj, SLOT_CODE);
	if (vtype(code_val) == T_STR \|\| vtype(code_val) == T_CFUNC) {
	set_slot(js, bound_func, SLOT_CODE, code_val);
	set_slot(js, bound_func, SLOT_CODE_LEN, get_slot(js, func_obj, SLOT_CODE_LEN));
	}

	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);
	if (vtype(cfunc_slot) == T_CFUNC) {
	set_slot(js, bound_func, SLOT_CFUNC, cfunc_slot);
	}

	jsval_t scope_slot = get_slot(js, func_obj, SLOT_SCOPE);
	if (vtype(scope_slot) != T_UNDEF) {
	set_slot(js, bound_func, SLOT_SCOPE, scope_slot);
	}

	jsval_t async_slot = get_slot(js, func_obj, SLOT_ASYNC);
	if (vtype(async_slot) == T_BOOL && vdata(async_slot) == 1) {
	set_slot(js, bound_func, SLOT_ASYNC, js_mktrue());
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, bound_func, async_proto);
	} else {
	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, bound_func, func_proto);
	}

	jsval_t data_slot = get_slot(js, func_obj, SLOT_DATA);
	if (vtype(data_slot) != T_UNDEF) {
	set_slot(js, bound_func, SLOT_DATA, data_slot);
	}

	set_slot(js, bound_func, SLOT_TARGET_FUNC, func);
	set_slot(js, bound_func, SLOT_BOUND_THIS, this_arg);

	if (bound_argc > 0) {
	jsval_t bound_arr = mkarr(js);
	for (int i = 0; i < bound_argc; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	setprop(js, bound_arr, js_mkstr(js, idx, strlen(idx)), bound_args[i]);
	}
	setprop(js, bound_arr, js_mkstr(js, "length", 6), tov((double) bound_argc));
	set_slot(js, bound_func, SLOT_BOUND_ARGS, bound_arr);
	}

	setprop(js, bound_func, js_mkstr(js, "length", 6), tov((double) bound_length));

	jsval_t bound = mkval(T_FUNC, (unsigned long) vdata(bound_func));
	jsval_t proto_setup = setup_func_prototype(js, bound);
	if (is_err(proto_setup)) return proto_setup;

	return bound;
	}

	static jsval_t builtin_Array(struct js js, jsval_t args, int nargs) {
	jsval_t arr = mkarr(js);

	if (nargs == 1 && vtype(args[0]) == T_NUM) {
	jsval_t err = validate_array_length(js, args[0]);
	if (is_err(err)) return err;
	setprop(js, arr, ANT_STRING("length"), tov(tod(args[0])));
	} else if (nargs > 0) {
	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	setprop(js, arr, js_mkstr(js, idxstr, idxlen), args[i]);
	}
	setprop(js, arr, ANT_STRING("length"), tov((double)nargs));
	}

	return arr;
	}

	static jsval_t builtin_Error(struct js js, jsval_t args, int nargs) {
	bool is_new = (vtype(js->new_target) != T_UNDEF);
	jsval_t this_val = js->this_val;

	jsval_t target = is_new ? js->new_target : js->current_func;
	jsval_t name = ANT_STRING("Error");

	if (vtype(target) == T_FUNC) {
	jsoff_t off = lkp(js, mkval(T_OBJ, vdata(target)), "name", 4);
	if (off) name = resolveprop(js, mkval(T_PROP, off));
	}

	if (!is_new) {
	this_val = js_mkobj(js);
	jsoff_t proto_off = lkp_interned(js, mkval(T_OBJ, vdata(js->current_func)), INTERN_PROTOTYPE, 9);
	if (proto_off) set_proto(js, this_val, resolveprop(js, mkval(T_PROP, proto_off)));
	else set_proto(js, this_val, get_ctor_proto(js, "Error", 5));
	}

	if (nargs > 0) {
	jsval_t msg = args[0];
	if (vtype(msg) != T_STR) {
	const char *str = js_str(js, msg);
	msg = js_mkstr(js, str, strlen(str));
	}
	js_mkprop_fast(js, this_val, "message", 7, msg);
	}

	js_mkprop_fast(js, this_val, "name", 4, name);
	return this_val;
	}

	static jsval_t builtin_AggregateError(struct js js, jsval_t args, int nargs) {
	bool is_new = (vtype(js->new_target) != T_UNDEF);
	jsval_t this_val = js->this_val;

	if (!is_new) {
	this_val = js_mkobj(js);
	jsoff_t proto_off = lkp_interned(js, mkval(T_OBJ, vdata(js->current_func)), INTERN_PROTOTYPE, 9);
	if (proto_off) set_proto(js, this_val, resolveprop(js, mkval(T_PROP, proto_off)));
	else set_proto(js, this_val, get_ctor_proto(js, "AggregateError", 14));
	}

	jsval_t errors = nargs > 0 ? args[0] : mkarr(js);
	if (vtype(errors) != T_ARR) errors = mkarr(js);
	js_mkprop_fast(js, this_val, "errors", 6, errors);

	if (nargs > 1 && vtype(args[1]) != T_UNDEF) {
	jsval_t msg = args[1];
	if (vtype(msg) != T_STR) {
	const char *str = js_str(js, msg);
	msg = js_mkstr(js, str, strlen(str));
	}
	js_mkprop_fast(js, this_val, "message", 7, msg);
	}

	js_mkprop_fast(js, this_val, "name", 4, ANT_STRING("AggregateError"));
	return this_val;
	}

	static jsval_t builtin_RegExp(struct js js, jsval_t args, int nargs) {
	jsval_t regexp_obj = js->this_val;
	bool use_this = (vtype(regexp_obj) == T_OBJ);

	if (!use_this) {
	regexp_obj = mkobj(js, 0);
	}
	jsval_t regexp_proto = get_ctor_proto(js, "RegExp", 6);
	if (vtype(regexp_proto) == T_OBJ) set_proto(js, regexp_obj, regexp_proto);

	jsval_t pattern = js_mkstr(js, "", 0);
	if (nargs > 0) {
	if (vtype(args[0]) == T_STR) {
	pattern = args[0];
	} else {
	const char *str = js_str(js, args[0]);
	pattern = js_mkstr(js, str, strlen(str));
	}
	}

	jsval_t flags = js_mkstr(js, "", 0);
	if (nargs > 1 && vtype(args[1]) == T_STR) {
	flags = args[1];
	}

	jsval_t source_key = js_mkstr(js, "source", 6);
	setprop(js, regexp_obj, source_key, pattern);

	jsval_t flags_key = js_mkstr(js, "flags", 5);
	setprop(js, regexp_obj, flags_key, flags);

	jsoff_t flags_len, flags_off = vstr(js, flags, &flags_len);
	const char flags_str = (char ) &js->mem[flags_off];

	bool global = false, ignoreCase = false, multiline = false, dotAll = false, sticky = false;
	for (jsoff_t i = 0; i < flags_len; i++) {
	if (flags_str[i] == 'g') global = true;
	if (flags_str[i] == 'i') ignoreCase = true;
	if (flags_str[i] == 'm') multiline = true;
	if (flags_str[i] == 's') dotAll = true;
	if (flags_str[i] == 'y') sticky = true;
	}

	setprop(js, regexp_obj, js_mkstr(js, "global", 6), mkval(T_BOOL, global ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "ignoreCase", 10), mkval(T_BOOL, ignoreCase ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "multiline", 9), mkval(T_BOOL, multiline ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "dotAll", 6), mkval(T_BOOL, dotAll ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "sticky", 6), mkval(T_BOOL, sticky ? 1 : 0));
	setprop(js, regexp_obj, js_mkstr(js, "lastIndex", 9), tov(0));

	return regexp_obj;
	}

	static jsval_t builtin_regexp_test(struct js js, jsval_t args, int nargs) {
	jsval_t regexp = js->this_val;
	if (vtype(regexp) != T_OBJ) return js_mkerr(js, "test called on non-regexp");
	if (nargs < 1) return mkval(T_BOOL, 0);

	jsval_t str_arg = args[0];
	if (vtype(str_arg) != T_STR) return mkval(T_BOOL, 0);

	jsoff_t source_off = lkp(js, regexp, "source", 6);
	if (source_off == 0) return mkval(T_BOOL, 0);
	jsval_t source_val = resolveprop(js, mkval(T_PROP, source_off));
	if (vtype(source_val) != T_STR) return mkval(T_BOOL, 0);

	jsoff_t plen, poff = vstr(js, source_val, &plen);
	const char pattern_ptr = (char ) &js->mem[poff];

	bool ignore_case = false, multiline = false;
	jsoff_t flags_off = lkp(js, regexp, "flags", 5);
	if (flags_off != 0) {
	jsval_t flags_val = resolveprop(js, mkval(T_PROP, flags_off));
	if (vtype(flags_val) == T_STR) {
	jsoff_t flen, foff = vstr(js, flags_val, &flen);
	const char flags_str = (char ) &js->mem[foff];
	for (jsoff_t i = 0; i < flen; i++) {
	if (flags_str[i] == 'i') ignore_case = true;
	if (flags_str[i] == 'm') multiline = true;
	}
	}
	}

	jsoff_t str_len, str_off = vstr(js, str_arg, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	char pcre2_pattern[512];
	size_t pcre2_len = js_to_pcre2_pattern(pattern_ptr, plen, pcre2_pattern, sizeof(pcre2_pattern));

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	if (ignore_case) options \|= PCRE2_CASELESS;
	if (multiline) options \|= PCRE2_MULTILINE;

	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	if (re == NULL) return mkval(T_BOOL, 0);

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, 0, 0, match_data, NULL);

	pcre2_match_data_free(match_data);
	pcre2_code_free(re);

	return mkval(T_BOOL, rc >= 0 ? 1 : 0);
	}

	static jsval_t builtin_regexp_exec(struct js js, jsval_t args, int nargs) {
	jsval_t regexp = js->this_val;
	if (vtype(regexp) != T_OBJ) return js_mkerr(js, "exec called on non-regexp");
	if (nargs < 1) return js_mknull();

	jsval_t str_arg = args[0];
	if (vtype(str_arg) != T_STR) return js_mknull();

	jsoff_t source_off = lkp(js, regexp, "source", 6);
	if (source_off == 0) return js_mknull();
	jsval_t source_val = resolveprop(js, mkval(T_PROP, source_off));
	if (vtype(source_val) != T_STR) return js_mknull();

	jsoff_t plen, poff = vstr(js, source_val, &plen);
	const char pattern_ptr = (char ) &js->mem[poff];

	bool ignore_case = false, multiline = false, global_flag = false;
	jsoff_t flags_off = lkp(js, regexp, "flags", 5);
	if (flags_off != 0) {
	jsval_t flags_val = resolveprop(js, mkval(T_PROP, flags_off));
	if (vtype(flags_val) == T_STR) {
	jsoff_t flen, foff = vstr(js, flags_val, &flen);
	const char flags_str = (char ) &js->mem[foff];
	for (jsoff_t i = 0; i < flen; i++) {
	if (flags_str[i] == 'i') ignore_case = true;
	if (flags_str[i] == 'm') multiline = true;
	if (flags_str[i] == 'g') global_flag = true;
	}
	}
	}

	jsoff_t str_len, str_off = vstr(js, str_arg, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	PCRE2_SIZE start_offset = 0;
	if (global_flag) {
	jsoff_t lastindex_off = lkp(js, regexp, "lastIndex", 9);
	if (lastindex_off != 0) {
	jsval_t li_val = resolveprop(js, mkval(T_PROP, lastindex_off));
	if (vtype(li_val) == T_NUM) {
	double li = tod(li_val);
	if (li >= 0 && li <= D(str_len)) start_offset = (PCRE2_SIZE)li;
	}
	}
	}

	char pcre2_pattern[512];
	size_t pcre2_len = js_to_pcre2_pattern(pattern_ptr, plen, pcre2_pattern, sizeof(pcre2_pattern));

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	if (ignore_case) options \|= PCRE2_CASELESS;
	if (multiline) options \|= PCRE2_MULTILINE;

	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	if (re == NULL) return js_mknull();

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, start_offset, 0, match_data, NULL);

	if (rc < 0) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	if (global_flag) {
	setprop(js, regexp, js_mkstr(js, "lastIndex", 9), tov(0));
	}
	return js_mknull();
	}

	PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
	uint32_t ovcount = pcre2_get_ovector_count(match_data);

	jsval_t result_arr = js_mkarr(js);
	for (uint32_t i = 0; i < ovcount && i < 32; i++) {
	PCRE2_SIZE start = ovector[2*i];
	PCRE2_SIZE end = ovector[2*i+1];
	if (start == PCRE2_UNSET) {
	js_arr_push(js, result_arr, js_mkundef());
	} else {
	jsval_t match_str = js_mkstr(js, str_ptr + start, end - start);
	js_arr_push(js, result_arr, match_str);
	}
	}

	setprop(js, result_arr, js_mkstr(js, "index", 5), tov((double)ovector[0]));
	setprop(js, result_arr, js_mkstr(js, "input", 5), str_arg);

	if (global_flag) {
	PCRE2_SIZE new_lastindex = ovector[1];
	if (ovector[0] == ovector[1]) new_lastindex++;
	setprop(js, regexp, js_mkstr(js, "lastIndex", 9), tov((double)new_lastindex));
	}

	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return result_arr;
	}

	static jsval_t builtin_regexp_toString(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t regexp = js->this_val;
	if (vtype(regexp) != T_OBJ) return js_mkerr(js, "toString called on non-regexp");

	jsoff_t source_off = lkp(js, regexp, "source", 6);
	if (source_off == 0) return js_mkstr(js, "/undefined/", 11);
	jsval_t source_val = resolveprop(js, mkval(T_PROP, source_off));
	if (vtype(source_val) != T_STR) return js_mkstr(js, "/undefined/", 11);

	jsoff_t src_len;
	jsoff_t src_off = vstr(js, source_val, &src_len);
	const char src_ptr = (const char )(js->mem + src_off);

	char flags[8] = {0};
	int fi = 0;
	jsoff_t prop_off;

	prop_off = lkp(js, regexp, "global", 6);
	if (prop_off && vdata(resolveprop(js, mkval(T_PROP, prop_off)))) flags[fi++] = 'g';

	prop_off = lkp(js, regexp, "ignoreCase", 10);
	if (prop_off && vdata(resolveprop(js, mkval(T_PROP, prop_off)))) flags[fi++] = 'i';

	prop_off = lkp(js, regexp, "multiline", 9);
	if (prop_off && vdata(resolveprop(js, mkval(T_PROP, prop_off)))) flags[fi++] = 'm';

	prop_off = lkp(js, regexp, "dotAll", 6);
	if (prop_off && vdata(resolveprop(js, mkval(T_PROP, prop_off)))) flags[fi++] = 's';

	prop_off = lkp(js, regexp, "sticky", 6);
	if (prop_off && vdata(resolveprop(js, mkval(T_PROP, prop_off)))) flags[fi++] = 'y';

	size_t result_len = 1 + src_len + 1 + fi;
	char result = (char )malloc(result_len + 1);
	if (!result) return js_mkerr(js, "out of memory");

	result[0] = '/';
	memcpy(result + 1, src_ptr, src_len);
	result[1 + src_len] = '/';
	memcpy(result + 2 + src_len, flags, fi);
	result[result_len] = '\0';

	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	}

	static jsval_t builtin_string_search(struct js js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;
	if (nargs < 1) return tov(-1);

	jsval_t pattern = args[0];
	const char *pattern_ptr = NULL;
	jsoff_t pattern_len = 0;
	bool ignore_case = false, multiline = false;

	if (vtype(pattern) == T_OBJ) {
	jsoff_t source_off = lkp(js, pattern, "source", 6);
	if (source_off == 0) return tov(-1);
	jsval_t source_val = resolveprop(js, mkval(T_PROP, source_off));
	if (vtype(source_val) != T_STR) return tov(-1);

	jsoff_t poff;
	poff = vstr(js, source_val, &pattern_len);
	pattern_ptr = (char *) &js->mem[poff];

	jsoff_t flags_off = lkp(js, pattern, "flags", 5);
	if (flags_off != 0) {
	jsval_t flags_val = resolveprop(js, mkval(T_PROP, flags_off));
	if (vtype(flags_val) == T_STR) {
	jsoff_t flen, foff = vstr(js, flags_val, &flen);
	const char flags_str = (char ) &js->mem[foff];
	for (jsoff_t i = 0; i < flen; i++) {
	if (flags_str[i] == 'i') ignore_case = true;
	if (flags_str[i] == 'm') multiline = true;
	}
	}
	}
	} else if (vtype(pattern) == T_STR) {
	jsoff_t poff;
	poff = vstr(js, pattern, &pattern_len);
	pattern_ptr = (char *) &js->mem[poff];
	} else {
	return tov(-1);
	}

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	char pcre2_pattern[512];
	size_t pcre2_len = js_to_pcre2_pattern(pattern_ptr, pattern_len, pcre2_pattern, sizeof(pcre2_pattern));

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	if (ignore_case) options \|= PCRE2_CASELESS;
	if (multiline) options \|= PCRE2_MULTILINE;

	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	if (re == NULL) return tov(-1);

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, 0, 0, match_data, NULL);

	if (rc < 0) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return tov(-1);
	}

	PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
	double result = (double)ovector[0];

	pcre2_match_data_free(match_data);
	pcre2_code_free(re);

	return tov(result);
	}

	static jsval_t builtin_Date(struct js js, jsval_t args, int nargs) {
	jsval_t date_obj = js->this_val;

	if (vtype(js->new_target) == T_UNDEF) {
	struct timeval tv;
	gettimeofday(&tv, NULL);

	time_t t = tv.tv_sec;
	struct tm *tm = localtime(&t);

	static const char *days[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
	static const char *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
	char buf[64];

	snprintf(
	buf, sizeof(buf), "%s %s %02d %04d %02d:%02d:%02d GMT%+03ld%02ld",
	days[tm->tm_wday], months[tm->tm_mon], tm->tm_mday, tm->tm_year + 1900,
	tm->tm_hour, tm->tm_min, tm->tm_sec, -timezone/3600, (labs(timezone)/60)%60
	);

	return js_mkstr(js, buf, strlen(buf));
	}

	double timestamp_ms;

	if (nargs == 0) {
	struct timeval tv;
	gettimeofday(&tv, NULL);
	// NOLINTNEXTLINE(bugprone-integer-division)
	timestamp_ms = (double)tv.tv_sec * 1000.0 + (double)(tv.tv_usec / 1000);
	} else if (nargs == 1) {
	if (vtype(args[0]) == T_NUM) {
	timestamp_ms = tod(args[0]);
	} else if (vtype(args[0]) == T_STR) {
	timestamp_ms = 0;
	} else timestamp_ms = 0;
	} else {
	int year = (int)tod(args[0]);
	int month = nargs >= 2 ? (int)tod(args[1]) : 0;
	int day = nargs >= 3 ? (int)tod(args[2]) : 1;
	int hour = nargs >= 4 ? (int)tod(args[3]) : 0;
	int minute = nargs >= 5 ? (int)tod(args[4]) : 0;
	int sec = nargs >= 6 ? (int)tod(args[5]) : 0;
	int ms = nargs >= 7 ? (int)tod(args[6]) : 0;
	if (year >= 0 && year <= 99) year += 1900;
	struct tm tm_val = {0};
	tm_val.tm_year = year - 1900;
	tm_val.tm_mon = month;
	tm_val.tm_mday = day;
	tm_val.tm_hour = hour;
	tm_val.tm_min = minute;
	tm_val.tm_sec = sec;
	tm_val.tm_isdst = -1;
	time_t t = mktime(&tm_val);
	timestamp_ms = (double)t * 1000.0 + ms;
	}

	js_set_slot(js, date_obj, SLOT_DATA, tov(timestamp_ms));

	return date_obj;
	}

	static jsval_t builtin_Date_now(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;

	struct timeval tv;
	gettimeofday(&tv, NULL);
	// NOLINTNEXTLINE(bugprone-integer-division)
	double timestamp_ms = (double)tv.tv_sec * 1000.0 + (double)(tv.tv_usec / 1000);

	return tov(timestamp_ms);
	}

	static jsval_t builtin_Date_UTC(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1) return tov(JS_NAN);

	int year = (int)tod(args[0]);
	int month = nargs >= 2 ? (int)tod(args[1]) : 0;
	int day = nargs >= 3 ? (int)tod(args[2]) : 1;
	int hour = nargs >= 4 ? (int)tod(args[3]) : 0;
	int min = nargs >= 5 ? (int)tod(args[4]) : 0;
	int sec = nargs >= 6 ? (int)tod(args[5]) : 0;
	int ms = nargs >= 7 ? (int)tod(args[6]) : 0;

	if (year >= 0 && year <= 99) year += 1900;

	struct tm tm = {0};
	tm.tm_year = year - 1900;
	tm.tm_mon = month;
	tm.tm_mday = day;
	tm.tm_hour = hour;
	tm.tm_min = min;
	tm.tm_sec = sec;

	time_t t = timegm(&tm);
	return tov((double)t * 1000.0 + ms);
	}

	static double date_get_time(struct js *js, jsval_t this_val) {
	jsval_t time_val = js_get_slot(js, this_val, SLOT_DATA);
	if (vtype(time_val) != T_NUM) return JS_NAN;
	return tod(time_val);
	}

	static jsval_t builtin_Date_getTime(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	return tov(date_get_time(js, js->this_val));
	}

	static jsval_t builtin_Date_getFullYear(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)(tm->tm_year + 1900));
	}

	static jsval_t builtin_Date_getMonth(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)tm->tm_mon);
	}

	static jsval_t builtin_Date_getDate(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)tm->tm_mday);
	}

	static jsval_t builtin_Date_getHours(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)tm->tm_hour);
	}

	static jsval_t builtin_Date_getMinutes(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)tm->tm_min);
	}

	static jsval_t builtin_Date_getSeconds(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)tm->tm_sec);
	}

	static jsval_t builtin_Date_getMilliseconds(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	return tov(fmod(ms, 1000.0));
	}

	static jsval_t builtin_Date_getDay(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)tm->tm_wday);
	}

	static jsval_t builtin_Date_toISOString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid time value");
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	int millis = (int)fmod(ms, 1000.0);
	if (millis < 0) millis += 1000;
	char buf[32];
	snprintf(buf, sizeof(buf), "%04d-%02d-%02dT%02d:%02d:%02d.%03dZ",
	tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
	tm->tm_hour, tm->tm_min, tm->tm_sec, millis);
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_Date_toString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mkstr(js, "Invalid Date", 12);
	time_t t = (time_t)(ms / 1000.0);
	char *s = ctime(&t);
	size_t len = strlen(s);
	if (len > 0 && s[len - 1] == '\n') len--;
	return js_mkstr(js, s, len);
	}

	static jsval_t builtin_Date_valueOf(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	return tov(date_get_time(js, js->this_val));
	}

	static jsval_t builtin_Date_getTimezoneOffset(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *local = localtime(&t);
	struct tm *utc = gmtime(&t);
	int diff = (local->tm_hour - utc->tm_hour) * 60 + (local->tm_min - utc->tm_min);
	if (local->tm_mday != utc->tm_mday) {
	diff += (local->tm_mday > utc->tm_mday \|\| (local->tm_mday == 1 && utc->tm_mday > 1)) ? 1440 : -1440;
	}
	return tov((double)(-diff));
	}

	static jsval_t builtin_Date_getUTCFullYear(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	return tov((double)(tm->tm_year + 1900));
	}

	static jsval_t builtin_Date_getUTCMonth(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	return tov((double)tm->tm_mon);
	}

	static jsval_t builtin_Date_getUTCDate(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	return tov((double)tm->tm_mday);
	}

	static jsval_t builtin_Date_getUTCHours(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	return tov((double)tm->tm_hour);
	}

	static jsval_t builtin_Date_getUTCMinutes(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	return tov((double)tm->tm_min);
	}

	static jsval_t builtin_Date_getUTCSeconds(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	return tov((double)tm->tm_sec);
	}

	static jsval_t builtin_Date_getUTCMilliseconds(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	return tov(fmod(ms, 1000.0));
	}

	static jsval_t builtin_Date_getUTCDay(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	return tov((double)tm->tm_wday);
	}

	static void date_set_time(struct js *js, jsval_t date, double ms) {
	if (vtype(date) != T_OBJ) return;
	js_set_slot(js, date, SLOT_DATA, tov(ms));
	}

	static jsval_t builtin_Date_setTime(struct js js, jsval_t args, int nargs) {
	double ms = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setMilliseconds(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double newMs = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(newMs)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	ms = floor(ms / 1000.0) * 1000.0 + newMs;
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setSeconds(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double sec = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(sec)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	tm->tm_sec = (int)sec;
	if (nargs >= 2) ms = floor(ms / 1000.0) * 1000.0 + tod(args[1]);
	else ms = floor(ms / 1000.0) * 1000.0 + fmod(ms, 1000.0);
	time_t newt = mktime(tm);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setMinutes(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double min = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(min)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	tm->tm_min = (int)min;
	if (nargs >= 2) tm->tm_sec = (int)tod(args[1]);
	time_t newt = mktime(tm);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setHours(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double hour = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(hour)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	tm->tm_hour = (int)hour;
	if (nargs >= 2) tm->tm_min = (int)tod(args[1]);
	if (nargs >= 3) tm->tm_sec = (int)tod(args[2]);
	time_t newt = mktime(tm);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setDate(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double day = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(day)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	tm->tm_mday = (int)day;
	time_t newt = mktime(tm);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setMonth(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double mon = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(mon)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	tm->tm_mon = (int)mon;
	if (nargs >= 2) tm->tm_mday = (int)tod(args[1]);
	time_t newt = mktime(tm);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setFullYear(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double year = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(year)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	if (isnan(ms)) ms = 0;
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	tm->tm_year = (int)year - 1900;
	if (nargs >= 2) tm->tm_mon = (int)tod(args[1]);
	if (nargs >= 3) tm->tm_mday = (int)tod(args[2]);
	time_t newt = mktime(tm);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setUTCMilliseconds(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double newMs = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(newMs)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	ms = floor(ms / 1000.0) * 1000.0 + newMs;
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setUTCSeconds(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double sec = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(sec)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	struct tm copy = *tm;
	copy.tm_sec = (int)sec;
	time_t newt = timegm(&copy);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setUTCMinutes(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double min = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(min)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	struct tm copy = *tm;
	copy.tm_min = (int)min;
	if (nargs >= 2) copy.tm_sec = (int)tod(args[1]);
	time_t newt = timegm(&copy);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setUTCHours(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double hour = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(hour)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	struct tm copy = *tm;
	copy.tm_hour = (int)hour;
	if (nargs >= 2) copy.tm_min = (int)tod(args[1]);
	if (nargs >= 3) copy.tm_sec = (int)tod(args[2]);
	time_t newt = timegm(&copy);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setUTCDate(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double day = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(day)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	struct tm copy = *tm;
	copy.tm_mday = (int)day;
	time_t newt = timegm(&copy);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setUTCMonth(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double mon = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(ms) \|\| isnan(mon)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	struct tm copy = *tm;
	copy.tm_mon = (int)mon;
	if (nargs >= 2) copy.tm_mday = (int)tod(args[1]);
	time_t newt = timegm(&copy);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_setUTCFullYear(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	double year = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(year)) { date_set_time(js, js->this_val, JS_NAN); return tov(JS_NAN); }
	if (isnan(ms)) ms = 0;
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	struct tm copy = *tm;
	copy.tm_year = (int)year - 1900;
	if (nargs >= 2) copy.tm_mon = (int)tod(args[1]);
	if (nargs >= 3) copy.tm_mday = (int)tod(args[2]);
	time_t newt = timegm(&copy);
	ms = (double)newt * 1000.0 + fmod(ms, 1000.0);
	date_set_time(js, js->this_val, ms);
	return tov(ms);
	}

	static jsval_t builtin_Date_toUTCString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mkstr(js, "Invalid Date", 12);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = gmtime(&t);
	static const char *days[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
	static const char *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
	char buf[64];
	snprintf(buf, sizeof(buf), "%s, %02d %s %04d %02d:%02d:%02d GMT",
	days[tm->tm_wday], tm->tm_mday, months[tm->tm_mon],
	tm->tm_year + 1900, tm->tm_hour, tm->tm_min, tm->tm_sec);
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_Date_toDateString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mkstr(js, "Invalid Date", 12);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	static const char *days[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
	static const char *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
	char buf[32];
	snprintf(buf, sizeof(buf), "%s %s %02d %04d",
	days[tm->tm_wday], months[tm->tm_mon], tm->tm_mday, tm->tm_year + 1900);
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_Date_toTimeString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mkstr(js, "Invalid Date", 12);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	char buf[32];
	int offset = (int)(-timezone / 60);
	int offset_hours = offset / 60;
	int offset_mins = abs(offset % 60);
	snprintf(buf, sizeof(buf), "%02d:%02d:%02d GMT%+03d%02d",
	tm->tm_hour, tm->tm_min, tm->tm_sec, offset_hours, offset_mins);
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_Date_toLocaleDateString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mkstr(js, "Invalid Date", 12);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	char buf[32];
	snprintf(buf, sizeof(buf), "%d/%d/%04d", tm->tm_mon + 1, tm->tm_mday, tm->tm_year + 1900);
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_Date_toLocaleTimeString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mkstr(js, "Invalid Date", 12);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	char buf[16];
	snprintf(buf, sizeof(buf), "%02d:%02d:%02d", tm->tm_hour, tm->tm_min, tm->tm_sec);
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_Date_getYear(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return tov(JS_NAN);
	time_t t = (time_t)(ms / 1000.0);
	struct tm *tm = localtime(&t);
	return tov((double)(tm->tm_year));
	}

	static jsval_t builtin_Date_setYear(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) {
	date_set_time(js, js->this_val, JS_NAN);
	return tov(JS_NAN);
	}
	double year_arg = tod(args[0]);
	if (isnan(year_arg)) {
	date_set_time(js, js->this_val, JS_NAN);
	return tov(JS_NAN);
	}
	int year = (int)year_arg;
	if (year >= 0 && year <= 99) year += 1900;
	double ms = date_get_time(js, js->this_val);
	time_t t;
	struct tm tm_val;
	if (isnan(ms)) {
	t = 0;
	tm_val = *localtime(&t);
	tm_val.tm_mday = 1;
	tm_val.tm_mon = 0;
	tm_val.tm_hour = 0;
	tm_val.tm_min = 0;
	tm_val.tm_sec = 0;
	} else {
	t = (time_t)(ms / 1000.0);
	tm_val = *localtime(&t);
	}
	tm_val.tm_year = year - 1900;
	time_t new_t = mktime(&tm_val);
	double new_ms = (double)new_t * 1000.0;
	date_set_time(js, js->this_val, new_ms);
	return tov(new_ms);
	}

	static jsval_t builtin_Date_toJSON(struct js js, jsval_t args, int nargs) {
	double ms = date_get_time(js, js->this_val);
	if (isnan(ms)) return js_mknull();
	return builtin_Date_toISOString(js, args, nargs);
	}

	static jsval_t builtin_Math_abs(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(fabs(x));
	}

	static jsval_t builtin_Math_acos(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(acos(x));
	}

	static jsval_t builtin_Math_acosh(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(acosh(x));
	}

	static jsval_t builtin_Math_asin(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(asin(x));
	}

	static jsval_t builtin_Math_asinh(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(asinh(x));
	}

	static jsval_t builtin_Math_atan(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(atan(x));
	}

	static jsval_t builtin_Math_atanh(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(atanh(x));
	}

	static jsval_t builtin_Math_atan2(struct js js, jsval_t args, int nargs) {
	double y = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	double x = (nargs < 2) ? JS_NAN : js_to_number(js, args[1]);
	if (isnan(y) \|\| isnan(x)) return tov(JS_NAN);
	return tov(atan2(y, x));
	}

	static jsval_t builtin_Math_cbrt(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(cbrt(x));
	}

	static jsval_t builtin_Math_ceil(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(ceil(x));
	}

	static jsval_t builtin_Math_clz32(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(32);
	double x = js_to_number(js, args[0]);
	if (isnan(x) \|\| isinf(x)) return tov(32);
	uint32_t n = (uint32_t) x;
	if (n == 0) return tov(32);
	int count = 0;
	while ((n & 0x80000000U) == 0) { count++; n <<= 1; }
	return tov((double) count);
	}

	static jsval_t builtin_Math_cos(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(cos(x));
	}

	static jsval_t builtin_Math_cosh(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(cosh(x));
	}

	static jsval_t builtin_Math_exp(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(exp(x));
	}

	static jsval_t builtin_Math_expm1(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(expm1(x));
	}

	static jsval_t builtin_Math_floor(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(floor(x));
	}

	static jsval_t builtin_Math_fround(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov((double)(float)x);
	}

	static jsval_t builtin_Math_hypot(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return tov(0.0);
	double sum = 0.0;
	for (int i = 0; i < nargs; i++) {
	double v = js_to_number(js, args[i]);
	if (isnan(v)) return tov(JS_NAN);
	sum += v * v;
	}
	return tov(sqrt(sum));
	}

	static int32_t toInt32(double d) {
	if (isnan(d) \|\| isinf(d) \|\| d == 0) return 0;
	double int_val = trunc(d);
	double two32 = (double)(1ULL << 32);
	double two31 = (double)(1ULL << 31);
	double mod_val = fmod(int_val, two32);
	if (mod_val < 0) mod_val += two32;
	if (mod_val >= two31) mod_val -= two32;
	return (int32_t)mod_val;
	}

	static jsval_t builtin_Math_imul(struct js js, jsval_t args, int nargs) {
	if (nargs < 2) return tov(0);
	int32_t a = toInt32(js_to_number(js, args[0]));
	int32_t b = toInt32(js_to_number(js, args[1]));
	return tov((double)((int32_t)((uint32_t)a * (uint32_t)b)));
	}

	static jsval_t builtin_Math_log(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log(x));
	}

	static jsval_t builtin_Math_log1p(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log1p(x));
	}

	static jsval_t builtin_Math_log10(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log10(x));
	}

	static jsval_t builtin_Math_log2(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log2(x));
	}

	static jsval_t builtin_Math_max(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return tov(JS_NEG_INF);
	double max_val = JS_NEG_INF;
	for (int i = 0; i < nargs; i++) {
	double v = js_to_number(js, args[i]);
	if (isnan(v)) return tov(JS_NAN);
	if (v > max_val) max_val = v;
	}
	return tov(max_val);
	}

	static jsval_t builtin_Math_min(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return tov(JS_INF);
	double min_val = JS_INF;
	for (int i = 0; i < nargs; i++) {
	double v = js_to_number(js, args[i]);
	if (isnan(v)) return tov(JS_NAN);
	if (v < min_val) min_val = v;
	}
	return tov(min_val);
	}

	static jsval_t builtin_Math_pow(struct js js, jsval_t args, int nargs) {
	double base = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	double exp = (nargs < 2) ? JS_NAN : js_to_number(js, args[1]);
	if (isnan(base) \|\| isnan(exp)) return tov(JS_NAN);
	return tov(pow(base, exp));
	}

	static bool random_seeded = false;

	static jsval_t builtin_Math_random(struct js js, jsval_t args, int nargs) {
	if (!random_seeded) {
	srand((unsigned int) time(NULL));
	random_seeded = true;
	}
	return tov((double) rand() / ((double) RAND_MAX + 1.0));
	}

	static jsval_t builtin_Math_round(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x) \|\| isinf(x)) return tov(x);
	return tov(floor(x + 0.5));
	}

	static jsval_t builtin_Math_sign(struct js js, jsval_t args, int nargs) {
	double v = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(v)) return tov(JS_NAN);
	if (v > 0) return tov(1.0);
	if (v < 0) return tov(-1.0);
	return tov(v);
	}

	static jsval_t builtin_Math_sin(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(sin(x));
	}

	static jsval_t builtin_Math_sinh(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(sinh(x));
	}

	static jsval_t builtin_Math_sqrt(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(sqrt(x));
	}

	static jsval_t builtin_Math_tan(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(tan(x));
	}

	static jsval_t builtin_Math_tanh(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(tanh(x));
	}

	static jsval_t builtin_Math_trunc(struct js js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(trunc(x));
	}

	static jsval_t builtin_object_keys(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkarr(js);
	jsval_t obj = args[0];

	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR && vtype(obj) != T_FUNC) return mkarr(js);
	if (vtype(obj) == T_FUNC) obj = mkval(T_OBJ, vdata(obj));

	jsval_t arr = mkarr(js);
	jsoff_t idx = 0;

	jsoff_t obj_off = (jsoff_t)vdata(obj);
	jsoff_t next = loadoff(js, obj_off) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];

	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	bool should_include = true;
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key, klen);
	if (desc) should_include = desc->enumerable;

	if (should_include) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key_val = js_mkstr(js, key, klen);
	js_mkprop_fast(js, arr, idxstr, idxlen, key_val);
	idx++;
	}
	}

	descriptor_entry_t desc, tmp;
	HASH_ITER(hh, desc_registry, desc, tmp) {
	if (desc->obj_off != obj_off) continue;
	if (!desc->enumerable) continue;
	if (!desc->has_getter && !desc->has_setter) continue;

	char idxstr[16]; size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key_val = js_mkstr(js, desc->prop_name, desc->prop_len);
	js_mkprop_fast(js, arr, idxstr, idxlen, key_val); idx++;
	}

	jsval_t len_val = tov((double) idx);
	js_mkprop_fast(js, arr, "length", 6, len_val);

	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_object_values(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkarr(js);
	jsval_t obj = args[0];

	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR && vtype(obj) != T_FUNC) return mkarr(js);
	if (vtype(obj) == T_FUNC) obj = mkval(T_OBJ, vdata(obj));

	jsval_t arr = mkarr(js);
	jsoff_t idx = 0;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	bool should_include = true;
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key, klen);
	if (desc) {
	should_include = desc->enumerable;
	}

	if (should_include) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	js_mkprop_fast(js, arr, idxstr, idxlen, val);
	idx++;
	}
	}

	jsval_t len_val = tov((double) idx);
	js_mkprop_fast(js, arr, "length", 6, len_val);

	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_object_entries(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkarr(js);
	jsval_t obj = args[0];

	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR && vtype(obj) != T_FUNC) return mkarr(js);
	if (vtype(obj) == T_FUNC) obj = mkval(T_OBJ, vdata(obj));

	jsval_t arr = mkarr(js);
	jsoff_t idx = 0;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	next = next_prop(header);

	if (is_internal_prop(key, klen)) continue;

	bool should_include = true;
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key, klen);
	if (desc) {
	should_include = desc->enumerable;
	}

	if (should_include) {
	jsval_t pair = mkarr(js);
	jsval_t key_val = js_mkstr(js, key, klen);
	js_mkprop_fast(js, pair, "0", 1, key_val);
	js_mkprop_fast(js, pair, "1", 1, val);
	js_mkprop_fast(js, pair, "length", 6, tov(2.0));

	char idxstr[16]; size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	js_mkprop_fast(js, arr, idxstr, idxlen, mkval(T_ARR, vdata(pair))); idx++;
	}
	}

	jsval_t len_val = tov((double) idx);
	js_mkprop_fast(js, arr, "length", 6, len_val);

	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_object_getPrototypeOf(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkerr(js, "Object.getPrototypeOf requires an argument");
	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_BIGINT) return get_prototype_for_type(js, t);
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) return get_proto(js, obj);

	return js_mknull();
	}

	static jsval_t builtin_object_setPrototypeOf(struct js js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "Object.setPrototypeOf requires 2 arguments");

	jsval_t obj = args[0];
	jsval_t proto = args[1];

	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	return js_mkerr(js, "Object.setPrototypeOf: first argument must be an object");
	}

	uint8_t pt = vtype(proto);
	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC && pt != T_NULL) {
	return js_mkerr(js, "Object.setPrototypeOf: prototype must be an object or null");
	}

	for (jsval_t cur = proto; pt != T_NULL && vtype(cur) != T_NULL; cur = get_proto(js, cur)) {
	if (vdata(cur) == vdata(obj)) return js_mkerr(js, "Cyclic __proto__ value");
	}

	set_proto(js, obj, proto);
	return obj;
	}

	static jsval_t builtin_proto_getter(struct js js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	uint8_t t = vtype(this_val);

	if (t == T_UNDEF \|\| t == T_NULL) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot read property '__proto__' of %s", typestr(t));
	}

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	return get_proto(js, this_val);
	}

	return get_prototype_for_type(js, t);
	}

	static jsval_t builtin_proto_setter(struct js js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	uint8_t t = vtype(this_val);

	if (t == T_UNDEF \|\| t == T_NULL) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot set property '__proto__' of %s", typestr(t));
	}

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	return js_mkundef();
	}

	if (nargs == 0) return js_mkundef();

	jsval_t proto = args[0];
	uint8_t pt = vtype(proto);

	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC && pt != T_NULL) {
	return js_mkundef();
	}

	for (jsval_t cur = proto; pt != T_NULL && vtype(cur) == T_OBJ; cur = get_proto(js, cur)) {
	if (vdata(cur) == vdata(this_val)) return js_mkundef();
	}

	set_proto(js, this_val, proto);
	return js_mkundef();
	}

	static jsval_t builtin_object_create(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkerr(js, "Object.create requires a prototype argument");

	jsval_t proto = args[0];
	uint8_t pt = vtype(proto);

	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC && pt != T_NULL) {
	return js_mkerr(js, "Object.create: prototype must be an object or null");
	}

	jsval_t obj = js_mkobj(js);
	if (pt == T_NULL) {
	set_proto(js, obj, js_mknull());
	} else set_proto(js, obj, proto);

	if (nargs >= 2 && vtype(args[1]) == T_OBJ) {
	jsval_t props = args[1];
	jsoff_t next = loadoff(js, (jsoff_t) vdata(props)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t descriptor = resolveprop(js, mkval(T_PROP, next));

	if (vtype(descriptor) == T_OBJ) {
	jsoff_t val_off = lkp(js, descriptor, "value", 5);
	if (val_off != 0) {
	jsval_t val = resolveprop(js, mkval(T_PROP, val_off));
	jsval_t key_str = js_mkstr(js, key, klen);
	setprop(js, obj, key_str, val);
	}
	}

	next = next_prop(header);
	}
	}

	return obj;
	}

	static jsval_t builtin_object_hasOwn(struct js js, jsval_t args, int nargs) {
	if (nargs < 2) return mkval(T_BOOL, 0);

	jsval_t obj = args[0];
	jsval_t key = args[1];

	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return mkval(T_BOOL, 0);
	if (vtype(key) != T_STR) return mkval(T_BOOL, 0);

	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));
	jsoff_t key_len, key_off = vstr(js, key, &key_len);
	const char key_str = (char ) &js->mem[key_off];

	jsoff_t off = lkp(js, as_obj, key_str, key_len);
	return mkval(T_BOOL, off != 0 ? 1 : 0);
	}

	static jsval_t builtin_object_defineProperty(struct js js, jsval_t args, int nargs) {
	if (nargs < 3) return js_mkerr(js, "Object.defineProperty requires 3 arguments");

	jsval_t obj = args[0];
	jsval_t prop = args[1];
	jsval_t descriptor = args[2];

