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

	#include <assert.h>
	#include <math.h>
	#include <regex.h>
	#include <stdarg.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/time.h>
	#include <time.h>
	#include <unistd.h>
	#include <libgen.h>
	#include <sys/stat.h>
	#include <utarray.h>
	#include <uthash.h>

	#include "ant.h"
	#include "config.h"
	#include "arena.h"

	#include "modules/fs.h"
	#include "modules/timer.h"
	#include "modules/fetch.h"

	#define MINICORO_IMPL
	#include "minicoro.h"

	typedef uint32_t jsoff_t;

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

	typedef struct call_frame {
	const char *filename;
	const char *function_name;
	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 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 *next;
	mco_coro* mco;
	bool mco_started;
	bool is_ready;
	} 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;

	typedef struct {
	jsoff_t offset;
	jsoff_t size;
	uint8_t type;
	char detail[128];
	} FreeListEntry;

	static UT_array *global_free_list = NULL;
	static UT_array *global_scope_stack = NULL;
	static jsoff_t protected_brk = 0;

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

	static const UT_icd free_list_icd = {
	.sz = sizeof(FreeListEntry),
	.init = NULL,
	.copy = NULL,
	.dtor = 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 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;
	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;

	typedef struct {
	char key[64];
	jsoff_t offset;
	uint32_t hash;
	UT_hash_handle hh;
	} prop_cache_entry_t;

	typedef struct {
	jsoff_t obj_offset;
	prop_cache_entry_t *cache;
	uint32_t hit_count;
	UT_hash_handle hh;
	} obj_prop_cache_t;

	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;

	static ant_library_t *library_registry = NULL;
	static esm_module_cache_t global_module_cache = {NULL, 0};
	static obj_prop_cache_t *global_property_cache = NULL;

	void js_protect_init_memory(struct js *js) {
	protected_brk = js_getbrk(js);
	if (protected_brk < 0x2000) protected_brk = 0x2000;
	}

	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_GC_MALLOC(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;
	}

	struct js {
	jsoff_t css; // max observed C stack size
	jsoff_t lwm; // JS ram low watermark: min free ram observed
	const char *code; // currently parsed code snippet
	char *errmsg; // dynamic error message buffer
	size_t errmsg_size; // size of error message buffer
	const char *filename; // current filename for error reporting
	uint8_t tok; // last parsed token value
	uint8_t consumed; // indicator that last parsed token was consumed
	uint8_t flags; // execution flags, see F_* constants below
	#define F_NOEXEC 1U // parse code, but not execute
	#define F_LOOP 2U // we are inside the loop
	#define F_CALL 4U // we are inside a function call
	#define F_BREAK 8U // exit the loop
	#define F_RETURN 16U // return has been executed
	#define F_THROW 32U // throw has been executed
	#define F_SWITCH 64U // we are inside a switch statement
	#define F_STRICT 128U // strict mode is enabled
	jsoff_t clen; // code snippet length
	jsoff_t pos; // current parsing position
	jsoff_t toff; // offset of the last parsed token
	jsoff_t tlen; // length of the last parsed token
	jsoff_t nogc; // entity offset to exclude from GC
	jsval_t tval; // holds last parsed numeric or string literal value
	jsval_t scope; // current scope
	jsval_t this_val; // 'this' value for currently executing function
	uint8_t *mem; // available JS memory
	jsoff_t size; // memory size
	jsoff_t brk; // current mem usage boundary
	jsoff_t gct; // GC threshold. if brk > gct, trigger GC
	jsoff_t maxcss; // maximum allowed C stack size usage
	void *cstk; // C stack pointer at the beginning of js_eval()
	jsval_t current_func; // currently executing function (for native closures)
	bool var_warning_shown; // flag to show var deprecation warning only once
	bool owns_mem; // true if js owns the memory buffer (dynamic allocation)
	jsoff_t max_size; // maximum allowed memory size (for dynamic growth)
	bool had_newline; // true if newline was crossed before current token
	jsval_t thrown_value; // stores the actual thrown value for catch blocks
	};

	enum {
	TOK_ERR, TOK_EOF, TOK_IDENTIFIER, TOK_NUMBER, TOK_STRING, TOK_SEMICOLON, TOK_BIGINT,
	TOK_LPAREN, TOK_RPAREN, TOK_LBRACE, TOK_RBRACE, TOK_LBRACKET, TOK_RBRACKET,
	TOK_ASYNC = 50, TOK_AWAIT, TOK_BREAK, TOK_CASE, TOK_CATCH, TOK_CLASS, TOK_CONST, TOK_CONTINUE,
	TOK_DEFAULT, TOK_DELETE, TOK_DO, 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_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_WINDOW, TOK_GLOBAL_THIS,
	TOK_DOT = 100, TOK_CALL, TOK_BRACKET, TOK_POSTINC, TOK_POSTDEC, TOK_NOT, TOK_TILDA,
	TOK_TYPEOF, 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_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_COMMA, TOK_TEMPLATE, TOK_ARROW,
	};

	enum {
	T_OBJ, T_PROP, T_STR, T_UNDEF, T_NULL, T_NUM,
	T_BOOL, T_FUNC, T_CODEREF, T_CFUNC, T_ERR, T_ARR,
	T_PROMISE, T_GENERATOR, T_BIGINT, T_PROPREF
	};

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

	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 size_t vdata(jsval_t v) { return (size_t) (v & ~((jsval_t) 0x7fffUL << 48U)); }

	static jsoff_t coderefoff(jsval_t v) { return v & 0xffffffU; }
	static jsoff_t codereflen(jsval_t v) { return (v >> 24U) & 0xffffffU; }
	static jsoff_t propref_obj(jsval_t v) { return v & 0xffffffU; }
	static jsoff_t propref_key(jsval_t v) { return (v >> 24U) & 0xffffffU; }

	static bool is_nan(jsval_t v) {
	if ((v >> 52U) != 0x7feU) return false;
	// real doubles in 0x7FE range have large mantissa values
	// tagged values have small memory offsets, so upper data bits are 0
	return (v & 0xf00000000000UL) == 0;
	}

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

	uint8_t vtype(jsval_t v) {
	return is_nan(v) ? ((v >> 48U) & 15U) : (uint8_t) T_NUM;
	}

	static jsval_t mkval(uint8_t type, uint64_t data) {
	return ((jsval_t) 0x7fe0U << 48U) \| ((jsval_t) (type) << 48) \| (data & 0xffffffffffffUL);
	}

	static jsval_t mkcoderef(jsval_t off, jsoff_t len) {
	return mkval(T_CODEREF, (off & 0xffffffU) \| ((jsval_t)(len & 0xffffffU) << 24U));
	}

	static jsval_t mkpropref(jsoff_t obj_off, jsoff_t key_off) {
	return mkval(T_PROPREF, (obj_off & 0xffffffU) \| ((jsval_t)(key_off & 0xffffffU) << 24U));
	}

	static uint8_t unhex(uint8_t c) { return (c >= '0' && c <= '9') ? (uint8_t) (c - '0') : (c >= 'a' && c <= 'f') ? (uint8_t) (c - 'W') : (c >= 'A' && c <= 'F') ? (uint8_t) (c - '7') : 0; }
	static bool is_space(int c) { return c == ' ' \|\| c == '\r' \|\| c == '\n' \|\| c == '\t' \|\| c == '\f' \|\| c == '\v'; }
	static bool is_digit(int c) { return c >= '0' && c <= '9'; }
	static bool is_xdigit(int c) { return is_digit(c) \|\| (c >= 'a' && c <= 'f') \|\| (c >= 'A' && c <= 'F'); }
	static bool is_alpha(int c) { return (c >= 'a' && c <= 'z') \|\| (c >= 'A' && c <= 'Z'); }
	static bool is_ident_begin(int c) { return c == '_' \|\| c == '$' \|\| is_alpha(c); }
	static bool is_ident_continue(int c) { return c == '_' \|\| c == '$' \|\| is_alpha(c) \|\| is_digit(c); }
	static bool is_err(jsval_t v) { return vtype(v) == T_ERR; }
	static bool is_unary(uint8_t tok) { return (tok >= TOK_POSTINC && tok <= TOK_UMINUS) \|\| tok == TOK_NOT \|\| tok == TOK_TILDA \|\| tok == TOK_TYPEOF \|\| tok == TOK_VOID; }
	static bool is_assign(uint8_t tok) { return (tok >= TOK_ASSIGN && tok <= TOK_OR_ASSIGN); }
	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 jsoff_t loadoff(struct js *js, jsoff_t off) { jsoff_t v = 0; assert(js->brk <= js->size); memcpy(&v, &js->mem[off], sizeof(v)); return v; }
	static jsoff_t offtolen(jsoff_t off) { return (off >> 2) - 1; }
	static jsoff_t vstrlen(struct js *js, jsval_t v) { return offtolen(loadoff(js, (jsoff_t) vdata(v))); }
	static jsval_t loadval(struct js *js, jsoff_t off) { jsval_t v = 0; memcpy(&v, &js->mem[off], sizeof(v)); return v; }
	static jsval_t upper(struct js *js, jsval_t scope) { return mkval(T_OBJ, loadoff(js, (jsoff_t) (vdata(scope) + sizeof(jsoff_t)))); }
	static jsoff_t align32(jsoff_t v) { return ((v + 3) >> 2) << 2; }

	#define CHECKV(_v) do { if (is_err(_v)) { res = (_v); goto done; } } while (0)
	#define EXPECT(_tok, _e) do { if (next(js) != _tok) { _e; return js_mkerr_typed(js, JS_ERR_SYNTAX, "parse error"); }; js->consumed = 1; } while (0)

	static bool streq(const char buf, size_t len, const char p, size_t n);
	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 inline jsoff_t esize(jsoff_t w);
	static jsval_t js_expr(struct js *js);
	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_while(struct js *js);
	static jsval_t js_do_while(struct js *js);
	static jsval_t js_block_or_stmt(struct js *js);
	static jsval_t js_var_decl(struct js *js);
	static bool parse_func_params(struct js js, uint8_t flags, int *out_count);
	static jsval_t js_regex_literal(struct js *js);
	static jsval_t js_try(struct js *js);
	static jsval_t js_switch(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 free_list_allocate(size_t size);
	static jsoff_t lkp(struct js js, jsval_t obj, const char buf, size_t len);
	static jsval_t builtin_array_push(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_pop(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_slice(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_join(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_includes(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_every(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_reverse(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_map(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_filter(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_reduce(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_flat(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_concat(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_at(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_fill(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_find(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_findIndex(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_findLast(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_findLastIndex(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_flatMap(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_forEach(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_indexOf(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_lastIndexOf(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_reduceRight(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_shift(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_unshift(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_some(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_sort(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_splice(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_copyWithin(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_toReversed(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_toSorted(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_toSpliced(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_with(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_keys(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_values(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_entries(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_array_toString(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Array_isArray(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Array_from(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Array_of(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Error(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_EvalError(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_RangeError(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_ReferenceError(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_SyntaxError(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_TypeError(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_URIError(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_InternalError(struct js js, jsval_t args, int nargs);
	static jsval_t js_import_stmt(struct js *js);
	static jsval_t js_export_stmt(struct js *js);
	static jsval_t builtin_import(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_import_meta_resolve(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_indexOf(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_substring(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_split(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_slice(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_includes(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_startsWith(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_endsWith(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_replace(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_template(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_charCodeAt(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_toLowerCase(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_toUpperCase(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_trim(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_repeat(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_padStart(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_padEnd(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_string_charAt(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_number_toString(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_number_toFixed(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_number_toPrecision(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_number_toExponential(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_parseInt(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_parseFloat(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_btoa(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_atob(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Object(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_RegExp(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Promise(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Promise_resolve(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Promise_reject(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Promise_try(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Promise_all(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Promise_race(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 builtin_promise_catch(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_promise_finally(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Date(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Date_now(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Map(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Set(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_WeakMap(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_WeakSet(struct js js, jsval_t args, int nargs);
	static jsval_t map_set(struct js js, jsval_t args, int nargs);
	static jsval_t map_get(struct js js, jsval_t args, int nargs);
	static jsval_t map_has(struct js js, jsval_t args, int nargs);
	static jsval_t map_delete(struct js js, jsval_t args, int nargs);
	static jsval_t map_clear(struct js js, jsval_t args, int nargs);
	static jsval_t map_size(struct js js, jsval_t args, int nargs);
	static jsval_t map_entries(struct js js, jsval_t args, int nargs);
	static jsval_t map_keys(struct js js, jsval_t args, int nargs);
	static jsval_t map_values(struct js js, jsval_t args, int nargs);
	static jsval_t map_forEach(struct js js, jsval_t args, int nargs);
	static jsval_t set_add(struct js js, jsval_t args, int nargs);
	static jsval_t set_has(struct js js, jsval_t args, int nargs);
	static jsval_t set_delete(struct js js, jsval_t args, int nargs);
	static jsval_t set_clear(struct js js, jsval_t args, int nargs);
	static jsval_t set_size(struct js js, jsval_t args, int nargs);
	static jsval_t set_values(struct js js, jsval_t args, int nargs);
	static jsval_t set_forEach(struct js js, jsval_t args, int nargs);
	static jsval_t weakmap_set(struct js js, jsval_t args, int nargs);
	static jsval_t weakmap_get(struct js js, jsval_t args, int nargs);
	static jsval_t weakmap_has(struct js js, jsval_t args, int nargs);
	static jsval_t weakmap_delete(struct js js, jsval_t args, int nargs);
	static jsval_t weakset_add(struct js js, jsval_t args, int nargs);
	static jsval_t weakset_has(struct js js, jsval_t args, int nargs);
	static jsval_t weakset_delete(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_function_call(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_function_apply(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_function_bind(struct js js, jsval_t args, int nargs);

	static jsval_t builtin_Math_abs(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_acos(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_acosh(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_asin(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_asinh(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_atan(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_atanh(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_atan2(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_cbrt(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_ceil(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_clz32(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_cos(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_cosh(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_exp(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_expm1(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_floor(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_fround(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_hypot(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_imul(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_log(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_log1p(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_log10(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_log2(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_max(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_min(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_pow(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_random(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_round(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_sign(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_sin(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_sinh(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_sqrt(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_tan(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_tanh(struct js js, jsval_t args, int nargs);
	static jsval_t builtin_Math_trunc(struct js js, jsval_t args, int nargs);

	static jsval_t call_js(struct js js, const char fn, jsoff_t fnlen, jsval_t closure_scope);
	static jsval_t call_js_with_args(struct js js, jsval_t func, 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);
	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 js_get_proto(struct js *js, jsval_t obj);
	void js_set_proto(struct js *js, jsval_t obj, jsval_t proto);
	jsval_t js_setprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v);
	static jsoff_t lkp_proto(struct js js, jsval_t obj, const char key, size_t len);
	jsval_t js_get_ctor_proto(struct js js, const char name, size_t len);
	static jsval_t get_prototype_for_type(struct js *js, uint8_t type);