	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	return js_mkerr(js, "Object.defineProperty called on non-object");
	}

	if (vtype(prop) == T_SYMBOL) {
	char keybuf[64];
	snprintf(keybuf, sizeof(keybuf), "__sym_%llu__", (unsigned long long)sym_get_id(prop));
	prop = js_mkstr(js, keybuf, strlen(keybuf));
	} else if (vtype(prop) != T_STR) {
	char buf[64];
	size_t len = tostr(js, prop, buf, sizeof(buf));
	prop = js_mkstr(js, buf, len);
	}

	if (vtype(descriptor) != T_OBJ) {
	return js_mkerr(js, "Property descriptor must be an object");
	}

	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	jsoff_t prop_len, prop_off = vstr(js, prop, &prop_len);
	const char prop_str = (char ) &js->mem[prop_off];

	if (streq(prop_str, prop_len, STR_PROTO, STR_PROTO_LEN)) {
	return js_mkerr(js, "Cannot define " STR_PROTO " property");
	}

	bool has_value = false, has_get = false, has_set = false, has_writable = false;
	jsval_t value = js_mkundef();
	bool writable = true, enumerable = false, configurable = false;

	jsoff_t value_off = lkp(js, descriptor, "value", 5);
	if (value_off != 0) {
	has_value = true;
	value = resolveprop(js, mkval(T_PROP, value_off));
	}

	jsoff_t get_off = lkp_interned(js, descriptor, INTERN_GET, 3);
	if (get_off != 0) {
	has_get = true;
	jsval_t getter = resolveprop(js, mkval(T_PROP, get_off));
	if (vtype(getter) != T_FUNC && vtype(getter) != T_UNDEF) {
	return js_mkerr(js, "Getter must be a function");
	}
	}

	jsoff_t set_off = lkp_interned(js, descriptor, INTERN_SET, 3);
	if (set_off != 0) {
	has_set = true;
	jsval_t setter = resolveprop(js, mkval(T_PROP, set_off));
	if (vtype(setter) != T_FUNC && vtype(setter) != T_UNDEF) {
	return js_mkerr(js, "Setter must be a function");
	}
	}

	if ((has_value \|\| has_writable) && (has_get \|\| has_set)) {
	return js_mkerr(js, "Invalid property descriptor. Cannot both specify accessors and a value or writable attribute");
	}

	jsoff_t writable_off = lkp(js, descriptor, "writable", 8);
	if (writable_off != 0) {
	has_writable = true;
	jsval_t w_val = resolveprop(js, mkval(T_PROP, writable_off));
	writable = js_truthy(js, w_val);
	}

	jsoff_t enumerable_off = lkp(js, descriptor, "enumerable", 10);
	if (enumerable_off != 0) {
	jsval_t e_val = resolveprop(js, mkval(T_PROP, enumerable_off));
	enumerable = js_truthy(js, e_val);
	}

	jsoff_t configurable_off = lkp(js, descriptor, "configurable", 12);
	if (configurable_off != 0) {
	jsval_t c_val = resolveprop(js, mkval(T_PROP, configurable_off));
	configurable = js_truthy(js, c_val);
	}

	jsoff_t existing_off = lkp(js, as_obj, prop_str, prop_len);

	if (has_get \|\| has_set) {
	int desc_flags =
	(enumerable ? JS_DESC_E : 0) \|
	(configurable ? JS_DESC_C : 0);

	if (has_get && has_set) {
	jsval_t getter = resolveprop(js, mkval(T_PROP, get_off));
	jsval_t setter = resolveprop(js, mkval(T_PROP, set_off));
	js_set_accessor_desc(js, as_obj, prop_str, prop_len, getter, setter, desc_flags);
	} else if (has_get) {
	jsval_t getter = resolveprop(js, mkval(T_PROP, get_off));
	js_set_getter_desc(js, as_obj, prop_str, prop_len, getter, desc_flags);
	} else {
	jsval_t setter = resolveprop(js, mkval(T_PROP, set_off));
	js_set_setter_desc(js, as_obj, prop_str, prop_len, setter, desc_flags);
	}
	} else {
	int desc_flags =
	(writable ? JS_DESC_W : 0) \|
	(enumerable ? JS_DESC_E : 0) \|
	(configurable ? JS_DESC_C : 0);

	js_set_descriptor(js, as_obj, prop_str, prop_len, desc_flags);

	if (existing_off > 0) {
	if (is_nonconfig_prop(js, existing_off)) {
	return js_mkerr(js, "Cannot redefine non-configurable property");
	}

	if (has_value) {
	saveval(js, existing_off + sizeof(jsoff_t) * 2, value);
	}

	if (!writable \|\| !configurable) {
	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| FLAGMASK)) == existing_off) {
	jsoff_t flags = 0;
	if (!writable) flags \|= CONSTMASK;
	if (!configurable) flags \|= NONCONFIGMASK;
	saveoff(js, head, firstprop \| flags);
	} else {
	jsoff_t prop_header = loadoff(js, existing_off);
	jsoff_t flags = 0;
	if (!writable) flags \|= CONSTMASK;
	if (!configurable) flags \|= NONCONFIGMASK;
	saveoff(js, existing_off, prop_header \| flags);
	}
	}
	} else {
	if (!has_value) value = js_mkundef();
	jsval_t prop_key = js_mkstr(js, prop_str, prop_len);
	jsoff_t flags = (writable ? 0 : CONSTMASK) \| (configurable ? 0 : NONCONFIGMASK);
	mkprop(js, as_obj, prop_key, value, flags);
	}
	}

	return obj;
	}

	static jsval_t builtin_object_defineProperties(struct js js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "Object.defineProperties requires 2 arguments");

	jsval_t obj = args[0];
	jsval_t props = args[1];

	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	return js_mkerr(js, "Object.defineProperties called on non-object");
	}

	if (vtype(props) != T_OBJ) {
	return js_mkerr(js, "Property descriptors must be an object");
	}

	jsval_t props_obj = props;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(props_obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t descriptor = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	jsval_t prop_key = js_mkstr(js, key, klen);
	jsval_t define_args[3] = { obj, prop_key, descriptor };
	jsval_t result = builtin_object_defineProperty(js, define_args, 3);
	if (is_err(result)) return result;
	}

	return obj;
	}

	static jsval_t builtin_object_assign(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkerr(js, "Object.assign requires at least 1 argument");

	jsval_t target = args[0];
	uint8_t t = vtype(target);

	if (t == T_NULL \|\| t == T_UNDEF) {
	return js_mkerr(js, "Cannot convert undefined or null to object");
	}

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	target = js_mkobj(js);
	}

	jsval_t as_obj = (vtype(target) == T_OBJ) ? target : mkval(T_OBJ, vdata(target));

	for (int i = 1; i < nargs; i++) {
	jsval_t source = args[i];
	uint8_t st = vtype(source);

	if (st == T_NULL \|\| st == T_UNDEF) continue;
	if (st != T_OBJ && st != T_ARR && st != T_FUNC) continue;

	jsval_t src_obj = (st == T_OBJ) ? source : mkval(T_OBJ, vdata(source));
	jsoff_t next = loadoff(js, (jsoff_t) vdata(src_obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	bool should_copy = true;
	jsoff_t src_obj_off = (jsoff_t)vdata(src_obj);
	descriptor_entry_t *desc = lookup_descriptor(src_obj_off, key, klen);
	if (desc) {
	should_copy = desc->enumerable;
	}

	if (should_copy) {
	jsval_t key_str = js_mkstr(js, key, klen);
	setprop(js, as_obj, key_str, val);
	}
	}
	}

	return target;
	}

	static jsval_t builtin_object_freeze(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkundef();

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return obj;
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	jsoff_t next = loadoff(js, (jsoff_t) vdata(as_obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];

	jsoff_t cur_prop = next;
	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	jsoff_t freeze_flags = CONSTMASK \| NONCONFIGMASK;
	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| FLAGMASK)) == cur_prop) {
	saveoff(js, head, firstprop \| freeze_flags);
	} else {
	jsoff_t prop_header = loadoff(js, cur_prop);
	saveoff(js, cur_prop, prop_header \| freeze_flags);
	}

	js_set_descriptor(js, as_obj, key, klen, JS_DESC_E);
	}

	set_slot(js, as_obj, SLOT_FROZEN, js_mktrue());
	return obj;
	}

	static jsval_t builtin_object_isFrozen(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mktrue();

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_mktrue();
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	return js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN)) ? js_mktrue() : js_mkfalse();
	}

	static jsval_t builtin_object_seal(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkundef();

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return obj;
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	set_slot(js, as_obj, SLOT_SEALED, js_mktrue());
	jsoff_t next = loadoff(js, (jsoff_t) vdata(as_obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];

	jsoff_t cur_prop = next;
	next = next_prop(header);

	if (is_internal_prop(key, klen)) continue;

	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| FLAGMASK)) == cur_prop) {
	saveoff(js, head, firstprop \| NONCONFIGMASK);
	} else {
	jsoff_t prop_header = loadoff(js, cur_prop);
	saveoff(js, cur_prop, prop_header \| NONCONFIGMASK);
	}

	js_set_descriptor(js, as_obj, key, klen, JS_DESC_W \| JS_DESC_E);
	}

	return obj;
	}

	static jsval_t builtin_object_isSealed(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mktrue();

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_mktrue();
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	if (js_truthy(js, get_slot(js, as_obj, SLOT_SEALED))) return js_mktrue();
	if (js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN))) return js_mktrue();

	return js_mkfalse();
	}

	static jsval_t builtin_object_fromEntries(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkerr(js, "Object.fromEntries requires an iterable argument");

	jsval_t iterable = args[0];
	uint8_t t = vtype(iterable);

	if (t != T_ARR && t != T_OBJ) {
	return js_mkerr(js, "Object.fromEntries requires an iterable");
	}

	jsval_t result = js_mkobj(js);
	jsoff_t len_off = lkp_interned(js, iterable, INTERN_LENGTH, 6);
	if (len_off == 0) return result;

	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) != T_NUM) return result;

	jsoff_t len = (jsoff_t) tod(len_val);

	for (jsoff_t i = 0; i < len; i++) {
	char idx_str[16];
	snprintf(idx_str, sizeof(idx_str), "%u", (unsigned) i);

	jsoff_t entry_off = lkp(js, iterable, idx_str, strlen(idx_str));
	if (entry_off == 0) continue;

	jsval_t entry = resolveprop(js, mkval(T_PROP, entry_off));
	if (vtype(entry) != T_ARR && vtype(entry) != T_OBJ) continue;

	jsoff_t key_off = lkp(js, entry, "0", 1);
	if (key_off == 0) continue;
	jsval_t key = resolveprop(js, mkval(T_PROP, key_off));

	jsoff_t val_off = lkp(js, entry, "1", 1);
	jsval_t val = (val_off != 0) ? resolveprop(js, mkval(T_PROP, val_off)) : js_mkundef();

	if (vtype(key) != T_STR) {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}

	setprop(js, result, key, val);
	}

	return result;
	}

	static jsval_t builtin_object_getOwnPropertyDescriptor(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkundef();

	jsval_t obj = args[0];
	jsval_t key = args[1];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_mkundef();
	if (vtype(key) != T_STR) {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}

	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));
	jsoff_t key_len, key_off = vstr(js, key, &key_len);
	const char key_str = (char ) &js->mem[key_off];

	jsoff_t obj_off = (jsoff_t)vdata(as_obj);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key_str, key_len);

	jsoff_t prop_off = lkp(js, as_obj, key_str, key_len);
	if (prop_off == 0 && !desc) {
	return js_mkundef();
	}

	jsval_t result = js_mkobj(js);

	if (desc && (desc->has_getter \|\| desc->has_setter)) {
	if (desc->has_getter) {
	setprop(js, result, js_mkstr(js, "get", 3), desc->getter);
	}
	if (desc->has_setter) {
	setprop(js, result, js_mkstr(js, "set", 3), desc->setter);
	}
	setprop(js, result, js_mkstr(js, "enumerable", 10), desc->enumerable ? js_mktrue() : js_mkfalse());
	setprop(js, result, js_mkstr(js, "configurable", 12), desc->configurable ? js_mktrue() : js_mkfalse());
	} else {
	if (prop_off != 0) {
	jsval_t prop_val = resolveprop(js, mkval(T_PROP, prop_off));
	setprop(js, result, js_mkstr(js, "value", 5), prop_val);
	}
	setprop(js, result, js_mkstr(js, "writable", 8), desc ? (desc->writable ? js_mktrue() : js_mkfalse()) : js_mktrue());
	setprop(js, result, js_mkstr(js, "enumerable", 10), desc ? (desc->enumerable ? js_mktrue() : js_mkfalse()) : js_mktrue());
	setprop(js, result, js_mkstr(js, "configurable", 12), desc ? (desc->configurable ? js_mktrue() : js_mkfalse()) : js_mktrue());
	}

	return result;

	return js_mkundef();
	}

	static jsval_t builtin_object_getOwnPropertyNames(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkarr(js);
	jsval_t obj = args[0];

	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR && vtype(obj) != T_FUNC) return mkarr(js);
	if (vtype(obj) == T_FUNC) obj = mkval(T_OBJ, vdata(obj));

	jsoff_t count = 0;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (!is_slot_prop(header)) {
	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	if (!is_internal_prop(key, klen)) count++;
	}
	next = next_prop(header);
	}

	if (count == 0) {
	jsval_t arr = mkarr(js);
	js_mkprop_fast(js, arr, "length", 6, tov(0));
	return mkval(T_ARR, vdata(arr));
	}

	jsval_t keys = malloc(count sizeof(jsval_t));
	if (!keys) return js_mkerr(js, "out of memory");

	jsoff_t idx = 0;
	next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0 && idx < count) {
	jsoff_t header = loadoff(js, next);
	if (!is_slot_prop(header)) {
	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	if (!is_internal_prop(key, klen)) {
	keys[idx++] = js_mkstr(js, key, klen);
	}
	}
	next = next_prop(header);
	}

	jsval_t arr = mkarr(js);
	for (jsoff_t i = 0; i < idx; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	js_mkprop_fast(js, arr, idxstr, idxlen, keys[i]);
	}

	free(keys);
	js_mkprop_fast(js, arr, "length", 6, tov((double) idx));
	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_object_isExtensible(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mktrue();

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_mktrue();
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	if (js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN))) return js_mkfalse();
	if (js_truthy(js, get_slot(js, as_obj, SLOT_SEALED))) return js_mkfalse();

	jsval_t ext_slot = get_slot(js, as_obj, SLOT_EXTENSIBLE);
	if (vtype(ext_slot) != T_UNDEF) {
	return js_truthy(js, ext_slot) ? js_mktrue() : js_mkfalse();
	}

	return js_mktrue();
	}

	static jsval_t builtin_object_preventExtensions(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkundef();

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return obj;
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	set_slot(js, as_obj, SLOT_EXTENSIBLE, js_mkfalse());
	return obj;
	}

	static jsval_t builtin_object_hasOwnProperty(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return mkval(T_BOOL, 0);

	jsval_t obj = js->this_val;
	jsval_t key = args[0];

	obj = resolveprop(js, obj);
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return mkval(T_BOOL, 0);
	if (vtype(key) != T_STR) {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}

	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));
	jsoff_t key_len, key_off = vstr(js, key, &key_len);
	const char key_str = (char ) &js->mem[key_off];

	jsoff_t off = lkp(js, as_obj, key_str, key_len);
	return mkval(T_BOOL, off != 0 ? 1 : 0);
	}

	static jsval_t builtin_object_isPrototypeOf(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return mkval(T_BOOL, 0);

	jsval_t proto_obj = resolveprop(js, js->this_val);
	jsval_t obj = args[0];

	uint8_t obj_type = vtype(obj);
	if (obj_type != T_OBJ && obj_type != T_ARR && obj_type != T_FUNC) return mkval(T_BOOL, 0);

	uint8_t proto_type = vtype(proto_obj);
	if (proto_type != T_OBJ && proto_type != T_ARR && proto_type != T_FUNC) return mkval(T_BOOL, 0);
	jsoff_t proto_data = (jsoff_t)vdata(proto_obj);

	jsval_t current = get_proto(js, obj);
	while (!is_undefined(current) && !is_null(current)) {
	uint8_t cur_type = vtype(current);
	if (cur_type != T_OBJ && cur_type != T_ARR && cur_type != T_FUNC) break;
	if (vdata(current) == proto_data) return mkval(T_BOOL, 1);
	current = get_proto(js, current);
	}

	return mkval(T_BOOL, 0);
	}

	static jsval_t builtin_object_propertyIsEnumerable(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return mkval(T_BOOL, 0);

	jsval_t obj = js->this_val;
	jsval_t key = args[0];

	obj = resolveprop(js, obj);
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return mkval(T_BOOL, 0);
	if (vtype(key) != T_STR) {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}

	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));
	jsoff_t key_len, key_off = vstr(js, key, &key_len);
	const char key_str = (char ) &js->mem[key_off];

	if (t == T_ARR && streq(key_str, key_len, "length", 6)) {
	return mkval(T_BOOL, 0);
	}

	jsoff_t off = lkp(js, as_obj, key_str, key_len);
	if (off == 0) return mkval(T_BOOL, 0);

	jsoff_t obj_off = (jsoff_t)vdata(as_obj);
	descriptor_entry_t *desc = lookup_descriptor(obj_off, key_str, key_len);
	if (desc) {
	return mkval(T_BOOL, desc->enumerable ? 1 : 0);
	}

	return mkval(T_BOOL, 1);
	}

	static jsval_t builtin_object_toString(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t obj = js->this_val;

	obj = resolveprop(js, obj);
	uint8_t t = vtype(obj);

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	jsval_t check_obj = (t == T_FUNC) ? mkval(T_OBJ, vdata(obj)) : obj;
	const char *tostr_tag_key = get_toStringTag_sym_key();
	jsoff_t tag_off = lkp(js, check_obj, tostr_tag_key, strlen(tostr_tag_key));
	if (tag_off == 0) tag_off = lkp_proto(js, check_obj, tostr_tag_key, strlen(tostr_tag_key));
	if (tag_off != 0) {
	jsval_t tag_val = resolveprop(js, mkval(T_PROP, tag_off));
	if (vtype(tag_val) == T_STR) {
	jsoff_t tag_len, tag_str_off = vstr(js, tag_val, &tag_len);
	const char tag_str = (const char )&js->mem[tag_str_off];

	char buf[256];
	int n = snprintf(buf, sizeof(buf), "[object %.*s]", (int)tag_len, tag_str);
	return js_mkstr(js, buf, n);
	}
	}
	}

	const char *type_name = NULL;

	switch (t) {
	case T_UNDEF: type_name = "Undefined"; break;
	case T_NULL: type_name = "Null"; break;
	case T_BOOL: type_name = "Boolean"; break;
	case T_NUM: type_name = "Number"; break;
	case T_STR: type_name = "String"; break;
	case T_ARR: type_name = "Array"; break;
	case T_FUNC: type_name = "Function"; break;
	case T_ERR: type_name = "Error"; break;
	case T_BIGINT: type_name = "BigInt"; break;
	case T_OBJ: type_name = "Object"; break;
	default: type_name = "Unknown"; break;
	}

	char buf[256];
	int n = snprintf(buf, sizeof(buf), "[object %s]", type_name);
	return js_mkstr(js, buf, n);
	}

	static jsval_t builtin_object_valueOf(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	return js->this_val;
	}

	static jsval_t builtin_object_toLocaleString(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	return js_call_toString(js, js->this_val);
	}

	static inline bool parse_array_index(const char key, size_t key_len, jsoff_t len, unsigned out_idx) {
	if (key_len == 0 \|\| key[0] > '9' \|\| key[0] < '0') return false;
	unsigned parsed_idx = 0;
	for (size_t i = 0; i < key_len; i++) {
	if (key[i] < '0' \|\| key[i] > '9') return false;
	parsed_idx = parsed_idx * 10 + (key[i] - '0');
	}
	if (parsed_idx >= len) return false;
	*out_idx = parsed_idx;
	return true;
	}

	static inline bool is_callable(jsval_t v) {
	uint8_t t = vtype(v);
	return t == T_FUNC \|\| t == T_CFUNC;
	}

	static inline jsval_t require_callback(struct js js, jsval_t args, int nargs, const char *name) {
	if (nargs == 0 \|\| !is_callable(args[0]))
	return js_mkerr(js, "%s requires a function argument", name);
	return args[0];
	}

	static jsval_t array_shallow_copy(struct js *js, jsval_t arr, jsoff_t len) {
	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	if (key_len == 0 \|\| key[0] > '9' \|\| key[0] < '0') continue;
	js_mkprop_fast(js, result, key, key_len, val);
	}

	js_prop_iter_end(&iter);
	js_mkprop_fast(js, result, "length", 6, tov((double)len));
	return result;
	}

	static jsval_t builtin_array_push(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	arr = resolveprop(js, arr);

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "push called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, arr, key, args[i]);
	len++;
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double) len);

	setprop(js, arr, len_key, len_val);
	return len_val;
	}

	void js_arr_push(struct js *js, jsval_t arr, jsval_t val) {
	arr = resolveprop(js, arr);
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) return;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);
	js_mkprop_fast(js, arr, idxstr, idxlen, val);

	if (len_off != 0) saveval(js, len_off + sizeof(jsoff_t) * 2, tov((double)(len + 1)));
	else js_mkprop_fast(js, arr, "length", 6, tov((double)(len + 1)));
	}

	static jsval_t builtin_array_pop(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "pop called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;

	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	if (len == 0) return js_mkundef();
	len--;
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);

	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	jsval_t result = js_mkundef();
	if (elem_off != 0) {
	result = resolveprop(js, mkval(T_PROP, elem_off));
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double) len);
	setprop(js, arr, len_key, len_val);
	js->needs_gc = true;

	return result;
	}

	static jsval_t builtin_array_slice(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "slice called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;

	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	jsoff_t start = 0, end = len;
	double dlen = D(len);
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	double d = tod(args[0]);
	if (d < 0) {
	start = (jsoff_t) (d + dlen < 0 ? 0 : d + dlen);
	} else {
	start = (jsoff_t) (d > dlen ? dlen : d);
	}
	}

	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d < 0) {
	end = (jsoff_t) (d + dlen < 0 ? 0 : d + dlen);
	} else {
	end = (jsoff_t) (d > dlen ? dlen : d);
	}
	}

	if (start > end) start = end;
	jsval_t result = mkarr(js);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	for (jsoff_t i = start; i < end; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	size_t result_idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)result_idx);
	jsval_t key = js_mkstr(js, idxstr, result_idxlen);
	setprop(js, result, key, elem);
	}
	result_idx++;
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) result_idx));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_join(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "join called on non-array");
	}
	const char *sep = ",";
	jsoff_t sep_len = 1;

	if (nargs >= 1) {
	if (vtype(args[0]) == T_STR) {
	sep_len = 0;
	jsoff_t sep_off = vstr(js, args[0], &sep_len);
	sep = (const char *) &js->mem[sep_off];
	} else if (vtype(args[0]) != T_UNDEF) {
	const char *sep_str = js_str(js, args[0]);
	sep = sep_str;
	sep_len = (jsoff_t) strlen(sep_str);
	}
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;

	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	if (len == 0) return js_mkstr(js, "", 0);

	size_t capacity = 1024;
	size_t result_len = 0;
	char result = (char )ant_calloc(capacity);
	if (!result) return js_mkerr(js, "oom");

	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);

	if (i > 0) {
	if (result_len + sep_len >= capacity) {
	capacity = (result_len + sep_len + 1) * 2;
	char new_result = (char )ant_realloc(result, capacity);
	if (!new_result) return js_mkerr(js, "oom");
	result = new_result;
	}
	memcpy(result + result_len, sep, sep_len);
	result_len += sep_len;
	}

	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	if (vtype(elem) == T_STR) {
	jsoff_t elem_len, elem_off_str = vstr(js, elem, &elem_len);
	if (result_len + elem_len >= capacity) {
	capacity = (result_len + elem_len + 1) * 2;
	char new_result = (char )ant_realloc(result, capacity);
	if (!new_result) return js_mkerr(js, "oom");
	result = new_result;
	}
	memcpy(result + result_len, &js->mem[elem_off_str], elem_len);
	result_len += elem_len;
	} else if (vtype(elem) == T_NUM) {
	char numstr[32];
	snprintf(numstr, sizeof(numstr), "%g", tod(elem));
	size_t num_len = strlen(numstr);
	if (result_len + num_len >= capacity) {
	capacity = (result_len + num_len + 1) * 2;
	char new_result = (char )ant_realloc(result, capacity);
	if (!new_result) return js_mkerr(js, "oom");
	result = new_result;
	}
	memcpy(result + result_len, numstr, num_len);
	result_len += num_len;
	} else if (vtype(elem) == T_BOOL) {
	const char *boolstr = vdata(elem) ? "true" : "false";
	size_t bool_len = strlen(boolstr);
	if (result_len + bool_len >= capacity) {
	capacity = (result_len + bool_len + 1) * 2;
	char new_result = (char )ant_realloc(result, capacity);
	if (!new_result) return js_mkerr(js, "oom");
	result = new_result;
	}
	memcpy(result + result_len, boolstr, bool_len);
	result_len += bool_len;
	}
	}
	}
	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	}

	static jsval_t builtin_array_includes(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "includes called on non-array");

	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;

	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return mkval(T_BOOL, 0);

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key; size_t key_len; jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	if (vtype(val) == vtype(search)) {
	bool match = false;
	if (vtype(val) == T_NUM && tod(val) == tod(search)) match = true;
	else if (vtype(val) == T_BOOL && vdata(val) == vdata(search)) match = true;
	else if (vtype(val) == T_STR) {
	jsoff_t vl, vo = vstr(js, val, &vl);
	jsoff_t sl, so = vstr(js, search, &sl);
	if (vl == sl && memcmp(&js->mem[vo], &js->mem[so], vl) == 0) match = true;
	}
	else if ((vtype(val) == T_OBJ \|\| vtype(val) == T_ARR \|\| vtype(val) == T_FUNC) && vdata(val) == vdata(search)) match = true;

	if (match) {
	js_prop_iter_end(&iter);
	return mkval(T_BOOL, 1);
	}
	}
	}

	js_prop_iter_end(&iter);
	return mkval(T_BOOL, 0);
	}

	static jsval_t builtin_array_every(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "every called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "every");
	if (is_err(callback)) return callback;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return mkval(T_BOOL, 1);

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	jsval_t call_args[3] = { val, tov((double)parsed_idx), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);

	if (is_err(result)) {
	js_prop_iter_end(&iter);
	return result;
	}
	if (!js_truthy(js, result)) {
	js_prop_iter_end(&iter);
	return mkval(T_BOOL, 0);
	}
	}
	js_prop_iter_end(&iter);

	return mkval(T_BOOL, 1);
	}

	static jsval_t builtin_array_forEach(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "forEach called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "forEach");
	if (is_err(callback)) return callback;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return js_mkundef();

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	jsval_t call_args[3] = { val, tov((double)parsed_idx), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);

	if (is_err(result)) {
	js_prop_iter_end(&iter);
	return result;
	}
	}
	js_prop_iter_end(&iter);

	return js_mkundef();
	}

	static jsval_t builtin_array_reverse(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "reverse called on non-array");

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len <= 1) return arr;

	jsval_t vals = malloc(len sizeof(jsval_t));
	jsoff_t offs = malloc(len sizeof(jsoff_t));
	if (!vals \|\| !offs) { free(vals); free(offs); return js_mkerr(js, "out of memory"); }

	jsoff_t count = 0;
	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx) \|\| count >= len) continue;

	vals[count] = val;
	offs[count] = iter.off;
	count++;
	}
	js_prop_iter_end(&iter);

	for (jsoff_t i = 0; i < count / 2; i++) {
	jsval_t tmp = vals[i];
	vals[i] = vals[count - 1 - i];
	vals[count - 1 - i] = tmp;
	}

	for (jsoff_t i = 0; i < count; i++) {
	saveval(js, offs[i] + sizeof(jsoff_t) * 2, vals[i]);
	}

	free(vals);
	free(offs);
	return arr;
	}

	static jsval_t builtin_array_map(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "map called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "map");
	if (is_err(callback)) return callback;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	if (len == 0) {
	js_mkprop_fast(js, result, "length", 6, tov(0.0));
	return mkval(T_ARR, vdata(result));
	}

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	jsval_t call_args[3] = { val, tov((double)parsed_idx), arr };
	jsval_t mapped = call_js_with_args(js, callback, call_args, 3);

	if (is_err(mapped)) {
	js_prop_iter_end(&iter);
	return mapped;
	}

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), parsed_idx);
	js_mkprop_fast(js, result, idxstr, idxlen, mapped);
	}
	js_prop_iter_end(&iter);

	js_mkprop_fast(js, result, "length", 6, tov((double)len));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_filter(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "filter called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "filter");
	if (is_err(callback)) return callback;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	if (len == 0) {
	js_mkprop_fast(js, result, "length", 6, tov(0.0));
	return mkval(T_ARR, vdata(result));
	}

	jsoff_t result_idx = 0;
	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	jsval_t call_args[3] = { val, tov((double)parsed_idx), arr };
	jsval_t test = call_js_with_args(js, callback, call_args, 3);

	if (is_err(test)) {
	js_prop_iter_end(&iter);
	return test;
	}

	if (js_truthy(js, test)) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)result_idx);
	js_mkprop_fast(js, result, idxstr, idxlen, val);
	result_idx++;
	}
	}
	js_prop_iter_end(&iter);

	js_mkprop_fast(js, result, "length", 6, tov((double)result_idx));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_reduce(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "reduce called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "reduce");
	if (is_err(callback)) return callback;
	bool has_initial = (nargs >= 2);

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}

	if (len == 0) {
	if (has_initial) return args[1];
	return js_mkerr(js, "reduce of empty array with no initial value");
	}

	jsval_t accumulator = has_initial ? args[1] : js_mkundef();
	bool first = !has_initial;

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	if (first) {
	accumulator = val;
	first = false;
	continue;
	}

	jsval_t call_args[4] = { accumulator, val, tov((double)parsed_idx), arr };
	accumulator = call_js_with_args(js, callback, call_args, 4);

	if (is_err(accumulator)) {
	js_prop_iter_end(&iter);
	return accumulator;
	}
	}

	js_prop_iter_end(&iter);
	if (first) return js_mkerr(js, "reduce of empty array with no initial value");

	return accumulator;
	}

	static void flat_helper(struct js js, jsval_t arr, jsval_t result, jsoff_t result_idx, int depth) {
	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return;

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	if (depth > 0 && (vtype(val) == T_ARR \|\| vtype(val) == T_OBJ)) {
	flat_helper(js, val, result, result_idx, depth - 1);
	} else {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)*result_idx);
	js_mkprop_fast(js, result, idxstr, idxlen, val);
	(*result_idx)++;
	}
	}

	js_prop_iter_end(&iter);
	}

	static jsval_t builtin_array_flat(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "flat called on non-array");
	}

	int depth = 1;
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	depth = (int) tod(args[0]);
	if (depth < 0) depth = 0;
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	flat_helper(js, arr, result, &result_idx, depth);

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) result_idx));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_concat(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "concat called on non-array");
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	char res_idx[16];
	size_t res_idx_len = uint_to_str(res_idx, sizeof(res_idx), (unsigned)result_idx);
	js_mkprop_fast(js, result, res_idx, res_idx_len, elem);
	}
	result_idx++;
	}

	for (int a = 0; a < nargs; a++) {
	jsval_t arg = args[a];
	if (vtype(arg) == T_ARR \|\| vtype(arg) == T_OBJ) {
	jsoff_t arg_off = lkp_interned(js, arg, INTERN_LENGTH, 6);
	jsoff_t arg_len = 0;
	if (arg_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, arg_off));
	if (vtype(len_val) == T_NUM) arg_len = (jsoff_t) tod(len_val);
	}

	for (jsoff_t i = 0; i < arg_len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arg, idxstr, idxlen);
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	char res_idx[16];
	size_t res_idx_len = uint_to_str(res_idx, sizeof(res_idx), (unsigned)result_idx);
	js_mkprop_fast(js, result, res_idx, res_idx_len, elem);
	}
	result_idx++;
	}
	} else {
	char res_idx[16];
	size_t res_idx_len = uint_to_str(res_idx, sizeof(res_idx), (unsigned)result_idx);
	js_mkprop_fast(js, result, res_idx, res_idx_len, arg);
	result_idx++;
	}
	}

	js_mkprop_fast(js, result, "length", 6, tov((double)result_idx));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_at(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "at called on non-array");
	}

	if (nargs == 0 \|\| vtype(args[0]) != T_NUM) return js_mkundef();

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	int idx = (int) tod(args[0]);
	if (idx < 0) idx = (int)len + idx;
	if (idx < 0 \|\| (jsoff_t)idx >= len) return js_mkundef();

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	return elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	}

	static jsval_t builtin_array_fill(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "fill called on non-array");
	}

	jsval_t value = nargs >= 1 ? args[0] : js_mkundef();

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	jsoff_t start = 0, end = len;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	int s = (int) tod(args[1]);
	if (s < 0) s = (int)len + s;
	if (s < 0) s = 0;
	start = (jsoff_t) s;
	}
	if (nargs >= 3 && vtype(args[2]) == T_NUM) {
	int e = (int) tod(args[2]);
	if (e < 0) e = (int)len + e;
	if (e < 0) e = 0;
	end = (jsoff_t) e;
	}
	if (start > len) start = len;
	if (end > len) end = len;

	for (jsoff_t i = start; i < end; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, arr, key, value);
	}

	return arr;
	}

	static jsval_t array_find_impl(struct js js, jsval_t args, int nargs, bool return_index, const char *name) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "%s called on non-array", name);

	jsval_t callback = require_callback(js, args, nargs, name);
	if (is_err(callback)) return callback;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return return_index ? tov(-1) : js_mkundef();

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	jsval_t call_args[3] = { val, tov((double)parsed_idx), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);

	if (is_err(result)) {
	js_prop_iter_end(&iter);
	return result;
	}
	if (js_truthy(js, result)) {
	js_prop_iter_end(&iter);
	return return_index ? tov((double)parsed_idx) : val;
	}
	}
	js_prop_iter_end(&iter);

	return return_index ? tov(-1) : js_mkundef();
	}

	static jsval_t builtin_array_find(struct js js, jsval_t args, int nargs) {
	return array_find_impl(js, args, nargs, false, "find");
	}

	static jsval_t builtin_array_findIndex(struct js js, jsval_t args, int nargs) {
	return array_find_impl(js, args, nargs, true, "findIndex");
	}

	static jsval_t array_find_last_impl(struct js js, jsval_t args, int nargs, bool return_index, const char *name) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "%s called on non-array", name);

	jsval_t callback = require_callback(js, args, nargs, name);
	if (is_err(callback)) return callback;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return return_index ? tov(-1) : js_mkundef();

	jsval_t vals = malloc(len sizeof(jsval_t));
	unsigned idxs = malloc(len sizeof(unsigned));
	if (!vals \|\| !idxs) { free(vals); free(idxs); return js_mkerr(js, "out of memory"); }

	jsoff_t count = 0;
	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key; size_t key_len; jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx) \|\| count >= len) continue;

	vals[count] = val;
	idxs[count] = parsed_idx;
	count++;
	}
	js_prop_iter_end(&iter);

	for (jsoff_t i = count; i > 0; i--) {
	jsval_t call_args[3] = { vals[i-1], tov((double)idxs[i-1]), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);

	if (is_err(result)) {
	free(vals); free(idxs);
	return result;
	}
	if (js_truthy(js, result)) {
	jsval_t found_val = vals[i-1];
	unsigned found_idx = idxs[i-1];
	free(vals); free(idxs);
	return return_index ? tov((double)found_idx) : found_val;
	}
	}

	free(vals); free(idxs);
	return return_index ? tov(-1) : js_mkundef();
	}

	static jsval_t builtin_array_findLast(struct js js, jsval_t args, int nargs) {
	return array_find_last_impl(js, args, nargs, false, "findLast");
	}

	static jsval_t builtin_array_findLastIndex(struct js js, jsval_t args, int nargs) {
	return array_find_last_impl(js, args, nargs, true, "findLastIndex");
	}

	static jsval_t builtin_array_flatMap(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "flatMap called on non-array");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "flatMap requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t call_args[3] = { elem, tov((double)i), arr };
	jsval_t mapped = call_js_with_args(js, callback, call_args, 3);
	if (is_err(mapped)) return mapped;

	if (vtype(mapped) == T_ARR \|\| vtype(mapped) == T_OBJ) {
	jsoff_t m_off = lkp_interned(js, mapped, INTERN_LENGTH, 6);
	jsoff_t m_len = 0;
	if (m_off != 0) {
	jsval_t m_len_val = resolveprop(js, mkval(T_PROP, m_off));
	if (vtype(m_len_val) == T_NUM) m_len = (jsoff_t) tod(m_len_val);
	}
	for (jsoff_t j = 0; j < m_len; j++) {
	char jstr[16];
	snprintf(jstr, sizeof(jstr), "%u", (unsigned) j);
	jsoff_t m_elem_off = lkp(js, mapped, jstr, strlen(jstr));
	if (m_elem_off != 0) {
	jsval_t m_elem = resolveprop(js, mkval(T_PROP, m_elem_off));
	char res_idx[16];
	snprintf(res_idx, sizeof(res_idx), "%u", (unsigned) result_idx);
	jsval_t key = js_mkstr(js, res_idx, strlen(res_idx));
	setprop(js, result, key, m_elem);
	}
	result_idx++;
	}
	} else {
	char res_idx[16];
	snprintf(res_idx, sizeof(res_idx), "%u", (unsigned) result_idx);
	jsval_t key = js_mkstr(js, res_idx, strlen(res_idx));
	setprop(js, result, key, mapped);
	result_idx++;
	}
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) result_idx));
	return mkval(T_ARR, vdata(result));
	}

	static const char js_tostring(struct js js, jsval_t v) {
	if (vtype(v) == T_STR) {
	jsoff_t slen, off = vstr(js, v, &slen);
	return (const char *)&js->mem[off];
	}
	return js_str(js, v);
	}

	static int js_compare_values(struct js *js, jsval_t a, jsval_t b, jsval_t compareFn) {
	uint8_t t = vtype(compareFn);
	if (t == T_FUNC \|\| t == T_CFUNC) {
	jsval_t call_args[2] = { a, b };
	jsval_t result = call_js_with_args(js, compareFn, call_args, 2);
	if (vtype(result) == T_NUM) return (int)tod(result);
	return 0;
	}

	if (vtype(a) == T_STR && vtype(b) == T_STR) {
	jsoff_t len_a, len_b;
	const char sa = (const char )&js->mem[vstr(js, a, &len_a)];
	const char sb = (const char )&js->mem[vstr(js, b, &len_b)];
	return strcmp(sa, sb);
	}

	const char *sa = js_tostring(js, a);
	size_t len = strlen(sa);

	char *copy = alloca(len + 1);
	memcpy(copy, sa, len + 1);

	return strcmp(copy, js_tostring(js, b));
	}

	static jsval_t builtin_array_indexOf(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "indexOf called on non-array");
	}
	if (nargs == 0) return tov(-1);

	jsval_t search = args[0];
	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	jsoff_t start = 0;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	int s = (int) tod(args[1]);
	if (s < 0) s = (int)len + s;
	if (s < 0) s = 0;
	start = (jsoff_t) s;
	}

	for (jsoff_t i = start; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	if (vtype(elem) == vtype(search)) {
	if (vtype(elem) == T_NUM && tod(elem) == tod(search)) return tov((double)i);
	if (vtype(elem) == T_BOOL && vdata(elem) == vdata(search)) return tov((double)i);
	if (vtype(elem) == T_STR) {
	jsoff_t el, eo = vstr(js, elem, &el);
	jsoff_t sl, so = vstr(js, search, &sl);
	if (el == sl && memcmp(&js->mem[eo], &js->mem[so], el) == 0) return tov((double)i);
	}
	if ((vtype(elem) == T_OBJ \|\| vtype(elem) == T_ARR \|\| vtype(elem) == T_FUNC) && vdata(elem) == vdata(search)) return tov((double)i);
	}
	}
	}
	return tov(-1);
	}

	static jsval_t builtin_array_lastIndexOf(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "lastIndexOf called on non-array");
	}
	if (nargs == 0) return tov(-1);

	jsval_t search = args[0];
	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	int start = (int)len - 1;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	start = (int) tod(args[1]);
	if (start < 0) start = (int)len + start;
	}
	if (start >= (int)len) start = (int)len - 1;

	for (int i = start; i >= 0; i--) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	if (vtype(elem) == vtype(search)) {
	if (vtype(elem) == T_NUM && tod(elem) == tod(search)) return tov((double)i);
	if (vtype(elem) == T_BOOL && vdata(elem) == vdata(search)) return tov((double)i);
	if (vtype(elem) == T_STR) {
	jsoff_t el, eo = vstr(js, elem, &el);
	jsoff_t sl, so = vstr(js, search, &sl);
	if (el == sl && memcmp(&js->mem[eo], &js->mem[so], el) == 0) return tov((double)i);
	}
	if ((vtype(elem) == T_OBJ \|\| vtype(elem) == T_ARR \|\| vtype(elem) == T_FUNC) && vdata(elem) == vdata(search)) return tov((double)i);
	}
	}
	}
	return tov(-1);
	}

	static jsval_t builtin_array_reduceRight(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "reduceRight called on non-array");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "reduceRight requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	int start_idx = (int)len - 1;
	jsval_t accumulator;

	if (nargs >= 2) {
	accumulator = args[1];
	} else {
	if (len == 0) return js_mkerr(js, "reduceRight of empty array with no initial value");
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)(len - 1));
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	accumulator = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	start_idx = (int)len - 2;
	}

	for (int i = start_idx; i >= 0; i--) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t call_args[4] = { accumulator, elem, tov((double)i), arr };
	accumulator = call_js_with_args(js, callback, call_args, 4);
	if (is_err(accumulator)) return accumulator;
	}

	return accumulator;
	}

	static jsval_t builtin_array_shift(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "shift called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	if (len == 0) return js_mkundef();

	jsoff_t first_off = lkp(js, arr, "0", 1);
	jsval_t first = first_off ? resolveprop(js, mkval(T_PROP, first_off)) : js_mkundef();

	for (jsoff_t i = 1; i < len; i++) {
	char src[16], dst[16];
	snprintf(src, sizeof(src), "%u", (unsigned) i);
	snprintf(dst, sizeof(dst), "%u", (unsigned)(i - 1));
	jsoff_t elem_off = lkp(js, arr, src, strlen(src));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t key = js_mkstr(js, dst, strlen(dst));
	setprop(js, arr, key, elem);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, tov((double)(len - 1)));
	js->needs_gc = true;
	return first;
	}

	static jsval_t builtin_array_unshift(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "unshift called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	for (int i = (int)len - 1; i >= 0; i--) {
	char src[16], dst[16];
	snprintf(src, sizeof(src), "%u", (unsigned) i);
	snprintf(dst, sizeof(dst), "%u", (unsigned)(i + nargs));
	jsoff_t elem_off = lkp(js, arr, src, strlen(src));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t key = js_mkstr(js, dst, strlen(dst));
	setprop(js, arr, key, elem);
	}

	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, arr, key, args[i]);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	jsoff_t new_len = len + nargs;
	setprop(js, arr, len_key, tov((double) new_len));
	return tov((double) new_len);
	}

	static jsval_t builtin_array_some(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "some called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "some");
	if (is_err(callback)) return callback;

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return mkval(T_BOOL, 0);

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx)) continue;

	jsval_t call_args[3] = { val, tov((double)parsed_idx), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);

	if (is_err(result)) {
	js_prop_iter_end(&iter);
	return result;
	}
	if (js_truthy(js, result)) {
	js_prop_iter_end(&iter);
	return mkval(T_BOOL, 1);
	}
	}
	js_prop_iter_end(&iter);

	return mkval(T_BOOL, 0);
	}

	static jsval_t builtin_array_sort(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	jsval_t compareFn = js_mkundef();
	jsval_t vals = NULL, keys = NULL, temp_vals = NULL, temp_keys = NULL;
	jsoff_t *offs = NULL;
	jsoff_t count = 0, undef_count = 0, len = 0;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "sort called on non-array");

	if (nargs >= 1) {
	uint8_t t = vtype(args[0]);
	if (t == T_FUNC \|\| t == T_CFUNC) compareFn = args[0];
	else if (t != T_UNDEF) return js_mkerr_typed(js, JS_ERR_TYPE, "compareFn must be a function or undefined");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return arr;

	vals = malloc(len * sizeof(jsval_t));
	offs = malloc(len * sizeof(jsoff_t));
	if (!vals \|\| !offs) goto oom;

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	if (key_len == 0 \|\| key[0] > '9' \|\| key[0] < '0') continue;

	unsigned idx = 0;
	bool valid = true;
	for (size_t i = 0; i < key_len && valid; i++) {
	if (key[i] < '0' \|\| key[i] > '9') valid = false;
	else idx = idx * 10 + (key[i] - '0');
	}
	if (!valid \|\| idx >= len \|\| (count + undef_count) >= len) continue;

	offs[count + undef_count] = iter.off;
	if (vtype(val) == T_UNDEF) undef_count++;
	else vals[count++] = val;
	}

	js_prop_iter_end(&iter);
	if (count <= 1) goto writeback;

	bool use_keys = (vtype(compareFn) == T_UNDEF);
	if (use_keys) {
	keys = malloc(count * sizeof(jsval_t));
	if (!keys) goto oom;
	for (jsoff_t i = 0; i < count; i++) {
	const char *s = js_tostring(js, vals[i]);
	keys[i] = js_mkstr(js, s, strlen(s));
	}
	}

	temp_vals = malloc(count * sizeof(jsval_t));
	if (use_keys) temp_keys = malloc(count * sizeof(jsval_t));
	if (!temp_vals \|\| (use_keys && !temp_keys)) goto oom;

	for (jsoff_t width = 1; width < count; width *= 2) {
	for (jsoff_t left = 0; left < count; left += width * 2) {
	jsoff_t mid = left + width;
	jsoff_t right = (mid + width < count) ? mid + width : count;
	if (mid >= count) break;

	jsoff_t i = left, j = mid, k = 0;
	while (i < mid && j < right) {
	int cmp;
	if (use_keys) {
	jsoff_t len_a, len_b;
	const char sa = (const char )&js->mem[vstr(js, keys[i], &len_a)];
	const char sb = (const char )&js->mem[vstr(js, keys[j], &len_b)];
	cmp = strcmp(sa, sb);
	} else {
	cmp = js_compare_values(js, vals[i], vals[j], compareFn);
	}
	if (cmp <= 0) {
	temp_vals[k] = vals[i];
	if (use_keys) temp_keys[k] = keys[i];
	k++; i++;
	} else {
	temp_vals[k] = vals[j];
	if (use_keys) temp_keys[k] = keys[j];
	k++; j++;
	}
	}
	while (i < mid) {
	temp_vals[k] = vals[i];
	if (use_keys) temp_keys[k] = keys[i];
	k++; i++;
	}
	while (j < right) {
	temp_vals[k] = vals[j];
	if (use_keys) temp_keys[k] = keys[j];
	k++; j++;
	}

	memcpy(&vals[left], temp_vals, k * sizeof(jsval_t));
	if (use_keys) memcpy(&keys[left], temp_keys, k * sizeof(jsval_t));
	}
	}

	writeback:
	for (jsoff_t i = 0; i < count; i++)
	saveval(js, offs[i] + sizeof(jsoff_t) * 2, vals[i]);
	for (jsoff_t i = 0; i < undef_count; i++)
	saveval(js, offs[count + i] + sizeof(jsoff_t) * 2, js_mkundef());

	free(temp_keys);
	free(temp_vals);
	free(keys);
	free(vals);
	free(offs);
	return arr;

	oom:
	free(temp_keys);
	free(temp_vals);
	free(keys);
	free(vals);
	free(offs);
	return js_mkerr(js, "out of memory");
	}

	static jsval_t builtin_array_splice(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "splice called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	int start = 0;
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	start = (int) tod(args[0]);
	if (start < 0) start = (int)len + start;
	if (start < 0) start = 0;
	if (start > (int)len) start = (int)len;
	}

	int deleteCount = (int)len - start;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	deleteCount = (int) tod(args[1]);
	if (deleteCount < 0) deleteCount = 0;
	if (deleteCount > (int)len - start) deleteCount = (int)len - start;
	}

	int insertCount = nargs > 2 ? nargs - 2 : 0;

	jsval_t removed = mkarr(js);
	if (is_err(removed)) return removed;

	for (int i = 0; i < deleteCount; i++) {
	char src[16], dst[16];
	snprintf(src, sizeof(src), "%u", (unsigned)(start + i));
	snprintf(dst, sizeof(dst), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, src, strlen(src));
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	jsval_t key = js_mkstr(js, dst, strlen(dst));
	setprop(js, removed, key, elem);
	}
	}
	jsval_t rem_len_key = js_mkstr(js, "length", 6);
	setprop(js, removed, rem_len_key, tov((double) deleteCount));

	int shift = insertCount - deleteCount;
	if (shift > 0) {
	for (int i = (int)len - 1; i >= start + deleteCount; i--) {
	char src[16], dst[16];
	snprintf(src, sizeof(src), "%u", (unsigned) i);
	snprintf(dst, sizeof(dst), "%u", (unsigned)(i + shift));
	jsoff_t elem_off = lkp(js, arr, src, strlen(src));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t key = js_mkstr(js, dst, strlen(dst));
	setprop(js, arr, key, elem);
	}
	} else if (shift < 0) {
	for (int i = start + deleteCount; i < (int)len; i++) {
	char src[16], dst[16];
	snprintf(src, sizeof(src), "%u", (unsigned) i);
	snprintf(dst, sizeof(dst), "%u", (unsigned)(i + shift));
	jsoff_t elem_off = lkp(js, arr, src, strlen(src));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t key = js_mkstr(js, dst, strlen(dst));
	setprop(js, arr, key, elem);
	}
	}

	for (int i = 0; i < insertCount; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)(start + i));
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, arr, key, args[2 + i]);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, tov((double)((int)len + shift)));
	if (deleteCount > 0) js->needs_gc = true;
	return mkval(T_ARR, vdata(removed));
	}

	static jsval_t builtin_array_copyWithin(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "copyWithin called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	int target = 0, start = 0, end = (int)len;
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	target = (int) tod(args[0]);
	if (target < 0) target = (int)len + target;
	if (target < 0) target = 0;
	}
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	start = (int) tod(args[1]);
	if (start < 0) start = (int)len + start;
	if (start < 0) start = 0;
	}
	if (nargs >= 3 && vtype(args[2]) == T_NUM) {
	end = (int) tod(args[2]);
	if (end < 0) end = (int)len + end;
	if (end < 0) end = 0;
	}
	if (end > (int)len) end = (int)len;

	int count = end - start;
	if (count > (int)len - target) count = (int)len - target;

	jsval_t temp = (jsval_t )malloc(count * sizeof(jsval_t));
	for (int i = 0; i < count; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)(start + i));
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	temp[i] = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	}

	for (int i = 0; i < count; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)(target + i));
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, arr, key, temp[i]);
	}

	free(temp);
	return arr;
	}

	static jsval_t builtin_array_toSorted(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "toSorted called on non-array");

	jsval_t result = array_shallow_copy(js, arr, get_array_length(js, arr));
	if (is_err(result)) return result;

	jsval_t saved_this = js->this_val;
	js->this_val = result;
	jsval_t sorted = builtin_array_sort(js, args, nargs);
	js->this_val = saved_this;

	if (is_err(sorted)) return sorted;
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_toReversed(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "toReversed called on non-array");

	jsval_t result = array_shallow_copy(js, arr, get_array_length(js, arr));
	if (is_err(result)) return result;

	jsval_t saved_this = js->this_val;
	js->this_val = result;
	jsval_t reversed = builtin_array_reverse(js, NULL, 0);
	js->this_val = saved_this;

	if (is_err(reversed)) return reversed;
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_toSpliced(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "toSpliced called on non-array");

	jsval_t result = array_shallow_copy(js, arr, get_array_length(js, arr));
	if (is_err(result)) return result;

	jsval_t saved_this = js->this_val;
	js->this_val = result;
	builtin_array_splice(js, args, nargs);
	js->this_val = saved_this;

	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_with(struct js js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "with called on non-array");
	}

	if (nargs < 2) return js_mkerr(js, "with requires index and value arguments");

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	int idx = (int) tod(args[0]);
	if (idx < 0) idx = (int)len + idx;
	if (idx < 0 \|\| (jsoff_t)idx >= len) return js_mkerr(js, "Invalid index");

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t elem;
	if ((jsoff_t)idx == i) {
	elem = args[1];
	} else {
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	}
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, result, key, elem);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) len));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_keys(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "keys called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, result, key, tov((double) i));
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) len));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_values(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "values called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, result, key, elem);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) len));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_entries(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "entries called on non-array");
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	for (jsoff_t i = 0; i < len; i++) {
	jsval_t entry = mkarr(js);
	if (is_err(entry)) return entry;

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idxstr, idxlen);
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();

	setprop(js, entry, js_mkstr(js, "0", 1), tov((double) i));
	setprop(js, entry, js_mkstr(js, "1", 1), elem);
	setprop(js, entry, js_mkstr(js, "length", 6), tov(2));

	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, result, key, mkval(T_ARR, vdata(entry)));
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) len));
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_toString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;
	jsval_t sep_args[1] = { js_mkstr(js, ",", 1) };
	jsval_t old_this = js->this_val;
	js->this_val = arr;
	jsval_t result = builtin_array_join(js, sep_args, 1);
	js->this_val = old_this;
	return result;
	}

	static jsval_t builtin_array_toLocaleString(struct js js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR) return js_mkerr(js, "toLocaleString called on non-array");

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t)tod(len_val);
	}
	if (len == 0) return js_mkstr(js, "", 0);

	char *result = NULL;
	size_t result_len = 0, result_cap = 256;
	result = (char *)ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");

	for (jsoff_t i = 0; i < len; i++) {
	if (i > 0) {
	if (result_len + 1 >= result_cap) {
	result_cap *= 2;
	char new_result = (char )ant_calloc(result_cap);
	if (!new_result) { free(result); return js_mkerr(js, "oom"); }
	memcpy(new_result, result, result_len);
	free(result);
	result = new_result;
	}
	result[result_len++] = ',';
	}

	char idx_str[16];
	snprintf(idx_str, sizeof(idx_str), "%u", (unsigned)i);
	jsoff_t elem_off = lkp(js, arr, idx_str, strlen(idx_str));
	if (elem_off == 0) continue;

	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	if (vtype(elem) == T_NULL \|\| vtype(elem) == T_UNDEF) continue;

	char buf[64];
	size_t elem_len = tostr(js, elem, buf, sizeof(buf));

	if (result_len + elem_len >= result_cap) {
	while (result_len + elem_len >= result_cap) result_cap *= 2;
	char new_result = (char )ant_calloc(result_cap);
	if (!new_result) { free(result); return js_mkerr(js, "oom"); }
	memcpy(new_result, result, result_len);
	free(result);
	result = new_result;
	}
	memcpy(result + result_len, buf, elem_len);
	result_len += elem_len;
	}

	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	}

	static jsval_t builtin_Array_isArray(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs == 0) return mkval(T_BOOL, 0);
	return mkval(T_BOOL, vtype(args[0]) == T_ARR ? 1 : 0);
	}

	static jsval_t builtin_Array_from(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkarr(js);

	jsval_t src = args[0];
	jsval_t mapFn = (nargs >= 2 && vtype(args[1]) == T_FUNC) ? args[1] : js_mkundef();

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	if (vtype(src) == T_STR) {
	jsoff_t str_len, str_off = vstr(js, src, &str_len);
	const char str_ptr = (const char )&js->mem[str_off];
	for (jsoff_t i = 0; i < str_len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t elem = js_mkstr(js, str_ptr + i, 1);
	if (vtype(mapFn) == T_FUNC) {
	jsval_t call_args[2] = { elem, tov((double)i) };
	elem = call_js_with_args(js, mapFn, call_args, 2);
	if (is_err(elem)) return elem;
	}
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, result, key, elem);
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) str_len));
	} else if (vtype(src) == T_ARR \|\| vtype(src) == T_OBJ) {
	jsoff_t off = lkp_interned(js, src, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}
	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsoff_t elem_off = lkp(js, src, idxstr, idxlen);
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	if (vtype(mapFn) == T_FUNC) {
	jsval_t call_args[2] = { elem, tov((double)i) };
	elem = call_js_with_args(js, mapFn, call_args, 2);
	if (is_err(elem)) return elem;
	}
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, result, key, elem);
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) len));
	}

	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_Array_of(struct js js, jsval_t args, int nargs) {
	jsval_t arr = mkarr(js);
	if (is_err(arr)) return arr;

	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, arr, key, args[i]);
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, tov((double) nargs));
	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_string_indexOf(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "indexOf called on non-string");
	if (nargs == 0) return tov(-1);

	jsval_t search = args[0];
	if (vtype(search) != T_STR) return tov(-1);

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);

	jsoff_t start = 0;
	double dstr_len = D(str_len);
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double pos = tod(args[1]);
	if (pos < 0) pos = 0;
	if (pos > dstr_len) pos = dstr_len;
	start = (jsoff_t) pos;
	}

	if (search_len == 0) return tov(D(start));
	if (start + search_len > str_len) return tov(-1);

	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	for (jsoff_t i = start; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) return tov(D(i));
	}
	return tov(-1);
	}

	static jsval_t builtin_string_substring(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "substring called on non-string");
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	jsoff_t start = 0, end = str_len;
	double dstr_len2 = D(str_len);

	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	double d = tod(args[0]);
	start = (jsoff_t) (d < 0 ? 0 : (d > dstr_len2 ? dstr_len2 : d));
	}

	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	end = (jsoff_t) (d < 0 ? 0 : (d > dstr_len2 ? dstr_len2 : d));
	}

	if (start > end) {
	jsoff_t tmp = start;
	start = end;
	end = tmp;
	}

	jsoff_t sub_len = end - start;
	return js_mkstr(js, str_ptr + start, sub_len);
	}

	static jsval_t builtin_string_substr(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "substr called on non-string");
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	if (nargs < 1) return js_mkstr(js, str_ptr, str_len);

	double d_start = tod(args[0]);
	jsoff_t start;
	if (d_start < 0) {
	start = (jsoff_t)((double)str_len + d_start);
	if ((int)start < 0) start = 0;
	} else {
	start = (jsoff_t)d_start;
	}
	if (start > str_len) start = str_len;

	jsoff_t len = str_len - start;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d < 0) d = 0;
	len = (jsoff_t)d;
	}
	if (start + len > str_len) len = str_len - start;

	return js_mkstr(js, str_ptr + start, len);
	}

	static jsval_t builtin_string_split(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "split called on non-string");
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	jsval_t arr = mkarr(js);

	if (is_err(arr)) return arr;

	uint32_t limit = UINT32_MAX;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d >= 0 && d <= UINT32_MAX) {
	limit = (uint32_t)d;
	}
	}
	if (limit == 0) {
	setprop(js, arr, js_mkstr(js, "length", 6), tov(0));
	return mkval(T_ARR, vdata(arr));
	}
	if (nargs == 0) goto return_whole;

	jsval_t sep_arg = args[0];
	if (vtype(sep_arg) == T_OBJ) {
	jsoff_t source_off = lkp(js, sep_arg, "source", 6);
	if (source_off == 0) goto return_whole;
	jsval_t source_val = resolveprop(js, mkval(T_PROP, source_off));
	if (vtype(source_val) != T_STR) goto return_whole;

	jsoff_t plen, poff = vstr(js, source_val, &plen);
	const char pattern_ptr = (char ) &js->mem[poff];

	if (plen == 0 \|\| (plen == 4 && memcmp(pattern_ptr, "(?:)", 4) == 0)) {
	jsoff_t idx = 0;
	for (jsoff_t i = 0; i < str_len && idx < limit; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t part = js_mkstr(js, str_ptr + i, 1);
	setprop(js, arr, key, part);
	idx++;
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, tov((double)idx));
	return mkval(T_ARR, vdata(arr));
	}

	char pcre2_pattern[512];
	size_t pcre2_len = js_to_pcre2_pattern(pattern_ptr, plen, pcre2_pattern, sizeof(pcre2_pattern));

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	if (re == NULL) goto return_whole;

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	uint32_t capture_count;
	pcre2_pattern_info(re, PCRE2_INFO_CAPTURECOUNT, &capture_count);

	if (str_len == 0) {
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, 0, 0, 0, match_data, NULL);
	if (rc >= 0) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	setprop(js, arr, js_mkstr(js, "length", 6), tov(0));
	return mkval(T_ARR, vdata(arr));
	}
	}

	jsoff_t idx = 0;
	PCRE2_SIZE search_pos = 0;
	PCRE2_SIZE segment_start = 0;
	PCRE2_SIZE last_match_end = (PCRE2_SIZE)-1;
	bool had_any_split = false;

	while (idx < limit && search_pos <= str_len) {
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, search_pos, 0, match_data, NULL);
	if (rc < 0) break;

	PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
	PCRE2_SIZE match_start = ovector[0];
	PCRE2_SIZE match_end = ovector[1];

	if (match_start == match_end && match_start == last_match_end) {
	search_pos = match_end + 1;
	continue;
	}

	if (match_start == match_end && capture_count > 0) {
	bool is_pure_empty_capture = true;
	for (uint32_t i = 1; i <= capture_count; i++) {
	PCRE2_SIZE cap_start = ovector[2*i];
	PCRE2_SIZE cap_end = ovector[2*i+1];
	if (cap_start == PCRE2_UNSET \|\| cap_end != cap_start) {
	is_pure_empty_capture = false;
	break;
	}
	}
	if (is_pure_empty_capture) {
	search_pos = match_end + 1;
	continue;
	}
	}

	had_any_split = true;

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t part = js_mkstr(js, str_ptr + segment_start, match_start - segment_start);
	setprop(js, arr, key, part);
	idx++;

	for (uint32_t i = 1; i <= capture_count && idx < limit; i++) {
	PCRE2_SIZE cap_start = ovector[2*i];
	PCRE2_SIZE cap_end = ovector[2*i+1];
	size_t cap_idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	key = js_mkstr(js, idxstr, cap_idxlen);
	if (cap_start == PCRE2_UNSET) {
	setprop(js, arr, key, js_mkundef());
	} else {
	part = js_mkstr(js, str_ptr + cap_start, cap_end - cap_start);
	setprop(js, arr, key, part);
	}
	idx++;
	}

	last_match_end = match_end;
	segment_start = match_end;
	if (match_start == match_end) {
	search_pos = match_end + 1;
	} else {
	search_pos = match_end;
	}
	}

	if (!had_any_split) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	setprop(js, arr, js_mkstr(js, "0", 1), js_mkstr(js, str_ptr, str_len));
	setprop(js, arr, js_mkstr(js, "length", 6), tov(1));
	return mkval(T_ARR, vdata(arr));
	}

	if (idx < limit) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t part = js_mkstr(js, str_ptr + segment_start, str_len - segment_start);
	setprop(js, arr, key, part);
	idx++;
	}

	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, tov((double)idx));
	return mkval(T_ARR, vdata(arr));
	}

	if (vtype(sep_arg) != T_STR) goto return_whole;

	jsoff_t sep_len, sep_off = vstr(js, sep_arg, &sep_len);
	const char sep_ptr = (char ) &js->mem[sep_off];
	jsoff_t idx = 0, start = 0;

	if (sep_len == 0) {
	for (jsoff_t i = 0; i < str_len && idx < limit; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t part = js_mkstr(js, str_ptr + i, 1);
	setprop(js, arr, key, part);
	idx++;
	}
	goto set_length;
	}

	for (jsoff_t i = 0; i + sep_len <= str_len && idx < limit; i++) {
	if (memcmp(str_ptr + i, sep_ptr, sep_len) != 0) continue;
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t part = js_mkstr(js, str_ptr + start, i - start);
	setprop(js, arr, key, part);
	idx++;
	start = i + sep_len;
	i += sep_len - 1;
	}
	if (idx < limit && start <= str_len) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	jsval_t part = js_mkstr(js, str_ptr + start, str_len - start);
	setprop(js, arr, key, part);
	idx++;
	}

	set_length:;
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, tov((double) idx));
	return mkval(T_ARR, vdata(arr));

	return_whole:
	if (limit > 0) {
	setprop(js, arr, js_mkstr(js, "0", 1), str);
	setprop(js, arr, js_mkstr(js, "length", 6), tov(1));
	} else {
	setprop(js, arr, js_mkstr(js, "length", 6), tov(0));
	}
	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_string_slice(struct js js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	jsoff_t start = 0, end = str_len;
	double dstr_len = D(str_len);

	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	double d = tod(args[0]);
	if (d < 0) {
	start = (jsoff_t) (d + dstr_len < 0 ? 0 : d + dstr_len);
	} else {
	start = (jsoff_t) (d > dstr_len ? dstr_len : d);
	}
	}
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d < 0) {
	end = (jsoff_t) (d + dstr_len < 0 ? 0 : d + dstr_len);
	} else {
	end = (jsoff_t) (d > dstr_len ? dstr_len : d);
	}
	}

	if (start > end) start = end;
	jsoff_t sub_len = end - start;
	return js_mkstr(js, str_ptr + start, sub_len);
	}

	static jsval_t builtin_string_includes(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "includes called on non-string");
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	if (vtype(search) != T_STR) return mkval(T_BOOL, 0);
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	jsoff_t start = 0;
	if (nargs >= 2) {
	double pos = tod(args[1]);
	if (isnan(pos) \|\| pos < 0) pos = 0;
	if (pos > D(str_len)) return mkval(T_BOOL, 0);
	start = (jsoff_t) pos;
	}

	if (search_len == 0) return mkval(T_BOOL, 1);
	if (start + search_len > str_len) return mkval(T_BOOL, 0);
	for (jsoff_t i = start; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) {
	return mkval(T_BOOL, 1);
	}
	}

	return mkval(T_BOOL, 0);
	}

	static jsval_t builtin_string_startsWith(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "startsWith called on non-string");
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	if (vtype(search) != T_STR) return mkval(T_BOOL, 0);
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	if (search_len > str_len) return mkval(T_BOOL, 0);
	if (search_len == 0) return mkval(T_BOOL, 1);

	return mkval(T_BOOL, memcmp(str_ptr, search_ptr, search_len) == 0 ? 1 : 0);
	}

	static jsval_t builtin_string_endsWith(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "endsWith called on non-string");
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	if (vtype(search) != T_STR) return mkval(T_BOOL, 0);
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);

	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	if (search_len > str_len) return mkval(T_BOOL, 0);
	if (search_len == 0) return mkval(T_BOOL, 1);

	return mkval(T_BOOL, memcmp(str_ptr + str_len - search_len, search_ptr, search_len) == 0 ? 1 : 0);
	}

	static jsval_t builtin_string_replace(struct js js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;
	if (nargs < 2) return str;

	jsval_t search = args[0];
	jsval_t replacement = args[1];

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	bool is_regex = false;
	bool global_flag = false;
	bool is_func_replacement = (vtype(replacement) == T_FUNC);
	char *pattern_buf = NULL;
	jsoff_t pattern_len = 0;

	if (vtype(search) == T_OBJ) {
	jsoff_t pattern_off = lkp(js, search, "source", 6);
	if (pattern_off == 0) goto not_regex;

	jsval_t pattern_val = resolveprop(js, mkval(T_PROP, pattern_off));
	if (vtype(pattern_val) != T_STR) goto not_regex;

	is_regex = true;
	jsoff_t plen, poff = vstr(js, pattern_val, &plen);
	pattern_len = plen;
	pattern_buf = (char *)ant_calloc(plen + 1);
	if (!pattern_buf) return js_mkerr(js, "oom");
	memcpy(pattern_buf, &js->mem[poff], plen);
	pattern_buf[plen] = '\0';

	jsoff_t flags_off = lkp(js, search, "flags", 5);
	if (flags_off == 0) { free(pattern_buf); pattern_buf = NULL; goto not_regex; }

	jsval_t flags_val = resolveprop(js, mkval(T_PROP, flags_off));
	if (vtype(flags_val) != T_STR) { free(pattern_buf); pattern_buf = NULL; goto not_regex; }

	jsoff_t flen, foff = vstr(js, flags_val, &flen);
	const char flags_str = (char ) &js->mem[foff];
	for (jsoff_t i = 0; i < flen; i++) {
	if (flags_str[i] == 'g') global_flag = true;
	}
	}
	not_regex:

	jsoff_t repl_len = 0;
	const char *repl_ptr = NULL;
	if (!is_func_replacement) {
	if (vtype(replacement) != T_STR) { if (pattern_buf) free(pattern_buf); return str; }
	jsoff_t repl_off;
	repl_off = vstr(js, replacement, &repl_len);
	repl_ptr = (char *) &js->mem[repl_off];
	}

	size_t result_cap = str_len + repl_len + 256;
	size_t result_len = 0;
	char result = (char )ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");

	#define ENSURE_RESULT_CAP(need) do { \
	if (result_len + (need) >= result_cap) { \
	result_cap = (result_len + (need) + 1) * 2; \
	char nr = (char )ant_realloc(result, result_cap); \
	if (!nr) return js_mkerr(js, "oom"); \
	result = nr; \
	} \
	} while(0)

	if (is_regex) {
	size_t pcre2_cap = pattern_len * 2 + 16;
	char pcre2_pattern = (char )ant_calloc(pcre2_cap);
	if (!pcre2_pattern) return js_mkerr(js, "oom");
	size_t pcre2_len = js_to_pcre2_pattern(pattern_buf, pattern_len, pcre2_pattern, pcre2_cap);

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	free(pcre2_pattern);
	if (re == NULL) return js_mkerr(js, "invalid regex pattern");

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	uint32_t capture_count;
	pcre2_pattern_info(re, PCRE2_INFO_CAPTURECOUNT, &capture_count);

	PCRE2_SIZE pos = 0;
	bool replaced = false;

	while (pos <= str_len) {
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, pos, 0, match_data, NULL);
	if (rc < 0) break;

	PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
	PCRE2_SIZE match_start = ovector[0];
	PCRE2_SIZE match_end = ovector[1];

	PCRE2_SIZE before_len = match_start - pos;
	ENSURE_RESULT_CAP(before_len);
	memcpy(result + result_len, str_ptr + pos, before_len);
	result_len += before_len;

	if (is_func_replacement) {
	int nargs_cb = 1 + capture_count + 2;
	jsval_t cb_args = (jsval_t )ant_calloc(nargs_cb * sizeof(jsval_t));
	if (!cb_args) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return js_mkerr(js, "oom");
	}
	cb_args[0] = js_mkstr(js, str_ptr + match_start, match_end - match_start);
	for (uint32_t i = 1; i <= capture_count; i++) {
	PCRE2_SIZE cap_start = ovector[2*i];
	PCRE2_SIZE cap_end = ovector[2*i+1];
	if (cap_start == PCRE2_UNSET) {
	cb_args[i] = js_mkundef();
	} else {
	cb_args[i] = js_mkstr(js, str_ptr + cap_start, cap_end - cap_start);
	}
	}
	cb_args[1 + capture_count] = tov((double)match_start);
	cb_args[2 + capture_count] = str;

	jsval_t cb_result = js_call(js, replacement, cb_args, nargs_cb);
	free(cb_args);

	if (vtype(cb_result) == T_ERR) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return cb_result;
	}

	if (vtype(cb_result) == T_STR) {
	jsoff_t cb_len, cb_off = vstr(js, cb_result, &cb_len);
	ENSURE_RESULT_CAP(cb_len);
	memcpy(result + result_len, &js->mem[cb_off], cb_len);
	result_len += cb_len;
	} else {
	char numbuf[32];
	size_t n = tostr(js, cb_result, numbuf, sizeof(numbuf));
	ENSURE_RESULT_CAP(n);
	memcpy(result + result_len, numbuf, n);
	result_len += n;
	}
	} else {
	for (jsoff_t ri = 0; ri < repl_len; ) {
	if (repl_ptr[ri] == '$' && ri + 1 < repl_len) {
	char next = repl_ptr[ri + 1];
	if (next == '$') {
	ENSURE_RESULT_CAP(1);
	result[result_len++] = '$';
	ri += 2;
	} else if (next == '&') {
	PCRE2_SIZE mlen = match_end - match_start;
	ENSURE_RESULT_CAP(mlen);
	memcpy(result + result_len, str_ptr + match_start, mlen);
	result_len += mlen;
	ri += 2;
	} else if (next == '`') {
	ENSURE_RESULT_CAP(match_start);
	memcpy(result + result_len, str_ptr, match_start);
	result_len += match_start;
	ri += 2;
	} else if (next == '\'') {
	PCRE2_SIZE after_len = str_len - match_end;
	ENSURE_RESULT_CAP(after_len);
	memcpy(result + result_len, str_ptr + match_end, after_len);
	result_len += after_len;
	ri += 2;
	} else if (next >= '0' && next <= '9') {
	int group_num = next - '0';
	ri += 2;
	if (ri < repl_len && repl_ptr[ri] >= '0' && repl_ptr[ri] <= '9') {
	int second_digit = repl_ptr[ri] - '0';
	int two_digit = group_num * 10 + second_digit;
	if (two_digit <= (int)capture_count) {
	group_num = two_digit;
	ri++;
	}
	}
	if (group_num > 0 && group_num <= (int)capture_count) {
	PCRE2_SIZE cap_start = ovector[2*group_num];
	PCRE2_SIZE cap_end = ovector[2*group_num+1];
	if (cap_start != PCRE2_UNSET) {
	PCRE2_SIZE cap_len = cap_end - cap_start;
	ENSURE_RESULT_CAP(cap_len);
	memcpy(result + result_len, str_ptr + cap_start, cap_len);
	result_len += cap_len;
	}
	} else {
	ENSURE_RESULT_CAP(2);
	result[result_len++] = '$';
	result[result_len++] = next;
	}
	} else {
	ENSURE_RESULT_CAP(1);
	result[result_len++] = repl_ptr[ri++];
	}
	} else {
	ENSURE_RESULT_CAP(1);
	result[result_len++] = repl_ptr[ri++];
	}
	}
	}

	if (match_start == match_end) {
	if (pos < str_len) {
	ENSURE_RESULT_CAP(1);
	result[result_len++] = str_ptr[pos];
	}
	pos = match_end + 1;
	} else pos = match_end;

	replaced = true;
	if (!global_flag) break;
	}

	if (pos < str_len) {
	size_t remaining = str_len - pos;
	ENSURE_RESULT_CAP(remaining);
	memcpy(result + result_len, str_ptr + pos, remaining);
	result_len += remaining;
	}

	pcre2_match_data_free(match_data); pcre2_code_free(re);
	if (pattern_buf) free(pattern_buf);

	jsval_t ret = replaced ? js_mkstr(js, result, result_len) : str;
	free(result); return ret;
	} else {
	if (vtype(search) != T_STR) { free(result); return str; }
	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	const char search_ptr = (char ) &js->mem[search_off];

	if (search_len > str_len) { free(result); return str; }

	for (jsoff_t i = 0; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) {
	ENSURE_RESULT_CAP(i);
	memcpy(result + result_len, str_ptr, i);
	result_len += i;

	if (is_func_replacement) {
	jsval_t match_str = js_mkstr(js, search_ptr, search_len);
	jsval_t cb_args[1] = { match_str };
	jsval_t cb_result = js_call(js, replacement, cb_args, 1);

	if (vtype(cb_result) == T_ERR) { free(result); return cb_result; }

	if (vtype(cb_result) == T_STR) {
	jsoff_t cb_len, cb_off = vstr(js, cb_result, &cb_len);
	ENSURE_RESULT_CAP(cb_len);
	memcpy(result + result_len, &js->mem[cb_off], cb_len);
	result_len += cb_len;
	} else {
	char numbuf[32];
	size_t n = tostr(js, cb_result, numbuf, sizeof(numbuf));
	ENSURE_RESULT_CAP(n);
	memcpy(result + result_len, numbuf, n);
	result_len += n;
	}
	} else {
	ENSURE_RESULT_CAP(repl_len);
	memcpy(result + result_len, repl_ptr, repl_len);
	result_len += repl_len;
	}

	jsoff_t after_start = i + search_len;
	jsoff_t after_len = str_len - after_start;
	if (after_len > 0) {
	ENSURE_RESULT_CAP(after_len);
	memcpy(result + result_len, str_ptr + after_start, after_len);
	result_len += after_len;
	}
	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	}
	}
	free(result);
	return str;
	}
	#undef ENSURE_RESULT_CAP
	}

	static jsval_t builtin_string_replaceAll(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "replaceAll called on non-string");
	if (nargs < 2) return str;

	jsval_t search = args[0];
	jsval_t replacement = args[1];

	if (vtype(search) != T_STR) return js_mkerr(js, "replaceAll requires string search pattern");
	if (vtype(replacement) != T_STR) return js_mkerr(js, "replaceAll requires string replacement");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	const char search_ptr = (char ) &js->mem[search_off];

	jsoff_t repl_len, repl_off = vstr(js, replacement, &repl_len);
	const char repl_ptr = (char ) &js->mem[repl_off];

	if (search_len == 0) {
	size_t total_len = str_len + (str_len + 1) * repl_len;
	char result = (char )ant_calloc(total_len + 1);
	if (!result) return js_mkerr(js, "oom");

	size_t pos = 0;
	memcpy(result + pos, repl_ptr, repl_len);
	pos += repl_len;
	for (jsoff_t i = 0; i < str_len; i++) {
	result[pos++] = str_ptr[i];
	memcpy(result + pos, repl_ptr, repl_len);
	pos += repl_len;
	}
	jsval_t ret = js_mkstr(js, result, pos);
	free(result);
	return ret;
	}

	jsoff_t count = 0;
	for (jsoff_t i = 0; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) {
	count++;
	i += search_len - 1;
	}
	}

	if (count == 0) return str;

	size_t result_total = str_len - (count * search_len) + (count * repl_len);
	char result = (char )ant_calloc(result_total + 1);
	if (!result) return js_mkerr(js, "oom");

	size_t result_pos = 0;
	jsoff_t str_pos = 0;

	while (str_pos <= str_len - search_len) {
	if (memcmp(str_ptr + str_pos, search_ptr, search_len) == 0) {
	memcpy(result + result_pos, repl_ptr, repl_len);
	result_pos += repl_len;
	str_pos += search_len;
	} else {
	result[result_pos++] = str_ptr[str_pos++];
	}
	}

	while (str_pos < str_len) {
	result[result_pos++] = str_ptr[str_pos++];
	}

	jsval_t ret = js_mkstr(js, result, result_pos);
	free(result);
	return ret;
	}

	static size_t js_to_pcre2_pattern(const char src, size_t src_len, char dst, size_t dst_size) {
	size_t di = 0;
	for (size_t si = 0; si < src_len && di < dst_size - 1; si++) {
	if (src[si] == '\\' && si + 1 < src_len) {
	char next = src[si + 1];

	if (next == 'u' && si + 5 < src_len) {
	bool valid = true;
	for (int i = 0; i < 4; i++) {
	char c = src[si + 2 + i];
	if (!((c >= '0' && c <= '9') \|\| (c >= 'a' && c <= 'f') \|\| (c >= 'A' && c <= 'F'))) {
	valid = false;
	break;
	}
	}
	if (valid && di + 8 < dst_size) {
	dst[di++] = '\\';
	dst[di++] = 'x';
	dst[di++] = '{';
	dst[di++] = src[si + 2];
	dst[di++] = src[si + 3];
	dst[di++] = src[si + 4];
	dst[di++] = src[si + 5];
	dst[di++] = '}';
	si += 5;
	continue;
	}
	}

	if (next == '0' && (si + 2 >= src_len \|\| src[si + 2] < '0' \|\| src[si + 2] > '9')) {
	if (di + 5 < dst_size) {
	dst[di++] = '\\';
	dst[di++] = 'x';
	dst[di++] = '{';
	dst[di++] = '0';
	dst[di++] = '}';
	si += 1;
	continue;
	}
	}
	}
	dst[di++] = src[si];
	}
	dst[di] = '\0';
	return di;
	}

	static jsval_t do_regex_match_pcre2(
	struct js js, const char pattern_ptr, jsoff_t pattern_len,
	const char *str_ptr, jsoff_t str_len,
	bool global_flag, bool ignore_case, bool multiline
	) {
	char pcre2_pattern[512];
	size_t pcre2_len = js_to_pcre2_pattern(pattern_ptr, pattern_len, pcre2_pattern, sizeof(pcre2_pattern));

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	if (ignore_case) options \|= PCRE2_CASELESS;
	if (multiline) options \|= PCRE2_MULTILINE;

	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	if (re == NULL) return js_mknull();

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	uint32_t capture_count;
	pcre2_pattern_info(re, PCRE2_INFO_CAPTURECOUNT, &capture_count);

	jsval_t result_arr = js_mkarr(js);
	if (is_err(result_arr)) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return result_arr;
	}

	PCRE2_SIZE pos = 0;
	int match_count = 0;

	while (pos <= str_len) {
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, pos, 0, match_data, NULL);
	if (rc < 0) break;

	PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
	PCRE2_SIZE match_start = ovector[0];
	PCRE2_SIZE match_end = ovector[1];

	if (global_flag) {
	jsval_t match_str = js_mkstr(js, str_ptr + match_start, match_end - match_start);
	if (is_err(match_str)) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return match_str;
	}
	js_arr_push(js, result_arr, match_str);
	} else {
	for (uint32_t i = 0; i <= capture_count; i++) {
	PCRE2_SIZE start = ovector[2*i];
	PCRE2_SIZE end = ovector[2*i+1];
	if (start == PCRE2_UNSET) {
	js_arr_push(js, result_arr, js_mkundef());
	} else {
	jsval_t match_str = js_mkstr(js, str_ptr + start, end - start);
	if (is_err(match_str)) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return match_str;
	}
	js_arr_push(js, result_arr, match_str);
	}
	}
	setprop(js, result_arr, js_mkstr(js, "index", 5), tov((double)match_start));
	}
	match_count++;

	if (!global_flag) break;

	if (match_start == match_end) {
	pos = match_end + 1;
	} else { pos = match_end; }
	}

	pcre2_match_data_free(match_data);
	pcre2_code_free(re);

	if (match_count == 0) return js_mknull();
	return result_arr;
	}

	static jsval_t builtin_string_match(struct js js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;
	if (nargs < 1) return js_mknull();

	jsval_t pattern = args[0];
	const char *pattern_ptr = NULL;
	jsoff_t pattern_len = 0;
	bool global_flag = false;
	bool ignore_case = false;
	bool multiline = false;

	if (vtype(pattern) == T_OBJ) {
	jsoff_t source_off = lkp(js, pattern, "source", 6);
	if (source_off == 0) return js_mknull();

	jsval_t source_val = resolveprop(js, mkval(T_PROP, source_off));
	if (vtype(source_val) != T_STR) return js_mknull();

	jsoff_t poff;
	poff = vstr(js, source_val, &pattern_len);
	pattern_ptr = (char *) &js->mem[poff];

	jsoff_t flags_off = lkp(js, pattern, "flags", 5);
	if (flags_off != 0) {
	jsval_t flags_val = resolveprop(js, mkval(T_PROP, flags_off));
	if (vtype(flags_val) == T_STR) {
	jsoff_t flen, foff = vstr(js, flags_val, &flen);
	const char flags_str = (char ) &js->mem[foff];
	for (jsoff_t i = 0; i < flen; i++) {
	if (flags_str[i] == 'g') global_flag = true;
	if (flags_str[i] == 'i') ignore_case = true;
	if (flags_str[i] == 'm') multiline = true;
	}
	}
	}
	} else if (vtype(pattern) == T_STR) {
	jsoff_t poff;
	poff = vstr(js, pattern, &pattern_len);
	pattern_ptr = (char *) &js->mem[poff];
	} else {
	return js_mknull();
	}

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsval_t result = do_regex_match_pcre2(js, pattern_ptr, pattern_len, str_ptr, str_len, global_flag, ignore_case, multiline);

	if (!global_flag && vtype(result) == T_ARR) {
	setprop(js, result, js_mkstr(js, "input", 5), str);
	}

	return result;
	}

	static jsval_t builtin_string_template(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "template called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_OBJ) return str;

	jsval_t data = args[0];
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	size_t result_cap = str_len + 256;
	size_t result_len = 0;
	char result = (char )ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");
	jsoff_t i = 0;