	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 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 void free_coroutine(coroutine_t *coro);
	static bool has_ready_coroutines(void);

	static size_t calculate_coro_stack_size(void) {
	const char *env_stack = getenv("ANT_CORO_STACK_SIZE");
	if (env_stack) {
	size_t size = (size_t)atoi(env_stack) * 1024;
	if (size >= 16 * 1024 && size <= 8 * 1024 * 1024) return size;
	}

	return 128 * 1024;
	}

	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;

	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);
	} else {
	result = call_js(js, ctx->code, (jsoff_t)ctx->code_len, ctx->closure_scope);
	}

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

	if (ctx->has_error) {
	js_reject_promise(js, ctx->promise, result);
	} else {
	js_resolve_promise(js, ctx->promise, result);
	}

	}

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

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

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

	static bool 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();

	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_microtasks(js);

	coroutine_t *temp = pending_coroutines.head;
	coroutine_t *prev = NULL;

	while (temp) {
	coroutine_t *next = temp->next;

	if (temp->is_ready && temp->mco && mco_status(temp->mco) == MCO_SUSPENDED) {
	if (prev) {
	prev->next = next;
	} else {
	pending_coroutines.head = next;
	}
	if (pending_coroutines.tail == temp) {
	pending_coroutines.tail = prev;
	}

	mco_result res = mco_resume(temp->mco);

	if (res == MCO_SUCCESS && mco_status(temp->mco) == MCO_DEAD) {
	free_coroutine(temp);
	} else if (res == MCO_SUCCESS) {
	temp->is_ready = false;
	temp->next = NULL;
	if (pending_coroutines.tail) {
	pending_coroutines.tail->next = temp;
	} else {
	pending_coroutines.head = temp;
	}
	pending_coroutines.tail = temp;
	} else {
	free_coroutine(temp);
	}

	temp = next;
	} else {
	prev = temp;
	temp = next;
	}
	}
	}

	void js_run_event_loop(struct js *js) {
	while (has_pending_microtasks() \|\| has_pending_timers() \|\| has_pending_coroutines() \|\| has_pending_fetches() \|\| has_pending_fs_ops()) {
	js_poll_events(js);

	if (!has_pending_microtasks() && has_pending_timers() && !has_ready_coroutines()) {
	int64_t next_timeout_ms = get_next_timer_timeout();
	if (next_timeout_ms > 0) usleep(next_timeout_ms > 1000000 ? 1000000 : next_timeout_ms * 1000);
	}

	if (!has_pending_microtasks() && !has_pending_timers() && !has_pending_coroutines() && !has_pending_fetches() && !has_pending_fs_ops()) break;
	}

	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 )ANT_GC_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) {
	ANT_GC_FREE(ctx);
	return js_mkerr(js, "failed to create minicoro coroutine");
	}

	coroutine_t coro = (coroutine_t )ANT_GC_MALLOC(sizeof(coroutine_t));
	if (!coro) {
	mco_destroy(mco);
	ANT_GC_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->awaited_promise = js_mkundef();
	coro->result = js_mkundef();
	coro->async_func = js->current_func;
	if (nargs > 0) {
	coro->args = (jsval_t )ANT_GC_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;

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

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

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

	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");
	mco_destroy(coro->mco);
	coro->mco = NULL;
	}
	if (coro->args) ANT_GC_FREE(coro->args);
	ANT_GC_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 void setlwm(struct js *js) {
	jsoff_t n = 0, css = 0;
	if (js->brk < js->size) n = js->size - js->brk;
	if (js->lwm > n) js->lwm = n;
	if ((char ) js->cstk > (char ) &n)
	css = (jsoff_t) ((char ) js->cstk - (char ) &n);
	if (css > js->css) js->css = css;
	}

	static size_t cpy(char dst, size_t dstlen, const char src, size_t srclen) {
	size_t i = 0;
	for (i = 0; i < dstlen && i < srclen && src[i] != 0; i++) dst[i] = src[i];
	if (dstlen > 0) dst[i < dstlen ? i : dstlen - 1] = '\0';
	return i;
	}

	#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 \| CONSTMASK);
	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);
	}

	jsoff_t proto_off = lkp(js, obj, "__proto__", 9);
	if (proto_off != 0) {
	jsval_t proto_val = resolveprop(js, mkval(T_PROP, proto_off));
	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 \| CONSTMASK);
	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);
	}

	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 \| CONSTMASK);
	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);
	}

	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 size_t strbigint(struct js js, jsval_t value, char buf, size_t len);

	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);
	size_t n = cpy(buf, len, "[ ", 2);
	jsoff_t next = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| CONSTMASK);
	jsoff_t length = 0;
	jsoff_t scan = next;

	while (scan < js->brk && scan != 0) {
	jsoff_t koff = loadoff(js, scan + (jsoff_t) sizeof(scan));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];

	if (streq(key, klen, "length", 6)) {
	jsval_t val = loadval(js, scan + (jsoff_t) (sizeof(scan) + sizeof(koff)));
	if (vtype(val) == T_NUM) length = (jsoff_t) tod(val);
	break;
	}
	scan = loadoff(js, scan) & ~(3U \| CONSTMASK);
	}

	for (jsoff_t i = 0; i < length; i++) {
	if (i > 0) n += cpy(buf + n, len - n, ", ", 2);
	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) {
	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)];
	if (streq(key, klen, idx, idxlen)) {
	val = loadval(js, prop + (jsoff_t) (sizeof(prop) + sizeof(koff)));
	found = true;
	break;
	}
	prop = loadoff(js, prop) & ~(3U \| CONSTMASK);
	}

	if (found) {
	n += tostr(js, val, buf + n, len - n);
	} else {
	n += cpy(buf + n, len - n, "undefined", 9);
	}
	}

	n += cpy(buf + n, len - n, " ]", 2);
	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 \| CONSTMASK);
	jsoff_t length = 0;
	jsoff_t scan = next;

	while (scan < js->brk && scan != 0) {
	jsoff_t koff = loadoff(js, scan + (jsoff_t) sizeof(scan));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];

	if (streq(key, klen, "length", 6)) {
	jsval_t val = loadval(js, scan + (jsoff_t) (sizeof(scan) + sizeof(koff)));
	if (vtype(val) == T_NUM) length = (jsoff_t) tod(val);
	break;
	}
	scan = loadoff(js, scan) & ~(3U \| CONSTMASK);
	}