	#define ENSURE_CAP(need) do { \
	if (result_len + (need) >= result_cap) { \
	result_cap = (result_len + (need) + 1) * 2; \
	char nr = (char )ant_realloc(result, result_cap); \
	if (!nr) return js_mkerr(js, "oom"); \
	result = nr; \
	} \
	} while(0)

	while (i < str_len) {
	if (i < str_len - 3 && str_ptr[i] == '{' && str_ptr[i + 1] == '{') {
	jsoff_t start = i + 2;
	jsoff_t end = start;
	while (end < str_len - 1 && !(str_ptr[end] == '}' && str_ptr[end + 1] == '}')) {
	end++;
	}
	if (end < str_len - 1 && str_ptr[end] == '}' && str_ptr[end + 1] == '}') {
	jsoff_t key_len = end - start;
	jsoff_t prop_off = lkp(js, data, str_ptr + start, key_len);

	if (prop_off != 0) {
	jsval_t value = resolveprop(js, mkval(T_PROP, prop_off));
	if (vtype(value) == T_STR) {
	jsoff_t val_len, val_off = vstr(js, value, &val_len);
	ENSURE_CAP(val_len);
	memcpy(result + result_len, &js->mem[val_off], val_len);
	result_len += val_len;
	} else if (vtype(value) == T_NUM) {
	char numstr[32];
	snprintf(numstr, sizeof(numstr), "%g", tod(value));
	size_t num_len = strlen(numstr);
	ENSURE_CAP(num_len);
	memcpy(result + result_len, numstr, num_len);
	result_len += num_len;
	} else if (vtype(value) == T_BOOL) {
	const char *boolstr = vdata(value) ? "true" : "false";
	size_t bool_len = strlen(boolstr);
	ENSURE_CAP(bool_len);
	memcpy(result + result_len, boolstr, bool_len);
	result_len += bool_len;
	}
	}
	i = end + 2;
	continue;
	}
	}
	ENSURE_CAP(1);
	result[result_len++] = str_ptr[i++];
	}
	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	#undef ENSURE_CAP
	}

	static jsval_t builtin_string_charCodeAt(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "charCodeAt called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d)) idx_d = 0.0;
	if (isinf(idx_d) \|\| idx_d > (double)LONG_MAX) return tov(JS_NAN);

	long idx_l = (long) idx_d;
	if (idx_l < 0) return tov(JS_NAN);

	jsoff_t idx = (jsoff_t) idx_l;
	jsoff_t str_len = offtolen(loadoff(js, (jsoff_t) vdata(str)));

	if (idx >= str_len) return tov(JS_NAN);

	jsoff_t str_off = (jsoff_t) vdata(str) + sizeof(jsoff_t);
	unsigned char ch = (unsigned char) js->mem[str_off + idx];

	return tov((double) ch);
	}

	static jsval_t builtin_string_codePointAt(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "codePointAt called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d)) idx_d = 0.0;
	if (isinf(idx_d) \|\| idx_d > (double)LONG_MAX) return js_mkundef();

	long idx_l = (long) idx_d;
	if (idx_l < 0) return js_mkundef();

	jsoff_t idx = (jsoff_t) idx_l;
	jsoff_t str_len = offtolen(loadoff(js, (jsoff_t) vdata(str)));

	if (idx >= str_len) return js_mkundef();

	jsoff_t str_off = (jsoff_t) vdata(str) + sizeof(jsoff_t);
	const unsigned char *s = &js->mem[str_off + idx];
	jsoff_t remaining = str_len - idx;

	unsigned char c0 = s[0];
	if (c0 < 0x80) return tov((double) c0);

	if ((c0 & 0xE0) == 0xC0 && remaining >= 2 && (s[1] & 0xC0) == 0x80) {
	uint32_t cp = ((c0 & 0x1F) << 6) \| (s[1] & 0x3F);
	return tov((double) cp);
	}

	if ((c0 & 0xF0) == 0xE0 && remaining >= 3 && (s[1] & 0xC0) == 0x80 && (s[2] & 0xC0) == 0x80) {
	uint32_t cp = ((c0 & 0x0F) << 12) \| ((s[1] & 0x3F) << 6) \| (s[2] & 0x3F);
	return tov((double) cp);
	}

	if ((c0 & 0xF8) == 0xF0 && remaining >= 4 && (s[1] & 0xC0) == 0x80 && (s[2] & 0xC0) == 0x80 && (s[3] & 0xC0) == 0x80) {
	uint32_t cp = ((c0 & 0x07) << 18) \| ((s[1] & 0x3F) << 12) \| ((s[2] & 0x3F) << 6) \| (s[3] & 0x3F);
	return tov((double) cp);
	}

	return tov((double) c0);
	}

	static jsval_t builtin_string_toLowerCase(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "toLowerCase called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	jsval_t result = js_mkstr(js, NULL, str_len);
	if (is_err(result)) return result;

	jsoff_t result_len, result_off = vstr(js, result, &result_len);
	char result_ptr = (char ) &js->mem[result_off];

	for (jsoff_t i = 0; i < str_len; i++) {
	char ch = str_ptr[i];
	result_ptr[i] = (ch >= 'A' && ch <= 'Z') ? ch + 32 : ch;
	}

	return result;
	}

	static jsval_t builtin_string_toUpperCase(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "toUpperCase called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	jsval_t result = js_mkstr(js, NULL, str_len);
	if (is_err(result)) return result;

	jsoff_t result_len, result_off = vstr(js, result, &result_len);
	char result_ptr = (char ) &js->mem[result_off];

	for (jsoff_t i = 0; i < str_len; i++) {
	char ch = str_ptr[i];
	result_ptr[i] = (ch >= 'a' && ch <= 'z') ? ch - 32 : ch;
	}

	return result;
	}

	static jsval_t builtin_string_trim(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "trim called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t start = 0, end = str_len;
	while (start < end && is_space(str_ptr[start])) start++;
	while (end > start && is_space(str_ptr[end - 1])) end--;

	return js_mkstr(js, str_ptr + start, end - start);
	}

	static jsval_t builtin_string_trimStart(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "trimStart called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t start = 0;
	while (start < str_len && is_space(str_ptr[start])) start++;

	return js_mkstr(js, str_ptr + start, str_len - start);
	}

	static jsval_t builtin_string_trimEnd(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "trimEnd called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t end = str_len;
	while (end > 0 && is_space(str_ptr[end - 1])) end--;

	return js_mkstr(js, str_ptr, end);
	}

	static jsval_t builtin_string_repeat(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "repeat called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return js_mkerr(js, "repeat count required");

	double count_d = tod(args[0]);
	if (count_d < 0 \|\| count_d != (double)(long)count_d) return js_mkerr(js, "invalid repeat count");
	jsoff_t count = (jsoff_t) count_d;

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	if (count == 0 \|\| str_len == 0) return js_mkstr(js, "", 0);

	jsval_t result = js_mkstr(js, NULL, str_len * count);
	if (is_err(result)) return result;

	jsoff_t result_len, result_off = vstr(js, result, &result_len);
	char result_ptr = (char ) &js->mem[result_off];

	for (jsoff_t i = 0; i < count; i++) {
	memcpy(result_ptr + i * str_len, str_ptr, str_len);
	}

	return result;
	}

	static jsval_t builtin_string_padStart(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "padStart called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return str;

	jsoff_t target_len = (jsoff_t) tod(args[0]);
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	if (target_len <= str_len) return str;

	const char *pad_str = " ";
	jsoff_t pad_len = 1;
	if (nargs >= 2 && vtype(args[1]) == T_STR) {
	pad_len = vstr(js, args[1], &pad_len);
	pad_str = (char *) &js->mem[pad_len];
	pad_len = offtolen(loadoff(js, (jsoff_t) vdata(args[1])));
	}

	if (pad_len == 0) return str;

	jsoff_t fill_len = target_len - str_len;
	jsval_t result = js_mkstr(js, NULL, target_len);
	if (is_err(result)) return result;

	jsoff_t result_len, result_off = vstr(js, result, &result_len);
	char result_ptr = (char ) &js->mem[result_off];

	jsoff_t pos = 0;
	while (pos < fill_len) {
	jsoff_t copy_len = (fill_len - pos < pad_len) ? fill_len - pos : pad_len;
	memcpy(result_ptr + pos, pad_str, copy_len);
	pos += copy_len;
	}
	memcpy(result_ptr + fill_len, str_ptr, str_len);

	return result;
	}

	static jsval_t builtin_string_padEnd(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "padEnd called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return str;

	jsoff_t target_len = (jsoff_t) tod(args[0]);
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	if (target_len <= str_len) return str;

	const char *pad_str = " ";
	jsoff_t pad_len = 1;
	if (nargs >= 2 && vtype(args[1]) == T_STR) {
	pad_len = vstr(js, args[1], &pad_len);
	pad_str = (char *) &js->mem[pad_len];
	pad_len = offtolen(loadoff(js, (jsoff_t) vdata(args[1])));
	}

	if (pad_len == 0) return str;

	jsval_t result = js_mkstr(js, NULL, target_len);
	if (is_err(result)) return result;

	jsoff_t result_len, result_off = vstr(js, result, &result_len);
	char result_ptr = (char ) &js->mem[result_off];

	memcpy(result_ptr, str_ptr, str_len);
	jsoff_t pos = str_len;
	while (pos < target_len) {
	jsoff_t copy_len = (target_len - pos < pad_len) ? target_len - pos : pad_len;
	memcpy(result_ptr + pos, pad_str, copy_len);
	pos += copy_len;
	}

	return result;
	}

	static jsval_t builtin_string_charAt(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "charAt called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d)) idx_d = 0;
	else if (idx_d < 0) idx_d = -floor(-idx_d);
	else idx_d = floor(idx_d);
	if (idx_d < 0 \|\| isinf(idx_d)) return js_mkstr(js, "", 0);

	jsoff_t idx = (jsoff_t) idx_d;
	jsoff_t str_len = offtolen(loadoff(js, (jsoff_t) vdata(str)));

	if (idx >= str_len) return js_mkstr(js, "", 0);

	jsoff_t str_off = (jsoff_t) vdata(str) + sizeof(jsoff_t);
	char ch[2] = { js->mem[str_off + idx], '\0' };

	return js_mkstr(js, ch, 1);
	}

	static jsval_t builtin_string_at(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "at called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d) \|\| isinf(idx_d)) return js_mkundef();

	jsoff_t str_len = offtolen(loadoff(js, (jsoff_t) vdata(str)));
	long idx = (long) idx_d;

	if (idx < 0) idx += (long) str_len;
	if (idx < 0 \|\| idx >= (long) str_len) return js_mkundef();

	jsoff_t str_off = (jsoff_t) vdata(str) + sizeof(jsoff_t);
	char ch[2] = { js->mem[str_off + idx], '\0' };
	return js_mkstr(js, ch, 1);
	}

	static jsval_t builtin_string_localeCompare(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "localeCompare called on non-string");
	if (nargs < 1) return tov(0);

	jsval_t that = args[0];
	if (vtype(that) != T_STR) {
	char buf[64];
	size_t n = tostr(js, that, buf, sizeof(buf));
	that = js_mkstr(js, buf, n);
	}

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t that_len, that_off = vstr(js, that, &that_len);
	const char str_ptr = (char )&js->mem[str_off];
	const char that_ptr = (char )&js->mem[that_off];

	int result = strcoll(str_ptr, that_ptr);
	if (result < 0) return tov(-1);
	if (result > 0) return tov(1);
	return tov(0);
	}

	static jsval_t builtin_string_lastIndexOf(struct js js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "lastIndexOf called on non-string");
	if (nargs == 0) return tov(-1);

	jsval_t search = args[0];
	if (vtype(search) != T_STR) return tov(-1);

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);

	jsoff_t max_start = str_len;
	double dstr_len = D(str_len);
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double pos = tod(args[1]);
	if (isnan(pos)) pos = dstr_len;
	if (pos < 0) pos = 0;
	if (pos > dstr_len) pos = dstr_len;
	max_start = (jsoff_t) pos;
	}

	if (search_len == 0) return tov((double) (max_start > str_len ? str_len : max_start));
	if (search_len > str_len) return tov(-1);

	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	jsoff_t start = (max_start + search_len > str_len) ? str_len - search_len : max_start;
	for (jsoff_t i = start + 1; i > 0; i--) {
	if (memcmp(str_ptr + i - 1, search_ptr, search_len) == 0) return tov((double)(i - 1));
	}
	return tov(-1);
	}

	static jsval_t builtin_string_concat(struct js js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;

	jsoff_t total_len;
	jsoff_t base_off = vstr(js, str, &total_len);

	jsval_t *str_args = NULL;
	if (nargs > 0) {
	str_args = (jsval_t )ant_calloc(nargs sizeof(jsval_t));
	if (!str_args) return js_mkerr(js, "oom");
	for (int i = 0; i < nargs; i++) {
	str_args[i] = js_tostring_val(js, args[i]);
	if (is_err(str_args[i])) {
	free(str_args);
	return str_args[i];
	}
	jsoff_t arg_len;
	vstr(js, str_args[i], &arg_len);
	total_len += arg_len;
	}
	}

	char result = (char )ant_calloc(total_len + 1);
	if (!result) {
	if (str_args) free(str_args);
	return js_mkerr(js, "oom");
	}

	jsoff_t base_len;
	base_off = vstr(js, str, &base_len);
	memcpy(result, &js->mem[base_off], base_len);
	jsoff_t pos = base_len;

	for (int i = 0; i < nargs; i++) {
	jsoff_t arg_len, arg_off = vstr(js, str_args[i], &arg_len);
	memcpy(result + pos, &js->mem[arg_off], arg_len);
	pos += arg_len;
	}
	result[pos] = '\0';

	jsval_t ret = js_mkstr(js, result, pos);
	free(result); if (str_args) free(str_args);

	return ret;
	}

	static jsval_t builtin_string_fromCharCode(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkstr(js, "", 0);

	char buf = (char )ant_calloc(nargs + 1);
	if (!buf) return js_mkerr(js, "oom");

	for (int i = 0; i < nargs; i++) {
	if (vtype(args[i]) != T_NUM) { buf[i] = 0; continue; }
	int code = (int) tod(args[i]);
	buf[i] = (char)(code & 0xFF);
	}
	buf[nargs] = '\0';

	jsval_t ret = js_mkstr(js, buf, nargs);
	free(buf);
	return ret;
	}

	static jsval_t builtin_string_fromCodePoint(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkstr(js, "", 0);

	char buf = (char )ant_calloc(nargs * 4 + 1);
	if (!buf) return js_mkerr(js, "oom");

	size_t len = 0;
	for (int i = 0; i < nargs; i++) {
	if (vtype(args[i]) != T_NUM) continue;
	double d = tod(args[i]);
	if (d < 0 \|\| d > 0x10FFFF \|\| d != floor(d)) {
	free(buf);
	return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid code point");
	}
	uint32_t cp = (uint32_t)d;
	if (cp < 0x80) {
	buf[len++] = (char)cp;
	} else if (cp < 0x800) {
	buf[len++] = (char)(0xC0 \| (cp >> 6));
	buf[len++] = (char)(0x80 \| (cp & 0x3F));
	} else if (cp < 0x10000) {
	buf[len++] = (char)(0xE0 \| (cp >> 12));
	buf[len++] = (char)(0x80 \| ((cp >> 6) & 0x3F));
	buf[len++] = (char)(0x80 \| (cp & 0x3F));
	} else {
	buf[len++] = (char)(0xF0 \| (cp >> 18));
	buf[len++] = (char)(0x80 \| ((cp >> 12) & 0x3F));
	buf[len++] = (char)(0x80 \| ((cp >> 6) & 0x3F));
	buf[len++] = (char)(0x80 \| (cp & 0x3F));
	}
	}
	buf[len] = '\0';

	jsval_t ret = js_mkstr(js, buf, len);
	free(buf);
	return ret;
	}

	static jsval_t builtin_number_toString(struct js js, jsval_t args, int nargs) {
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "toString called on non-number");

	int radix = 10;
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	radix = (int)tod(args[0]);
	if (radix < 2 \|\| radix > 36) {
	return js_mkerr(js, "radix must be between 2 and 36");
	}
	}

	if (radix == 10) {
	char buf[64];
	size_t len = strnum(num, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	double val = tod(num);

	if (isnan(val)) return js_mkstr(js, "NaN", 3);
	if (isinf(val)) return val > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	char buf[128];
	char *p = buf + sizeof(buf) - 1;
	*p = '\0';

	bool negative = val < 0;
	if (negative) val = -val;

	long long int_part = (long long)val;
	double frac_part = val - (double)int_part;

	if (int_part == 0) {
	*--p = '0';
	} else {
	while (int_part > 0 && p > buf) {
	int digit = int_part % radix;
	*--p = (char)(digit < 10 ? '0' + digit : 'a' + (digit - 10));
	int_part /= radix;
	}
	}

	if (negative && p > buf) {
	*--p = '-';
	}

	size_t int_len = strlen(p);

	if (frac_part > 0.0000001) {
	char frac_buf[64];
	int frac_pos = 0;
	frac_buf[frac_pos++] = '.';

	for (int i = 0; i < 16 && frac_part > 0.0000001 && frac_pos < 63; i++) {
	frac_part *= radix;
	int digit = (int)frac_part;
	frac_buf[frac_pos++] = (char)(digit < 10 ? '0' + digit : 'a' + (digit - 10));
	frac_part -= digit;
	}
	frac_buf[frac_pos] = '\0';

	char result[192];
	snprintf(result, sizeof(result), "%s%s", p, frac_buf);
	return js_mkstr(js, result, strlen(result));
	}

	return js_mkstr(js, p, int_len);
	}

	static jsval_t builtin_number_toFixed(struct js js, jsval_t args, int nargs) {
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "toFixed called on non-number");

	double d = tod(num);
	if (isnan(d)) return js_mkstr(js, "NaN", 3);
	if (isinf(d)) return d > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	int digits = 0;
	if (nargs >= 1 && vtype(args[0]) != T_UNDEF) {
	digits = (int) tod(args[0]);
	if (digits < 0 \|\| digits > 100) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "toFixed() digits argument must be between 0 and 100");
	}
	}

	bool negative = d < 0;
	if (negative) d = -d;

	if (d >= 1e21) {
	char buf[64];
	snprintf(buf, sizeof(buf), "%.0f", negative ? -d : d);
	return js_mkstr(js, buf, strlen(buf));
	}

	double scale = pow(10, digits);
	double scaled = d * scale;
	double rounded = floor(scaled + 0.5);

	char digit_buf[128];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	while (digit_len < digits + 1) {
	memmove(digit_buf + 1, digit_buf, digit_len + 1);
	digit_buf[0] = '0';
	digit_len++;
	}

	char buf[128];
	int pos = 0;

	if (negative && rounded != 0) buf[pos++] = '-';
	int int_digits = digit_len - digits;
	if (int_digits <= 0) int_digits = 1;

	for (int i = 0; i < int_digits; i++) {
	buf[pos++] = digit_buf[i];
	}

	if (digits > 0) {
	buf[pos++] = '.';
	for (int i = int_digits; i < digit_len; i++) {
	buf[pos++] = digit_buf[i];
	}
	}

	buf[pos] = '\0';
	return js_mkstr(js, buf, pos);
	}

	static jsval_t builtin_number_toPrecision(struct js js, jsval_t args, int nargs) {
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "toPrecision called on non-number");

	double d = tod(num);
	if (isnan(d)) return js_mkstr(js, "NaN", 3);
	if (isinf(d)) return d > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	if (nargs < 1 \|\| vtype(args[0]) == T_UNDEF) {
	char buf[64];
	size_t len = strnum(num, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	int precision = (int) tod(args[0]);
	if (precision < 1 \|\| precision > 100) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "toPrecision() argument must be between 1 and 100");
	}

	bool negative = d < 0;
	if (negative) d = -d;

	if (d == 0) {
	char buf[128];
	int pos = 0;
	if (negative) buf[pos++] = '-';
	buf[pos++] = '0';
	if (precision > 1) {
	buf[pos++] = '.';
	for (int i = 1; i < precision; i++) buf[pos++] = '0';
	}
	buf[pos] = '\0';
	return js_mkstr(js, buf, pos);
	}

	int exp = (int) floor(log10(d));
	bool use_exp = (exp < -(precision - 1) - 1) \|\| (exp >= precision);

	if (use_exp) {
	double mantissa = d / pow(10, exp);
	double scale = pow(10, precision - 1);
	double rounded = floor(mantissa * scale + 0.5);

	if (rounded >= scale * 10) {
	rounded /= 10;
	exp++;
	}

	char digit_buf[32];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	char buf[128];
	int pos = 0;
	if (negative) buf[pos++] = '-';
	buf[pos++] = digit_buf[0];
	if (precision > 1) {
	buf[pos++] = '.';
	for (int i = 1; i < precision; i++) {
	buf[pos++] = (i < digit_len) ? digit_buf[i] : '0';
	}
	}
	buf[pos++] = 'e';
	buf[pos++] = (exp >= 0) ? '+' : '-';
	if (exp < 0) exp = -exp;
	snprintf(buf + pos, sizeof(buf) - pos, "%d", exp);
	return js_mkstr(js, buf, strlen(buf));
	} else {
	int digits_after_point = precision - exp - 1;
	if (digits_after_point < 0) digits_after_point = 0;

	double scale = pow(10, digits_after_point);
	double rounded = floor(d * scale + 0.5);

	char digit_buf[64];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	while (digit_len < digits_after_point + 1) {
	memmove(digit_buf + 1, digit_buf, digit_len + 1);
	digit_buf[0] = '0';
	digit_len++;
	}

	char buf[128];
	int pos = 0;
	if (negative) buf[pos++] = '-';

	int int_digits = digit_len - digits_after_point;
	for (int i = 0; i < int_digits; i++) {
	buf[pos++] = digit_buf[i];
	}

	if (digits_after_point > 0) {
	buf[pos++] = '.';
	for (int i = int_digits; i < digit_len; i++) {
	buf[pos++] = digit_buf[i];
	}
	}

	buf[pos] = '\0';
	return js_mkstr(js, buf, pos);
	}
	}

	static jsval_t builtin_number_toExponential(struct js js, jsval_t args, int nargs) {
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "toExponential called on non-number");

	double d = tod(num);
	if (isnan(d)) return js_mkstr(js, "NaN", 3);
	if (isinf(d)) return d > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	int digits = -1;
	if (nargs >= 1 && vtype(args[0]) != T_UNDEF) {
	digits = (int) tod(args[0]);
	if (digits < 0 \|\| digits > 100) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "toExponential() argument must be between 0 and 100");
	}
	}

	bool negative = d < 0;
	if (negative) d = -d;

	int exp = 0;
	if (d != 0) {
	exp = (int) floor(log10(d));
	double test = d / pow(10, exp);
	if (test >= 10) { exp++; test /= 10; }
	if (test < 1) { exp--; test *= 10; }
	}

	if (digits < 0) {
	char temp[32];
	snprintf(temp, sizeof(temp), "%.15g", d);
	int sig = 0;
	for (int i = 0; temp[i] && temp[i] != 'e' && temp[i] != 'E'; i++) {
	if (temp[i] == '.') continue;
	if (temp[i] >= '0' && temp[i] <= '9') if (temp[i] != '0' \|\| sig > 0) sig++;
	}
	digits = sig > 0 ? sig - 1 : 0;
	if (digits > 20) digits = 20;
	}

	double mantissa = d / pow(10, exp);
	double scale = pow(10, digits);
	double scaled = mantissa * scale;
	double rounded = floor(scaled + 0.5);

	if (rounded >= scale * 10) {
	rounded /= 10;
	exp++;
	}

	char buf[64];
	int pos = 0;

	if (negative) buf[pos++] = '-';

	char digit_buf[32];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	while (digit_len < digits + 1) {
	memmove(digit_buf + 1, digit_buf, digit_len + 1);
	digit_buf[0] = '0';
	digit_len++;
	}

	buf[pos++] = digit_buf[0];

	if (digits > 0) {
	buf[pos++] = '.';
	for (int i = 1; i <= digits; i++) {
	buf[pos++] = (i < digit_len) ? digit_buf[i] : '0';
	}
	}

	buf[pos++] = 'e';
	buf[pos++] = (exp >= 0) ? '+' : '-';
	if (exp < 0) exp = -exp;
	snprintf(buf + pos, sizeof(buf) - pos, "%d", exp);

	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_number_valueOf(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "valueOf called on non-number");
	return num;
	}

	static jsval_t builtin_number_toLocaleString(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "toLocaleString called on non-number");
	char buf[64];
	strnum(num, buf, sizeof(buf));
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_string_valueOf(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "valueOf called on non-string");
	return str;
	}

	static jsval_t builtin_string_toString(struct js js, jsval_t args, int nargs) {
	return builtin_string_valueOf(js, args, nargs);
	}

	static jsval_t builtin_boolean_valueOf(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t b = unwrap_primitive(js, js->this_val);
	if (vtype(b) != T_BOOL) return js_mkerr(js, "valueOf called on non-boolean");
	return b;
	}

	static jsval_t builtin_boolean_toString(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t b = unwrap_primitive(js, js->this_val);
	if (vtype(b) != T_BOOL) return js_mkerr(js, "toString called on non-boolean");
	return vdata(b) ? js_mkstr(js, "true", 4) : js_mkstr(js, "false", 5);
	}

	static jsval_t builtin_parseInt(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(JS_NAN);

	jsval_t str_val = args[0];
	if (vtype(str_val) != T_STR) {
	const char *str = js_str(js, str_val);
	str_val = js_mkstr(js, str, strlen(str));
	}

	jsoff_t str_len, str_off = vstr(js, str_val, &str_len);
	const char str = (char ) &js->mem[str_off];

	int radix = 0;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	radix = (int) tod(args[1]);
	if (radix != 0 && (radix < 2 \|\| radix > 36)) return tov(JS_NAN);
	}

	jsoff_t i = 0;
	while (i < str_len && is_space(str[i])) i++;

	if (i >= str_len) return tov(JS_NAN);

	int sign = 1;
	if (str[i] == '-') {
	sign = -1;
	i++;
	} else if (str[i] == '+') {
	i++;
	}

	if ((radix == 0 \|\| radix == 16) && i + 1 < str_len && str[i] == '0' && (str[i + 1] == 'x' \|\| str[i + 1] == 'X')) {
	radix = 16;
	i += 2;
	}

	if (radix == 0) radix = 10;

	double result = 0;
	bool found_digit = false;

	while (i < str_len) {
	char ch = str[i];
	int digit = -1;

	if (ch >= '0' && ch <= '9') {
	digit = ch - '0';
	} else if (ch >= 'a' && ch <= 'z') {
	digit = ch - 'a' + 10;
	} else if (ch >= 'A' && ch <= 'Z') {
	digit = ch - 'A' + 10;
	}

	if (digit < 0 \|\| digit >= radix) break;

	result = result * radix + digit;
	found_digit = true;
	i++;
	}

	if (!found_digit) return tov(JS_NAN);

	return tov(sign * result);
	}

	static jsval_t builtin_parseFloat(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(JS_NAN);

	jsval_t str_val = args[0];
	if (vtype(str_val) != T_STR) {
	const char *str = js_str(js, str_val);
	str_val = js_mkstr(js, str, strlen(str));
	}

	jsoff_t str_len, str_off = vstr(js, str_val, &str_len);
	const char str = (char ) &js->mem[str_off];

	jsoff_t i = 0;
	while (i < str_len && is_space(str[i])) i++;

	if (i >= str_len) return tov(JS_NAN);

	char *end;
	double result = strtod(&str[i], &end);

	if (end == &str[i]) return tov(JS_NAN);

	return tov(result);
	}

	static const char base64_chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

	static jsval_t builtin_btoa(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "btoa requires 1 argument");

	jsval_t str_val = args[0];
	if (vtype(str_val) != T_STR) {
	const char *str = js_str(js, str_val);
	str_val = js_mkstr(js, str, strlen(str));
	}

	jsoff_t str_len, str_off = vstr(js, str_val, &str_len);
	const char str = (char ) &js->mem[str_off];

	for (jsoff_t i = 0; i < str_len; i++) {
	if ((unsigned char)str[i] > 255) {
	return js_mkerr(js, "btoa: character out of range");
	}
	}

	size_t out_len = ((str_len + 2) / 3) * 4;
	char out = (char )ant_calloc(out_len + 1);
	if (!out) return js_mkerr(js, "out of memory");

	size_t i = 0, j = 0;
	while (i < str_len) {
	size_t remaining = str_len - i;
	uint32_t a = (unsigned char)str[i++];
	uint32_t b = (remaining > 1) ? (unsigned char)str[i++] : 0;
	uint32_t c = (remaining > 2) ? (unsigned char)str[i++] : 0;
	uint32_t triple = (a << 16) \| (b << 8) \| c;

	out[j++] = base64_chars[(triple >> 18) & 0x3F];
	out[j++] = base64_chars[(triple >> 12) & 0x3F];
	out[j++] = (remaining > 1) ? base64_chars[(triple >> 6) & 0x3F] : '=';
	out[j++] = (remaining > 2) ? base64_chars[triple & 0x3F] : '=';
	}
	out[j] = '\0';

	jsval_t result = js_mkstr(js, out, j);
	free(out);
	return result;
	}

	static const int8_t decode_table[256] = {
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
	52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-1,-1,-1,
	-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
	15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
	-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
	41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
	-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
	};

	static jsval_t builtin_atob(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "atob requires 1 argument");

	jsval_t str_val = args[0];
	if (vtype(str_val) != T_STR) {
	const char *str = js_str(js, str_val);
	str_val = js_mkstr(js, str, strlen(str));
	}

	jsoff_t str_len, str_off = vstr(js, str_val, &str_len);
	const char str = (char ) &js->mem[str_off];

	if (str_len == 0) return js_mkstr(js, "", 0);
	if (str_len % 4 != 0) return js_mkerr(js, "atob: invalid base64 string");

	size_t out_len = (str_len / 4) * 3;
	if (str_len > 0 && str[str_len - 1] == '=') out_len--;
	if (str_len > 1 && str[str_len - 2] == '=') out_len--;

	char out = (char )ant_calloc(out_len + 1);
	if (!out) return js_mkerr(js, "out of memory");

	size_t i = 0, j = 0;
	while (i < str_len) {
	int8_t a = decode_table[(unsigned char)str[i++]];
	int8_t b = decode_table[(unsigned char)str[i++]];
	int8_t c = (str[i] == '=') ? 0 : decode_table[(unsigned char)str[i]]; i++;
	int8_t d = (str[i] == '=') ? 0 : decode_table[(unsigned char)str[i]]; i++;

	if (a < 0 \|\| b < 0 \|\| (str[i-2] != '=' && c < 0) \|\| (str[i-1] != '=' && d < 0)) {
	free(out);
	return js_mkerr(js, "atob: invalid character in base64 string");
	}

	uint32_t triple = ((uint32_t)a << 18) \| ((uint32_t)b << 12) \| ((uint32_t)c << 6) \| (uint32_t)d;
	if (j < out_len) out[j++] = (triple >> 16) & 0xFF;
	if (j < out_len) out[j++] = (triple >> 8) & 0xFF;
	if (j < out_len) out[j++] = triple & 0xFF;
	}

	jsval_t result = js_mkstr(js, out, out_len);
	free(out);
	return result;
	}

	static jsval_t builtin_resolve_internal(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_reject_internal(struct js js, jsval_t args, int nargs);
	static void resolve_promise(struct js *js, jsval_t p, jsval_t val);
	static void reject_promise(struct js *js, jsval_t p, jsval_t val);

	static size_t strpromise(struct js js, jsval_t value, char buf, size_t len) {
	uint32_t pid = get_promise_id(js, value);
	promise_data_entry_t *pd = get_promise_data(pid, false);

	const char *content;
	char *allocated = NULL;

	if (!pd \|\| pd->state == 0) {
	content = "<pending>";
	} else if (pd->state == 2) {
	char *val = tostr_alloc(js, pd->value);
	allocated = ant_calloc(strlen(val) + 12);
	sprintf(allocated, "<rejected> %s", val);
	free(val);
	content = allocated;
	} else { content = allocated = tostr_alloc(js, pd->value); }

	size_t result = (pd && pd->trigger_pid)
	? (size_t)snprintf(buf, len, "Promise {\n %s,\n Symbol(async_id): %u,\n Symbol(trigger_async_id): %u\n}", content, pid, pd->trigger_pid)
	: (size_t)snprintf(buf, len, "Promise {\n %s,\n Symbol(async_id): %u\n}", content, pid);

	if (allocated) free(allocated);
	return result;
	}

	static promise_data_entry_t *get_promise_data(uint32_t promise_id, bool create) {
	promise_data_entry_t *entry = NULL;
	HASH_FIND(hh, promise_registry, &promise_id, sizeof(uint32_t), entry);
	if (entry) return entry;
	if (!create) return NULL;

	entry = (promise_data_entry_t *)malloc(sizeof(promise_data_entry_t));
	entry->promise_id = promise_id;
	entry->trigger_pid = 0;
	entry->obj_offset = 0;
	entry->state = 0;
	entry->value = js_mkundef();
	entry->has_rejection_handler = false;
	utarray_new(entry->handlers, &promise_handler_icd);
	HASH_ADD(hh, promise_registry, promise_id, sizeof(uint32_t), entry);

	return entry;
	}

	static uint32_t get_promise_id(struct js *js, jsval_t p) {
	jsval_t p_obj = mkval(T_OBJ, vdata(p));
	jsval_t pid_val = get_slot(js, p_obj, SLOT_PID);
	if (vtype(pid_val) == T_UNDEF) return 0;
	return (uint32_t)tod(pid_val);
	}

	static jsval_t mkpromise(struct js *js) {
	jsval_t obj = mkobj(js, 0);
	if (is_err(obj)) return obj;

	uint32_t pid = next_promise_id++;
	set_slot(js, obj, SLOT_PID, tov((double)pid));
	promise_data_entry_t *pd = get_promise_data(pid, true);
	if (pd) pd->obj_offset = (jsoff_t)vdata(obj);

	return mkval(T_PROMISE, vdata(obj));
	}

	static inline void trigger_handlers(struct js *js, jsval_t p) {
	uint32_t pid = get_promise_id(js, p);
	queue_promise_trigger(pid);
	}

	void js_process_promise_handlers(struct js *js, uint32_t pid) {
	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (!pd) return;

	int state = pd->state;
	jsval_t val = pd->value;

	unsigned int len = utarray_len(pd->handlers);
	for (unsigned int i = 0; i < len; i++) {
	promise_handler_t h = (promise_handler_t )utarray_eltptr(pd->handlers, i);
	jsval_t handler = (state == 1) ? h->onFulfilled : h->onRejected;

	if (vtype(handler) == T_FUNC \|\| vtype(handler) == T_CFUNC) {
	jsval_t res;
	if (vtype(handler) == T_CFUNC) {
	jsval_t (fn)(struct js , jsval_t , int) = (jsval_t()(struct js , jsval_t , int)) vdata(handler);
	res = fn(js, &val, 1);
	} else {
	jsval_t call_args[] = { val };
	res = js_call(js, handler, call_args, 1);
	}

	if (is_err(res)) {
	jsval_t reject_val = js->thrown_value;
	if (vtype(reject_val) == T_UNDEF) {
	reject_val = js_mkstr(js, js->errmsg, strlen(js->errmsg));
	}
	js->thrown_value = js_mkundef();
	reject_promise(js, h->nextPromise, reject_val);
	} else resolve_promise(js, h->nextPromise, res);
	} else {
	if (state == 1) resolve_promise(js, h->nextPromise, val);
	else reject_promise(js, h->nextPromise, val);
	}
	}

	utarray_clear(pd->handlers);
	}

	static void resolve_promise(struct js *js, jsval_t p, jsval_t val) {
	uint32_t pid = get_promise_id(js, p);
	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (!pd \|\| pd->state != 0) return;

	if (vtype(val) == T_PROMISE) {
	uint32_t val_pid = get_promise_id(js, val);
	if (val_pid == pid) {
	jsval_t err = js_mkerr(js, "TypeError: Chaining cycle");
	return reject_promise(js, p, err);
	}

	jsval_t res_obj = mkobj(js, 0);
	set_slot(js, res_obj, SLOT_CFUNC, js_mkfun(builtin_resolve_internal));
	set_slot(js, res_obj, SLOT_DATA, p);
	jsval_t res_fn = mkval(T_FUNC, vdata(res_obj));

	jsval_t rej_obj = mkobj(js, 0);
	set_slot(js, rej_obj, SLOT_CFUNC, js_mkfun(builtin_reject_internal));
	set_slot(js, rej_obj, SLOT_DATA, p);
	jsval_t rej_fn = mkval(T_FUNC, vdata(rej_obj));

	jsval_t call_args[] = { res_fn, rej_fn };
	jsval_t then_prop = js_get(js, val, "then");

	if (vtype(then_prop) == T_FUNC \|\| vtype(then_prop) == T_CFUNC) {
	(void)js_call_with_this(js, then_prop, val, call_args, 2); return;
	}
	}

	pd->state = 1;
	pd->value = val;
	trigger_handlers(js, p);
	}

	static void reject_promise(struct js *js, jsval_t p, jsval_t val) {
	uint32_t pid = get_promise_id(js, p);
	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (!pd \|\| pd->state != 0) return;

	pd->state = 2;
	pd->value = val;

	if (!pd->has_rejection_handler) {
	promise_data_entry_t *existing = NULL;
	HASH_FIND(hh_unhandled, unhandled_rejections, &pd->promise_id, sizeof(uint32_t), existing);
	if (!existing) {
	HASH_ADD(hh_unhandled, unhandled_rejections, promise_id, sizeof(uint32_t), pd);
	}
	}

	trigger_handlers(js, p);
	}

	static jsval_t builtin_resolve_internal(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t p = get_slot(js, me, SLOT_DATA);
	if (vtype(p) != T_PROMISE) return js_mkundef();
	resolve_promise(js, p, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_reject_internal(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t p = get_slot(js, me, SLOT_DATA);
	if (vtype(p) != T_PROMISE) return js_mkundef();
	reject_promise(js, p, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_Promise(struct js js, jsval_t args, int nargs) {
	if (vtype(js->new_target) == T_UNDEF) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Promise constructor cannot be invoked without 'new'");
	}

	if (nargs == 0 \|\| (vtype(args[0]) != T_FUNC && vtype(args[0]) != T_CFUNC)) {
	const char *val_str = nargs == 0 ? "undefined" : js_str(js, args[0]);
	return js_mkerr_typed(js, JS_ERR_TYPE, "Promise resolver %s is not a function", val_str);
	}

	jsval_t p = mkpromise(js);
	jsval_t new_target = js->new_target;

	if (vtype(new_target) == T_FUNC) {
	jsoff_t proto_off = lkp_interned(js, mkval(T_OBJ, vdata(new_target)), INTERN_PROTOTYPE, 9);
	jsval_t subclass_proto = proto_off ? resolveprop(js, mkval(T_PROP, proto_off)) : js_mkundef();

	if (vtype(subclass_proto) == T_OBJ) {
	jsval_t p_obj = mkval(T_OBJ, vdata(p));
	set_slot(js, p_obj, SLOT_PROTO, subclass_proto);
	set_slot(js, p_obj, SLOT_CTOR, new_target);
	}
	}

	jsval_t res_obj = mkobj(js, 0);

	set_slot(js, res_obj, SLOT_CFUNC, js_mkfun(builtin_resolve_internal));
	set_slot(js, res_obj, SLOT_DATA, p);

	jsval_t res_fn = mkval(T_FUNC, vdata(res_obj));
	jsval_t rej_obj = mkobj(js, 0);

	set_slot(js, rej_obj, SLOT_CFUNC, js_mkfun(builtin_reject_internal));
	set_slot(js, rej_obj, SLOT_DATA, p);

	jsval_t rej_fn = mkval(T_FUNC, vdata(rej_obj));
	jsval_t exec_args[] = { res_fn, rej_fn };
	js_call(js, args[0], exec_args, 2);

	return p;
	}

	static jsval_t builtin_Promise_resolve(struct js js, jsval_t args, int nargs) {
	jsval_t val = nargs > 0 ? args[0] : js_mkundef();
	if (vtype(val) == T_PROMISE) return val;
	jsval_t p = mkpromise(js);
	resolve_promise(js, p, val);
	return p;
	}

	static jsval_t builtin_Promise_reject(struct js js, jsval_t args, int nargs) {
	jsval_t val = nargs > 0 ? args[0] : js_mkundef();
	jsval_t p = mkpromise(js);
	reject_promise(js, p, val);
	return p;
	}

	static jsval_t builtin_promise_then(struct js js, jsval_t args, int nargs) {
	jsval_t p = js->this_val;
	if (vtype(p) != T_PROMISE) return js_mkerr(js, "not a promise");

	jsval_t nextP = mkpromise(js);

	jsval_t p_proto = get_slot(js, mkval(T_OBJ, vdata(p)), SLOT_PROTO);
	if (vtype(p_proto) == T_OBJ) {
	set_slot(js, mkval(T_OBJ, vdata(nextP)), SLOT_PROTO, p_proto);
	jsval_t p_ctor = get_slot(js, mkval(T_OBJ, vdata(p)), SLOT_CTOR);
	if (vtype(p_ctor) == T_FUNC) set_slot(js, mkval(T_OBJ, vdata(nextP)), SLOT_CTOR, p_ctor);
	}

	jsval_t onFulfilled = nargs > 0 ? args[0] : js_mkundef();
	jsval_t onRejected = nargs > 1 ? args[1] : js_mkundef();

	uint32_t pid = get_promise_id(js, p);
	uint32_t next_pid = get_promise_id(js, nextP);

	promise_data_entry_t *next_pd = get_promise_data(next_pid, false);
	if (next_pd) next_pd->trigger_pid = pid;

	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (pd) {
	promise_handler_t h = { onFulfilled, onRejected, nextP };
	utarray_push_back(pd->handlers, &h);

	if (vtype(onRejected) == T_FUNC \|\| vtype(onRejected) == T_CFUNC) {
	pd->has_rejection_handler = true;
	promise_data_entry_t *in_unhandled = NULL;
	HASH_FIND(hh_unhandled, unhandled_rejections, &pd->promise_id, sizeof(uint32_t), in_unhandled);
	if (in_unhandled) HASH_DELETE(hh_unhandled, unhandled_rejections, pd);
	}
	}

	if (pd && pd->state != 0) trigger_handlers(js, p);
	return nextP;
	}

	static jsval_t builtin_promise_catch(struct js js, jsval_t args, int nargs) {
	jsval_t args_then[] = { js_mkundef(), nargs > 0 ? args[0] : js_mkundef() };
	return builtin_promise_then(js, args_then, 2);
	}

	static jsval_t finally_value_thunk(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	return get_slot(js, me, SLOT_DATA);
	}

	static jsval_t finally_thrower(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t reason = get_slot(js, me, SLOT_DATA);
	jsval_t rejected = js_mkpromise(js);
	js_reject_promise(js, rejected, reason);
	return rejected;
	}

	static jsval_t finally_identity_reject(struct js js, jsval_t args, int nargs) {
	jsval_t reason = nargs > 0 ? args[0] : js_mkundef();
	jsval_t rejected = js_mkpromise(js);
	js_reject_promise(js, rejected, reason);
	return rejected;
	}

	static jsval_t finally_fulfilled_wrapper(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t callback = get_slot(js, me, SLOT_DATA);
	jsval_t value = nargs > 0 ? args[0] : js_mkundef();

	jsval_t result = js_mkundef();
	if (vtype(callback) == T_FUNC \|\| vtype(callback) == T_CFUNC) {
	result = js_call(js, callback, NULL, 0);
	if (is_err(result)) return result;
	}

	if (vtype(result) == T_PROMISE \|\| (vtype(result) == T_OBJ && vtype(js_get(js, result, "then")) == T_FUNC)) {
	jsval_t thunk_obj = mkobj(js, 0);
	set_slot(js, thunk_obj, SLOT_CFUNC, js_mkfun(finally_value_thunk));
	set_slot(js, thunk_obj, SLOT_DATA, value);
	jsval_t thunk_fn = mkval(T_FUNC, vdata(thunk_obj));

	jsval_t identity_rej_fn = js_mkfun(finally_identity_reject);

	jsval_t then_fn = js_get(js, result, "then");
	jsval_t call_args[] = { thunk_fn, identity_rej_fn };
	return js_call_with_this(js, then_fn, result, call_args, 2);
	}

	return value;
	}

	static jsval_t finally_rejected_wrapper(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t callback = get_slot(js, me, SLOT_DATA);
	jsval_t reason = nargs > 0 ? args[0] : js_mkundef();

	jsval_t result = js_mkundef();
	if (vtype(callback) == T_FUNC \|\| vtype(callback) == T_CFUNC) {
	result = js_call(js, callback, NULL, 0);
	if (is_err(result)) return result;
	}

	if (vtype(result) == T_PROMISE \|\| (vtype(result) == T_OBJ && vtype(js_get(js, result, "then")) == T_FUNC)) {
	jsval_t thrower_obj = mkobj(js, 0);
	set_slot(js, thrower_obj, SLOT_CFUNC, js_mkfun(finally_thrower));
	set_slot(js, thrower_obj, SLOT_DATA, reason);

	jsval_t thrower_fn = mkval(T_FUNC, vdata(thrower_obj));
	jsval_t identity_rej_fn = js_mkfun(finally_identity_reject);

	jsval_t then_prop = js_get(js, result, "then");
	jsval_t call_args[] = { thrower_fn, identity_rej_fn };

	return js_call_with_this(js, then_prop, result, call_args, 2);
	}

	jsval_t rejected = js_mkpromise(js);
	js_reject_promise(js, rejected, reason);
	return rejected;
	}

	static jsval_t builtin_promise_finally(struct js js, jsval_t args, int nargs) {
	jsval_t callback = nargs > 0 ? args[0] : js_mkundef();

	jsval_t fulfilled_obj = mkobj(js, 0);
	set_slot(js, fulfilled_obj, SLOT_CFUNC, js_mkfun(finally_fulfilled_wrapper));
	set_slot(js, fulfilled_obj, SLOT_DATA, callback);
	jsval_t fulfilled_fn = mkval(T_FUNC, vdata(fulfilled_obj));

	jsval_t rejected_obj = mkobj(js, 0);
	set_slot(js, rejected_obj, SLOT_CFUNC, js_mkfun(finally_rejected_wrapper));
	set_slot(js, rejected_obj, SLOT_DATA, callback);
	jsval_t rejected_fn = mkval(T_FUNC, vdata(rejected_obj));

	jsval_t args_then[] = { fulfilled_fn, rejected_fn };
	return builtin_promise_then(js, args_then, 2);
	}

	static jsval_t builtin_Promise_try(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return builtin_Promise_resolve(js, args, 0);
	jsval_t fn = args[0];
	jsval_t *call_args = nargs > 1 ? &args[1] : NULL;
	int call_nargs = nargs > 1 ? nargs - 1 : 0;
	jsval_t res = js_call_with_this(js, fn, js_mkundef(), call_args, call_nargs);
	if (is_err(res)) {
	jsval_t reject_val = js->thrown_value;
	if (vtype(reject_val) == T_UNDEF) {
	reject_val = js_mkstr(js, js->errmsg, strlen(js->errmsg));
	}
	js->thrown_value = js_mkundef();
	jsval_t rej_args[] = { reject_val };
	return builtin_Promise_reject(js, rej_args, 1);
	}
	jsval_t res_args[] = { res };
	return builtin_Promise_resolve(js, res_args, 1);
	}

	static jsval_t resume_coroutine_wrapper(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t coro_val = get_slot(js, me, SLOT_CORO);
	if (vtype(coro_val) != T_NUM) return js_mkundef();

	coroutine_t coro = (coroutine_t )(uintptr_t)tod(coro_val);
	if (!coro) return js_mkundef();

	coro->result = nargs > 0 ? args[0] : js_mkundef();
	coro->is_settled = true;
	coro->is_error = false;
	coro->is_ready = true;

	return js_mkundef();
	}

	static jsval_t reject_coroutine_wrapper(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t coro_val = get_slot(js, me, SLOT_CORO);

	if (vtype(coro_val) != T_NUM) return js_mkundef();

	coroutine_t coro = (coroutine_t )(uintptr_t)tod(coro_val);
	if (!coro) return js_mkundef();

	coro->result = nargs > 0 ? args[0] : js_mkundef();
	coro->is_settled = true;
	coro->is_error = true;
	coro->is_ready = true;

	return js_mkundef();
	}

	static jsval_t builtin_Promise_all_resolve_handler(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t tracker = js_get(js, me, "tracker");
	jsval_t index_val = js_get(js, me, "index");

	int index = (int)tod(index_val);
	jsval_t value = nargs > 0 ? args[0] : js_mkundef();

	jsval_t results = js_get(js, tracker, "results");
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", index);
	setprop(js, results, js_mkstr(js, idx, strlen(idx)), value);

	jsval_t remaining_val = js_get(js, tracker, "remaining");
	int remaining = (int)tod(remaining_val) - 1;
	setprop(js, tracker, js_mkstr(js, "remaining", 9), tov((double)remaining));

	if (remaining == 0) {
	jsval_t result_promise = get_slot(js, tracker, SLOT_DATA);
	resolve_promise(js, result_promise, mkval(T_ARR, vdata(results)));
	}

	return js_mkundef();
	}

	static jsval_t builtin_Promise_all_reject_handler(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t tracker = js_get(js, me, "tracker");
	jsval_t result_promise = get_slot(js, tracker, SLOT_DATA);

	jsval_t reason = nargs > 0 ? args[0] : js_mkundef();
	reject_promise(js, result_promise, reason);

	return js_mkundef();
	}

	static jsval_t builtin_Promise_all(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Promise.all requires an array");

	jsval_t arr = args[0];
	if (vtype(arr) != T_ARR) return js_mkerr(js, "Promise.all requires an array");

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	if (len_off == 0) return builtin_Promise_resolve(js, NULL, 0);
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	int len = (int)tod(len_val);

	if (len == 0) {
	jsval_t empty_arr = mkarr(js);
	setprop(js, empty_arr, js_mkstr(js, "length", 6), tov(0.0));
	jsval_t resolve_args[] = { mkval(T_ARR, vdata(empty_arr)) };
	return builtin_Promise_resolve(js, resolve_args, 1);
	}

	jsval_t result_promise = mkpromise(js);
	jsval_t tracker = mkobj(js, 0);

	setprop(js, tracker, js_mkstr(js, "remaining", 9), tov((double)len));
	setprop(js, tracker, js_mkstr(js, "results", 7), mkarr(js));
	set_slot(js, tracker, SLOT_DATA, result_promise);

	jsval_t results = resolveprop(js, js_get(js, tracker, "results"));
	setprop(js, results, js_mkstr(js, "length", 6), tov((double)len));

	for (int i = 0; i < len; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	jsval_t item = resolveprop(js, js_get(js, arr, idx));

	if (vtype(item) != T_PROMISE) {
	jsval_t wrap_args[] = { item };
	item = builtin_Promise_resolve(js, wrap_args, 1);
	}

	jsval_t resolve_obj = mkobj(js, 0);
	set_slot(js, resolve_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_all_resolve_handler));
	setprop(js, resolve_obj, js_mkstr(js, "index", 5), tov((double)i));
	setprop(js, resolve_obj, js_mkstr(js, "tracker", 7), tracker);
	jsval_t resolve_fn = mkval(T_FUNC, vdata(resolve_obj));

	jsval_t reject_obj = mkobj(js, 0);
	set_slot(js, reject_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_all_reject_handler));
	setprop(js, reject_obj, js_mkstr(js, "tracker", 7), tracker);
	jsval_t reject_fn = mkval(T_FUNC, vdata(reject_obj));

	jsval_t then_args[] = { resolve_fn, reject_fn };
	jsval_t saved_this = js->this_val;
	js->this_val = item;
	builtin_promise_then(js, then_args, 2);
	js->this_val = saved_this;
	}

	return result_promise;
	}

	static jsval_t builtin_Promise_race(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Promise.race requires an array");

	jsval_t arr = args[0];
	if (vtype(arr) != T_ARR) return js_mkerr(js, "Promise.race requires an array");

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	if (len_off == 0) return mkpromise(js);
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	int len = (int)tod(len_val);

	if (len == 0) return mkpromise(js);
	jsval_t result_promise = mkpromise(js);

	jsval_t resolve_obj = mkobj(js, 0);
	set_slot(js, resolve_obj, SLOT_CFUNC, js_mkfun(builtin_resolve_internal));
	set_slot(js, resolve_obj, SLOT_DATA, result_promise);
	jsval_t resolve_fn = mkval(T_FUNC, vdata(resolve_obj));

	jsval_t reject_obj = mkobj(js, 0);
	set_slot(js, reject_obj, SLOT_CFUNC, js_mkfun(builtin_reject_internal));
	set_slot(js, reject_obj, SLOT_DATA, result_promise);
	jsval_t reject_fn = mkval(T_FUNC, vdata(reject_obj));

	for (int i = 0; i < len; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	jsval_t item = resolveprop(js, js_get(js, arr, idx));

	if (vtype(item) != T_PROMISE) {
	resolve_promise(js, result_promise, item);
	return result_promise;
	}

	uint32_t item_pid = get_promise_id(js, item);
	promise_data_entry_t *pd = get_promise_data(item_pid, false);
	if (pd) {
	if (pd->state == 1) {
	resolve_promise(js, result_promise, pd->value);
	return result_promise;
	} else if (pd->state == 2) {
	reject_promise(js, result_promise, pd->value);
	return result_promise;
	}
	}

	jsval_t then_args[] = { resolve_fn, reject_fn };
	jsval_t saved_this = js->this_val;
	js->this_val = item;
	builtin_promise_then(js, then_args, 2);
	js->this_val = saved_this;
	}

	return result_promise;
	}

	static jsval_t mk_aggregate_error(struct js *js, jsval_t errors) {
	jsval_t args[] = { errors, js_mkstr(js, "All promises were rejected", 26) };
	jsoff_t off = lkp(js, js_glob(js), "AggregateError", 14);
	jsval_t ctor = off ? resolveprop(js, mkval(T_PROP, off)) : js_mkundef();
	return js_call(js, ctor, args, 2);
	}

	static bool promise_any_try_resolve(struct js *js, jsval_t tracker, jsval_t value) {
	if (js_truthy(js, js_get(js, tracker, "resolved"))) return false;
	js_set(js, tracker, "resolved", js_mktrue());
	resolve_promise(js, get_slot(js, tracker, SLOT_DATA), value);
	return true;
	}

	static void promise_any_record_rejection(struct js *js, jsval_t tracker, int index, jsval_t reason) {
	jsval_t errors = resolveprop(js, js_get(js, tracker, "errors"));
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", index);
	setprop(js, errors, js_mkstr(js, idx, strlen(idx)), reason);

	int remaining = (int)tod(js_get(js, tracker, "remaining")) - 1;
	js_set(js, tracker, "remaining", tov((double)remaining));

	if (remaining == 0) reject_promise(js, get_slot(js, tracker, SLOT_DATA), mk_aggregate_error(js, errors));
	}

	static jsval_t builtin_Promise_any_resolve_handler(struct js js, jsval_t args, int nargs) {
	jsval_t tracker = js_get(js, js->this_val, "tracker");
	promise_any_try_resolve(js, tracker, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_Promise_any_reject_handler(struct js js, jsval_t args, int nargs) {
	jsval_t tracker = js_get(js, js->this_val, "tracker");
	if (js_truthy(js, js_get(js, tracker, "resolved"))) return js_mkundef();

	int index = (int)tod(js_get(js, js->this_val, "index"));
	promise_any_record_rejection(js, tracker, index, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_Promise_any(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Promise.any requires an array");

	jsval_t arr = args[0];
	if (vtype(arr) != T_ARR) return js_mkerr(js, "Promise.any requires an array");

	jsoff_t len_off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	int len = len_off ? (int)tod(resolveprop(js, mkval(T_PROP, len_off))) : 0;

	if (len == 0) {
	jsval_t reject_args[] = { mk_aggregate_error(js, mkarr(js)) };
	return builtin_Promise_reject(js, reject_args, 1);
	}

	jsval_t result_promise = mkpromise(js);
	jsval_t tracker = mkobj(js, 0);
	jsval_t errors = mkarr(js);

	set_slot(js, tracker, SLOT_DATA, result_promise);

	setprop(js, tracker, js_mkstr(js, "remaining", 9), tov((double)len));
	setprop(js, tracker, js_mkstr(js, "errors", 6), errors);
	setprop(js, tracker, js_mkstr(js, "resolved", 8), js_mkfalse());
	setprop(js, errors, js_mkstr(js, "length", 6), tov((double)len));

	for (int i = 0; i < len; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%d", i);
	jsval_t item = resolveprop(js, js_get(js, arr, idx));

	if (vtype(item) != T_PROMISE) {
	promise_any_try_resolve(js, tracker, item);
	return result_promise;
	}

	uint32_t item_pid = get_promise_id(js, item);
	promise_data_entry_t *pd = get_promise_data(item_pid, false);
	if (pd) {
	pd->has_rejection_handler = true;
	promise_data_entry_t *in_unhandled = NULL;
	HASH_FIND(hh_unhandled, unhandled_rejections, &pd->promise_id, sizeof(uint32_t), in_unhandled);
	if (in_unhandled) HASH_DELETE(hh_unhandled, unhandled_rejections, pd);

	if (pd->state == 1) {
	promise_any_try_resolve(js, tracker, pd->value);
	return result_promise;
	} else if (pd->state == 2) {
	promise_any_record_rejection(js, tracker, i, pd->value);
	continue;
	}
	}

	jsval_t resolve_obj = mkobj(js, 0);
	set_slot(js, resolve_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_any_resolve_handler));
	setprop(js, resolve_obj, js_mkstr(js, "tracker", 7), tracker);

	jsval_t reject_obj = mkobj(js, 0);
	set_slot(js, reject_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_any_reject_handler));
	setprop(js, reject_obj, js_mkstr(js, "index", 5), tov((double)i));
	setprop(js, reject_obj, js_mkstr(js, "tracker", 7), tracker);

	jsval_t then_args[] = { mkval(T_FUNC, vdata(resolve_obj)), mkval(T_FUNC, vdata(reject_obj)) };
	jsval_t saved_this = js->this_val;
	js->this_val = item;
	builtin_promise_then(js, then_args, 2);
	js->this_val = saved_this;
	}

	return result_promise;
	}

	static jsval_t do_instanceof(struct js *js, jsval_t l, jsval_t r) {
	uint8_t ltype = vtype(l);
	uint8_t rtype = vtype(r);

	if (rtype != T_FUNC && rtype != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Right-hand side of 'instanceof' is not callable");
	}

	if (rtype == T_CFUNC) {
	// handle legacy T_CFUNC
	jsval_t (fn)(struct js , jsval_t , int) = (jsval_t()(struct js , jsval_t , int)) vdata(r);
	if (fn == builtin_Object) {
	return mkval(T_BOOL, ltype == T_OBJ ? 1 : 0);
	} else if (fn == builtin_Function) {
	return mkval(T_BOOL, (ltype == T_FUNC \|\| ltype == T_CFUNC) ? 1 : 0);
	} else if (fn == builtin_String) {
	return mkval(T_BOOL, ltype == T_STR ? 1 : 0);
	} else if (fn == builtin_Number) {
	return mkval(T_BOOL, ltype == T_NUM ? 1 : 0);
	} else if (fn == builtin_Boolean) {
	return mkval(T_BOOL, ltype == T_BOOL ? 1 : 0);
	} else if (fn == builtin_Array) {
	return mkval(T_BOOL, ltype == T_ARR ? 1 : 0);
	} else if (fn == builtin_Promise) {
	return mkval(T_BOOL, ltype == T_PROMISE ? 1 : 0);
	}
	return mkval(T_BOOL, 0);
	}

	jsval_t func_obj = mkval(T_OBJ, vdata(r));
	jsoff_t proto_off = lkp_interned(js, func_obj, INTERN_PROTOTYPE, 9);
	if (proto_off == 0) return mkval(T_BOOL, 0);
	jsval_t ctor_proto = resolveprop(js, mkval(T_PROP, proto_off));

	uint8_t pt = vtype(ctor_proto);
	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC) return mkval(T_BOOL, 0);

	if (ltype == T_STR \|\| ltype == T_NUM \|\| ltype == T_BOOL) {
	jsval_t type_proto = get_prototype_for_type(js, ltype);
	return mkval(T_BOOL, vdata(ctor_proto) == vdata(type_proto) ? 1 : 0);
	}

	if (ltype != T_OBJ && ltype != T_ARR && ltype != T_FUNC && ltype != T_PROMISE) {
	return mkval(T_BOOL, 0);
	}

	jsval_t current = get_proto(js, l);
	int depth = 0;
	const int MAX_DEPTH = 32;

	while (vtype(current) != T_NULL && depth < MAX_DEPTH) {
	if (vdata(current) == vdata(ctor_proto)) return mkval(T_BOOL, 1);
	current = get_proto(js, current);
	depth++;
	}

	return mkval(T_BOOL, 0);
	}

	static jsval_t do_in(struct js *js, jsval_t l, jsval_t r) {
	jsoff_t prop_len;
	const char *prop_name;
	char num_buf[32];

	if (vtype(l) == T_STR) {
	jsoff_t prop_off = vstr(js, l, &prop_len);
	prop_name = (char *) &js->mem[prop_off];
	} else if (vtype(l) == T_NUM) {
	prop_len = (jsoff_t) strnum(l, num_buf, sizeof(num_buf));
	prop_name = num_buf;
	} else {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot use 'in' operator to search for '%s' in non-object", js_str(js, l));
	}

	if (vtype(r) != T_OBJ && vtype(r) != T_ARR && vtype(r) != T_FUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot use 'in' operator to search for '%.*s' in non-object", (int)prop_len, prop_name);
	}

	if (is_proxy(js, r)) {
	jsval_t result = proxy_has(js, r, prop_name, prop_len);
	if (is_err(result)) return result;
	return js_truthy(js, result) ? js_mktrue() : js_mkfalse();
	}

	jsoff_t found = lkp_proto(js, r, prop_name, prop_len);
	return mkval(T_BOOL, found != 0 ? 1 : 0);
	}

	static char esm_get_extension(const char path) {
	const char *dot = strrchr(path, '.');
	const char *slash = strrchr(path, '/');

	if (dot && (!slash \|\| dot > slash)) {
	return strdup(dot);
	}
	return strdup(".js");
	}

	static char esm_try_resolve(const char dir, const char spec, const char suffix) {
	char path[PATH_MAX];
	snprintf(path, PATH_MAX, "%s/%s%s", dir, spec, suffix);
	char *resolved = realpath(path, NULL);
	if (resolved) {
	struct stat st;
	if (stat(resolved, &st) == 0 && S_ISREG(st.st_mode)) return resolved;
	free(resolved);
	}
	return NULL;
	}

	static bool esm_has_extension(const char *spec) {
	const char *dot = strrchr(spec, '.');
	const char *slash = strrchr(spec, '/');
	return dot && (!slash \|\| dot > slash);
	}

	static char esm_resolve_path(const char specifier, const char *base_path) {
	if (!(specifier[0] == '/' \|\|
	(specifier[0] == '.' && specifier[1] == '/') \|\|
	(specifier[0] == '.' && specifier[1] == '.' && specifier[2] == '/'))) {
	return strdup(specifier);
	}

	char *base_copy = strdup(base_path);
	char *dir = dirname(base_copy);
	char *result = NULL;

	const char *spec = (specifier[0] == '.' && specifier[1] == '/') ? specifier + 2 : specifier;
	bool has_ext = esm_has_extension(spec);

	if ((result = esm_try_resolve(dir, spec, ""))) goto cleanup;
	if (has_ext) goto cleanup;

	char *base_ext = esm_get_extension(base_path);

	if ((result = esm_try_resolve(dir, spec, base_ext))) goto cleanup_ext;
	if (strcmp(base_ext, ".js") != 0 && (result = esm_try_resolve(dir, spec, ".js"))) goto cleanup_ext;

	if ((result = esm_try_resolve(dir, spec, ".ts"))) goto cleanup_ext;
	if ((result = esm_try_resolve(dir, spec, ".mts"))) goto cleanup_ext;
	if ((result = esm_try_resolve(dir, spec, ".cts"))) goto cleanup_ext;
	if ((result = esm_try_resolve(dir, spec, ".json"))) goto cleanup_ext;

	char idx[PATH_MAX];
	snprintf(idx, PATH_MAX, "%s/index%s", spec, base_ext);
	if ((result = esm_try_resolve(dir, idx, ""))) goto cleanup_ext;

	if (strcmp(base_ext, ".js") != 0) {
	snprintf(idx, PATH_MAX, "%s/index.js", spec);
	if ((result = esm_try_resolve(dir, idx, ""))) goto cleanup_ext;
	}

	snprintf(idx, PATH_MAX, "%s/index.ts", spec);
	if ((result = esm_try_resolve(dir, idx, ""))) goto cleanup_ext;

	cleanup_ext:
	free(base_ext);
	cleanup:
	free(base_copy);
	return result;
	}

	static bool esm_has_suffix(const char path, const char ext) {
	size_t len = strlen(path);
	size_t elen = strlen(ext);
	return len > elen && strcmp(path + len - elen, ext) == 0;
	}

	static bool esm_is_json(const char *path) {
	return esm_has_suffix(path, ".json");
	}

	static bool esm_is_text(const char *path) {
	return esm_has_suffix(path, ".txt") \|\|
	esm_has_suffix(path, ".md") \|\|
	esm_has_suffix(path, ".html") \|\|
	esm_has_suffix(path, ".css");
	}

	static bool esm_is_image(const char *path) {
	return esm_has_suffix(path, ".png") \|\|
	esm_has_suffix(path, ".jpg") \|\|
	esm_has_suffix(path, ".jpeg") \|\|
	esm_has_suffix(path, ".gif") \|\|
	esm_has_suffix(path, ".svg") \|\|
	esm_has_suffix(path, ".webp");
	}

	static char esm_canonicalize_path(const char path) {
	if (!path) return NULL;

	char *canonical = strdup(path);
	if (!canonical) return NULL;

	char src = canonical, dst = canonical;

	while (*src) {
	if (*src == '/') {
	*dst++ = '/';
	while (*src == '/') src++;

	if (strncmp(src, "./", 2) == 0) {
	src += 2;
	} else if (strncmp(src, "../", 3) == 0) {
	src += 3;
	if (dst > canonical + 1) {
	dst--;
	while (dst > canonical && *(dst - 1) != '/') dst--;
	}
	}
	} else {
	dst++ = src++;
	}
	}

	*dst = '\0';

	if (strlen(canonical) > 1 && canonical[strlen(canonical) - 1] == '/') {
	canonical[strlen(canonical) - 1] = '\0';
	}

	return canonical;
	}

	static esm_module_t esm_find_module(const char resolved_path) {
	char *canonical_path = esm_canonicalize_path(resolved_path);
	if (!canonical_path) return NULL;

	esm_module_t *mod = NULL;
	HASH_FIND_STR(global_module_cache.modules, canonical_path, mod);

	free(canonical_path);
	return mod;
	}

	static esm_module_t esm_create_module(const char path, const char *resolved_path) {
	bool is_url = esm_is_url(resolved_path);
	char *canonical_path = is_url ? strdup(resolved_path) : esm_canonicalize_path(resolved_path);
	if (!canonical_path) return NULL;

	esm_module_t *existing_mod = NULL;
	HASH_FIND_STR(global_module_cache.modules, canonical_path, existing_mod);
	if (existing_mod) {
	free(canonical_path);
	return existing_mod;
	}

	esm_module_t mod = (esm_module_t )malloc(sizeof(esm_module_t));
	if (!mod) {
	free(canonical_path);
	return NULL;
	}

	mod->path = strdup(path);
	mod->resolved_path = canonical_path;
	mod->namespace_obj = js_mkundef();
	mod->default_export = js_mkundef();
	mod->is_loaded = false;
	mod->is_loading = false;
	mod->is_json = esm_is_json(resolved_path);
	mod->is_text = esm_is_text(resolved_path);
	mod->is_image = esm_is_image(resolved_path);
	mod->is_url = is_url;
	mod->url_content = NULL;
	mod->url_content_len = 0;
	mod->next = NULL;

	HASH_ADD_STR(global_module_cache.modules, resolved_path, mod);
	global_module_cache.count++;

	return mod;
	}

	static void esm_cleanup_module_cache(void) {
	esm_module_t current, tmp;
	HASH_ITER(hh, global_module_cache.modules, current, tmp) {
	HASH_DEL(global_module_cache.modules, current);
	if (current->path) free(current->path);
	if (current->resolved_path) free(current->resolved_path);
	if (current->url_content) free(current->url_content);
	free(current);
	}
	global_module_cache.count = 0;
	}

	typedef struct {
	char *data;
	size_t size;
	} esm_file_data_t;

	static jsval_t esm_read_file(struct js js, const char path, const char kind, esm_file_data_t out) {
	FILE *fp = fopen(path, "rb");
	if (!fp) return js_mkerr(js, "Cannot open %s: %s", kind, path);

	fseek(fp, 0, SEEK_END);
	long fsize = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	char buf = (char )malloc((size_t)fsize + 1);
	if (!buf) {
	fclose(fp);
	return js_mkerr(js, "OOM loading %s", kind);
	}

	fread(buf, 1, (size_t)fsize, fp);
	fclose(fp);
	buf[fsize] = '\0';

	out->data = buf;
	out->size = (size_t)fsize;
	return js_mkundef();
	}

	static jsval_t esm_load_json(struct js js, const char path) {
	esm_file_data_t file;
	jsval_t err = esm_read_file(js, path, "JSON file", &file);
	if (is_err(err)) return err;

	jsval_t json_str = js_mkstr(js, file.data, file.size);
	free(file.data);
	return js_json_parse(js, &json_str, 1);
	}

	static jsval_t esm_load_text(struct js js, const char path) {
	esm_file_data_t file;
	jsval_t err = esm_read_file(js, path, "text file", &file);
	if (is_err(err)) return err;

	jsval_t result = js_mkstr(js, file.data, file.size);
	free(file.data);
	return result;
	}

	static jsval_t esm_load_image(struct js js, const char path) {
	esm_file_data_t file;
	jsval_t err = esm_read_file(js, path, "image file", &file);
	if (is_err(err)) return err;

	unsigned char content = (unsigned char )file.data;
	size_t size = file.size;

	jsval_t obj = mkobj(js, 0);
	jsval_t data_arr = mkarr(js);

	for (size_t i = 0; i < size; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%zu", i);
	setprop(js, data_arr, js_mkstr(js, idx, strlen(idx)), tov((double)content[i]));
	}
	setprop(js, data_arr, js_mkstr(js, "length", 6), tov((double)size));

	setprop(js, obj, js_mkstr(js, "data", 4), mkval(T_ARR, vdata(data_arr)));
	setprop(js, obj, js_mkstr(js, "path", 4), js_mkstr(js, path, strlen(path)));
	setprop(js, obj, js_mkstr(js, "size", 4), tov((double)size));

	free(file.data);
	return obj;
	}

	static jsval_t esm_load_module(struct js js, esm_module_t mod) {
	if (mod->is_loaded) return mod->namespace_obj;
	if (mod->is_loading) return js_mkerr(js, "Circular dependency detected: %s", mod->path);

	mod->is_loading = true;

	if (mod->is_json) {
	jsval_t json_val = esm_load_json(js, mod->resolved_path);
	if (is_err(json_val)) {
	mod->is_loading = false;
	return json_val;
	}

	mod->namespace_obj = json_val;
	mod->default_export = json_val;
	mod->is_loaded = true;
	mod->is_loading = false;
	return json_val;
	}

	if (mod->is_text) {
	jsval_t text_val = esm_load_text(js, mod->resolved_path);
	if (is_err(text_val)) {
	mod->is_loading = false;
	return text_val;
	}

	mod->namespace_obj = text_val;
	mod->default_export = text_val;
	mod->is_loaded = true;
	mod->is_loading = false;
	return text_val;
	}

	if (mod->is_image) {
	jsval_t img_val = esm_load_image(js, mod->resolved_path);
	if (is_err(img_val)) {
	mod->is_loading = false;
	return img_val;
	}

	mod->namespace_obj = img_val;
	mod->default_export = img_val;
	mod->is_loaded = true;
	mod->is_loading = false;
	return img_val;
	}

	char *content = NULL;
	size_t size = 0;

	if (mod->is_url) {
	if (mod->url_content) {
	content = strdup(mod->url_content);
	size = mod->url_content_len;
	} else {
	char *error = NULL;
	content = esm_fetch_url(mod->resolved_path, &size, &error);
	if (!content) {
	mod->is_loading = false;
	jsval_t err = js_mkerr(js, "Cannot fetch module %s: %s", mod->resolved_path, error ? error : "unknown error");
	if (error) free(error);
	return err;
	}
	mod->url_content = strdup(content);
	mod->url_content_len = size;
	}
	} else {
	esm_file_data_t file;
	jsval_t err = esm_read_file(js, mod->resolved_path, "module", &file);
	if (is_err(err)) {
	mod->is_loading = false;
	return err;
	}
	content = file.data;
	size = file.size;
	}
	content[size] = '\0';

	char *js_code = content;
	size_t js_len = size;

	if (is_typescript_file(mod->resolved_path)) {
	int result = OXC_strip_types(content, mod->resolved_path, content, size + 1);
	if (result < 0) {
	free(content);
	mod->is_loading = false;
	return js_mkerr(js, "TypeScript error: strip failed (%d)", result);
	}
	js_len = (size_t)result;
	}

	jsval_t ns = mkobj(js, 0);
	mod->namespace_obj = ns;

	jsval_t prev_module = js->module_ns;
	js->module_ns = ns;

	const char *prev_filename = js->filename;
	jsval_t saved_scope = js->scope;

	js_set_filename(js, mod->resolved_path);
	mkscope(js); set_slot(js, js->scope, SLOT_MODULE_SCOPE, tov(1));

	jsval_t result = js_eval(js, js_code, js_len);
	free(content);

	js->scope = saved_scope;
	js_set_filename(js, prev_filename);
	js->module_ns = prev_module;

	if (is_err(result)) {
	mod->is_loading = false;
	return result;
	}

	jsval_t default_val = js_get_slot(js, ns, SLOT_DEFAULT);
	mod->default_export = js_type(default_val) != JS_UNDEF ? default_val : ns;

	mod->is_loaded = true;
	mod->is_loading = false;

	return ns;
	}

	static jsval_t esm_get_or_load(struct js js, const char specifier, const char *resolved_path) {
	esm_module_t *mod = esm_find_module(resolved_path);
	if (!mod) {
	mod = esm_create_module(specifier, resolved_path);
	if (!mod) return js_mkerr(js, "Cannot create module");
	}
	return esm_load_module(js, mod);
	}

	typedef struct {
	const char *import_name;
	size_t import_len;
	const char *local_name;
	size_t local_len;
	} esm_import_binding_t;

	static char esm_jsval_to_cstr(struct js js, jsval_t str, jsoff_t *out_len) {
	jsoff_t len;
	jsoff_t off = vstr(js, str, &len);
	if (out_len) *out_len = len;
	return strndup((char *)&js->mem[off], len);
	}

	static jsval_t esm_resolve_and_load(struct js js, const char spec_str, jsoff_t spec_len) {
	ant_library_t *lib = find_library(spec_str, spec_len);
	if (lib) return lib->init_fn(js);

	const char *base_path = js->filename ? js->filename : ".";
	char *resolved_path = esm_resolve(spec_str, base_path, esm_resolve_path);
	if (!resolved_path) return js_mkerr(js, "Cannot resolve module: %s", spec_str);

	jsval_t ns = esm_get_or_load(js, spec_str, resolved_path);
	free(resolved_path);
	return ns;
	}

	static jsval_t esm_make_file_url(struct js js, const char path) {
	size_t url_len = strlen(path) + 8;
	char *url = malloc(url_len);
	if (!url) return js_mkerr(js, "oom");

	snprintf(url, url_len, "file://%s", path);
	jsval_t val = js_mkstr(js, url, strlen(url));
	free(url);
	return val;
	}

	static int esm_parse_named_imports(struct js js, esm_import_binding_t bindings, int max_bindings) {
	int count = 0;

	while (next(js) != TOK_RBRACE && count < max_bindings) {
	if (next(js) != TOK_IDENTIFIER && next(js) != TOK_DEFAULT) {
	return -1;
	}
	const char *import_name = &js->code[js->toff];
	size_t import_len = js->tlen;
	js->consumed = 1;

	const char *local_name = import_name;
	size_t local_len = import_len;

	if (next(js) == TOK_AS) {
	js->consumed = 1;
	if (next(js) != TOK_IDENTIFIER && next(js) != TOK_DEFAULT) {
	return -1;
	}
	local_name = &js->code[js->toff];
	local_len = js->tlen;
	js->consumed = 1;
	}

	bindings[count].import_name = import_name;
	bindings[count].import_len = import_len;
	bindings[count].local_name = local_name;
	bindings[count].local_len = local_len;
	count++;

	if (next(js) == TOK_COMMA) js->consumed = 1;
	}

	if (next(js) != TOK_RBRACE) return -1;
	js->consumed = 1;
	return count;
	}

	static jsval_t builtin_import(struct js js, jsval_t args, int nargs) {
	if (nargs < 1 \|\| vtype(args[0]) != T_STR) {
	return js_mkerr(js, "import() requires a string specifier");
	}

	jsoff_t spec_len;
	char *specifier = esm_jsval_to_cstr(js, args[0], &spec_len);
	jsval_t ns = esm_resolve_and_load(js, specifier, spec_len);
	free(specifier);

	if (is_err(ns)) return builtin_Promise_reject(js, &ns, 1);

	jsval_t promise_args[] = { ns };
	return builtin_Promise_resolve(js, promise_args, 1);
	}

	static jsval_t builtin_import_meta_resolve(struct js js, jsval_t args, int nargs) {
	if (nargs < 1 \|\| vtype(args[0]) != T_STR) {
	return js_mkerr(js, "import.meta.resolve() requires a string specifier");
	}

	char *specifier = esm_jsval_to_cstr(js, args[0], NULL);

	const char *base_path = js->filename ? js->filename : ".";
	char *resolved_path = esm_resolve(specifier, base_path, esm_resolve_path);
	if (!resolved_path) {
	jsval_t err = js_mkerr(js, "Cannot resolve module: %s", specifier);
	free(specifier); return err;
	}
	free(specifier);

	if (esm_is_url(resolved_path)) {
	jsval_t result = js_mkstr(js, resolved_path, strlen(resolved_path));
	free(resolved_path); return result;
	}

	jsval_t result = esm_make_file_url(js, resolved_path);
	free(resolved_path);
	return result;
	}

	void js_setup_import_meta(struct js js, const char filename) {
	if (!filename) return;

	jsval_t import_meta = mkobj(js, 0);
	if (is_err(import_meta)) return;
	bool is_url = esm_is_url(filename);

	jsval_t url_val = is_url ? js_mkstr(js, filename, strlen(filename)) : esm_make_file_url(js, filename);
	if (!is_err(url_val)) setprop(js, import_meta, js_mkstr(js, "url", 3), url_val);

	jsval_t filename_val = js_mkstr(js, filename, strlen(filename));
	if (!is_err(filename_val)) setprop(js, import_meta, js_mkstr(js, "filename", 8), filename_val);

	if (is_url) {
	char *filename_copy = strdup(filename);
	if (filename_copy) {
	char *last_slash = strrchr(filename_copy, '/');
	char *scheme_end = strstr(filename_copy, "://");
	if (last_slash && scheme_end && last_slash > scheme_end + 2) {
	*last_slash = '\0';
	jsval_t dirname_val = js_mkstr(js, filename_copy, strlen(filename_copy));
	if (!is_err(dirname_val)) setprop(js, import_meta, js_mkstr(js, "dirname", 7), dirname_val);
	}
	free(filename_copy);
	}
	} else {
	char *filename_copy = strdup(filename);
	if (filename_copy) {
	char *dir = dirname(filename_copy);
	if (dir) {
	jsval_t dirname_val = js_mkstr(js, dir, strlen(dir));
	if (!is_err(dirname_val)) setprop(js, import_meta, js_mkstr(js, "dirname", 7), dirname_val);
	}
	free(filename_copy);
	}
	}

	setprop(js, import_meta, js_mkstr(js, "main", 4), js_mktrue());
	jsval_t resolve_fn = js_mkfun(builtin_import_meta_resolve);
	setprop(js, import_meta, js_mkstr(js, "resolve", 7), resolve_fn);

	jsval_t glob = js_glob(js);
	jsoff_t import_off = lkp(js, glob, "import", 6);

	if (import_off != 0) {
	jsval_t import_fn = resolveprop(js, mkval(T_PROP, import_off));
	if (vtype(import_fn) == T_FUNC) {
	jsval_t import_obj = mkval(T_OBJ, vdata(import_fn));
	setprop(js, import_obj, js_mkstr(js, "meta", 4), import_meta);
	}
	}
	}

	static jsval_t js_import_stmt(struct js *js) {
	js->consumed = 1;

	if (next(js) == TOK_LPAREN) {
	js->consumed = 1;
	jsval_t spec = js_expr(js);
	EXPECT(TOK_RPAREN);

	if (vtype(spec) != T_STR) {
	return js_mkerr(js, "import() requires string");
	}

	jsval_t args[] = { spec };
	return builtin_import(js, args, 1);
	}

	if (next(js) == TOK_MUL) {
	js->consumed = 1;
	EXPECT(TOK_AS);
	EXPECT(TOK_IDENTIFIER);

	const char *namespace_name = &js->code[js->toff];
	size_t namespace_len = js->tlen;
	js->consumed = 1;

	EXPECT(TOK_FROM);
	EXPECT(TOK_STRING);

	jsval_t spec = js_str_literal(js);
	jsoff_t spec_len;
	char *spec_str = esm_jsval_to_cstr(js, spec, &spec_len);

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	jsval_t ns = esm_resolve_and_load(js, spec_str, spec_len);
	JS_RESTORE_STATE(js, saved);
	free(spec_str);

	js->consumed = 1; next(js); js->consumed = 0;
	if (is_err(ns)) return ns;

	if (vtype(ns) != T_OBJ) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "Cannot re-export from non-object module");
	}

	setprop(js, js->scope, js_mkstr(js, namespace_name, namespace_len), ns);
	return js_mkundef();
	}

	if (next(js) == TOK_IDENTIFIER) {
	const char *default_name = &js->code[js->toff];
	size_t default_len = js->tlen;
	js->consumed = 1;

	esm_import_binding_t bindings[64];
	int binding_count = 0;

	if (next(js) == TOK_COMMA) {
	js->consumed = 1;

	if (next(js) == TOK_LBRACE) {
	js->consumed = 1;
	binding_count = esm_parse_named_imports(js, bindings, 64);
	if (binding_count < 0) return js_mkerr(js, "Failed to parse named imports");
	} else if (next(js) == TOK_MUL) {
	js->consumed = 1;
	EXPECT(TOK_AS);
	EXPECT(TOK_IDENTIFIER);
	bindings[binding_count].import_name = NULL;
	bindings[binding_count].import_len = 0;
	bindings[binding_count].local_name = &js->code[js->toff];
	bindings[binding_count].local_len = js->tlen;
	binding_count++;
	js->consumed = 1;
	} else {
	return js_mkerr(js, "Expected '{' or '*' after ',' in import");
	}
	}

	EXPECT(TOK_FROM);
	EXPECT(TOK_STRING);

	jsval_t spec = js_str_literal(js);
	jsoff_t spec_len;
	char *spec_str = esm_jsval_to_cstr(js, spec, &spec_len);

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	jsval_t ns = esm_resolve_and_load(js, spec_str, spec_len);
	JS_RESTORE_STATE(js, saved);
	free(spec_str);

	js->consumed = 1; next(js); js->consumed = 0;
	if (is_err(ns)) return ns;

	jsval_t default_val;
	if (vtype(ns) == T_OBJ) {
	jsval_t slot_val = js_get_slot(js, ns, SLOT_DEFAULT);
	default_val = js_type(slot_val) != JS_UNDEF ? slot_val : ns;
	} else default_val = ns;
	setprop(js, js->scope, js_mkstr(js, default_name, default_len), default_val);

	for (int i = 0; i < binding_count; i++) {
	if (bindings[i].import_name == NULL) {
	setprop(js, js->scope, js_mkstr(js, bindings[i].local_name, bindings[i].local_len), ns);
	} else if (vtype(ns) == T_OBJ) {
	jsoff_t prop_off = lkp(js, ns, bindings[i].import_name, bindings[i].import_len);
	if (prop_off == 0) return js_mkerr_typed(
	js, JS_ERR_SYNTAX, "The requested module does not provide an export named '%.*s'",
	(int)bindings[i].import_len, bindings[i].import_name
	);
	jsval_t imported_val = resolveprop(js, mkval(T_PROP, prop_off));
	setprop(js, js->scope, js_mkstr(js, bindings[i].local_name, bindings[i].local_len), imported_val);
	} else return js_mkerr_typed(js, JS_ERR_SYNTAX, "Cannot use named imports from non-object module");
	}

	return js_mkundef();
	}

	if (next(js) == TOK_LBRACE) {
	js->consumed = 1;

	esm_import_binding_t bindings[64];
	int binding_count = esm_parse_named_imports(js, bindings, 64);
	if (binding_count < 0) return js_mkerr(js, "Failed to parse named imports");

	EXPECT(TOK_FROM);
	EXPECT(TOK_STRING);

	jsval_t spec = js_str_literal(js);
	jsoff_t spec_len;
	char *spec_str = esm_jsval_to_cstr(js, spec, &spec_len);

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	jsoff_t saved_toff = js->toff, saved_tlen = js->tlen;
	jsval_t saved_scope = js->scope;

	jsval_t ns = esm_resolve_and_load(js, spec_str, spec_len);

	JS_RESTORE_STATE(js, saved);
	js->toff = saved_toff;
	js->tlen = saved_tlen;
	js->scope = saved_scope;
	free(spec_str);

	js->consumed = 1;
	next(js);
	js->consumed = 0;

	if (is_err(ns)) return ns;
	if (vtype(ns) != T_OBJ) return js_mkerr(js, "Cannot use named imports from non-object module");

	for (int i = 0; i < binding_count; i++) {
	jsoff_t prop_off = lkp(js, ns, bindings[i].import_name, bindings[i].import_len);
	if (prop_off == 0) return js_mkerr_typed(
	js, JS_ERR_SYNTAX, "The requested module does not provide an export named '%.*s'",
	(int)bindings[i].import_len, bindings[i].import_name
	);
	jsval_t imported_val = resolveprop(js, mkval(T_PROP, prop_off));
	setprop(js, js->scope, js_mkstr(js, bindings[i].local_name, bindings[i].local_len), imported_val);
	}

	return js_mkundef();
	}

	if (next(js) == TOK_STRING) {
	jsval_t spec = js_str_literal(js);
	jsoff_t spec_len;
	char *spec_str = esm_jsval_to_cstr(js, spec, &spec_len);