	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) {
	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)];
	if (streq(key, klen, idx, idxlen)) {
	val = loadval(js, prop + (jsoff_t) (sizeof(prop) + sizeof(koff)));
	found = true;
	break;
	}
	prop = loadoff(js, prop) & ~(3U \| CONSTMASK);
	}

	if (found) {
	n += tostr(js, val, buf + n, len - n);
	} else {
	n += cpy(buf + n, len - n, "", 0);
	}
	}

	pop_stringify();
	return n;
	}

	static size_t strdate(struct js js, jsval_t obj, char buf, size_t len) {
	jsoff_t time_off = lkp(js, obj, "__time", 6);
	if (time_off == 0) return cpy(buf, len, "Invalid Date", 12);

	jsval_t time_val = resolveprop(js, mkval(T_PROP, time_off));
	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 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 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];
	if (is_valid_identifier(str, slen)) {
	return cpy(buf, len, str, slen);
	}
	return strstring(js, value, buf, len);
	}

	static size_t print_prototype(struct js js, jsval_t proto_val, char buf, size_t len, bool *first) {
	size_t n = 0;

	int ref = get_circular_ref(proto_val);
	if (ref) {
	if (!*first) n += cpy(buf + n, len - n, ",\n", 2);
	*first = false;
	n += add_indent(buf + n, len - n, stringify_indent);
	n += ref > 0 ? (size_t) snprintf(buf + n, len - n, "[Prototype]: [Circular *%d]", ref) : cpy(buf + n, len - n, "[Prototype]: [Circular]", 23);
	return n;
	}

	push_stringify(proto_val);

	bool has_proto_props = false;
	jsoff_t proto_next = loadoff(js, (jsoff_t) vdata(proto_val)) & ~(3U \| CONSTMASK);

	while (proto_next < js->brk && proto_next != 0) {
	jsoff_t pkoff = loadoff(js, proto_next + (jsoff_t) sizeof(proto_next));
	jsoff_t pklen = offtolen(loadoff(js, pkoff));
	const char pkstr = (const char ) &js->mem[pkoff + sizeof(jsoff_t)];

	if (!streq(pkstr, pklen, "__proto__", 9) && !streq(pkstr, pklen, "constructor", 11) && !streq(pkstr, pklen, "@@toStringTag", 13) && !streq(pkstr, pklen, "__getter", 8)) {
	has_proto_props = true;
	break;
	}
	proto_next = loadoff(js, proto_next) & ~(3U \| CONSTMASK);
	}

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

	if (has_proto_props) {
	n += cpy(buf + n, len - n, "[Prototype]: {\n", 15);
	stringify_indent++;

	bool proto_first = true;
	proto_next = loadoff(js, (jsoff_t) vdata(proto_val)) & ~(3U \| CONSTMASK);
	while (proto_next < js->brk && proto_next != 0) {
	jsoff_t pkoff = loadoff(js, proto_next + (jsoff_t) sizeof(proto_next));
	jsval_t pval = loadval(js, proto_next + (jsoff_t) (sizeof(proto_next) + sizeof(pkoff)));

	jsoff_t pklen = offtolen(loadoff(js, pkoff));
	const char pkstr = (const char ) &js->mem[pkoff + sizeof(jsoff_t)];

	if (!streq(pkstr, pklen, "__proto__", 9) && !streq(pkstr, pklen, "constructor", 11) && !streq(pkstr, pklen, "@@toStringTag", 13) && !streq(pkstr, pklen, "__getter", 8)) {
	if (!proto_first) n += cpy(buf + n, len - n, ",\n", 2);
	proto_first = false;
	n += add_indent(buf + n, len - n, stringify_indent);
	n += strkey(js, mkval(T_STR, pkoff), buf + n, len - n);
	n += cpy(buf + n, len - n, ": ", 2);
	n += tostr(js, pval, buf + n, len - n);
	}
	proto_next = loadoff(js, proto_next) & ~(3U \| CONSTMASK);
	}

	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);
	} else {
	n += cpy(buf + n, len - n, "[Prototype]: {}", 15);
	}

	pop_stringify();
	return n;
	}

	static size_t strobj(struct js js, jsval_t obj, char buf, size_t len) {
	jsoff_t time_off = lkp(js, obj, "__time", 6);
	if (time_off != 0) 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);
	}

	jsoff_t tag_off = lkp_proto(js, obj, "@@toStringTag", 13);
	bool is_map = false, is_set = false;
	jsoff_t tlen = 0, toff = 0;
	const char *tag_str = NULL;

	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);

	if (is_map) {
	jsoff_t map_off = lkp(js, obj, "__map", 5);
	if (map_off == 0) goto print_tagged_object;

	jsval_t map_val = resolveprop(js, mkval(T_PROP, map_off));
	if (vtype(map_val) != T_NUM) goto print_tagged_object;

	map_entry_t map_ptr = (map_entry_t)(size_t)vdata(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) {
	jsoff_t set_off = lkp(js, obj, "__set", 5);
	if (set_off == 0) goto print_tagged_object;

	jsval_t set_val = resolveprop(js, mkval(T_PROP, set_off));
	if (vtype(set_val) != T_NUM) goto print_tagged_object;

	set_entry_t set_ptr = (set_entry_t)(size_t)vdata(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:
	n += cpy(buf + n, len - n, "{\n", 2);

	continue_object_print:

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

	while (next < js->brk && next != 0) {
	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)];

	bool is_desc = (klen > 7 && key[0] == '_' && key[1] == '_' && key[2] == 'd' && key[3] == 'e' && key[4] == 's' && key[5] == 'c' && key[6] == '_');
	bool should_hide = streq(key, klen, "__proto__", 9) \|\| streq(key, klen, "@@toStringTag", 13) \|\| streq(key, klen, "__getter", 8) \|\| is_desc;

	if (!should_hide) {
	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, obj, desc_key, strlen(desc_key));
	if (desc_off == 0) goto check_done;

	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) != T_OBJ) goto check_done;

	jsoff_t enumerable_off = lkp(js, desc_obj, "enumerable", 10);
	if (enumerable_off == 0) goto check_done;

	jsval_t enumerable_val = resolveprop(js, mkval(T_PROP, enumerable_off));
	if (!js_truthy(js, enumerable_val)) should_hide = true;

	check_done:;
	}

	if (!should_hide) {
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));
	if (!first) n += cpy(buf + n, len - n, ",\n", 2);
	first = false;
	n += add_indent(buf + n, len - n, stringify_indent);
	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);
	}
	next = loadoff(js, next) & ~(3U \| CONSTMASK);
	}

	jsoff_t proto_off = lkp(js, obj, "__proto__", 9);
	if (proto_off != 0) {
	jsval_t proto_val = resolveprop(js, mkval(T_PROP, proto_off));
	if (vtype(proto_val) == T_OBJ) n += print_prototype(js, proto_val, buf + n, len - n, &first);
	}

	stringify_indent--;
	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 strnum(jsval_t value, char *buf, size_t len) {
	double dv = tod(value), iv;
	double frac = modf(dv, &iv);

	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 >= -9007199254740991.0 && dv <= 9007199254740991.0) {
	if (frac == 0.0) {
	return (size_t) snprintf(buf, len, "%.0f", dv);
	} else {
	return (size_t) snprintf(buf, len, "%.17g", dv);
	}
	}
	return (size_t) snprintf(buf, len, "%g", dv);
	}