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	jsval_t ns = esm_resolve_and_load(js, spec_str, spec_len);
	JS_RESTORE_STATE(js, saved);
	free(spec_str);

	js->consumed = 1;
	next(js);
	js->consumed = 0;

	if (is_err(ns)) return ns;
	return js_mkundef();
	}

	return js_mkerr_typed(js, JS_ERR_SYNTAX, "Invalid import statement");
	}

	static jsval_t js_export_stmt(struct js *js) {
	js->consumed = 1;

	if (vtype(js->module_ns) != T_OBJ) {
	js->module_ns = mkobj(js, 0);
	}

	if (next(js) == TOK_DEFAULT) {
	js->consumed = 1;
	jsval_t value = js_assignment(js);
	if (is_err(value)) return value;

	jsval_t resolved = resolveprop(js, value);
	js_set_slot(js, js->module_ns, SLOT_DEFAULT, resolved);
	js_mkprop_fast(js, js->module_ns, "default", 7, resolved);

	return value;
	}

	if (next(js) == TOK_CONST \|\| next(js) == TOK_LET \|\| next(js) == TOK_VAR) {
	bool is_const = (next(js) == TOK_CONST);
	js->consumed = 1;

	EXPECT(TOK_IDENTIFIER);
	const char *name = &js->code[js->toff];
	size_t name_len = js->tlen;
	js->consumed = 1;

	jsval_t value = js_mkundef();
	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	value = js_assignment(js);
	if (is_err(value)) return value;
	}

	jsval_t key = js_mkstr(js, name, name_len);
	mkprop(js, js->scope, key, resolveprop(js, value), is_const ? CONSTMASK : 0);
	setprop(js, js->module_ns, key, resolveprop(js, value));

	return value;
	}

	if (next(js) == TOK_FUNC) {
	jsval_t func = js_func_literal(js, false);
	if (is_err(func)) return func;

	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsoff_t name_off = lkp(js, func_obj, "name", 4);
	if (name_off != 0) {
	jsval_t name_val = resolveprop(js, mkval(T_PROP, name_off));
	if (vtype(name_val) == T_STR) {
	setprop(js, js->scope, name_val, func);
	setprop(js, js->module_ns, name_val, func);
	}
	}

	return func;
	}

	if (next(js) == TOK_CLASS) {
	jsval_t cls = js_class_decl(js);
	if (is_err(cls)) return cls;

	jsval_t cls_obj = mkval(T_OBJ, vdata(cls));
	jsoff_t name_off = lkp(js, cls_obj, "name", 4);
	if (name_off != 0) {
	jsval_t name_val = resolveprop(js, mkval(T_PROP, name_off));
	if (vtype(name_val) == T_STR) {
	setprop(js, js->scope, name_val, cls);
	setprop(js, js->module_ns, name_val, cls);
	}
	}

	return cls;
	}

	if (next(js) == TOK_MUL) {
	js->consumed = 1;

	const char *alias_name = NULL;
	size_t alias_len = 0;

	if (next(js) == TOK_AS) {
	js->consumed = 1;
	EXPECT(TOK_IDENTIFIER);
	alias_name = &js->code[js->toff];
	alias_len = js->tlen;
	js->consumed = 1;
	}

	EXPECT(TOK_FROM);
	EXPECT(TOK_STRING);

	jsval_t spec = js_str_literal(js);
	jsoff_t spec_len;
	char *spec_str = esm_jsval_to_cstr(js, spec, &spec_len);

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	jsval_t ns = esm_resolve_and_load(js, spec_str, spec_len);
	JS_RESTORE_STATE(js, saved);
	free(spec_str);

	js->consumed = 1; next(js); js->consumed = 0;
	if (is_err(ns)) return ns;

	if (alias_name) {
	setprop(js, js->module_ns, js_mkstr(js, alias_name, alias_len), ns);
	} else if (vtype(ns) == T_OBJ) {
	ant_iter_t iter = js_prop_iter_begin(js, ns);
	const char *key; size_t key_len; jsval_t value;

	while (js_prop_iter_next(&iter, &key, &key_len, &value)) {
	setprop(js, js->module_ns, js_mkstr(js, key, key_len), resolveprop(js, value));
	}
	js_prop_iter_end(&iter);
	}

	return js_mkundef();
	}

	if (next(js) == TOK_LBRACE) {
	js->consumed = 1;

	typedef struct { const char local; size_t local_len; const char exported; size_t export_len; } export_spec_t;
	export_spec_t specs[64];
	int spec_count = 0;

	while (next(js) != TOK_RBRACE) {
	if (spec_count >= 64) return js_mkerr(js, "too many export specifiers");

	if (next(js) != TOK_IDENTIFIER && next(js) != TOK_DEFAULT) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "expected identifier or 'default' in export list");
	}
	specs[spec_count].local = &js->code[js->toff];
	specs[spec_count].local_len = js->tlen;
	specs[spec_count].exported = specs[spec_count].local;
	specs[spec_count].export_len = specs[spec_count].local_len;
	js->consumed = 1;

	if (next(js) == TOK_AS) {
	js->consumed = 1;
	if (next(js) != TOK_IDENTIFIER && next(js) != TOK_DEFAULT) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "expected identifier or 'default' after 'as'");
	}
	specs[spec_count].exported = &js->code[js->toff];
	specs[spec_count].export_len = js->tlen;
	js->consumed = 1;
	}

	spec_count++;
	if (next(js) == TOK_COMMA) js->consumed = 1;
	}

	EXPECT(TOK_RBRACE);

	if (next(js) == TOK_FROM) {
	js->consumed = 1;
	EXPECT(TOK_STRING);
	jsval_t spec = js_str_literal(js);
	jsoff_t spec_len;
	char *spec_str = esm_jsval_to_cstr(js, spec, &spec_len);

	js_parse_state_t saved;
	JS_SAVE_STATE(js, saved);
	jsval_t ns = esm_resolve_and_load(js, spec_str, spec_len);
	JS_RESTORE_STATE(js, saved);
	free(spec_str);

	js->consumed = 1; next(js); js->consumed = 0;
	if (is_err(ns)) return ns;

	for (int i = 0; i < spec_count; i++) {
	jsoff_t prop_off = lkp(js, ns, specs[i].local, specs[i].local_len);
	jsval_t import_val = prop_off != 0 ? resolveprop(js, mkval(T_PROP, prop_off)) : js_mkundef();
	setprop(js, js->module_ns, js_mkstr(js, specs[i].exported, specs[i].export_len), import_val);
	}
	} else {
	for (int i = 0; i < spec_count; i++) {
	jsval_t local_val = lookup(js, specs[i].local, specs[i].local_len);
	if (is_err(local_val)) return local_val;
	setprop(js, js->module_ns, js_mkstr(js, specs[i].exported, specs[i].export_len), resolveprop(js, local_val));
	}
	}

	if (next(js) == TOK_SEMICOLON) js->consumed = 1;
	return js_mkundef();
	}

	return js_mkerr(js, "Invalid export statement");
	}

	typedef struct weakmap_entry {
	jsval_t key_obj;
	jsval_t value;
	UT_hash_handle hh;
	} weakmap_entry_t;

	typedef struct weakset_entry {
	jsval_t value_obj;
	UT_hash_handle hh;
	} weakset_entry_t;

	static const char* jsval_to_key(struct js *js, jsval_t val) {
	if (vtype(val) == T_STR) {
	jsoff_t len;
	jsoff_t off = vstr(js, val, &len);
	return (char *)&js->mem[off];
	} else return js_str(js, val);
	}

	static jsval_t builtin_Map(struct js js, jsval_t args, int nargs) {
	jsval_t map_obj = mkobj(js, 0);

	jsval_t map_proto = get_ctor_proto(js, "Map", 3);
	if (vtype(map_proto) == T_OBJ) set_proto(js, map_obj, map_proto);

	map_entry_t map_head = (map_entry_t )ant_calloc(sizeof(map_entry_t *));
	if (!map_head) return js_mkerr(js, "out of memory");
	*map_head = NULL;

	map_registry_entry_t reg = (map_registry_entry_t )ant_calloc(sizeof(map_registry_entry_t));
	if (reg) {
	reg->head = map_head;
	HASH_ADD_PTR(map_registry, head, reg);
	}

	jsval_t map_ptr = tov((double)(size_t)map_head);
	set_slot(js, map_obj, SLOT_MAP, map_ptr);

	if (nargs == 0 \|\| vtype(args[0]) != T_ARR) return map_obj;

	jsval_t iterable = args[0];
	jsoff_t length = arr_length(js, iterable);

	for (jsoff_t i = 0; i < length; i++) {
	jsval_t entry = arr_get(js, iterable, i);
	if (vtype(entry) != T_ARR) continue;

	jsoff_t entry_len = arr_length(js, entry);
	if (entry_len < 2) continue;

	jsval_t key = arr_get(js, entry, 0);
	jsval_t value = arr_get(js, entry, 1);
	const char *key_str = jsval_to_key(js, key);

	map_entry_t *map_entry;
	HASH_FIND_STR(*map_head, key_str, map_entry);
	if (map_entry) {
	map_entry->value = value;
	continue;
	}

	map_entry = (map_entry_t *)ant_calloc(sizeof(map_entry_t));
	if (!map_entry) return js_mkerr(js, "out of memory");
	map_entry->key = strdup(key_str);
	map_entry->value = value;
	HASH_ADD_STR(*map_head, key, map_entry);
	}

	return map_obj;
	}

	static jsval_t builtin_Set(struct js js, jsval_t args, int nargs) {
	jsval_t set_obj = mkobj(js, 0);

	jsval_t set_proto_val = get_ctor_proto(js, "Set", 3);
	if (vtype(set_proto_val) == T_OBJ) set_proto(js, set_obj, set_proto_val);

	set_entry_t set_head = (set_entry_t )ant_calloc(sizeof(set_entry_t *));
	if (!set_head) return js_mkerr(js, "out of memory");
	*set_head = NULL;

	set_registry_entry_t reg = (set_registry_entry_t )ant_calloc(sizeof(set_registry_entry_t));
	if (reg) {
	reg->head = set_head;
	HASH_ADD_PTR(set_registry, head, reg);
	}

	jsval_t set_ptr = tov((double)(size_t)set_head);
	set_slot(js, set_obj, SLOT_SET, set_ptr);

	if (nargs == 0 \|\| vtype(args[0]) != T_ARR) return set_obj;

	jsval_t iterable = args[0];
	jsoff_t length = arr_length(js, iterable);

	for (jsoff_t i = 0; i < length; i++) {
	jsval_t value = arr_get(js, iterable, i);
	const char *key_str = jsval_to_key(js, value);

	set_entry_t *entry;
	HASH_FIND_STR(*set_head, key_str, entry);
	if (entry) continue;

	entry = (set_entry_t *)ant_calloc(sizeof(set_entry_t));
	if (!entry) return js_mkerr(js, "out of memory");
	entry->value = value;
	entry->key = strdup(key_str);
	HASH_ADD_KEYPTR(hh, *set_head, entry->key, strlen(entry->key), entry);
	}

	return set_obj;
	}

	static map_entry_t** get_map_from_obj(struct js *js, jsval_t obj) {
	jsval_t map_val = js_get_slot(js, obj, SLOT_MAP);
	if (vtype(map_val) == T_UNDEF) return NULL;
	return (map_entry_t**)(size_t)tod(map_val);
	}

	static set_entry_t** get_set_from_obj(struct js *js, jsval_t obj) {
	jsval_t set_val = js_get_slot(js, obj, SLOT_SET);
	if (vtype(set_val) == T_UNDEF) return NULL;
	return (set_entry_t**)(size_t)tod(set_val);
	}

	static jsval_t map_set(struct js js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "Map.set() requires 2 arguments");

	jsval_t this_val = js->this_val;
	map_entry_t **map_ptr = get_map_from_obj(js, this_val);
	if (!map_ptr) return js_mkerr(js, "Invalid Map object");

	const char *key_str;
	if (vtype(args[0]) == T_STR) {
	jsoff_t len;
	jsoff_t off = vstr(js, args[0], &len);
	key_str = (char *)&js->mem[off];
	} else key_str = js_str(js, args[0]);

	map_entry_t *entry;
	HASH_FIND_STR(*map_ptr, key_str, entry);
	if (entry) {
	entry->value = args[1];
	} else {
	entry = (map_entry_t *)ant_calloc(sizeof(map_entry_t));
	if (!entry) return js_mkerr(js, "out of memory");
	entry->key = strdup(key_str);
	entry->value = args[1];
	HASH_ADD_STR(*map_ptr, key, entry);
	}

	return this_val;
	}

	static jsval_t map_get(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Map.get() requires 1 argument");

	jsval_t this_val = js->this_val;
	map_entry_t **map_ptr = get_map_from_obj(js, this_val);
	if (!map_ptr) return js_mkundef();

	const char *key_str;
	if (vtype(args[0]) == T_STR) {
	jsoff_t len;
	jsoff_t off = vstr(js, args[0], &len);
	key_str = (char *)&js->mem[off];
	} else key_str = js_str(js, args[0]);

	map_entry_t *entry;
	HASH_FIND_STR(*map_ptr, key_str, entry);
	return entry ? entry->value : js_mkundef();
	}

	static jsval_t map_has(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Map.has() requires 1 argument");

	jsval_t this_val = js->this_val;
	map_entry_t **map_ptr = get_map_from_obj(js, this_val);
	if (!map_ptr) return mkval(T_BOOL, 0);

	const char *key_str;
	if (vtype(args[0]) == T_STR) {
	jsoff_t len;
	jsoff_t off = vstr(js, args[0], &len);
	key_str = (char *)&js->mem[off];
	} else key_str = js_str(js, args[0]);

	map_entry_t *entry;
	HASH_FIND_STR(*map_ptr, key_str, entry);
	return mkval(T_BOOL, entry ? 1 : 0);
	}

	static jsval_t map_delete(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Map.delete() requires 1 argument");

	jsval_t this_val = js->this_val;
	map_entry_t **map_ptr = get_map_from_obj(js, this_val);
	if (!map_ptr) return mkval(T_BOOL, 0);

	const char *key_str;
	if (vtype(args[0]) == T_STR) {
	jsoff_t len;
	jsoff_t off = vstr(js, args[0], &len);
	key_str = (char *)&js->mem[off];
	} else key_str = js_str(js, args[0]);

	map_entry_t *entry;
	HASH_FIND_STR(*map_ptr, key_str, entry);
	if (entry) {
	HASH_DEL(*map_ptr, entry);
	free(entry->key);
	free(entry);
	return mkval(T_BOOL, 1);
	}
	return mkval(T_BOOL, 0);
	}

	static jsval_t map_clear(struct js js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	map_entry_t **map_ptr = get_map_from_obj(js, this_val);
	if (!map_ptr) return js_mkundef();

	map_entry_t entry, tmp;
	HASH_ITER(hh, *map_ptr, entry, tmp) {
	HASH_DEL(*map_ptr, entry);
	free(entry->key);
	free(entry);
	}
	*map_ptr = NULL;

	return js_mkundef();
	}

	static jsval_t map_size(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t this_val = js->this_val;
	map_entry_t **map_ptr = get_map_from_obj(js, this_val);
	if (!map_ptr) return tov(0);

	size_t count = HASH_COUNT(*map_ptr);
	return tov((double)count);
	}

	static jsval_t map_iter_next(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t this_val = js->this_val;
	jsval_t idx_val = js_get(js, this_val, "__idx");
	jsval_t keys = js_get(js, this_val, "__keys");
	jsval_t vals = js_get(js, this_val, "__vals");
	jsval_t len_val = js_get(js, this_val, "__len");

	int idx = (int)js_getnum(idx_val);
	int len = (int)js_getnum(len_val);

	jsval_t result = js_mkobj(js);
	if (idx >= len) {
	js_set(js, result, "done", js_mktrue());
	js_set(js, result, "value", js_mkundef());
	} else {
	char idxstr[16];
	uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t k = js_get(js, keys, idxstr);
	jsval_t v = js_get(js, vals, idxstr);
	jsval_t entry = js_mkarr(js);
	js_arr_push(js, entry, k);
	js_arr_push(js, entry, v);
	js_set(js, result, "value", entry);
	js_set(js, result, "done", js_mkfalse());
	js_set(js, this_val, "__idx", js_mknum(idx + 1));
	}
	return result;
	}

	static jsval_t map_entries(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t this_val = js->this_val;
	map_entry_t **map_ptr = get_map_from_obj(js, this_val);

	jsval_t keys = js_mkarr(js);
	jsval_t vals = js_mkarr(js);
	int count = 0;

	if (map_ptr && *map_ptr) {
	map_entry_t entry, tmp;
	HASH_ITER(hh, *map_ptr, entry, tmp) {
	js_arr_push(js, keys, js_mkstr(js, entry->key, strlen(entry->key)));
	js_arr_push(js, vals, entry->value);
	count++;
	}
	}

	jsval_t iter = js_mkobj(js);
	js_set(js, iter, "__keys", keys);
	js_set(js, iter, "__vals", vals);
	js_set(js, iter, "__idx", js_mknum(0));
	js_set(js, iter, "__len", js_mknum(count));
	js_set(js, iter, "next", js_mkfun(map_iter_next));
	return iter;
	}

	static jsval_t set_iter_next(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t this_val = js->this_val;
	jsval_t idx_val = js_get(js, this_val, "__idx");
	jsval_t vals = js_get(js, this_val, "__vals");
	jsval_t len_val = js_get(js, this_val, "__len");

	int idx = (int)js_getnum(idx_val);
	int len = (int)js_getnum(len_val);

	jsval_t result = js_mkobj(js);
	if (idx >= len) {
	js_set(js, result, "done", js_mktrue());
	js_set(js, result, "value", js_mkundef());
	} else {
	char idxstr[16];
	uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t v = js_get(js, vals, idxstr);
	js_set(js, result, "value", v);
	js_set(js, result, "done", js_mkfalse());
	js_set(js, this_val, "__idx", js_mknum(idx + 1));
	}
	return result;
	}

	static jsval_t set_values(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t this_val = js->this_val;
	set_entry_t **set_ptr = get_set_from_obj(js, this_val);

	jsval_t vals = js_mkarr(js);
	int count = 0;

	if (set_ptr && *set_ptr) {
	set_entry_t entry, tmp;
	HASH_ITER(hh, *set_ptr, entry, tmp) {
	js_arr_push(js, vals, entry->value);
	count++;
	}
	}

	jsval_t iter = js_mkobj(js);
	js_set(js, iter, "__vals", vals);
	js_set(js, iter, "__idx", js_mknum(0));
	js_set(js, iter, "__len", js_mknum(count));
	js_set(js, iter, "next", js_mkfun(set_iter_next));
	return iter;
	}

	static jsval_t set_add(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Set.add() requires 1 argument");

	jsval_t this_val = js->this_val;
	set_entry_t **set_ptr = get_set_from_obj(js, this_val);
	if (!set_ptr) return js_mkerr(js, "Invalid Set object");

	const char *key_str = jsval_to_key(js, args[0]);

	set_entry_t *entry;
	HASH_FIND_STR(*set_ptr, key_str, entry);

	if (!entry) {
	entry = (set_entry_t *)ant_calloc(sizeof(set_entry_t));
	if (!entry) return js_mkerr(js, "out of memory");
	entry->value = args[0];
	entry->key = strdup(key_str);
	HASH_ADD_KEYPTR(hh, *set_ptr, entry->key, strlen(entry->key), entry);
	}

	return this_val;
	}

	static jsval_t set_has(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Set.has() requires 1 argument");

	jsval_t this_val = js->this_val;
	set_entry_t **set_ptr = get_set_from_obj(js, this_val);
	if (!set_ptr) return mkval(T_BOOL, 0);

	const char *key_str = jsval_to_key(js, args[0]);

	set_entry_t *entry;
	HASH_FIND_STR(*set_ptr, key_str, entry);

	return mkval(T_BOOL, entry ? 1 : 0);
	}

	static jsval_t set_delete(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Set.delete() requires 1 argument");

	jsval_t this_val = js->this_val;
	set_entry_t **set_ptr = get_set_from_obj(js, this_val);
	if (!set_ptr) return mkval(T_BOOL, 0);

	const char *key_str = jsval_to_key(js, args[0]);
	set_entry_t *entry;
	HASH_FIND_STR(*set_ptr, key_str, entry);

	if (entry) {
	HASH_DEL(*set_ptr, entry);
	free(entry->key);
	free(entry);
	return mkval(T_BOOL, 1);
	}
	return mkval(T_BOOL, 0);
	}

	static jsval_t set_clear(struct js js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	set_entry_t **set_ptr = get_set_from_obj(js, this_val);
	if (!set_ptr) return js_mkundef();

	set_entry_t entry, tmp;
	HASH_ITER(hh, *set_ptr, entry, tmp) {
	HASH_DEL(*set_ptr, entry);
	free(entry->key);
	free(entry);
	}
	*set_ptr = NULL;

	return js_mkundef();
	}

	static jsval_t set_size(struct js js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	set_entry_t **set_ptr = get_set_from_obj(js, this_val);
	if (!set_ptr) return tov(0);

	size_t count = HASH_COUNT(*set_ptr);
	return tov((double)count);
	}

	static jsval_t builtin_WeakMap(struct js js, jsval_t args, int nargs) {
	jsval_t wm_obj = mkobj(js, 0);

	jsval_t wm_proto = get_ctor_proto(js, "WeakMap", 7);
	if (vtype(wm_proto) == T_OBJ) set_proto(js, wm_obj, wm_proto);

	weakmap_entry_t wm_head = (weakmap_entry_t )ant_calloc(sizeof(weakmap_entry_t *));
	if (!wm_head) return js_mkerr(js, "out of memory");
	*wm_head = NULL;

	jsval_t wm_ptr = mkval(T_NUM, (size_t)wm_head);
	jsval_t wm_key = js_mkstr(js, "__weakmap", 9);
	setprop(js, wm_obj, wm_key, wm_ptr);

	if (nargs == 0 \|\| vtype(args[0]) != T_ARR) return wm_obj;

	jsval_t iterable = args[0];
	jsoff_t length = arr_length(js, iterable);

	for (jsoff_t i = 0; i < length; i++) {
	jsval_t entry = arr_get(js, iterable, i);
	if (vtype(entry) != T_ARR) continue;

	jsoff_t entry_len = arr_length(js, entry);
	if (entry_len < 2) continue;

	jsval_t key = arr_get(js, entry, 0);
	jsval_t value = arr_get(js, entry, 1);

	if (vtype(key) != T_OBJ) return js_mkerr(js, "WeakMap key must be an object");

	weakmap_entry_t *wm_entry;
	HASH_FIND(hh, *wm_head, &key, sizeof(jsval_t), wm_entry);
	if (wm_entry) {
	wm_entry->value = value;
	continue;
	}

	wm_entry = (weakmap_entry_t *)ant_calloc(sizeof(weakmap_entry_t));
	if (!wm_entry) return js_mkerr(js, "out of memory");
	wm_entry->key_obj = key;
	wm_entry->value = value;
	HASH_ADD(hh, *wm_head, key_obj, sizeof(jsval_t), wm_entry);
	}

	return wm_obj;
	}

	static jsval_t builtin_WeakSet(struct js js, jsval_t args, int nargs) {
	jsval_t ws_obj = mkobj(js, 0);

	jsval_t ws_proto = get_ctor_proto(js, "WeakSet", 7);
	if (vtype(ws_proto) == T_OBJ) set_proto(js, ws_obj, ws_proto);

	weakset_entry_t ws_head = (weakset_entry_t )ant_calloc(sizeof(weakset_entry_t *));
	if (!ws_head) return js_mkerr(js, "out of memory");
	*ws_head = NULL;

	jsval_t ws_ptr = mkval(T_NUM, (size_t)ws_head);
	jsval_t ws_key = js_mkstr(js, "__weakset", 9);
	setprop(js, ws_obj, ws_key, ws_ptr);

	if (nargs == 0 \|\| vtype(args[0]) != T_ARR) return ws_obj;

	jsval_t iterable = args[0];
	jsoff_t length = arr_length(js, iterable);

	for (jsoff_t i = 0; i < length; i++) {
	jsval_t value = arr_get(js, iterable, i);

	if (vtype(value) != T_OBJ) return js_mkerr(js, "WeakSet value must be an object");

	weakset_entry_t *entry;
	HASH_FIND(hh, *ws_head, &value, sizeof(jsval_t), entry);
	if (entry) continue;

	entry = (weakset_entry_t *)ant_calloc(sizeof(weakset_entry_t));
	if (!entry) return js_mkerr(js, "out of memory");
	entry->value_obj = value;
	HASH_ADD(hh, *ws_head, value_obj, sizeof(jsval_t), entry);
	}

	return ws_obj;
	}

	static jsval_t builtin_WeakRef(struct js js, jsval_t args, int nargs) {
	if (nargs < 1 \|\| vtype(args[0]) != T_OBJ) {
	return js_mkerr(js, "WeakRef target must be an object");
	}

	jsval_t wr_obj = mkobj(js, 0);
	jsval_t wr_proto = get_ctor_proto(js, "WeakRef", 7);
	if (vtype(wr_proto) == T_OBJ) set_proto(js, wr_obj, wr_proto);
	set_slot(js, wr_obj, SLOT_DATA, args[0]);

	return wr_obj;
	}

	static jsval_t weakref_deref(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t this_val = js->this_val;
	if (vtype(this_val) != T_OBJ) return js_mkundef();

	jsval_t target = get_slot(js, this_val, SLOT_DATA);
	if (vtype(target) != T_OBJ) return js_mkundef();

	return target;
	}

	static jsval_t builtin_FinalizationRegistry(struct js js, jsval_t args, int nargs) {
	if (nargs < 1 \|\| (vtype(args[0]) != T_FUNC && vtype(args[0]) != T_CFUNC)) {
	return js_mkerr(js, "FinalizationRegistry callback must be a function");
	}

	jsval_t fr_obj = mkobj(js, 0);
	jsval_t fr_proto = get_ctor_proto(js, "FinalizationRegistry", 20);
	if (vtype(fr_proto) == T_OBJ) set_proto(js, fr_obj, fr_proto);

	set_slot(js, fr_obj, SLOT_DATA, args[0]);
	set_slot(js, fr_obj, SLOT_MAP, mkarr(js));

	return fr_obj;
	}

	static jsval_t finreg_register(struct js js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	if (vtype(this_val) != T_OBJ) return js_mkundef();

	if (nargs < 1 \|\| vtype(args[0]) != T_OBJ) {
	return js_mkerr(js, "FinalizationRegistry.register target must be an object");
	}

	jsval_t target = args[0];
	jsval_t held_value = nargs > 1 ? args[1] : js_mkundef();
	jsval_t unregister_token = nargs > 2 ? args[2] : js_mkundef();

	if (vdata(target) == vdata(held_value) && vtype(held_value) == T_OBJ) {
	return js_mkerr(js, "target and held value must not be the same");
	}

	jsval_t registrations = get_slot(js, this_val, SLOT_MAP);
	if (vtype(registrations) != T_ARR) return js_mkundef();

	jsval_t entry = mkarr(js);
	jsoff_t len = arr_length(js, registrations);

	char idx[16];
	size_t idx_len = uint_to_str(idx, sizeof(idx), 0);
	setprop(js, entry, js_mkstr(js, idx, idx_len), target);
	idx_len = uint_to_str(idx, sizeof(idx), 1);
	setprop(js, entry, js_mkstr(js, idx, idx_len), held_value);
	idx_len = uint_to_str(idx, sizeof(idx), 2);
	setprop(js, entry, js_mkstr(js, idx, idx_len), unregister_token);
	setprop(js, entry, js_mkstr(js, "length", 6), tov(3.0));

	idx_len = uint_to_str(idx, sizeof(idx), len);
	setprop(js, registrations, js_mkstr(js, idx, idx_len), entry);
	setprop(js, registrations, js_mkstr(js, "length", 6), tov((double)(len + 1)));

	return js_mkundef();
	}

	static jsval_t finreg_unregister(struct js js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	if (vtype(this_val) != T_OBJ) return js_mkfalse();

	if (nargs < 1 \|\| vtype(args[0]) != T_OBJ) {
	return js_mkerr(js, "FinalizationRegistry.unregister token must be an object");
	}

	jsval_t token = args[0];
	jsval_t registrations = get_slot(js, this_val, SLOT_MAP);
	if (vtype(registrations) != T_ARR) return js_mkfalse();

	jsoff_t len = arr_length(js, registrations);
	bool removed = false;

	for (jsoff_t i = 0; i < len; i++) {
	jsval_t entry = arr_get(js, registrations, i);
	if (vtype(entry) != T_ARR) continue;
	jsval_t entry_token = arr_get(js, entry, 2);
	if (vtype(entry_token) == T_OBJ && vdata(entry_token) == vdata(token)) {
	char idx[16]; size_t idx_len = uint_to_str(idx, sizeof(idx), i);
	setprop(js, registrations, js_mkstr(js, idx, idx_len), js_mkundef());
	removed = true;
	}
	}

	return removed ? js_mktrue() : js_mkfalse();
	}

	static proxy_data_t *get_proxy_data(jsval_t obj) {
	if (vtype(obj) != T_OBJ) return NULL;
	jsoff_t off = (jsoff_t)vdata(obj);
	proxy_data_t *data = NULL;
	HASH_FIND(hh, proxy_registry, &off, sizeof(jsoff_t), data);
	return data;
	}

	static bool is_proxy(struct js *js, jsval_t obj) {
	(void)js;
	return get_proxy_data(obj) != NULL;
	}

	static jsval_t throw_proxy_error(struct js js, const char message) {
	jsval_t err_obj = mkobj(js, 0);
	setprop(js, err_obj, js_mkstr(js, "message", 7), js_mkstr(js, message, strlen(message)));
	setprop(js, err_obj, js_mkstr(js, "name", 4), js_mkstr(js, "TypeError", 9));
	return js_throw(js, err_obj);
	}

	static jsval_t proxy_get(struct js js, jsval_t proxy, const char key, size_t key_len) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkundef();
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'get' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t get_trap_off = vtype(handler) == T_OBJ ? lkp_interned(js, handler, INTERN_GET, 3) : 0;
	if (get_trap_off != 0) {
	jsval_t get_trap = resolveprop(js, mkval(T_PROP, get_trap_off));
	if (vtype(get_trap) == T_FUNC \|\| vtype(get_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);
	jsval_t args[3] = { target, key_val, proxy };
	return js_call(js, get_trap, args, 3);
	}
	}

	char key_buf[256];
	size_t len = key_len < sizeof(key_buf) - 1 ? key_len : sizeof(key_buf) - 1;
	memcpy(key_buf, key, len);
	key_buf[len] = '\0';

	jsoff_t off = lkp(js, target, key_buf, len);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));

	jsoff_t proto_off = lkp_proto(js, target, key_buf, len);
	if (proto_off != 0) return resolveprop(js, mkval(T_PROP, proto_off));

	return js_mkundef();
	}

	static jsval_t proxy_set(struct js js, jsval_t proxy, const char key, size_t key_len, jsval_t value) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkundef();
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'set' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t set_trap_off = vtype(handler) == T_OBJ ? lkp_interned(js, handler, INTERN_SET, 3) : 0;
	if (set_trap_off != 0) {
	jsval_t set_trap = resolveprop(js, mkval(T_PROP, set_trap_off));
	if (vtype(set_trap) == T_FUNC \|\| vtype(set_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);
	jsval_t args[4] = { target, key_val, value, proxy };
	jsval_t result = js_call(js, set_trap, args, 4);
	if (is_err(result)) return result;
	return js_mktrue();
	}
	}

	jsval_t key_str = js_mkstr(js, key, key_len);
	setprop(js, target, key_str, value);
	return js_mktrue();
	}

	static jsval_t proxy_has(struct js js, jsval_t proxy, const char key, size_t key_len) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkfalse();
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'has' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t has_trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "has", 3) : 0;
	if (has_trap_off != 0) {
	jsval_t has_trap = resolveprop(js, mkval(T_PROP, has_trap_off));
	if (vtype(has_trap) == T_FUNC \|\| vtype(has_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);
	jsval_t args[2] = { target, key_val };
	return js_call(js, has_trap, args, 2);
	}
	}

	char key_buf[256];
	size_t len = key_len < sizeof(key_buf) - 1 ? key_len : sizeof(key_buf) - 1;
	memcpy(key_buf, key, len);
	key_buf[len] = '\0';

	jsoff_t off = lkp_proto(js, target, key_buf, len);
	return off != 0 ? js_mktrue() : js_mkfalse();
	}

	static jsval_t proxy_delete(struct js js, jsval_t proxy, const char key, size_t key_len) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mktrue();
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'deleteProperty' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t delete_trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "deleteProperty", 14) : 0;
	if (delete_trap_off != 0) {
	jsval_t delete_trap = resolveprop(js, mkval(T_PROP, delete_trap_off));
	if (vtype(delete_trap) == T_FUNC \|\| vtype(delete_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);
	jsval_t args[2] = { target, key_val };
	return js_call(js, delete_trap, args, 2);
	}
	}

	jsval_t key_str = js_mkstr(js, key, key_len);
	setprop(js, target, key_str, js_mkundef());
	return js_mktrue();
	}

	static jsval_t mkproxy(struct js *js, jsval_t target, jsval_t handler) {
	jsval_t proxy_obj = mkobj(js, 0);
	jsoff_t off = (jsoff_t)vdata(proxy_obj);

	proxy_data_t data = (proxy_data_t )ant_calloc(sizeof(proxy_data_t));
	if (!data) return js_mkerr(js, "out of memory");

	data->obj_offset = off;
	data->target = target;
	data->handler = handler;
	data->revoked = false;

	HASH_ADD(hh, proxy_registry, obj_offset, sizeof(jsoff_t), data);
	return proxy_obj;
	}

	static jsval_t builtin_Proxy(struct js js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "Proxy requires two arguments: target and handler");

	jsval_t target = args[0];
	jsval_t handler = args[1];

	uint8_t target_type = vtype(target);
	if (target_type != T_OBJ && target_type != T_FUNC && target_type != T_ARR) {
	return js_mkerr(js, "Proxy target must be an object");
	}

	uint8_t handler_type = vtype(handler);
	if (handler_type != T_OBJ && handler_type != T_FUNC) {
	return js_mkerr(js, "Proxy handler must be an object");
	}

	return mkproxy(js, target, handler);
	}

	static jsval_t proxy_revoke_fn(struct js js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t func = js->current_func;
	jsval_t ref_slot = get_slot(js, func, SLOT_PROXY_REF);

	if (vtype(ref_slot) != T_UNDEF && vdata(ref_slot) != 0) {
	jsval_t proxy = resolveprop(js, mkval(T_PROP, (jsoff_t)vdata(ref_slot)));
	proxy_data_t *data = get_proxy_data(proxy);
	if (data) data->revoked = true;
	}

	return js_mkundef();
	}

	static jsval_t builtin_Proxy_revocable(struct js js, jsval_t args, int nargs) {
	jsval_t proxy = builtin_Proxy(js, args, nargs);
	if (is_err(proxy)) return proxy;

	jsval_t revoke_obj = mkobj(js, 0);
	set_slot(js, revoke_obj, SLOT_CFUNC, js_mkfun(proxy_revoke_fn));
	set_slot(js, revoke_obj, SLOT_PROXY_REF, proxy);

	jsval_t revoke_func = mkval(T_FUNC, vdata(revoke_obj));

	jsval_t result = mkobj(js, 0);
	setprop(js, result, js_mkstr(js, "proxy", 5), proxy);
	setprop(js, result, js_mkstr(js, "revoke", 6), revoke_func);

	return result;
	}

	static weakmap_entry_t** get_weakmap_from_obj(struct js *js, jsval_t obj) {
	jsoff_t wm_off = lkp(js, obj, "__weakmap", 9);
	if (wm_off == 0) return NULL;
	jsval_t wm_val = resolveprop(js, mkval(T_PROP, wm_off));
	if (vtype(wm_val) != T_NUM) return NULL;
	return (weakmap_entry_t**)(size_t)vdata(wm_val);
	}

	static weakset_entry_t** get_weakset_from_obj(struct js *js, jsval_t obj) {
	jsoff_t ws_off = lkp(js, obj, "__weakset", 9);
	if (ws_off == 0) return NULL;
	jsval_t ws_val = resolveprop(js, mkval(T_PROP, ws_off));
	if (vtype(ws_val) != T_NUM) return NULL;
	return (weakset_entry_t**)(size_t)vdata(ws_val);
	}

	static jsval_t weakmap_set(struct js js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "WeakMap.set() requires 2 arguments");

	jsval_t this_val = js->this_val;
	weakmap_entry_t **wm_ptr = get_weakmap_from_obj(js, this_val);
	if (!wm_ptr) return js_mkerr(js, "Invalid WeakMap object");

	if (vtype(args[0]) != T_OBJ) {
	return js_mkerr(js, "WeakMap key must be an object");
	}

	jsval_t key_obj = args[0];

	weakmap_entry_t *entry;
	HASH_FIND(hh, *wm_ptr, &key_obj, sizeof(jsval_t), entry);
	if (entry) {
	entry->value = args[1];
	} else {
	entry = (weakmap_entry_t *)ant_calloc(sizeof(weakmap_entry_t));
	if (!entry) return js_mkerr(js, "out of memory");
	entry->key_obj = key_obj;
	entry->value = args[1];
	HASH_ADD(hh, *wm_ptr, key_obj, sizeof(jsval_t), entry);
	}

	return this_val;
	}

	static jsval_t weakmap_get(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "WeakMap.get() requires 1 argument");

	jsval_t this_val = js->this_val;
	weakmap_entry_t **wm_ptr = get_weakmap_from_obj(js, this_val);
	if (!wm_ptr) return js_mkundef();

	if (vtype(args[0]) != T_OBJ) return js_mkundef();

	jsval_t key_obj = args[0];
	weakmap_entry_t *entry;
	HASH_FIND(hh, *wm_ptr, &key_obj, sizeof(jsval_t), entry);
	return entry ? entry->value : js_mkundef();
	}

	static jsval_t weakmap_has(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "WeakMap.has() requires 1 argument");

	jsval_t this_val = js->this_val;
	weakmap_entry_t **wm_ptr = get_weakmap_from_obj(js, this_val);
	if (!wm_ptr) return mkval(T_BOOL, 0);

	if (vtype(args[0]) != T_OBJ) return mkval(T_BOOL, 0);

	jsval_t key_obj = args[0];
	weakmap_entry_t *entry;
	HASH_FIND(hh, *wm_ptr, &key_obj, sizeof(jsval_t), entry);
	return mkval(T_BOOL, entry ? 1 : 0);
	}

	static jsval_t weakmap_delete(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "WeakMap.delete() requires 1 argument");

	jsval_t this_val = js->this_val;
	weakmap_entry_t **wm_ptr = get_weakmap_from_obj(js, this_val);
	if (!wm_ptr) return mkval(T_BOOL, 0);

	if (vtype(args[0]) != T_OBJ) return mkval(T_BOOL, 0);

	jsval_t key_obj = args[0];
	weakmap_entry_t *entry;
	HASH_FIND(hh, *wm_ptr, &key_obj, sizeof(jsval_t), entry);
	if (entry) {
	HASH_DEL(*wm_ptr, entry);
	free(entry);
	return mkval(T_BOOL, 1);
	}
	return mkval(T_BOOL, 0);
	}

	static jsval_t weakset_add(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "WeakSet.add() requires 1 argument");

	jsval_t this_val = js->this_val;
	weakset_entry_t **ws_ptr = get_weakset_from_obj(js, this_val);
	if (!ws_ptr) return js_mkerr(js, "Invalid WeakSet object");

	if (vtype(args[0]) != T_OBJ) {
	return js_mkerr(js, "WeakSet value must be an object");
	}

	jsval_t value_obj = args[0];

	weakset_entry_t *entry;
	HASH_FIND(hh, *ws_ptr, &value_obj, sizeof(jsval_t), entry);

	if (!entry) {
	entry = (weakset_entry_t *)ant_calloc(sizeof(weakset_entry_t));
	if (!entry) return js_mkerr(js, "out of memory");
	entry->value_obj = value_obj;
	HASH_ADD(hh, *ws_ptr, value_obj, sizeof(jsval_t), entry);
	}

	return this_val;
	}

	static jsval_t weakset_has(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "WeakSet.has() requires 1 argument");

	jsval_t this_val = js->this_val;
	weakset_entry_t **ws_ptr = get_weakset_from_obj(js, this_val);
	if (!ws_ptr) return mkval(T_BOOL, 0);

	if (vtype(args[0]) != T_OBJ) return mkval(T_BOOL, 0);

	jsval_t value_obj = args[0];
	weakset_entry_t *entry;
	HASH_FIND(hh, *ws_ptr, &value_obj, sizeof(jsval_t), entry);

	return mkval(T_BOOL, entry ? 1 : 0);
	}

	static jsval_t weakset_delete(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "WeakSet.delete() requires 1 argument");

	jsval_t this_val = js->this_val;
	weakset_entry_t **ws_ptr = get_weakset_from_obj(js, this_val);
	if (!ws_ptr) return mkval(T_BOOL, 0);

	if (vtype(args[0]) != T_OBJ) return mkval(T_BOOL, 0);

	jsval_t value_obj = args[0];
	weakset_entry_t *entry;
	HASH_FIND(hh, *ws_ptr, &value_obj, sizeof(jsval_t), entry);

	if (entry) {
	HASH_DEL(*ws_ptr, entry);
	free(entry);
	return mkval(T_BOOL, 1);
	}
	return mkval(T_BOOL, 0);
	}

	ant_t js_create(void buf, size_t len) {
	assert(
	(uintptr_t)buf <= ((1ULL << 53) - 1) &&
	"ANT_PTR: pointer exceeds 53-bit NaN-boxing limit"
	);

	intern_init();
	ant_t *js = NULL;

	if (len < sizeof(*js) + esize(T_OBJ)) return js;
	memset(buf, 0, len);

	js = (struct js *) buf;
	js->mem = (uint8_t *) (js + 1);
	js->size = (jsoff_t) (len - sizeof(*js));
	js->scope = mkobj(js, 0);
	js->size = js->size / 8U * 8U;
	js->this_val = js->scope;
	js->super_val = js_mkundef();
	js->new_target = js_mkundef();
	js->errmsg_size = 4096;
	js->errmsg = (char *)malloc(js->errmsg_size);
	if (js->errmsg) js->errmsg[0] = '\0';