	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 bool is_internal_prop(const char *key, jsoff_t klen) {
	if (klen == 6 && memcmp(key, "__code", 6) == 0) return true;
	if (klen == 13 && memcmp(key, "__native_func", 13) == 0) return true;
	if (klen == 9 && memcmp(key, "prototype", 9) == 0) return true;
	if (klen == 9 && memcmp(key, "__proto__", 9) == 0) return true;
	return false;
	}

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

	size_t n = cpy(buf, len, "{\n", 2);
	stringify_indent++;
	bool first = true;

	jsoff_t next = loadoff(js, (jsoff_t) vdata(func_obj)) & ~(3U \| CONSTMASK);
	while (next < js->brk && next != 0) {
	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	jsoff_t klen = offtolen(loadoff(js, koff));
	const char kstr = (const char ) &js->mem[koff + sizeof(jsoff_t)];

	if (!is_internal_prop(kstr, klen) && !streq(kstr, klen, "name", 4) && !streq(kstr, klen, "@@toStringTag", 13) && !streq(kstr, klen, "__getter", 8)) {
	if (!first) n += cpy(buf + n, len - n, ",\n", 2);
	first = false;
	n += add_indent(buf + n, len - n, stringify_indent);
	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);
	}
	next = loadoff(js, next) & ~(3U \| CONSTMASK);
	}

	jsoff_t proto_off = lkp(js, func_obj, "prototype", 9);
	if (proto_off != 0) {
	jsval_t proto_val = resolveprop(js, mkval(T_PROP, proto_off));
	if (vtype(proto_val) == T_OBJ) n += print_prototype(js, proto_val, buf + n, len - n, &first);
	}

	stringify_indent--;
	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 strfunc(struct js js, jsval_t value, char buf, size_t len) {
	jsval_t func_obj = mkval(T_OBJ, vdata(value));
	jsoff_t code_off = lkp(js, func_obj, "__code", 6);

	jsoff_t name_off = lkp(js, func_obj, "name", 4);
	const char *name = NULL;
	jsoff_t name_len = 0;
	if (name_off != 0) {
	jsval_t name_val = resolveprop(js, mkval(T_PROP, name_off));
	if (vtype(name_val) == T_STR) {
	name_len = 0;
	jsoff_t noff = vstr(js, name_val, &name_len);
	name = (const char *) &js->mem[noff];
	}
	}

	if (code_off == 0) {
	jsoff_t native_off = lkp(js, func_obj, "__native_func", 13);
	if (native_off != 0) {
	jsval_t native_val = resolveprop(js, mkval(T_PROP, native_off));
	if (vtype(native_val) == T_CFUNC) return strfunc_ctor(js, func_obj, buf, len);
	}
	if (name && name_len > 0) {
	size_t n = cpy(buf, len, "[Function: ", 11);
	n += cpy(buf + n, len - n, name, name_len);
	n += cpy(buf + n, len - n, "]", 1);
	return n;
	}
	return cpy(buf, len, "[Function (anonymous)]", 22);
	}
	jsval_t code_val = resolveprop(js, mkval(T_PROP, code_off));

	if (vtype(code_val) != T_STR) {
	if (name && name_len > 0) {
	size_t n = cpy(buf, len, "[Function: ", 11);
	n += cpy(buf + n, len - n, name, name_len);
	n += cpy(buf + n, len - n, "]", 1);
	return n;
	}
	return cpy(buf, len, "[Function (anonymous)]", 22);
	}

	jsoff_t sn, off = vstr(js, code_val, &sn);
	if (sn >= 9 && memcmp(&js->mem[off], "__builtin", 9) == 0) {
	return strfunc_ctor(js, func_obj, buf, len);
	}

	if (name && name_len > 0) {
	size_t n = cpy(buf, len, "[Function: ", 11);
	n += cpy(buf + n, len - n, name, name_len);
	n += cpy(buf + n, len - n, "]", 1);
	return n;
	}
	return cpy(buf, len, "[Function (anonymous)]", 22);
	}

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

	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 = 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>";

	n += (size_t) snprintf(js->errmsg + n, remaining, "\n at %s %s(%s:%d:%d)%s", fname, dim, ffile, frame->line, frame->col, 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:70:5)%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/main:217:5%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_GENERIC: return "Error";
	default: return "Error";
	}
	}

	jsval_t js_mkerr_typed(struct js js, js_err_type_t err_type, 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};

	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);

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

	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);
	}

	jsval_t js_mkerr(struct js js, const char xx, ...) {
	va_list ap;
	char error_msg[256] = {0};

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

	return js_mkerr_typed(js, JS_ERR_TYPE, "%s", error_msg);
	}

	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 cpy(buf, len, "undefined", 9);
	case T_NULL: return cpy(buf, len, "null", 4);
	case T_BOOL: return cpy(buf, len, vdata(value) & 1 ? "true" : "false", vdata(value) & 1 ? 4 : 5);
	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 cpy(buf, len, "[Function (native)]", 19);
	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));
	}
	}

	const char js_str(struct js js, jsval_t value) {
	char buf = (char ) &js->mem[js->brk + sizeof(jsoff_t)];
	size_t len, available = js->size - js->brk - sizeof(jsoff_t);

	if (is_err(value)) return js->errmsg;
	if (js->brk + sizeof(jsoff_t) >= js->size) return "";

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

	stringify_depth = 0;
	stringify_indent = 0;
	len = tostr(js, value, buf, available);
	js_mkstr(js, NULL, len);
	return buf;
	}

	static bool bigint_is_zero(struct js *js, jsval_t v);

	bool js_truthy(struct js *js, jsval_t v) {
	uint8_t t = vtype(v);
	return (t == T_BOOL && vdata(v) != 0) \|\| (t == T_NUM && tod(v) != 0.0) \|\|
	(t == T_OBJ \|\| t == T_FUNC \|\| t == T_ARR) \|\| (t == T_STR && vstrlen(js, v) > 0) \|\|
	(t == T_BIGINT && !bigint_is_zero(js, v));
	}

	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_total = sizeof(struct js) + js->size;
	size_t new_size = current_total * 2;

	while (new_size < current_total + needed && new_size <= (size_t)js->max_size) new_size *= 2;

	if (new_size > (size_t)js->max_size) new_size = (size_t)js->max_size;
	if (new_size <= current_total) return false;

	void old_buf = (void )((uint8_t *)js - 0);
	void *new_buf = ANT_GC_REALLOC(old_buf, new_size);

	if (new_buf == NULL) return false;
	struct js new_js = (struct js )new_buf;

	new_js->mem = (uint8_t *)(new_js + 1);
	jsoff_t old_size = new_js->size;
	new_js->size = (jsoff_t)(new_size - sizeof(struct js));
	new_js->size = new_js->size / 8U * 8U;

	if (old_size > 0) {
	new_js->gct = (new_js->size * new_js->gct) / old_size;
	} else {
	new_js->gct = new_js->size / 2;
	}

	return true;
	}


	static jsoff_t js_alloc(struct js *js, size_t size) {
	size = align32((jsoff_t) size);

	jsoff_t ofs = free_list_allocate(size);
	if (ofs != (jsoff_t) ~0) return ofs;