	#ifdef _WIN32
	js->stack_limit = 512 * 1024;
	#else
	struct rlimit rl;
	if (getrlimit(RLIMIT_STACK, &rl) == 0 && rl.rlim_cur != RLIM_INFINITY) {
	js->stack_limit = rl.rlim_cur / 2;
	} else {
	js->stack_limit = 512 * 1024;
	}
	#endif

	jsval_t glob = js->scope;
	jsval_t object_proto = js_mkobj(js);
	set_proto(js, object_proto, js_mknull());

	setprop(js, object_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_object_toString));
	js_set_descriptor(js, object_proto, "toString", 8, JS_DESC_W \| JS_DESC_C);

	setprop(js, object_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_object_valueOf));
	js_set_descriptor(js, object_proto, "valueOf", 7, JS_DESC_W \| JS_DESC_C);

	setprop(js, object_proto, js_mkstr(js, "toLocaleString", 14), js_mkfun(builtin_object_toLocaleString));
	js_set_descriptor(js, object_proto, "toLocaleString", 14, JS_DESC_W \| JS_DESC_C);

	setprop(js, object_proto, js_mkstr(js, "hasOwnProperty", 14), js_mkfun(builtin_object_hasOwnProperty));
	js_set_descriptor(js, object_proto, "hasOwnProperty", 14, JS_DESC_W \| JS_DESC_C);

	setprop(js, object_proto, js_mkstr(js, "isPrototypeOf", 13), js_mkfun(builtin_object_isPrototypeOf));
	js_set_descriptor(js, object_proto, "isPrototypeOf", 13, JS_DESC_W \| JS_DESC_C);

	setprop(js, object_proto, js_mkstr(js, "propertyIsEnumerable", 20), js_mkfun(builtin_object_propertyIsEnumerable));
	js_set_descriptor(js, object_proto, "propertyIsEnumerable", 20, JS_DESC_W \| JS_DESC_C);

	jsval_t proto_getter = js_mkfun(builtin_proto_getter);
	jsval_t proto_setter = js_mkfun(builtin_proto_setter);
	setprop(js, object_proto, js_mkstr(js, STR_PROTO, STR_PROTO_LEN), js_mkundef());
	js_set_accessor_desc(js, object_proto, STR_PROTO, STR_PROTO_LEN, proto_getter, proto_setter, JS_DESC_C);

	jsval_t function_proto_obj = js_mkobj(js);
	set_proto(js, function_proto_obj, object_proto);
	set_slot(js, function_proto_obj, SLOT_CFUNC, js_mkfun(builtin_function_empty));
	setprop(js, function_proto_obj, ANT_STRING("call"), js_mkfun(builtin_function_call));
	setprop(js, function_proto_obj, ANT_STRING("apply"), js_mkfun(builtin_function_apply));
	setprop(js, function_proto_obj, ANT_STRING("bind"), js_mkfun(builtin_function_bind));
	setprop(js, function_proto_obj, ANT_STRING("toString"), js_mkfun(builtin_function_toString));
	jsval_t function_proto = mkval(T_FUNC, vdata(function_proto_obj));
	set_slot(js, glob, SLOT_FUNC_PROTO, function_proto);

	jsval_t array_proto = js_mkobj(js);
	set_proto(js, array_proto, object_proto);
	setprop(js, array_proto, js_mkstr(js, "push", 4), js_mkfun(builtin_array_push));
	setprop(js, array_proto, js_mkstr(js, "pop", 3), js_mkfun(builtin_array_pop));
	setprop(js, array_proto, js_mkstr(js, "slice", 5), js_mkfun(builtin_array_slice));
	setprop(js, array_proto, js_mkstr(js, "join", 4), js_mkfun(builtin_array_join));
	setprop(js, array_proto, js_mkstr(js, "includes", 8), js_mkfun(builtin_array_includes));
	setprop(js, array_proto, js_mkstr(js, "every", 5), js_mkfun(builtin_array_every));
	setprop(js, array_proto, js_mkstr(js, "reverse", 7), js_mkfun(builtin_array_reverse));
	setprop(js, array_proto, js_mkstr(js, "map", 3), js_mkfun(builtin_array_map));
	setprop(js, array_proto, js_mkstr(js, "filter", 6), js_mkfun(builtin_array_filter));
	setprop(js, array_proto, js_mkstr(js, "reduce", 6), js_mkfun(builtin_array_reduce));
	setprop(js, array_proto, js_mkstr(js, "flat", 4), js_mkfun(builtin_array_flat));
	setprop(js, array_proto, js_mkstr(js, "concat", 6), js_mkfun(builtin_array_concat));
	setprop(js, array_proto, js_mkstr(js, "at", 2), js_mkfun(builtin_array_at));
	setprop(js, array_proto, js_mkstr(js, "fill", 4), js_mkfun(builtin_array_fill));
	setprop(js, array_proto, js_mkstr(js, "find", 4), js_mkfun(builtin_array_find));
	setprop(js, array_proto, js_mkstr(js, "findIndex", 9), js_mkfun(builtin_array_findIndex));
	setprop(js, array_proto, js_mkstr(js, "findLast", 8), js_mkfun(builtin_array_findLast));
	setprop(js, array_proto, js_mkstr(js, "findLastIndex", 13), js_mkfun(builtin_array_findLastIndex));
	setprop(js, array_proto, js_mkstr(js, "flatMap", 7), js_mkfun(builtin_array_flatMap));
	setprop(js, array_proto, js_mkstr(js, "forEach", 7), js_mkfun(builtin_array_forEach));
	setprop(js, array_proto, js_mkstr(js, "indexOf", 7), js_mkfun(builtin_array_indexOf));
	setprop(js, array_proto, js_mkstr(js, "lastIndexOf", 11), js_mkfun(builtin_array_lastIndexOf));
	setprop(js, array_proto, js_mkstr(js, "reduceRight", 11), js_mkfun(builtin_array_reduceRight));
	setprop(js, array_proto, js_mkstr(js, "shift", 5), js_mkfun(builtin_array_shift));
	setprop(js, array_proto, js_mkstr(js, "unshift", 7), js_mkfun(builtin_array_unshift));
	setprop(js, array_proto, js_mkstr(js, "some", 4), js_mkfun(builtin_array_some));
	setprop(js, array_proto, js_mkstr(js, "sort", 4), js_mkfun(builtin_array_sort));
	setprop(js, array_proto, js_mkstr(js, "splice", 6), js_mkfun(builtin_array_splice));
	setprop(js, array_proto, js_mkstr(js, "copyWithin", 10), js_mkfun(builtin_array_copyWithin));
	setprop(js, array_proto, js_mkstr(js, "toReversed", 10), js_mkfun(builtin_array_toReversed));
	setprop(js, array_proto, js_mkstr(js, "toSorted", 8), js_mkfun(builtin_array_toSorted));
	setprop(js, array_proto, js_mkstr(js, "toSpliced", 9), js_mkfun(builtin_array_toSpliced));
	setprop(js, array_proto, js_mkstr(js, "with", 4), js_mkfun(builtin_array_with));
	setprop(js, array_proto, js_mkstr(js, "keys", 4), js_mkfun(builtin_array_keys));
	setprop(js, array_proto, js_mkstr(js, "values", 6), js_mkfun(builtin_array_values));
	setprop(js, array_proto, js_mkstr(js, "entries", 7), js_mkfun(builtin_array_entries));
	setprop(js, array_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_array_toString));
	setprop(js, array_proto, js_mkstr(js, "toLocaleString", 14), js_mkfun(builtin_array_toLocaleString));

	jsval_t string_proto = js_mkobj(js);
	set_proto(js, string_proto, object_proto);
	setprop(js, string_proto, js_mkstr(js, "indexOf", 7), js_mkfun(builtin_string_indexOf));
	setprop(js, string_proto, js_mkstr(js, "substring", 9), js_mkfun(builtin_string_substring));
	setprop(js, string_proto, js_mkstr(js, "substr", 6), js_mkfun(builtin_string_substr));
	setprop(js, string_proto, js_mkstr(js, "split", 5), js_mkfun(builtin_string_split));
	setprop(js, string_proto, js_mkstr(js, "slice", 5), js_mkfun(builtin_string_slice));
	setprop(js, string_proto, js_mkstr(js, "includes", 8), js_mkfun(builtin_string_includes));
	setprop(js, string_proto, js_mkstr(js, "startsWith", 10), js_mkfun(builtin_string_startsWith));
	setprop(js, string_proto, js_mkstr(js, "endsWith", 8), js_mkfun(builtin_string_endsWith));
	setprop(js, string_proto, js_mkstr(js, "replace", 7), js_mkfun(builtin_string_replace));
	setprop(js, string_proto, js_mkstr(js, "replaceAll", 10), js_mkfun(builtin_string_replaceAll));
	setprop(js, string_proto, js_mkstr(js, "match", 5), js_mkfun(builtin_string_match));
	setprop(js, string_proto, js_mkstr(js, "template", 8), js_mkfun(builtin_string_template));
	setprop(js, string_proto, js_mkstr(js, "charCodeAt", 10), js_mkfun(builtin_string_charCodeAt));
	setprop(js, string_proto, js_mkstr(js, "codePointAt", 11), js_mkfun(builtin_string_codePointAt));
	setprop(js, string_proto, js_mkstr(js, "toLowerCase", 11), js_mkfun(builtin_string_toLowerCase));
	setprop(js, string_proto, js_mkstr(js, "toUpperCase", 11), js_mkfun(builtin_string_toUpperCase));
	setprop(js, string_proto, js_mkstr(js, "toLocaleLowerCase", 17), js_mkfun(builtin_string_toLowerCase));
	setprop(js, string_proto, js_mkstr(js, "toLocaleUpperCase", 17), js_mkfun(builtin_string_toUpperCase));
	setprop(js, string_proto, js_mkstr(js, "trim", 4), js_mkfun(builtin_string_trim));
	setprop(js, string_proto, js_mkstr(js, "trimStart", 9), js_mkfun(builtin_string_trimStart));
	setprop(js, string_proto, js_mkstr(js, "trimEnd", 7), js_mkfun(builtin_string_trimEnd));
	setprop(js, string_proto, js_mkstr(js, "repeat", 6), js_mkfun(builtin_string_repeat));
	setprop(js, string_proto, js_mkstr(js, "padStart", 8), js_mkfun(builtin_string_padStart));
	setprop(js, string_proto, js_mkstr(js, "padEnd", 6), js_mkfun(builtin_string_padEnd));
	setprop(js, string_proto, js_mkstr(js, "charAt", 6), js_mkfun(builtin_string_charAt));
	setprop(js, string_proto, js_mkstr(js, "at", 2), js_mkfun(builtin_string_at));
	setprop(js, string_proto, js_mkstr(js, "lastIndexOf", 11), js_mkfun(builtin_string_lastIndexOf));
	setprop(js, string_proto, js_mkstr(js, "concat", 6), js_mkfun(builtin_string_concat));
	setprop(js, string_proto, js_mkstr(js, "search", 6), js_mkfun(builtin_string_search));
	setprop(js, string_proto, js_mkstr(js, "localeCompare", 13), js_mkfun(builtin_string_localeCompare));
	setprop(js, string_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_string_valueOf));
	setprop(js, string_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_string_toString));

	jsval_t number_proto = js_mkobj(js);
	set_proto(js, number_proto, object_proto);
	setprop(js, number_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_number_toString));
	setprop(js, number_proto, js_mkstr(js, "toFixed", 7), js_mkfun(builtin_number_toFixed));
	setprop(js, number_proto, js_mkstr(js, "toPrecision", 11), js_mkfun(builtin_number_toPrecision));
	setprop(js, number_proto, js_mkstr(js, "toExponential", 13), js_mkfun(builtin_number_toExponential));
	setprop(js, number_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_number_valueOf));
	setprop(js, number_proto, js_mkstr(js, "toLocaleString", 14), js_mkfun(builtin_number_toLocaleString));

	jsval_t boolean_proto = js_mkobj(js);
	set_proto(js, boolean_proto, object_proto);
	setprop(js, boolean_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_boolean_valueOf));
	setprop(js, boolean_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_boolean_toString));

	jsval_t bigint_proto = js_mkobj(js);
	set_proto(js, bigint_proto, object_proto);
	setprop(js, bigint_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_bigint_toString));

	jsval_t error_proto = js_mkobj(js);
	set_proto(js, error_proto, object_proto);
	setprop(js, error_proto, ANT_STRING("name"), ANT_STRING("Error"));
	setprop(js, error_proto, ANT_STRING("message"), js_mkstr(js, "", 0));

	jsval_t err_ctor_obj = mkobj(js, 0);
	set_proto(js, err_ctor_obj, function_proto);
	set_slot(js, err_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Error));
	js_setprop_nonconfigurable(js, err_ctor_obj, "prototype", 9, error_proto);
	setprop(js, err_ctor_obj, ANT_STRING("name"), ANT_STRING("Error"));
	setprop(js, glob, ANT_STRING("Error"), mkval(T_FUNC, vdata(err_ctor_obj)));
	setprop(js, error_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(err_ctor_obj)));
	js_set_descriptor(js, error_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	#define REGISTER_ERROR_SUBTYPE(name_str) do { \
	jsval_t proto = js_mkobj(js); \
	set_proto(js, proto, error_proto); \
	setprop(js, proto, ANT_STRING("name"), ANT_STRING(name_str)); \
	jsval_t ctor = mkobj(js, 0); \
	set_proto(js, ctor, function_proto); \
	set_slot(js, ctor, SLOT_CFUNC, js_mkfun(builtin_Error)); \
	js_setprop_nonconfigurable(js, ctor, "prototype", 9, proto); \
	setprop(js, ctor, ANT_STRING("name"), ANT_STRING(name_str)); \
	setprop(js, proto, ANT_STRING("constructor"), mkval(T_FUNC, vdata(ctor))); \
	js_set_descriptor(js, proto, "constructor", 11, JS_DESC_W \| JS_DESC_C); \
	setprop(js, glob, ANT_STRING(name_str), mkval(T_FUNC, vdata(ctor))); \
	} while(0)

	REGISTER_ERROR_SUBTYPE("EvalError");
	REGISTER_ERROR_SUBTYPE("RangeError");
	REGISTER_ERROR_SUBTYPE("ReferenceError");
	REGISTER_ERROR_SUBTYPE("SyntaxError");
	REGISTER_ERROR_SUBTYPE("TypeError");
	REGISTER_ERROR_SUBTYPE("URIError");
	REGISTER_ERROR_SUBTYPE("InternalError");

	#undef REGISTER_ERROR_SUBTYPE

	jsval_t proto = js_mkobj(js);
	set_proto(js, proto, error_proto);
	setprop(js, proto, ANT_STRING("name"), ANT_STRING("AggregateError"));
	jsval_t ctor = mkobj(js, 0);
	set_proto(js, ctor, function_proto);
	set_slot(js, ctor, SLOT_CFUNC, js_mkfun(builtin_AggregateError));
	js_setprop_nonconfigurable(js, ctor, "prototype", 9, proto);
	setprop(js, ctor, ANT_STRING("name"), ANT_STRING("AggregateError"));
	setprop(js, proto, ANT_STRING("constructor"), mkval(T_FUNC, vdata(ctor)));
	js_set_descriptor(js, proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);
	setprop(js, glob, ANT_STRING("AggregateError"), mkval(T_FUNC, vdata(ctor)));

	jsval_t date_proto = js_mkobj(js);
	set_proto(js, date_proto, object_proto);
	setprop(js, date_proto, js_mkstr(js, "getTime", 7), js_mkfun(builtin_Date_getTime));
	setprop(js, date_proto, js_mkstr(js, "getFullYear", 11), js_mkfun(builtin_Date_getFullYear));
	setprop(js, date_proto, js_mkstr(js, "getMonth", 8), js_mkfun(builtin_Date_getMonth));
	setprop(js, date_proto, js_mkstr(js, "getDate", 7), js_mkfun(builtin_Date_getDate));
	setprop(js, date_proto, js_mkstr(js, "getHours", 8), js_mkfun(builtin_Date_getHours));
	setprop(js, date_proto, js_mkstr(js, "getMinutes", 10), js_mkfun(builtin_Date_getMinutes));
	setprop(js, date_proto, js_mkstr(js, "getSeconds", 10), js_mkfun(builtin_Date_getSeconds));
	setprop(js, date_proto, js_mkstr(js, "getMilliseconds", 15), js_mkfun(builtin_Date_getMilliseconds));
	setprop(js, date_proto, js_mkstr(js, "getDay", 6), js_mkfun(builtin_Date_getDay));
	setprop(js, date_proto, js_mkstr(js, "getTimezoneOffset", 17), js_mkfun(builtin_Date_getTimezoneOffset));
	setprop(js, date_proto, js_mkstr(js, "getUTCFullYear", 14), js_mkfun(builtin_Date_getUTCFullYear));
	setprop(js, date_proto, js_mkstr(js, "getUTCMonth", 11), js_mkfun(builtin_Date_getUTCMonth));
	setprop(js, date_proto, js_mkstr(js, "getUTCDate", 10), js_mkfun(builtin_Date_getUTCDate));
	setprop(js, date_proto, js_mkstr(js, "getUTCHours", 11), js_mkfun(builtin_Date_getUTCHours));
	setprop(js, date_proto, js_mkstr(js, "getUTCMinutes", 13), js_mkfun(builtin_Date_getUTCMinutes));
	setprop(js, date_proto, js_mkstr(js, "getUTCSeconds", 13), js_mkfun(builtin_Date_getUTCSeconds));
	setprop(js, date_proto, js_mkstr(js, "getUTCMilliseconds", 18), js_mkfun(builtin_Date_getUTCMilliseconds));
	setprop(js, date_proto, js_mkstr(js, "getUTCDay", 9), js_mkfun(builtin_Date_getUTCDay));
	setprop(js, date_proto, js_mkstr(js, "setTime", 7), js_mkfun(builtin_Date_setTime));
	setprop(js, date_proto, js_mkstr(js, "setMilliseconds", 15), js_mkfun(builtin_Date_setMilliseconds));
	setprop(js, date_proto, js_mkstr(js, "setSeconds", 10), js_mkfun(builtin_Date_setSeconds));
	setprop(js, date_proto, js_mkstr(js, "setMinutes", 10), js_mkfun(builtin_Date_setMinutes));
	setprop(js, date_proto, js_mkstr(js, "setHours", 8), js_mkfun(builtin_Date_setHours));
	setprop(js, date_proto, js_mkstr(js, "setDate", 7), js_mkfun(builtin_Date_setDate));
	setprop(js, date_proto, js_mkstr(js, "setMonth", 8), js_mkfun(builtin_Date_setMonth));
	setprop(js, date_proto, js_mkstr(js, "setFullYear", 11), js_mkfun(builtin_Date_setFullYear));
	setprop(js, date_proto, js_mkstr(js, "setUTCMilliseconds", 18), js_mkfun(builtin_Date_setUTCMilliseconds));
	setprop(js, date_proto, js_mkstr(js, "setUTCSeconds", 13), js_mkfun(builtin_Date_setUTCSeconds));
	setprop(js, date_proto, js_mkstr(js, "setUTCMinutes", 13), js_mkfun(builtin_Date_setUTCMinutes));
	setprop(js, date_proto, js_mkstr(js, "setUTCHours", 11), js_mkfun(builtin_Date_setUTCHours));
	setprop(js, date_proto, js_mkstr(js, "setUTCDate", 10), js_mkfun(builtin_Date_setUTCDate));
	setprop(js, date_proto, js_mkstr(js, "setUTCMonth", 11), js_mkfun(builtin_Date_setUTCMonth));
	setprop(js, date_proto, js_mkstr(js, "setUTCFullYear", 14), js_mkfun(builtin_Date_setUTCFullYear));
	setprop(js, date_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_Date_valueOf));
	setprop(js, date_proto, js_mkstr(js, "toISOString", 11), js_mkfun(builtin_Date_toISOString));
	setprop(js, date_proto, js_mkstr(js, "toUTCString", 11), js_mkfun(builtin_Date_toUTCString));
	setprop(js, date_proto, js_mkstr(js, "toGMTString", 11), js_mkfun(builtin_Date_toUTCString));
	setprop(js, date_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_Date_toString));
	setprop(js, date_proto, js_mkstr(js, "toDateString", 12), js_mkfun(builtin_Date_toDateString));
	setprop(js, date_proto, js_mkstr(js, "toTimeString", 12), js_mkfun(builtin_Date_toTimeString));
	setprop(js, date_proto, js_mkstr(js, "toLocaleDateString", 18), js_mkfun(builtin_Date_toLocaleDateString));
	setprop(js, date_proto, js_mkstr(js, "toLocaleTimeString", 18), js_mkfun(builtin_Date_toLocaleTimeString));
	setprop(js, date_proto, js_mkstr(js, "getYear", 7), js_mkfun(builtin_Date_getYear));
	setprop(js, date_proto, js_mkstr(js, "setYear", 7), js_mkfun(builtin_Date_setYear));
	setprop(js, date_proto, js_mkstr(js, "toJSON", 6), js_mkfun(builtin_Date_toJSON));

	jsval_t regexp_proto = js_mkobj(js);
	set_proto(js, regexp_proto, object_proto);
	setprop(js, regexp_proto, js_mkstr(js, "test", 4), js_mkfun(builtin_regexp_test));
	setprop(js, regexp_proto, js_mkstr(js, "exec", 4), js_mkfun(builtin_regexp_exec));
	setprop(js, regexp_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_regexp_toString));

	jsval_t map_proto = js_mkobj(js);
	set_proto(js, map_proto, object_proto);
	setprop(js, map_proto, js_mkstr(js, "set", 3), js_mkfun(map_set));
	setprop(js, map_proto, js_mkstr(js, "get", 3), js_mkfun(map_get));
	setprop(js, map_proto, js_mkstr(js, "has", 3), js_mkfun(map_has));
	setprop(js, map_proto, js_mkstr(js, "delete", 6), js_mkfun(map_delete));
	setprop(js, map_proto, js_mkstr(js, "clear", 5), js_mkfun(map_clear));
	setprop(js, map_proto, js_mkstr(js, "size", 4), js_mkfun(map_size));
	setprop(js, map_proto, js_mkstr(js, "entries", 7), js_mkfun(map_entries));

	jsval_t set_proto_obj = js_mkobj(js);
	set_proto(js, set_proto_obj, object_proto);
	setprop(js, set_proto_obj, js_mkstr(js, "add", 3), js_mkfun(set_add));
	setprop(js, set_proto_obj, js_mkstr(js, "has", 3), js_mkfun(set_has));
	setprop(js, set_proto_obj, js_mkstr(js, "delete", 6), js_mkfun(set_delete));
	setprop(js, set_proto_obj, js_mkstr(js, "clear", 5), js_mkfun(set_clear));
	setprop(js, set_proto_obj, js_mkstr(js, "size", 4), js_mkfun(set_size));
	setprop(js, set_proto_obj, js_mkstr(js, "values", 6), js_mkfun(set_values));

	jsval_t weakmap_proto = js_mkobj(js);
	set_proto(js, weakmap_proto, object_proto);
	setprop(js, weakmap_proto, js_mkstr(js, "set", 3), js_mkfun(weakmap_set));
	setprop(js, weakmap_proto, js_mkstr(js, "get", 3), js_mkfun(weakmap_get));
	setprop(js, weakmap_proto, js_mkstr(js, "has", 3), js_mkfun(weakmap_has));
	setprop(js, weakmap_proto, js_mkstr(js, "delete", 6), js_mkfun(weakmap_delete));

	jsval_t weakset_proto = js_mkobj(js);
	set_proto(js, weakset_proto, object_proto);
	setprop(js, weakset_proto, js_mkstr(js, "add", 3), js_mkfun(weakset_add));
	setprop(js, weakset_proto, js_mkstr(js, "has", 3), js_mkfun(weakset_has));
	setprop(js, weakset_proto, js_mkstr(js, "delete", 6), js_mkfun(weakset_delete));

	jsval_t weakref_proto = js_mkobj(js);
	set_proto(js, weakref_proto, object_proto);
	setprop(js, weakref_proto, js_mkstr(js, "deref", 5), js_mkfun(weakref_deref));

	jsval_t finreg_proto = js_mkobj(js);
	set_proto(js, finreg_proto, object_proto);
	setprop(js, finreg_proto, js_mkstr(js, "register", 8), js_mkfun(finreg_register));
	setprop(js, finreg_proto, js_mkstr(js, "unregister", 10), js_mkfun(finreg_unregister));

	jsval_t promise_proto = js_mkobj(js);
	set_proto(js, promise_proto, object_proto);
	setprop(js, promise_proto, js_mkstr(js, "then", 4), js_mkfun(builtin_promise_then));
	setprop(js, promise_proto, js_mkstr(js, "catch", 5), js_mkfun(builtin_promise_catch));
	setprop(js, promise_proto, js_mkstr(js, "finally", 7), js_mkfun(builtin_promise_finally));

	jsval_t obj_func_obj = mkobj(js, 0);
	set_proto(js, obj_func_obj, function_proto);
	set_slot(js, obj_func_obj, SLOT_BUILTIN, tov(BUILTIN_OBJECT));
	setprop(js, obj_func_obj, js_mkstr(js, "keys", 4), js_mkfun(builtin_object_keys));
	setprop(js, obj_func_obj, js_mkstr(js, "values", 6), js_mkfun(builtin_object_values));
	setprop(js, obj_func_obj, js_mkstr(js, "entries", 7), js_mkfun(builtin_object_entries));
	setprop(js, obj_func_obj, js_mkstr(js, "getPrototypeOf", 14), js_mkfun(builtin_object_getPrototypeOf));
	setprop(js, obj_func_obj, js_mkstr(js, "setPrototypeOf", 14), js_mkfun(builtin_object_setPrototypeOf));
	setprop(js, obj_func_obj, js_mkstr(js, "create", 6), js_mkfun(builtin_object_create));
	setprop(js, obj_func_obj, js_mkstr(js, "hasOwn", 6), js_mkfun(builtin_object_hasOwn));
	setprop(js, obj_func_obj, js_mkstr(js, "defineProperty", 14), js_mkfun(builtin_object_defineProperty));
	setprop(js, obj_func_obj, js_mkstr(js, "defineProperties", 16), js_mkfun(builtin_object_defineProperties));
	setprop(js, obj_func_obj, js_mkstr(js, "assign", 6), js_mkfun(builtin_object_assign));
	setprop(js, obj_func_obj, js_mkstr(js, "freeze", 6), js_mkfun(builtin_object_freeze));
	setprop(js, obj_func_obj, js_mkstr(js, "isFrozen", 8), js_mkfun(builtin_object_isFrozen));
	setprop(js, obj_func_obj, js_mkstr(js, "seal", 4), js_mkfun(builtin_object_seal));
	setprop(js, obj_func_obj, js_mkstr(js, "isSealed", 8), js_mkfun(builtin_object_isSealed));
	setprop(js, obj_func_obj, js_mkstr(js, "fromEntries", 11), js_mkfun(builtin_object_fromEntries));
	setprop(js, obj_func_obj, js_mkstr(js, "getOwnPropertyDescriptor", 24), js_mkfun(builtin_object_getOwnPropertyDescriptor));
	setprop(js, obj_func_obj, js_mkstr(js, "getOwnPropertyNames", 19), js_mkfun(builtin_object_getOwnPropertyNames));
	setprop(js, obj_func_obj, js_mkstr(js, "isExtensible", 12), js_mkfun(builtin_object_isExtensible));
	setprop(js, obj_func_obj, js_mkstr(js, "preventExtensions", 17), js_mkfun(builtin_object_preventExtensions));
	setprop(js, obj_func_obj, ANT_STRING("name"), ANT_STRING("Object"));
	js_setprop_nonconfigurable(js, obj_func_obj, "prototype", 9, object_proto);
	setprop(js, glob, js_mkstr(js, "Object", 6), mkval(T_FUNC, vdata(obj_func_obj)));

	jsval_t func_ctor_obj = mkobj(js, 0);
	set_proto(js, func_ctor_obj, function_proto);
	set_slot(js, func_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Function));
	js_setprop_nonconfigurable(js, func_ctor_obj, "prototype", 9, function_proto);
	setprop(js, func_ctor_obj, js_mkstr(js, "length", 6), tov(1.0));
	js_set_descriptor(js, func_ctor_obj, "length", 6, JS_DESC_C);
	setprop(js, func_ctor_obj, ANT_STRING("name"), ANT_STRING("Function"));
	setprop(js, glob, js_mkstr(js, "Function", 8), mkval(T_FUNC, vdata(func_ctor_obj)));

	jsval_t async_func_proto_obj = js_mkobj(js);
	set_proto(js, async_func_proto_obj, function_proto);
	set_slot(js, async_func_proto_obj, SLOT_ASYNC, js_mktrue());
	jsval_t async_func_proto = mkval(T_FUNC, vdata(async_func_proto_obj));
	set_slot(js, glob, SLOT_ASYNC_PROTO, async_func_proto);

	jsval_t async_func_ctor_obj = mkobj(js, 0);
	set_proto(js, async_func_ctor_obj, function_proto);
	set_slot(js, async_func_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_AsyncFunction));
	js_setprop_nonconfigurable(js, async_func_ctor_obj, "prototype", 9, async_func_proto);
	setprop(js, async_func_ctor_obj, js_mkstr(js, "length", 6), tov(1.0));
	js_set_descriptor(js, async_func_ctor_obj, "length", 6, JS_DESC_C);
	setprop(js, async_func_ctor_obj, ANT_STRING("name"), ANT_STRING("AsyncFunction"));
	jsval_t async_func_ctor = mkval(T_FUNC, vdata(async_func_ctor_obj));

	setprop(js, async_func_proto_obj, js_mkstr(js, "constructor", 11), async_func_ctor);
	js_set_descriptor(js, async_func_proto_obj, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	jsval_t str_ctor_obj = mkobj(js, 0);
	set_proto(js, str_ctor_obj, function_proto);
	set_slot(js, str_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_String));
	js_setprop_nonconfigurable(js, str_ctor_obj, "prototype", 9, string_proto);
	setprop(js, str_ctor_obj, js_mkstr(js, "fromCharCode", 12), js_mkfun(builtin_string_fromCharCode));
	setprop(js, str_ctor_obj, js_mkstr(js, "fromCodePoint", 13), js_mkfun(builtin_string_fromCodePoint));
	setprop(js, str_ctor_obj, ANT_STRING("name"), ANT_STRING("String"));
	setprop(js, glob, js_mkstr(js, "String", 6), mkval(T_FUNC, vdata(str_ctor_obj)));

	jsval_t number_ctor_obj = mkobj(js, 0);
	set_proto(js, number_ctor_obj, function_proto);

	set_slot(js, number_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Number));
	setprop(js, number_ctor_obj, js_mkstr(js, "isNaN", 5), js_mkfun(builtin_Number_isNaN));
	setprop(js, number_ctor_obj, js_mkstr(js, "isFinite", 8), js_mkfun(builtin_Number_isFinite));
	setprop(js, number_ctor_obj, js_mkstr(js, "isInteger", 9), js_mkfun(builtin_Number_isInteger));
	setprop(js, number_ctor_obj, js_mkstr(js, "isSafeInteger", 13), js_mkfun(builtin_Number_isSafeInteger));

	setprop(js, number_ctor_obj, js_mkstr(js, "MAX_VALUE", 9), tov(1.7976931348623157e+308));
	setprop(js, number_ctor_obj, js_mkstr(js, "MIN_VALUE", 9), tov(5e-324));
	setprop(js, number_ctor_obj, js_mkstr(js, "MAX_SAFE_INTEGER", 16), tov(9007199254740991.0));
	setprop(js, number_ctor_obj, js_mkstr(js, "MIN_SAFE_INTEGER", 16), tov(-9007199254740991.0));
	setprop(js, number_ctor_obj, js_mkstr(js, "POSITIVE_INFINITY", 17), tov(JS_INF));
	setprop(js, number_ctor_obj, js_mkstr(js, "NEGATIVE_INFINITY", 17), tov(JS_NEG_INF));
	setprop(js, number_ctor_obj, js_mkstr(js, "NaN", 3), tov(JS_NAN));
	setprop(js, number_ctor_obj, js_mkstr(js, "EPSILON", 7), tov(2.220446049250313e-16));

	js_setprop_nonconfigurable(js, number_ctor_obj, "prototype", 9, number_proto);
	setprop(js, number_ctor_obj, ANT_STRING("name"), ANT_STRING("Number"));
	setprop(js, glob, js_mkstr(js, "Number", 6), mkval(T_FUNC, vdata(number_ctor_obj)));

	jsval_t bool_ctor_obj = mkobj(js, 0);
	set_proto(js, bool_ctor_obj, function_proto);
	set_slot(js, bool_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Boolean));
	js_setprop_nonconfigurable(js, bool_ctor_obj, "prototype", 9, boolean_proto);
	setprop(js, bool_ctor_obj, ANT_STRING("name"), ANT_STRING("Boolean"));
	setprop(js, glob, js_mkstr(js, "Boolean", 7), mkval(T_FUNC, vdata(bool_ctor_obj)));

	jsval_t arr_ctor_obj = mkobj(js, 0);
	set_proto(js, arr_ctor_obj, function_proto);
	set_slot(js, arr_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Array));
	js_setprop_nonconfigurable(js, arr_ctor_obj, "prototype", 9, array_proto);
	setprop(js, arr_ctor_obj, js_mkstr(js, "isArray", 7), js_mkfun(builtin_Array_isArray));
	setprop(js, arr_ctor_obj, js_mkstr(js, "from", 4), js_mkfun(builtin_Array_from));
	setprop(js, arr_ctor_obj, js_mkstr(js, "of", 2), js_mkfun(builtin_Array_of));
	setprop(js, arr_ctor_obj, js_mkstr(js, "length", 6), tov(1.0));
	js_set_descriptor(js, arr_ctor_obj, "length", 6, JS_DESC_C);
	setprop(js, arr_ctor_obj, ANT_STRING("name"), ANT_STRING("Array"));
	setprop(js, glob, js_mkstr(js, "Array", 5), mkval(T_FUNC, vdata(arr_ctor_obj)));

	jsval_t map_ctor_obj = mkobj(js, 0);
	set_proto(js, map_ctor_obj, function_proto);
	set_slot(js, map_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Map));
	js_setprop_nonconfigurable(js, map_ctor_obj, "prototype", 9, map_proto);
	setprop(js, map_ctor_obj, ANT_STRING("name"), ANT_STRING("Map"));
	setprop(js, glob, js_mkstr(js, "Map", 3), mkval(T_FUNC, vdata(map_ctor_obj)));

	jsval_t set_ctor_obj = mkobj(js, 0);
	set_proto(js, set_ctor_obj, function_proto);
	set_slot(js, set_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Set));
	js_setprop_nonconfigurable(js, set_ctor_obj, "prototype", 9, set_proto_obj);
	setprop(js, set_ctor_obj, ANT_STRING("name"), ANT_STRING("Set"));
	setprop(js, glob, js_mkstr(js, "Set", 3), mkval(T_FUNC, vdata(set_ctor_obj)));

	jsval_t weakmap_ctor_obj = mkobj(js, 0);
	set_proto(js, weakmap_ctor_obj, function_proto);
	set_slot(js, weakmap_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_WeakMap));
	js_setprop_nonconfigurable(js, weakmap_ctor_obj, "prototype", 9, weakmap_proto);
	setprop(js, weakmap_ctor_obj, ANT_STRING("name"), ANT_STRING("WeakMap"));
	setprop(js, glob, js_mkstr(js, "WeakMap", 7), mkval(T_FUNC, vdata(weakmap_ctor_obj)));

	jsval_t weakset_ctor_obj = mkobj(js, 0);
	set_proto(js, weakset_ctor_obj, function_proto);
	set_slot(js, weakset_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_WeakSet));
	js_setprop_nonconfigurable(js, weakset_ctor_obj, "prototype", 9, weakset_proto);
	setprop(js, weakset_ctor_obj, ANT_STRING("name"), ANT_STRING("WeakSet"));
	setprop(js, glob, js_mkstr(js, "WeakSet", 7), mkval(T_FUNC, vdata(weakset_ctor_obj)));

	jsval_t weakref_ctor_obj = mkobj(js, 0);
	set_proto(js, weakref_ctor_obj, function_proto);
	set_slot(js, weakref_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_WeakRef));
	js_setprop_nonconfigurable(js, weakref_ctor_obj, "prototype", 9, weakref_proto);
	setprop(js, weakref_ctor_obj, ANT_STRING("name"), ANT_STRING("WeakRef"));
	setprop(js, glob, js_mkstr(js, "WeakRef", 7), mkval(T_FUNC, vdata(weakref_ctor_obj)));

	jsval_t finreg_ctor_obj = mkobj(js, 0);
	set_proto(js, finreg_ctor_obj, function_proto);
	set_slot(js, finreg_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_FinalizationRegistry));
	js_setprop_nonconfigurable(js, finreg_ctor_obj, "prototype", 9, finreg_proto);
	setprop(js, finreg_ctor_obj, ANT_STRING("name"), ANT_STRING("FinalizationRegistry"));
	setprop(js, glob, js_mkstr(js, "FinalizationRegistry", 20), mkval(T_FUNC, vdata(finreg_ctor_obj)));

	jsval_t proxy_ctor_obj = mkobj(js, 0);
	set_proto(js, proxy_ctor_obj, function_proto);
	set_slot(js, proxy_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Proxy));
	setprop(js, proxy_ctor_obj, js_mkstr(js, "revocable", 9), js_mkfun(builtin_Proxy_revocable));
	setprop(js, proxy_ctor_obj, ANT_STRING("name"), ANT_STRING("Proxy"));
	setprop(js, glob, js_mkstr(js, "Proxy", 5), mkval(T_FUNC, vdata(proxy_ctor_obj)));



	jsval_t regex_ctor_obj = mkobj(js, 0);
	set_proto(js, regex_ctor_obj, function_proto);
	set_slot(js, regex_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_RegExp));
	js_setprop_nonconfigurable(js, regex_ctor_obj, "prototype", 9, regexp_proto);
	setprop(js, regex_ctor_obj, ANT_STRING("name"), ANT_STRING("RegExp"));
	setprop(js, glob, js_mkstr(js, "RegExp", 6), mkval(T_FUNC, vdata(regex_ctor_obj)));

	jsval_t date_ctor_obj = mkobj(js, 0);
	set_proto(js, date_ctor_obj, function_proto);
	set_slot(js, date_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Date));
	setprop(js, date_ctor_obj, js_mkstr(js, "now", 3), js_mkfun(builtin_Date_now));
	setprop(js, date_ctor_obj, js_mkstr(js, "UTC", 3), js_mkfun(builtin_Date_UTC));
	js_setprop_nonconfigurable(js, date_ctor_obj, "prototype", 9, date_proto);
	setprop(js, date_ctor_obj, ANT_STRING("name"), ANT_STRING("Date"));
	setprop(js, glob, js_mkstr(js, "Date", 4), mkval(T_FUNC, vdata(date_ctor_obj)));

	jsval_t p_ctor_obj = mkobj(js, 0);
	set_proto(js, p_ctor_obj, function_proto);
	set_slot(js, p_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Promise));
	setprop(js, p_ctor_obj, js_mkstr(js, "resolve", 7), js_mkfun(builtin_Promise_resolve));
	setprop(js, p_ctor_obj, js_mkstr(js, "reject", 6), js_mkfun(builtin_Promise_reject));
	setprop(js, p_ctor_obj, js_mkstr(js, "try", 3), js_mkfun(builtin_Promise_try));
	setprop(js, p_ctor_obj, js_mkstr(js, "all", 3), js_mkfun(builtin_Promise_all));
	setprop(js, p_ctor_obj, js_mkstr(js, "race", 4), js_mkfun(builtin_Promise_race));
	setprop(js, p_ctor_obj, js_mkstr(js, "any", 3), js_mkfun(builtin_Promise_any));
	js_setprop_nonconfigurable(js, p_ctor_obj, "prototype", 9, promise_proto);
	setprop(js, p_ctor_obj, ANT_STRING("name"), ANT_STRING("Promise"));
	setprop(js, glob, js_mkstr(js, "Promise", 7), mkval(T_FUNC, vdata(p_ctor_obj)));

	jsval_t bigint_ctor_obj = mkobj(js, 0);
	set_proto(js, bigint_ctor_obj, function_proto);
	set_slot(js, bigint_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_BigInt));
	setprop(js, bigint_ctor_obj, js_mkstr(js, "asIntN", 6), js_mkfun(builtin_BigInt_asIntN));
	setprop(js, bigint_ctor_obj, js_mkstr(js, "asUintN", 7), js_mkfun(builtin_BigInt_asUintN));
	js_setprop_nonconfigurable(js, bigint_ctor_obj, "prototype", 9, bigint_proto);
	setprop(js, bigint_ctor_obj, ANT_STRING("name"), ANT_STRING("BigInt"));
	setprop(js, glob, js_mkstr(js, "BigInt", 6), mkval(T_FUNC, vdata(bigint_ctor_obj)));

	setprop(js, glob, js_mkstr(js, "eval", 4), js_mkfun(builtin_eval));
	setprop(js, glob, js_mkstr(js, "parseInt", 8), js_mkfun(builtin_parseInt));
	setprop(js, glob, js_mkstr(js, "parseFloat", 10), js_mkfun(builtin_parseFloat));
	setprop(js, glob, js_mkstr(js, "isNaN", 5), js_mkfun(builtin_global_isNaN));
	setprop(js, glob, js_mkstr(js, "isFinite", 8), js_mkfun(builtin_global_isFinite));
	setprop(js, glob, js_mkstr(js, "btoa", 4), js_mkfun(builtin_btoa));
	setprop(js, glob, js_mkstr(js, "atob", 4), js_mkfun(builtin_atob));
	setprop(js, glob, js_mkstr(js, "NaN", 3), tov(JS_NAN));
	setprop(js, glob, js_mkstr(js, "Infinity", 8), tov(JS_INF));
	setprop(js, glob, js_mkstr(js, "undefined", 9), js_mkundef());