	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 {
	ANT_GC_COLLECT();
	js_gc(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) memmove(&js->mem[ofs + sizeof(b)], buf, 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 << 2) \| T_STR), ptr, n);
	}

	static jsval_t 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 = 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 = 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 = 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 = 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 = 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 mkbigint(js, digits, len, false);
	return 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 mkbigint(js, "1", 1, false);
	jsval_t result = mkbigint(js, "1", 1, false);
	jsval_t b = base;
	jsval_t e = exp;
	jsval_t two = 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 (nargs < 1) return 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 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 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 mkbigint(js, str + i, slen - i, neg);
	}
	if (vtype(arg) == T_BOOL) {
	return 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) {
	char buf[1024];
	size_t n = 0;
	if (neg) buf[n++] = '-';
	memcpy(buf + n, digits, dlen);
	n += dlen;
	return js_mkstr(js, buf, n);
	}

	char result[2048];
	size_t rpos = sizeof(result) - 1;
	result[rpos] = '\0';

	char num = (char )malloc(dlen + 1);
	if (!num) 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] = '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;
	rpos--;
	result[rpos] = remainder < 10 ? '0' + remainder : 'a' + (remainder - 10);
	}

	free(num);

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

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

	return js_mkstr(js, result + rpos, sizeof(result) - 1 - rpos);
	}

	static jsval_t mkobj(struct js *js, jsoff_t parent) {
	return mkentity(js, 0 \| T_OBJ, &parent, sizeof(parent));
	}

	static jsval_t mkarr(struct js *js) {
	jsval_t arr = mkobj(js, 0);
	jsval_t array_proto = get_ctor_proto(js, "Array", 5);
	if (vtype(array_proto) == T_OBJ) {
	set_proto(js, arr, array_proto);
	}
	return mkval(T_ARR, vdata(arr));
	}

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

	static jsoff_t arr_length(struct js *js, jsval_t arr) {
	if (vtype(arr) != T_ARR) return 0;
	jsoff_t scan = loadoff(js, (jsoff_t) vdata(arr)) & ~(3U \| CONSTMASK);
	while (scan < js->brk && scan != 0) {
	jsoff_t koff = loadoff(js, scan + (jsoff_t) sizeof(scan));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	if (streq(key, klen, "length", 6)) {
	jsval_t val = loadval(js, scan + (jsoff_t) (sizeof(scan) + sizeof(koff)));
	if (vtype(val) == T_NUM) return (jsoff_t) tod(val);
	break;
	}
	scan = loadoff(js, scan) & ~(3U \| CONSTMASK);
	}
	return 0;
	}

	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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsoff_t idxlen = (jsoff_t) strlen(idxstr);
	jsoff_t prop = loadoff(js, (jsoff_t) vdata(arr)) & ~(3U \| CONSTMASK);
	while (prop < js->brk && prop != 0) {
	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)];
	if (streq(key, klen, idxstr, idxlen)) {
	return loadval(js, prop + (jsoff_t) (sizeof(prop) + sizeof(koff)));
	}
	prop = loadoff(js, prop) & ~(3U \| CONSTMASK);
	}
	return js_mkundef();
	}

	static bool is_const_prop(struct js *js, jsoff_t propoff) {
	for (jsoff_t off = 0; off < js->brk;) {
	jsoff_t v = loadoff(js, off);
	jsoff_t n = esize(v & ~(GCMASK \| CONSTMASK));
	jsoff_t cleaned = v & ~(GCMASK \| CONSTMASK);
	if ((cleaned & 3) == T_OBJ) {
	jsoff_t firstprop = cleaned & ~3U;
	if (firstprop == propoff && (v & CONSTMASK)) {
	return true;
	}
	} else if ((cleaned & 3) == T_PROP) {
	jsoff_t nextprop = cleaned & ~3U;
	if (nextprop == propoff && (v & CONSTMASK)) {
	return true;
	}
	}
	off += n;
	}
	return false;
	}

	static inline uint32_t hash_key(const char *key, size_t len) {
	uint32_t hash = 2166136261u;
	for (size_t i = 0; i < len && i < 64; i++) {
	hash ^= (uint8_t)key[i];
	hash *= 16777619u;
	}
	return hash;
	}

	static obj_prop_cache_t* get_obj_cache(jsoff_t obj_offset) {
	obj_prop_cache_t *cache = NULL;
	HASH_FIND(hh, global_property_cache, &obj_offset, sizeof(jsoff_t), cache);
	if (!cache) {
	cache = (obj_prop_cache_t *)malloc(sizeof(obj_prop_cache_t));
	if (!cache) return NULL;
	cache->obj_offset = obj_offset;
	cache->cache = NULL;
	cache->hit_count = 0;
	HASH_ADD(hh, global_property_cache, obj_offset, sizeof(jsoff_t), cache);
	}
	return cache;
	}

	static void cache_property(jsoff_t obj_offset, const char *key, size_t key_len, jsoff_t prop_offset) {
	if (key_len > 63) return;

	obj_prop_cache_t *obj_cache = get_obj_cache(obj_offset);
	if (!obj_cache) return;

	prop_cache_entry_t *entry = NULL;
	HASH_FIND_STR(obj_cache->cache, key, entry);

	if (!entry) {
	entry = (prop_cache_entry_t *)malloc(sizeof(prop_cache_entry_t));
	if (!entry) return;
	memcpy(entry->key, key, key_len);
	entry->key[key_len] = '\0';
	entry->hash = hash_key(key, key_len);
	HASH_ADD_STR(obj_cache->cache, key, entry);
	}
	entry->offset = prop_offset;
	}

	static jsoff_t cache_lookup(jsoff_t obj_offset, const char *key, size_t key_len) {
	if (key_len > 63) return 0;

	obj_prop_cache_t *obj_cache = NULL;
	HASH_FIND(hh, global_property_cache, &obj_offset, sizeof(jsoff_t), obj_cache);
	if (!obj_cache) return 0;

	prop_cache_entry_t *entry = NULL;
	HASH_FIND_STR(obj_cache->cache, key, entry);
	if (entry) {
	obj_cache->hit_count++;
	return entry->offset;
	}
	return 0;
	}

	static void invalidate_obj_cache(jsoff_t obj_offset) {
	obj_prop_cache_t *obj_cache = NULL;
	HASH_FIND(hh, global_property_cache, &obj_offset, sizeof(jsoff_t), obj_cache);
	if (!obj_cache) return;

	prop_cache_entry_t entry, tmp;
	HASH_ITER(hh, obj_cache->cache, entry, tmp) {
	HASH_DEL(obj_cache->cache, entry);
	free(entry);
	}
	HASH_DEL(global_property_cache, obj_cache);
	free(obj_cache);
	}

	static jsval_t mkprop(struct js *js, jsval_t obj, jsval_t k, jsval_t v, bool is_const) {
	jsoff_t koff = (jsoff_t) vdata(k);
	jsoff_t b, head = (jsoff_t) vdata(obj);
	char buf[sizeof(koff) + sizeof(v)];
	memcpy(&b, &js->mem[head], sizeof(b));
	memcpy(buf, &koff, sizeof(koff));
	memcpy(buf + sizeof(koff), &v, sizeof(v));
	jsoff_t brk = js->brk \| T_OBJ;

	if (is_const) brk \|= CONSTMASK;
	memcpy(&js->mem[head], &brk, sizeof(brk));
	invalidate_obj_cache(head);

	return mkentity(js, (b & ~(3U \| CONSTMASK)) \| T_PROP, buf, sizeof(buf));
	}

	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, false);
	if (is_err(res)) return res;

	jsval_t desc_key_str = js_mkstr(js, "__desc_constructor", 18);
	if (is_err(desc_key_str)) return desc_key_str;

	jsval_t desc_obj = js_mkobj(js);
	if (is_err(desc_obj)) return desc_obj;

	setprop(js, desc_obj, js_mkstr(js, "writable", 8), js_mktrue());
	setprop(js, desc_obj, js_mkstr(js, "enumerable", 10), js_mkfalse());
	setprop(js, desc_obj, js_mkstr(js, "configurable", 12), js_mktrue());
	setprop(js, proto_obj, desc_key_str, desc_obj);

	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;

	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 (streq(key, klen, "__proto__", 9)) {
	return js_mkerr(js, "cannot assign to __proto__");
	}
	jsoff_t existing = lkp(js, obj, key, klen);
	if (existing > 0) {
	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, obj, desc_key, strlen(desc_key));

	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	jsoff_t writable_off = lkp(js, desc_obj, "writable", 8);
	if (writable_off != 0) {
	jsval_t writable_val = resolveprop(js, mkval(T_PROP, writable_off));
	if (!js_truthy(js, writable_val)) {
	if (js->flags & F_STRICT) return js_mkerr(js, "assignment to read-only property");
	return mkval(T_PROP, existing);
	}
	}

	jsoff_t configurable_off = lkp(js, desc_obj, "configurable", 12);
	if (configurable_off != 0) {
	jsval_t configurable_val = resolveprop(js, mkval(T_PROP, configurable_off));
	if (!js_truthy(js, configurable_val)) {
	if (js->flags & F_STRICT) return js_mkerr(js, "assignment to non-configurable property");
	return mkval(T_PROP, existing);
	}
	}
	}
	} else if (is_const_prop(js, existing)) {
	return js_mkerr(js, "assignment to constant");
	}

	saveval(js, existing + sizeof(jsoff_t) * 2, v);
	return mkval(T_PROP, existing);
	}
	return mkprop(js, obj, k, v, false);
	}

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

	static inline jsoff_t esize(jsoff_t w) {
	jsoff_t cleaned = w & ~(GCMASK \| CONSTMASK);
	switch (cleaned & 3U) {
	case T_OBJ: return (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) + align32(cleaned >> 2U));
	default: return (jsoff_t) ~0U;
	}
	}

	static bool is_mem_entity(uint8_t t) {
	return t == T_OBJ \|\| t == T_PROP \|\| t == T_STR \|\| t == T_FUNC \|\| t == T_ARR \|\| t == T_PROMISE;
	}

	static void js_mark_all_entities_for_deletion(struct js *js) {
	for (jsoff_t v, off = 0; off < js->brk; off += esize(v & ~(GCMASK \| CONSTMASK))) {
	v = loadoff(js, off);
	saveoff(js, off, v \| GCMASK);
	}
	}

	static jsoff_t js_unmark_entity(struct js *js, jsoff_t off) {
	if (off >= js->brk) return 0;
	jsoff_t v = loadoff(js, off);
	if (v & GCMASK) {
	saveoff(js, off, v & ~GCMASK);
	jsoff_t cleaned = v & ~(GCMASK \| CONSTMASK);
	if ((cleaned & 3) == T_OBJ) js_unmark_entity(js, cleaned & ~3);
	if ((cleaned & 3) == T_PROP) {
	js_unmark_entity(js, cleaned & ~3);
	js_unmark_entity(js, loadoff(js, (jsoff_t) (off + sizeof(off))));
	jsval_t val = loadval(js, (jsoff_t) (off + sizeof(off) + sizeof(off)));
	if (is_mem_entity(vtype(val))) js_unmark_entity(js, (jsoff_t) vdata(val));
	}
	}
	return v & ~(GCMASK \| CONSTMASK \| 3U);
	}

	static void js_unmark_jsval(struct js *js, jsval_t v) {
	if (is_mem_entity(vtype(v))) js_unmark_entity(js, (jsoff_t) vdata(v));
	}

	static void js_unmark_used_entities(struct js *js) {
	js_unmark_entity(js, (jsoff_t) vdata(js->scope));
	if (global_scope_stack) {
	jsoff_t *p = NULL;
	while ((p = (jsoff_t *)utarray_next(global_scope_stack, p)) != NULL) {
	js_unmark_entity(js, *p);
	}
	}

	js_unmark_entity(js, 0);
	if (js->nogc) js_unmark_entity(js, js->nogc);

	mco_coro *running = mco_running();
	if (running) {
	async_exec_context_t ctx = (async_exec_context_t )mco_get_user_data(running);
	if (ctx) {
	js_unmark_jsval(js, ctx->closure_scope);
	js_unmark_jsval(js, ctx->result);
	js_unmark_jsval(js, ctx->promise);
	if (ctx->coro) {
	js_unmark_jsval(js, ctx->coro->scope);
	js_unmark_jsval(js, ctx->coro->this_val);
	js_unmark_jsval(js, ctx->coro->awaited_promise);
	js_unmark_jsval(js, ctx->coro->result);
	js_unmark_jsval(js, ctx->coro->async_func);
	js_unmark_jsval(js, ctx->coro->yield_value);
	for (int i = 0; i < ctx->coro->nargs; i++) js_unmark_jsval(js, ctx->coro->args[i]);
	}
	}
	}

	for (coroutine_t *coro = pending_coroutines.head; coro != NULL; coro = coro->next) {
	js_unmark_jsval(js, coro->scope);
	js_unmark_jsval(js, coro->this_val);
	js_unmark_jsval(js, coro->awaited_promise);
	js_unmark_jsval(js, coro->result);
	js_unmark_jsval(js, coro->async_func);
	js_unmark_jsval(js, coro->yield_value);
	for (int i = 0; i < coro->nargs; i++) js_unmark_jsval(js, coro->args[i]);
	}

	for (int i = 0; i < global_this_stack.depth; i++) {
	js_unmark_jsval(js, global_this_stack.stack[i]);
	}
	}

	static void init_free_list(void) {
	if (global_free_list == NULL) {
	utarray_new(global_free_list, &free_list_icd);
	} else {
	utarray_clear(global_free_list);
	}
	}

	static void free_list_clear(void) {
	if (global_free_list != NULL) utarray_clear(global_free_list);
	}

	static void free_list_compact(void) {
	unsigned int len = utarray_len(global_free_list);
	if (len <= 1) return;