	jsval_t math_obj = mkobj(js, 0);
	set_proto(js, math_obj, object_proto);
	setprop(js, math_obj, js_mkstr(js, "E", 1), tov(M_E));
	setprop(js, math_obj, js_mkstr(js, "LN10", 4), tov(M_LN10));
	setprop(js, math_obj, js_mkstr(js, "LN2", 3), tov(M_LN2));
	setprop(js, math_obj, js_mkstr(js, "LOG10E", 6), tov(M_LOG10E));
	setprop(js, math_obj, js_mkstr(js, "LOG2E", 5), tov(M_LOG2E));
	setprop(js, math_obj, js_mkstr(js, "PI", 2), tov(M_PI));
	setprop(js, math_obj, js_mkstr(js, "SQRT1_2", 7), tov(M_SQRT1_2));
	setprop(js, math_obj, js_mkstr(js, "SQRT2", 5), tov(M_SQRT2));
	setprop(js, math_obj, js_mkstr(js, "abs", 3), js_mkfun(builtin_Math_abs));
	setprop(js, math_obj, js_mkstr(js, "acos", 4), js_mkfun(builtin_Math_acos));
	setprop(js, math_obj, js_mkstr(js, "acosh", 5), js_mkfun(builtin_Math_acosh));
	setprop(js, math_obj, js_mkstr(js, "asin", 4), js_mkfun(builtin_Math_asin));
	setprop(js, math_obj, js_mkstr(js, "asinh", 5), js_mkfun(builtin_Math_asinh));
	setprop(js, math_obj, js_mkstr(js, "atan", 4), js_mkfun(builtin_Math_atan));
	setprop(js, math_obj, js_mkstr(js, "atanh", 5), js_mkfun(builtin_Math_atanh));
	setprop(js, math_obj, js_mkstr(js, "atan2", 5), js_mkfun(builtin_Math_atan2));
	setprop(js, math_obj, js_mkstr(js, "cbrt", 4), js_mkfun(builtin_Math_cbrt));
	setprop(js, math_obj, js_mkstr(js, "ceil", 4), js_mkfun(builtin_Math_ceil));
	setprop(js, math_obj, js_mkstr(js, "clz32", 5), js_mkfun(builtin_Math_clz32));
	setprop(js, math_obj, js_mkstr(js, "cos", 3), js_mkfun(builtin_Math_cos));
	setprop(js, math_obj, js_mkstr(js, "cosh", 4), js_mkfun(builtin_Math_cosh));
	setprop(js, math_obj, js_mkstr(js, "exp", 3), js_mkfun(builtin_Math_exp));
	setprop(js, math_obj, js_mkstr(js, "expm1", 5), js_mkfun(builtin_Math_expm1));
	setprop(js, math_obj, js_mkstr(js, "floor", 5), js_mkfun(builtin_Math_floor));
	setprop(js, math_obj, js_mkstr(js, "fround", 6), js_mkfun(builtin_Math_fround));
	setprop(js, math_obj, js_mkstr(js, "hypot", 5), js_mkfun(builtin_Math_hypot));
	setprop(js, math_obj, js_mkstr(js, "imul", 4), js_mkfun(builtin_Math_imul));
	setprop(js, math_obj, js_mkstr(js, "log", 3), js_mkfun(builtin_Math_log));
	setprop(js, math_obj, js_mkstr(js, "log1p", 5), js_mkfun(builtin_Math_log1p));
	setprop(js, math_obj, js_mkstr(js, "log10", 5), js_mkfun(builtin_Math_log10));
	setprop(js, math_obj, js_mkstr(js, "log2", 4), js_mkfun(builtin_Math_log2));
	setprop(js, math_obj, js_mkstr(js, "max", 3), js_mkfun(builtin_Math_max));
	setprop(js, math_obj, js_mkstr(js, "min", 3), js_mkfun(builtin_Math_min));
	setprop(js, math_obj, js_mkstr(js, "pow", 3), js_mkfun(builtin_Math_pow));
	setprop(js, math_obj, js_mkstr(js, "random", 6), js_mkfun(builtin_Math_random));
	setprop(js, math_obj, js_mkstr(js, "round", 5), js_mkfun(builtin_Math_round));
	setprop(js, math_obj, js_mkstr(js, "sign", 4), js_mkfun(builtin_Math_sign));
	setprop(js, math_obj, js_mkstr(js, "sin", 3), js_mkfun(builtin_Math_sin));
	setprop(js, math_obj, js_mkstr(js, "sinh", 4), js_mkfun(builtin_Math_sinh));
	setprop(js, math_obj, js_mkstr(js, "sqrt", 4), js_mkfun(builtin_Math_sqrt));
	setprop(js, math_obj, js_mkstr(js, "tan", 3), js_mkfun(builtin_Math_tan));
	setprop(js, math_obj, js_mkstr(js, "tanh", 4), js_mkfun(builtin_Math_tanh));
	setprop(js, math_obj, js_mkstr(js, "trunc", 5), js_mkfun(builtin_Math_trunc));
	setprop(js, glob, js_mkstr(js, "Math", 4), math_obj);

	jsval_t import_obj = mkobj(js, 0);
	set_proto(js, import_obj, function_proto);

	set_slot(js, import_obj, SLOT_CFUNC, js_mkfun(builtin_import));
	setprop(js, glob, js_mkstr(js, "import", 6), mkval(T_FUNC, vdata(import_obj)));
	js->module_ns = js_mkundef();

	setprop(js, object_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(obj_func_obj)));
	js_set_descriptor(js, object_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	setprop(js, function_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(func_ctor_obj)));
	js_set_descriptor(js, function_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	setprop(js, array_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(arr_ctor_obj)));
	js_set_descriptor(js, array_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	setprop(js, string_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(str_ctor_obj)));
	js_set_descriptor(js, string_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	setprop(js, number_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(number_ctor_obj)));
	js_set_descriptor(js, number_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	setprop(js, boolean_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(bool_ctor_obj)));
	js_set_descriptor(js, boolean_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	setprop(js, date_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(date_ctor_obj)));
	js_set_descriptor(js, date_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	setprop(js, regexp_proto, js_mkstr(js, "constructor", 11), mkval(T_FUNC, vdata(regex_ctor_obj)));
	js_set_descriptor(js, regexp_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	set_proto(js, glob, object_proto);

	js->owns_mem = false;
	js->max_size = 0;

	return js;
	}

	struct js *js_create_dynamic(size_t initial_size, size_t max_size) {
	if (initial_size < sizeof(struct js) + esize(T_OBJ)) initial_size = ANT_ARENA_MIN;
	if (max_size == 0 \|\| max_size < initial_size) max_size = ANT_ARENA_MAX;

	void *init_buf = ant_calloc(initial_size);
	if (init_buf == NULL) return NULL;

	struct js *js = js_create(init_buf, initial_size);
	if (js == NULL) { free(init_buf); return NULL; }

	uint8_t arena = (uint8_t )ant_arena_reserve(max_size);
	if (arena == NULL) { free(init_buf); return NULL; }

	if (ant_arena_commit(arena, 0, js->size) != 0) {
	ant_arena_free(arena, max_size);
	free(init_buf); return NULL;
	}

	memcpy(arena, js->mem, js->brk);
	js->mem = arena;

	js->owns_mem = true;
	js->max_size = (jsoff_t) max_size;

	volatile char stack_base;
	js->cstk = (void *)&stack_base;

	return js;
	}

	void js_destroy(struct js *js) {
	if (js == NULL) return;

	esm_cleanup_module_cache();
	code_arena_reset();

	if (js->errmsg) {
	free(js->errmsg);
	js->errmsg = NULL;
	}

	if (js->for_let_stack) {
	free(js->for_let_stack);
	js->for_let_stack = NULL;
	}

	if (js->owns_mem) ant_arena_free(js->mem, js->max_size);
	}

	inline double js_getnum(jsval_t value) { return tod(value); }
	inline int js_getbool(jsval_t value) { return vdata(value) & 1 ? 1 : 0; }

	inline void js_setstacklimit(struct js *js, size_t max) { js->stack_limit = max; }
	inline void js_setstackbase(struct js js, void base) { js->cstk = base; }
	inline void js_set_filename(struct js js, const char filename) { js->filename = filename; }

	inline jsval_t js_mktrue(void) { return mkval(T_BOOL, 1); }
	inline jsval_t js_mkfalse(void) { return mkval(T_BOOL, 0); }
	inline jsval_t js_mkundef(void) { return mkval(T_UNDEF, 0); }
	inline jsval_t js_mknull(void) { return mkval(T_NULL, 0); }
	inline jsval_t js_mknum(double value) { return tov(value); }
	inline jsval_t js_mkobj(struct js *js) { return mkobj(js, 0); }
	inline jsval_t js_glob(struct js *js) { (void) js; return mkval(T_OBJ, 0); }
	inline jsval_t js_getscope(struct js *js) { return js->scope; }
	inline jsval_t js_mkfun(jsval_t (fn)(struct js , jsval_t , int)) { return mkval(T_CFUNC, (size_t) (void ) fn); }

	inline jsval_t js_getthis(struct js *js) { return js->this_val; }
	inline void js_setthis(struct js *js, jsval_t val) { js->this_val = val; }
	inline jsval_t js_getcurrentfunc(struct js *js) { return js->current_func; }

	jsval_t js_heavy_mkfun(struct js js, jsval_t (fn)(struct js , jsval_t , int), jsval_t data) {
	jsval_t cfunc = js_mkfun(fn);
	jsval_t fn_obj = mkobj(js, 0);

	set_slot(js, fn_obj, SLOT_CFUNC, cfunc);
	set_slot(js, fn_obj, SLOT_DATA, data);

	return mkval(T_FUNC, (unsigned long)vdata(fn_obj));
	}

	void js_set(struct js js, jsval_t obj, const char key, jsval_t val) {
	size_t key_len = strlen(key);

	if (vtype(obj) == T_OBJ) {
	jsoff_t existing = lkp(js, obj, key, key_len);
	if (existing > 0) {
	if (is_const_prop(js, existing)) {
	if (js->flags & F_STRICT) js_mkerr(js, "assignment to constant");
	return;
	}
	saveval(js, existing + sizeof(jsoff_t) * 2, val);
	} else {
	jsval_t key_str = js_mkstr(js, key, key_len);
	mkprop(js, obj, key_str, val, 0);
	}
	} else if (vtype(obj) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(obj));
	jsoff_t existing = lkp(js, func_obj, key, key_len);
	if (existing > 0) {
	if (is_const_prop(js, existing)) {
	if (js->flags & F_STRICT) js_mkerr(js, "assignment to constant");
	return;
	}
	saveval(js, existing + sizeof(jsoff_t) * 2, val);
	} else {
	jsval_t key_str = js_mkstr(js, key, key_len);
	mkprop(js, func_obj, key_str, val, 0);
	}
	}
	}

	bool js_del(struct js js, jsval_t obj, const char key) {
	size_t len = strlen(key);
	jsoff_t obj_off;

	if (vtype(obj) == T_OBJ) {
	obj_off = (jsoff_t)vdata(obj);
	} else if (vtype(obj) == T_ARR \|\| vtype(obj) == T_FUNC) {
	obj_off = (jsoff_t)vdata(obj);
	obj = mkval(T_OBJ, obj_off);
	} else {
	return false;
	}

	jsoff_t prop_off = lkp(js, obj, key, len);
	if (prop_off == 0) return true;
	if (is_nonconfig_prop(js, prop_off)) return false;

	descriptor_entry_t *desc = lookup_descriptor(obj_off, key, len);
	if (desc && !desc->configurable) return false;

	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	jsoff_t tail = loadoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t));

	if (first_prop == prop_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~FLAGMASK;
	jsoff_t current = loadoff(js, obj_off);

	saveoff(js, obj_off, (deleted_next & ~3ULL) \| (current & (FLAGMASK \| 3ULL)));
	if (tail == prop_off) saveoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t), 0);

	invalidate_prop_cache(js, obj_off, prop_off);
	js->needs_gc = true;

	return true;
	}

	jsoff_t prev = first_prop;
	while (prev != 0 && prev < js->brk) {
	jsoff_t next = loadoff(js, prev) & ~(3U \| FLAGMASK);
	if (next == prop_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~(3U \| FLAGMASK);
	jsoff_t prev_flags = loadoff(js, prev) & FLAGMASK;

	saveoff(js, prev, deleted_next \| prev_flags);
	if (tail == prop_off) saveoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t), prev);

	invalidate_prop_cache(js, obj_off, prop_off);
	js->needs_gc = true;

	return true;
	}
	prev = next;
	}

	return false;
	}

	jsval_t js_get(struct js js, jsval_t obj, const char key) {
	size_t key_len = strlen(key);

	if (vtype(obj) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(obj));
	jsoff_t off = lkp(js, func_obj, key, key_len);
	return off == 0 ? js_mkundef() : resolveprop(js, mkval(T_PROP, off));
	}

	if (vtype(obj) == T_ARR) {
	jsval_t arr_obj = mkval(T_OBJ, vdata(obj));
	jsoff_t off = lkp(js, arr_obj, key, key_len);
	return off == 0 ? js_mkundef() : resolveprop(js, mkval(T_PROP, off));
	}

	uint8_t t = vtype(obj);
	bool is_promise = (t == T_PROMISE);
	if (is_promise) obj = mkval(T_OBJ, vdata(obj));
	else if (t != T_OBJ) return js_mkundef();
	jsoff_t off = lkp(js, obj, key, key_len);

	if (off == 0) {
	jsval_t result = try_dynamic_getter(js, obj, key, key_len);
	if (vtype(result) != T_UNDEF) return result;
	}

	if (off == 0 && is_promise) {
	jsval_t promise_proto = get_ctor_proto(js, "Promise", 7);
	if (vtype(promise_proto) != T_UNDEF && vtype(promise_proto) != T_NULL) {
	off = lkp(js, promise_proto, key, key_len);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	}
	}

	return off == 0 ? js_mkundef() : resolveprop(js, mkval(T_PROP, off));
	}

	jsval_t js_getprop_proto(struct js js, jsval_t obj, const char key) {
	size_t key_len = strlen(key);
	jsoff_t off = lkp_proto(js, obj, key, key_len);
	return off == 0 ? js_mkundef() : resolveprop(js, mkval(T_PROP, off));
	}

	typedef struct {
	bool (callback)(struct js js, jsval_t value, void *udata);
	void *udata;
	} js_iter_ctx_t;

	static iter_action_t js_iter_cb(struct js js, jsval_t value, void ctx, jsval_t *out) {
	(void)out;
	js_iter_ctx_t ictx = (js_iter_ctx_t )ctx;
	return ictx->callback(js, value, ictx->udata) ? ITER_CONTINUE : ITER_BREAK;
	}

	bool js_iter(struct js js, jsval_t iterable, bool (callback)(struct js js, jsval_t value, void udata), void *udata) {
	js_iter_ctx_t ctx = { .callback = callback, .udata = udata };
	jsval_t result = iter_foreach(js, iterable, js_iter_cb, &ctx);
	return !is_err(result);
	}

	char js_getstr(struct js js, jsval_t value, size_t *len) {
	if (vtype(value) != T_STR) return NULL;
	jsoff_t n, off = vstr(js, value, &n);
	if (len != NULL) *len = n;
	return (char *) &js->mem[off];
	}

	void js_merge_obj(struct js *js, jsval_t dst, jsval_t src) {
	if (vtype(dst) != T_OBJ \|\| vtype(src) != T_OBJ) return;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(src)) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	setprop(js, dst, mkval(T_STR, koff), val);
	next = next_prop(header);
	}
	}

	int js_type(jsval_t val) {
	switch (vtype(val)) {
	case T_UNDEF: return JS_UNDEF;
	case T_NULL: return JS_NULL;
	case T_BOOL: return vdata(val) == 0 ? JS_FALSE: JS_TRUE;
	case T_STR: return JS_STR;
	case T_NUM: return JS_NUM;
	case T_ERR: return JS_ERR;
	case T_PROMISE: return JS_PROMISE;
	case T_SYMBOL: return JS_SYMBOL;

	case T_OBJ:
	case T_ARR: return JS_OBJ;
	case T_FUNC: return JS_FUNC;

	default: return JS_PRIV;
	}
	}

	int js_type_ex(struct js *js, jsval_t val) {
	(void)js;
	if (vtype(val) == T_SYMBOL) return JS_SYMBOL;
	return js_type(val);
	}

	#define UTARRAY_EACH(arr, type, var) \
	if (arr) for (type var = (type )utarray_front(arr), *_end = var + utarray_len(arr); var < _end; var++)

	#define REHASH_REGISTRY(registry, entry, tmp, new_reg, key_field, key_size, body) \
	for (typeof(registry) new_reg = NULL, _once = NULL; !_once; _once = (void)1, registry = new_reg) \
	HASH_ITER(hh, registry, entry, tmp) { \
	HASH_DEL(registry, entry); \
	body; \
	HASH_ADD(hh, new_reg, key_field, key_size, entry); \
	}

	typedef jsoff_t (gc_fwd_off_fn)(void ctx, jsoff_t old);
	typedef jsval_t (gc_fwd_val_fn)(void ctx, jsval_t old);
	typedef void (gc_off_op_t)(void cb_ctx, jsoff_t *off);
	typedef void (gc_val_op_t)(void cb_ctx, jsval_t *val);

	typedef struct {
	gc_fwd_off_fn fwd_off;
	gc_fwd_val_fn fwd_val;
	void *ctx;
	ant_t *js;
	} gc_cb_ctx_t;

	static inline void gc_reserve_off_cb(void cb_ctx, jsoff_t off) {
	gc_cb_ctx_t *c = cb_ctx;
	if (off) (void)c->fwd_off(c->ctx, off);
	}

	static inline void gc_reserve_val_cb(void cb_ctx, jsval_t val) {
	gc_cb_ctx_t *c = cb_ctx;
	(void)c->fwd_val(c->ctx, *val);
	}

	static inline void gc_update_off_cb(void cb_ctx, jsoff_t off) {
	gc_cb_ctx_t *c = cb_ctx;
	if (off) off = c->fwd_off(c->ctx, *off);
	}

	static inline void gc_update_val_cb(void cb_ctx, jsval_t val) {
	gc_cb_ctx_t *c = cb_ctx;
	val = c->fwd_val(c->ctx, val);
	}

	static void gc_roots_common(gc_off_op_t op_off, gc_val_op_t op_val, gc_cb_ctx_t *c) {
	UTARRAY_EACH(global_scope_stack, jsoff_t, off) op_off(c, off);
	UTARRAY_EACH(saved_scope_stack, jsval_t, val) op_val(c, val);

	for (int i = 0; i < global_this_stack.depth; i++)
	op_val(c, &global_this_stack.stack[i]);

	UTARRAY_EACH(propref_stack, propref_data_t, pref) {
	op_off(c, &pref->obj_off);
	op_off(c, &pref->key_off);
	}

	UTARRAY_EACH(prim_propref_stack, prim_propref_data_t, ppref) {
	op_val(c, &ppref->prim_val);
	op_off(c, &ppref->key_off);
	}

	if (rt && rt->js == c->js)
	op_val(c, &rt->ant_obj);

	for (coroutine_t *coro = pending_coroutines.head; coro; coro = coro->next) {
	op_val(c, &coro->scope);
	op_val(c, &coro->this_val);
	op_val(c, &coro->super_val);
	op_val(c, &coro->new_target);
	op_val(c, &coro->awaited_promise);
	op_val(c, &coro->result);
	op_val(c, &coro->async_func);
	op_val(c, &coro->yield_value);

	for (int i = 0; i < coro->for_let_stack_len; i++) {
	op_val(c, &coro->for_let_stack[i].body_scope);
	op_off(c, &coro->for_let_stack[i].prop_off);
	}

	if (coro->scope_stack) {
	UTARRAY_EACH(coro->scope_stack, jsoff_t, off) op_off(c, off);
	}

	if (coro->mco) {
	async_exec_context_t actx = (async_exec_context_t )mco_get_user_data(coro->mco);
	if (actx) {
	op_val(c, &actx->closure_scope);
	op_val(c, &actx->result);
	op_val(c, &actx->promise);
	}
	}
	}

	esm_module_t mod, mod_tmp;
	HASH_ITER(hh, global_module_cache.modules, mod, mod_tmp) {
	op_val(c, &mod->namespace_obj);
	op_val(c, &mod->default_export);
	}

	timer_gc_update_roots(c->fwd_val, c->ctx);
	ffi_gc_update_roots(c->fwd_val, c->ctx);
	fetch_gc_update_roots(c->fwd_val, c->ctx);
	fs_gc_update_roots(c->fwd_val, c->ctx);
	child_process_gc_update_roots(c->fwd_val, c->ctx);
	readline_gc_update_roots(c->fwd_val, c->ctx);
	process_gc_update_roots(c->fwd_val, c->ctx);

	map_registry_entry_t map_reg, map_reg_tmp;
	HASH_ITER(hh, map_registry, map_reg, map_reg_tmp) {
	if (map_reg->head && *map_reg->head) {
	map_entry_t me, me_tmp;
	HASH_ITER(hh, *map_reg->head, me, me_tmp) op_val(c, &me->value);
	}
	}

	set_registry_entry_t set_reg, set_reg_tmp;
	HASH_ITER(hh, set_registry, set_reg, set_reg_tmp) {
	if (set_reg->head && *set_reg->head) {
	set_entry_t se, se_tmp;
	HASH_ITER(hh, *set_reg->head, se, se_tmp) op_val(c, &se->value);
	}
	}

	for (int i = 0; i < c->js->for_let_stack_len; i++) {
	op_val(c, &c->js->for_let_stack[i].body_scope);
	op_off(c, &c->js->for_let_stack[i].prop_off);
	}
	}

	void js_gc_reserve_roots(GC_UPDATE_ARGS) {
	#define RSV_OFF(x) ((x) ? (void)fwd_off(ctx, x) : (void)0)
	#define RSV_VAL(x) (void)fwd_val(ctx, x)

	gc_cb_ctx_t cb_ctx = { fwd_off, fwd_val, ctx, js };
	gc_roots_common(gc_reserve_off_cb, gc_reserve_val_cb, &cb_ctx);

	promise_data_entry_t pd, pd_tmp;
	HASH_ITER(hh, promise_registry, pd, pd_tmp) {
	(void)fwd_off(ctx, pd->obj_offset);
	RSV_VAL(pd->value);
	UTARRAY_EACH(pd->handlers, promise_handler_t, h) {
	RSV_VAL(h->onFulfilled); RSV_VAL(h->onRejected); RSV_VAL(h->nextPromise);
	}
	}

	// accessor registry is a weak reference
	// objects only survive if reachable from other roots
	(void)accessor_registry;

	proxy_data_t proxy, proxy_tmp;
	HASH_ITER(hh, proxy_registry, proxy, proxy_tmp) {
	RSV_VAL(proxy->target);
	RSV_VAL(proxy->handler);
	}

	descriptor_entry_t desc, desc_tmp;
	HASH_ITER(hh, desc_registry, desc, desc_tmp) {
	if (desc->has_getter) RSV_VAL(desc->getter);
	if (desc->has_setter) RSV_VAL(desc->setter);
	}

	#undef RSV_OFF
	#undef RSV_VAL
	}

	void js_gc_update_roots(GC_UPDATE_ARGS) {
	#define FWD_OFF(x) ((x) ? ((x) = fwd_off(ctx, x)) : 0)
	#define FWD_VAL(x) ((x) = fwd_val(ctx, x))

	gc_cb_ctx_t cb_ctx = { fwd_off, fwd_val, ctx, js };
	gc_roots_common(gc_update_off_cb, gc_update_val_cb, &cb_ctx);

	promise_data_entry_t pd, pd_tmp;
	promise_data_entry_t *new_unhandled = NULL;
	for (
	promise_data_entry_t new_promise_registry = NULL, _once = NULL; !_once; _once = (void*)1,
	promise_registry = new_promise_registry, unhandled_rejections = new_unhandled
	)
	HASH_ITER(hh, promise_registry, pd, pd_tmp) {
	HASH_DEL(promise_registry, pd);
	promise_data_entry_t *in_unhandled = NULL;
	HASH_FIND(hh_unhandled, unhandled_rejections, &pd->promise_id, sizeof(uint32_t), in_unhandled);
	if (in_unhandled) HASH_DELETE(hh_unhandled, unhandled_rejections, pd);

	jsoff_t new_off = fwd_off(ctx, pd->obj_offset);
	if (new_off == pd->obj_offset && pd->obj_offset != 0) {
	utarray_free(pd->handlers); free(pd); continue;
	}

	pd->obj_offset = new_off;
	FWD_VAL(pd->value);
	UTARRAY_EACH(pd->handlers, promise_handler_t, h) {
	FWD_VAL(h->onFulfilled); FWD_VAL(h->onRejected); FWD_VAL(h->nextPromise);
	}

	HASH_ADD(hh, new_promise_registry, promise_id, sizeof(uint32_t), pd);
	if (in_unhandled) HASH_ADD(hh_unhandled, new_unhandled, promise_id, sizeof(uint32_t), pd);
	}

	proxy_data_t proxy, proxy_tmp;
	for (proxy_data_t new_proxy_registry = NULL, _once = NULL; !_once; _once = (void*)1, proxy_registry = new_proxy_registry)
	HASH_ITER(hh, proxy_registry, proxy, proxy_tmp) {
	HASH_DEL(proxy_registry, proxy);
	jsoff_t old_off = proxy->obj_offset;
	jsoff_t new_off = fwd_off(ctx, old_off);
	if (new_off == old_off && old_off != 0) { free(proxy); continue; }
	proxy->obj_offset = new_off;
	FWD_VAL(proxy->target); FWD_VAL(proxy->handler);
	HASH_ADD(hh, new_proxy_registry, obj_offset, sizeof(jsoff_t), proxy);
	}

	dynamic_accessors_t acc, acc_tmp;
	for (dynamic_accessors_t new_acc_registry = NULL, _once = NULL; !_once; _once = (void*)1, accessor_registry = new_acc_registry)
	HASH_ITER(hh, accessor_registry, acc, acc_tmp) {
	HASH_DEL(accessor_registry, acc);
	jsoff_t old_off = acc->obj_offset;
	jsoff_t new_off = fwd_off(ctx, old_off);
	if (new_off == old_off && old_off != 0) { free(acc); continue; }
	acc->obj_offset = new_off;
	HASH_ADD(hh, new_acc_registry, obj_offset, sizeof(jsoff_t), acc);
	}

	descriptor_entry_t desc, desc_tmp;
	for (descriptor_entry_t new_desc_registry = NULL, _once = NULL; !_once; _once = (void*)1, desc_registry = new_desc_registry)
	HASH_ITER(hh, desc_registry, desc, desc_tmp) {
	HASH_DEL(desc_registry, desc);
	jsoff_t old_off = (jsoff_t)(desc->key >> 32);
	jsoff_t new_off = fwd_off(ctx, old_off);
	if (new_off == old_off && old_off != 0) { free(desc); continue; }
	if (desc->has_getter) FWD_VAL(desc->getter);
	if (desc->has_setter) FWD_VAL(desc->setter);
	desc->key = ((uint64_t)new_off << 32) \| (uint32_t)(desc->key & 0xFFFFFFFF);
	desc->obj_off = new_off;
	HASH_ADD(hh, new_desc_registry, key, sizeof(uint64_t), desc);
	}

	memset(intern_prop_cache, 0, sizeof(intern_prop_cache));

	#undef FWD_OFF
	#undef FWD_VAL
	}

	#undef UTARRAY_EACH
	#undef REHASH_REGISTRY

	bool js_chkargs(jsval_t args, int nargs, const char spec) {
	int i = 0, ok = 1;
	for (; ok && i < nargs && spec[i]; i++) {
	uint8_t t = vtype(args[i]), c = (uint8_t) spec[i];
	ok = (c == 'b' && t == T_BOOL) \|\| (c == 'd' && t == T_NUM) \|\|
	(c == 's' && t == T_STR) \|\| (c == 'j');
	}
	if (spec[i] != '\0' \|\| i != nargs) ok = 0;
	return ok;
	}

	static jsval_t js_eval_inherit_strict(struct js js, const char buf, size_t len, bool inherit_strict) {
	jsval_t res = js_mkundef();
	if (len == (size_t) ~0U) len = strlen(buf);
	js->eval_depth++;
	js->consumed = 1;
	js->tok = TOK_ERR;
	js->code = buf;
	js->clen = (jsoff_t) len;
	js->pos = 0;

	uint8_t saved_tok = js->tok;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_consumed = js->consumed;
	js->consumed = 1;

	bool is_strict = inherit_strict;
	if (inherit_strict) js->flags \|= F_STRICT;

	if (next(js) == TOK_STRING) {
	const char *str = &js->code[js->toff + 1];
	size_t str_len = js->tlen - 2;
	if (str_len == 10 && memcmp(str, "use strict", 10) == 0) {
	js->flags \|= F_STRICT;
	is_strict = true;
	}
	}

	js->tok = saved_tok;
	js->pos = saved_pos;
	js->consumed = saved_consumed;

	if (is_strict) {
	mkscope(js);
	set_slot(js, js->scope, SLOT_STRICT_EVAL_SCOPE, tov(1));
	}

	hoist_function_declarations(js);
	if (!(js->flags & F_CALL)) hoist_var_declarations(js, js->scope);

	while (next(js) != TOK_EOF && !is_err(res)) {
	res = js_stmt(js);
	if (js->needs_gc && js->eval_depth == 1 && !js->gc_suppress) {
	js->needs_gc = false;
	// js_gc_compact(js);
	}
	if (js->flags & F_RETURN) break;
	}

	if (is_strict) delscope(js);
	js->eval_depth--;
	return res;
	}

	jsval_t js_eval(struct js js, const char buf, size_t len) {
	return js_eval_inherit_strict(js, buf, len, false);
	}

	static jsval_t js_call_internal(struct js js, jsval_t func, jsval_t bound_this, jsval_t args, int nargs, bool use_bound_this) {
	if (vtype(func) == T_FFI) {
	return ffi_call_by_index(js, (unsigned int)vdata(func), args, nargs);
	} else if (vtype(func) == T_CFUNC) {
	jsval_t saved_this = js->this_val;
	if (use_bound_this) js->this_val = bound_this;
	jsval_t (fn)(struct js , jsval_t , int) = (jsval_t()(struct js , jsval_t , int)) vdata(func);
	jsval_t res = fn(js, args, nargs);
	js->this_val = saved_this;
	return res;
	} else if (vtype(func) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);

	if (vtype(cfunc_slot) == T_CFUNC) {
	jsval_t slot_bound_this = get_slot(js, func_obj, SLOT_BOUND_THIS);
	bool has_slot_bound_this = vtype(slot_bound_this) != T_UNDEF;

	int final_nargs;
	jsval_t *combined_args = resolve_bound_args(js, func_obj, args, nargs, &final_nargs);
	jsval_t *final_args = combined_args ? combined_args : args;

	jsval_t saved_func = js->current_func;
	jsval_t saved_this = js->this_val;
	js->current_func = func;

	if (has_slot_bound_this) {
	js->this_val = slot_bound_this;
	} else if (use_bound_this) js->this_val = bound_this;

	jsval_t (fn)(struct js , jsval_t , int) = (jsval_t()(struct js , jsval_t , int)) vdata(cfunc_slot);
	jsval_t res = fn(js, final_args, final_nargs);
	js->current_func = saved_func;
	js->this_val = saved_this;

	if (combined_args) free(combined_args);
	return res;
	}

	jsoff_t fnlen;
	const char *fn = get_func_code(js, func_obj, &fnlen);
	if (!fn) return js_mkerr(js, "function has no code");

	jsval_t slot_bound_this = get_slot(js, func_obj, SLOT_BOUND_THIS);
	bool has_slot_bound_this = vtype(slot_bound_this) != T_UNDEF;

	int final_nargs;
	jsval_t *combined_args = resolve_bound_args(js, func_obj, args, nargs, &final_nargs);
	jsval_t *final_args = combined_args ? combined_args : args;

	jsval_t async_slot = get_slot(js, func_obj, SLOT_ASYNC);
	bool is_async = vtype(async_slot) == T_BOOL && vdata(async_slot) == 1;

	if (is_async) {
	jsval_t closure_scope = get_slot(js, func_obj, SLOT_SCOPE);
	jsval_t res = start_async_in_coroutine(js, fn, fnlen, closure_scope, final_args, final_nargs);
	if (combined_args) free(combined_args);
	return res;
	}

	jsval_t saved_scope = js->scope;
	jsval_t closure_scope = get_slot(js, func_obj, SLOT_SCOPE);
	if (vtype(closure_scope) == T_OBJ) js->scope = closure_scope;

	uint8_t saved_flags = js->flags;
	js->flags = 0;
	mkscope(js);
	js->flags = saved_flags;

	parsed_func_t *pf = get_or_parse_func(fn, fnlen);
	if (!pf) {
	delscope(js);
	js->scope = saved_scope;
	if (combined_args) free(combined_args);
	return js_mkerr(js, "failed to parse function");
	}

	int arg_idx = 0;
	for (unsigned int i = 0; i < (unsigned int)pf->param_count; i++) {
	parsed_param_t pp = (parsed_param_t )utarray_eltptr(pf->params, i);

	if (pp->is_destruct) {
	jsval_t arg_val = (arg_idx < final_nargs) ? final_args[arg_idx++] : js_mkundef();
	if (vtype(arg_val) == T_UNDEF && pp->default_len > 0) {
	arg_val = js_eval_str(js, &fn[pp->default_start], pp->default_len);
	}
	bind_destruct_pattern(js, &fn[pp->pattern_off], pp->pattern_len, arg_val, js->scope);
	} else {
	jsval_t v = arg_idx < final_nargs ? final_args[arg_idx++] : js_mkundef();
	if (vtype(v) == T_UNDEF && pp->default_len > 0) {
	v = js_eval_str(js, &fn[pp->default_start], pp->default_len);
	}
	setprop(js, js->scope, js_mkstr(js, &fn[pp->name_off], pp->name_len), v);
	}
	}

	if (pf->has_rest && pf->rest_param_len > 0) {
	jsval_t rest_array = mkarr(js);
	if (!is_err(rest_array)) {
	jsoff_t idx = 0;
	while (arg_idx < final_nargs) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	setprop(js, rest_array, key, final_args[arg_idx]);
	idx++;
	arg_idx++;
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, rest_array, len_key, tov((double) idx));
	rest_array = mkval(T_ARR, vdata(rest_array));
	setprop(js, js->scope, js_mkstr(js, &fn[pf->rest_param_start], pf->rest_param_len), rest_array);
	}
	}

	if (code_uses_arguments(&fn[pf->body_start], pf->body_len)) {
	setup_arguments(js, js->scope, final_args, final_nargs, pf->is_strict);
	}

	jsval_t saved_this = js->this_val;
	if (has_slot_bound_this) {
	js->this_val = slot_bound_this;
	} else if (use_bound_this) {
	js->this_val = bound_this;
	} else js->this_val = js_glob(js);

	js_parse_state_t saved_state;
	JS_SAVE_STATE(js, saved_state);
	uint8_t caller_flags = js->flags;

	js->flags = F_CALL \| (pf->is_strict ? F_STRICT : 0);
	jsval_t res = js_eval(js, &fn[pf->body_start], pf->body_len);
	if (!is_err(res) && !(js->flags & F_RETURN)) res = js_mkundef();

	JS_RESTORE_STATE(js, saved_state);
	js->flags = caller_flags;

	js->this_val = saved_this;
	delscope(js);
	js->scope = saved_scope;
	if (combined_args) free(combined_args);

	return res;
	}
	return js_mkerr(js, "not a function");
	}

	jsval_t js_call(struct js js, jsval_t func, jsval_t args, int nargs) {
	return js_call_internal(js, func, js_mkundef(), args, nargs, false);
	}

	jsval_t js_call_with_this(struct js js, jsval_t func, jsval_t bound_this, jsval_t args, int nargs) {
	return js_call_internal(js, func, bound_this, args, nargs, true);
	}

	ant_iter_t js_prop_iter_begin(struct js *js, jsval_t obj) {
	ant_iter_t iter = {.ctx = js, .off = 0};

	uint8_t t = vtype(obj);
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	iter.off = (jsoff_t)vdata(obj);
	}

	return iter;
	}

	bool js_prop_iter_next(ant_iter_t iter, const char key, size_t key_len, jsval_t *value) {
	if (!iter \|\| !iter->ctx) return false;

	ant_t js = (ant_t )iter->ctx;
	jsoff_t next = loadoff(js, iter->off) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (!is_slot_prop(header)) break;
	next = next_prop(header);
	}

	if (next >= js->brk \|\| next == 0) return false;
	iter->off = next;

	jsoff_t koff = loadoff(js, next + (jsoff_t)sizeof(jsoff_t));
	jsval_t val = loadval(js, next + (jsoff_t)(sizeof(jsoff_t) * 2));

	if (key) {
	jsoff_t klen = offtolen(loadoff(js, koff));
	key = (const char )&js->mem[koff + sizeof(jsoff_t)];
	if (key_len) *key_len = klen;
	}
	if (value) *value = val;

	return true;
	}

	void js_prop_iter_end(ant_iter_t *iter) {
	if (iter) { iter->off = 0; iter->ctx = NULL; }
	}

	jsval_t js_mkpromise(struct js *js) { return mkpromise(js); }
	void js_resolve_promise(struct js *js, jsval_t promise, jsval_t value) { resolve_promise(js, promise, value); }
	void js_reject_promise(struct js *js, jsval_t promise, jsval_t value) { reject_promise(js, promise, value); }

	void js_check_unhandled_rejections(struct js *js) {
	promise_data_entry_t pd, tmp;

	HASH_ITER(hh_unhandled, unhandled_rejections, pd, tmp) {
	if (pd->has_rejection_handler) {
	HASH_DELETE(hh_unhandled, unhandled_rejections, pd); continue;
	}

	if (pd->trigger_pid != 0) {
	promise_data_entry_t *parent;
	HASH_FIND(hh, promise_registry, &pd->trigger_pid, sizeof(uint32_t), parent);
	if (parent && parent->has_rejection_handler) {
	HASH_DELETE(hh_unhandled, unhandled_rejections, pd); continue;
	}
	}

	char buf[1024];
	buf[tostr(js, pd->value, buf, sizeof(buf) - 1)] = '\0';
	fprintf(stderr, "Uncaught (in promise) %s\n", buf);

	pd->has_rejection_handler = true;
	HASH_DELETE(hh_unhandled, unhandled_rejections, pd);
	}
	}

	bool js_is_slot_prop(jsoff_t header) { return is_slot_prop(header); }
	jsoff_t js_next_prop(jsoff_t header) { return next_prop(header); }
	jsoff_t js_loadoff(struct js *js, jsoff_t off) { return loadoff(js, off); }

	void js_set_getter(struct js *js, jsval_t obj, js_getter_fn getter) {
	if (vtype(obj) != T_OBJ) return;
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry) {
	entry = (dynamic_accessors_t *)malloc(sizeof(dynamic_accessors_t));
	if (!entry) return;
	entry->obj_offset = obj_off;
	entry->getter = NULL;
	entry->setter = NULL;
	HASH_ADD(hh, accessor_registry, obj_offset, sizeof(jsoff_t), entry);
	}
	entry->getter = getter;
	}

	void js_set_setter(struct js *js, jsval_t obj, js_setter_fn setter) {
	if (vtype(obj) != T_OBJ) return;
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry) {
	entry = (dynamic_accessors_t *)malloc(sizeof(dynamic_accessors_t));
	if (!entry) return;
	entry->obj_offset = obj_off;
	entry->getter = NULL;
	entry->setter = NULL;
	HASH_ADD(hh, accessor_registry, obj_offset, sizeof(jsoff_t), entry);
	}
	entry->setter = setter;
	}

	static inline uint64_t make_desc_key(jsoff_t obj_off, const char *key, size_t klen) {
	uint32_t key_hash = (uint32_t)hash_key(key, klen);
	return ((uint64_t)obj_off << 32) \| key_hash;
	}

	static descriptor_entry_t lookup_descriptor(jsoff_t obj_off, const char key, size_t klen) {
	uint64_t desc_key = make_desc_key(obj_off, key, klen);
	descriptor_entry_t *entry = NULL;
	HASH_FIND(hh, desc_registry, &desc_key, sizeof(uint64_t), entry);
	return entry;
	}

	static descriptor_entry_t get_or_create_desc(struct js js, jsval_t obj, const char *key, size_t klen) {
	if (vtype(obj) != T_OBJ && vtype(obj) != T_FUNC && vtype(obj) != T_ARR) return NULL;
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	uint64_t desc_key = make_desc_key(obj_off, key, klen);

	descriptor_entry_t *entry = NULL;
	HASH_FIND(hh, desc_registry, &desc_key, sizeof(uint64_t), entry);
	if (!entry) {
	entry = (descriptor_entry_t *)ant_calloc(sizeof(descriptor_entry_t) + klen + 1);
	if (!entry) return NULL;

	entry->key = desc_key;
	entry->obj_off = obj_off;
	entry->prop_name = (char *)(entry + 1);
	memcpy(entry->prop_name, key, klen);
	entry->prop_name[klen] = '\0';
	entry->prop_len = klen;
	entry->writable = true;
	entry->enumerable = true;
	entry->configurable = true;
	entry->has_getter = false;
	entry->has_setter = false;
	entry->getter = js_mkundef();
	entry->setter = js_mkundef();

	HASH_ADD(hh, desc_registry, key, sizeof(uint64_t), entry);
	}
	return entry;
	}

	void js_set_descriptor(struct js js, jsval_t obj, const char key, size_t klen, int flags) {
	descriptor_entry_t *entry = get_or_create_desc(js, obj, key, klen);
	if (!entry) return;
	entry->writable = (flags & JS_DESC_W) != 0;
	entry->enumerable = (flags & JS_DESC_E) != 0;
	entry->configurable = (flags & JS_DESC_C) != 0;
	}

	void js_set_getter_desc(struct js js, jsval_t obj, const char key, size_t klen, jsval_t getter, int flags) {
	descriptor_entry_t *entry = get_or_create_desc(js, obj, key, klen);
	if (!entry) return;
	entry->enumerable = (flags & JS_DESC_E) != 0;
	entry->configurable = (flags & JS_DESC_C) != 0;
	entry->has_getter = true;
	entry->getter = getter;
	}

	void js_set_setter_desc(struct js js, jsval_t obj, const char key, size_t klen, jsval_t setter, int flags) {
	descriptor_entry_t *entry = get_or_create_desc(js, obj, key, klen);
	if (!entry) return;
	entry->enumerable = (flags & JS_DESC_E) != 0;
	entry->configurable = (flags & JS_DESC_C) != 0;
	entry->has_setter = true;
	entry->setter = setter;
	}

	void js_set_accessor_desc(struct js js, jsval_t obj, const char key, size_t klen, jsval_t getter, jsval_t setter, int flags) {
	descriptor_entry_t *entry = get_or_create_desc(js, obj, key, klen);
	if (!entry) return;
	entry->enumerable = (flags & JS_DESC_E) != 0;
	entry->configurable = (flags & JS_DESC_C) != 0;
	entry->has_getter = true;
	entry->has_setter = true;
	entry->getter = getter;
	entry->setter = setter;
	}

	void js_print_stack_trace(FILE *stream) {
	if (global_call_stack.depth > 0) {
	for (int i = global_call_stack.depth - 1; i >= 0; i--) {
	call_frame_t *frame = &global_call_stack.frames[i];
	fprintf(stream, " at ");

	if (frame->function_name) {
	fprintf(stream, "%s", frame->function_name);
	} else fprintf(stream, "<anonymous>");

	fprintf(stream, " (\x1b[90m");

	if (frame->line < 0 && frame->code) {
	get_line_col(frame->code, frame->pos, &frame->line, &frame->col);
	}
	int fline = frame->line > 0 ? frame->line : 1;
	int fcol = frame->col > 0 ? frame->col : 1;

	if (frame->filename) {
	fprintf(stream, "%s:%d:%d", frame->filename, fline, fcol);
	} else fprintf(stream, "<unknown>");

	fprintf(stream, "\x1b[0m)\n");
	}
	}
	}

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