	FreeListEntry entries = (FreeListEntry )utarray_front(global_free_list);

	for (unsigned int i = 0; i < len - 1; i++) {
	for (unsigned int j = 0; j < len - i - 1; j++) {
	if (entries[j].offset > entries[j + 1].offset) {
	FreeListEntry temp = entries[j];
	entries[j] = entries[j + 1];
	entries[j + 1] = temp;
	}
	}
	}

	unsigned int write_pos = 0;
	for (unsigned int i = 1; i < len; i++) {
	if (entries[write_pos].offset + entries[write_pos].size == entries[i].offset) {
	entries[write_pos].size += entries[i].size;
	} else {
	write_pos++;
	entries[write_pos] = entries[i];
	}
	}

	unsigned int final_count = write_pos + 1;
	while (utarray_len(global_free_list) > final_count) {
	utarray_pop_back(global_free_list);
	}
	}

	static jsoff_t free_list_zero_out(struct js *js) {
	unsigned int len = utarray_len(global_free_list);
	if (len == 0) return 0;

	jsoff_t safe_threshold = protected_brk > 0 ? protected_brk + 0x400 : 0x1000;
	jsoff_t total_freed = 0;
	FreeListEntry entries = (FreeListEntry )utarray_front(global_free_list);
	for (unsigned int i = 0; i < len; i++) {
	if (entries[i].offset > 0 && entries[i].size > 0) {
	if (entries[i].offset < safe_threshold) continue;
	if (entries[i].offset + entries[i].size > js->size) continue;
	// ugh disable zeroing for now until a better solution is found
	// memset(&js->mem[entries[i].offset], 0, entries[i].size);
	total_freed += entries[i].size;
	}
	}

	return total_freed;
	}

	static jsoff_t free_list_allocate(size_t size) {
	unsigned int len = utarray_len(global_free_list);
	if (len == 0) return ~(jsoff_t) 0;
	size = align32((jsoff_t) size);

	FreeListEntry entries = (FreeListEntry )utarray_front(global_free_list);
	jsoff_t safe_reuse_threshold = protected_brk > 0 ? protected_brk + 0x400 : 0x1000;

	for (unsigned int i = 0; i < len; i++) {
	if (entries[i].offset >= safe_reuse_threshold && entries[i].size >= size) {
	jsoff_t allocated_offset = entries[i].offset;

	entries[i].offset += size;
	entries[i].size -= size;

	if (entries[i].size == 0) utarray_erase(global_free_list, i, 1);
	return allocated_offset;
	}
	}

	return ~(jsoff_t) 0;
	}

	static bool is_builtin_or_system(jsoff_t offset, struct js *js) {
	jsval_t obj_val = mkval(T_OBJ, offset);

	jsoff_t native_off = lkp(js, obj_val, "__native_func", 13);
	if (native_off != 0) return true;

	jsoff_t code_off = lkp(js, obj_val, "__code", 6);
	if (code_off != 0) {
	jsval_t code_val = resolveprop(js, mkval(T_PROP, code_off));
	if (vtype(code_val) == T_STR) {
	jsoff_t slen, str_off = vstr(js, code_val, &slen);
	if (slen > 10 && memcmp(&js->mem[str_off], "__builtin_", 10) == 0) return true;
	}
	}

	return false;
	}

	static void free_list_add(jsoff_t offset, jsoff_t size, struct js *js) {
	if (offset >= js->size \|\| size == 0 \|\| offset + size > js->size * 2) return;
	jsoff_t safe_threshold = protected_brk > 0 ? protected_brk + 0x400 : 0x1000;
	if (offset < safe_threshold) return;

	jsoff_t entity_val = loadoff(js, offset);
	uint8_t entity_type = entity_val & 3;

	if (entity_type == T_OBJ && is_builtin_or_system(offset, js)) return;
	if (entity_type == T_STR && offset < 0x1000) return;

	FreeListEntry entry = {0};
	entry.offset = offset;
	entry.size = size;
	entry.type = entity_type;
	entry.detail[0] = '\0';

	utarray_push_back(global_free_list, &entry);
	}

	static void js_fixup_offsets(struct js *js, jsoff_t start, jsoff_t size) {
	for (jsoff_t n, v, off = 0; off < js->brk; off += n) {
	v = loadoff(js, off);
	n = esize(v & ~(GCMASK \| CONSTMASK));
	if (v & GCMASK) continue;

	jsoff_t flags = v & (GCMASK \| CONSTMASK);
	jsoff_t cleaned = v & ~(GCMASK \| CONSTMASK);
	if ((cleaned & 3) != T_OBJ && (cleaned & 3) != T_PROP) continue;
	jsoff_t adjusted = cleaned > start ? cleaned - size : cleaned;
	if (cleaned != adjusted) saveoff(js, off, adjusted \| flags);

	if ((cleaned & 3) == T_OBJ) {
	jsoff_t u = loadoff(js, (jsoff_t) (off + sizeof(jsoff_t)));
	if (u > start) saveoff(js, (jsoff_t) (off + sizeof(jsoff_t)), u - size);
	}

	#define FIXUP_JSVAL(val) do { \
	if (is_mem_entity(vtype(val)) && vdata(val) > start) \
	(val) = mkval(vtype(val), vdata(val) - size); \
	} while (0)

	#define FIXUP_JSVAL_AT(mem_off) do { \
	jsval_t _v = loadval(js, mem_off); \
	if (is_mem_entity(vtype(_v)) && vdata(_v) > start) \
	saveval(js, mem_off, mkval(vtype(_v), vdata(_v) - size)); \
	} while (0)

	#define FIXUP_OFF(off_var) do { if ((off_var) > start) (off_var) -= size; } while (0)

	if ((cleaned & 3) == T_PROP) {
	jsoff_t koff = loadoff(js, (jsoff_t) (off + sizeof(off)));
	if (koff > start) saveoff(js, (jsoff_t) (off + sizeof(off)), koff - size);
	FIXUP_JSVAL_AT((jsoff_t) (off + sizeof(off) + sizeof(off)));
	}
	}

	FIXUP_JSVAL(js->scope);
	FIXUP_OFF(js->nogc);
	if (js->code > (char ) js->mem && js->code - (char ) js->mem < js->size && js->code - (char *) js->mem > start) {
	js->code -= size;
	}

	if (global_scope_stack) {
	jsoff_t *p = NULL;
	while ((p = (jsoff_t )utarray_next(global_scope_stack, p)) != NULL) FIXUP_OFF(p);
	}

	for (coroutine_t *coro = pending_coroutines.head; coro != NULL; coro = coro->next) {
	FIXUP_JSVAL(coro->scope);
	FIXUP_JSVAL(coro->this_val);
	FIXUP_JSVAL(coro->awaited_promise);
	FIXUP_JSVAL(coro->result);
	FIXUP_JSVAL(coro->async_func);
	FIXUP_JSVAL(coro->yield_value);
	for (int i = 0; i < coro->nargs; i++) FIXUP_JSVAL(coro->args[i]);
	}

	#undef FIXUP_JSVAL
	#undef FIXUP_JSVAL_AT
	#undef FIXUP_OFF
	}

	static void js_compact_from_end(struct js *js) {
	jsoff_t new_brk = js->brk;

	jsoff_t min_brk = (jsoff_t) vdata(js->scope) + 8;
	if (global_scope_stack) {
	jsoff_t *p = NULL;
	while ((p = (jsoff_t *)utarray_next(global_scope_stack, p)) != NULL) {
	if (p + 8 > min_brk) min_brk = p + 8;
	}
	}

	for (jsoff_t off = 0; off < js->brk; off += esize(loadoff(js, off) & ~(GCMASK \| CONSTMASK))) {
	jsoff_t v = loadoff(js, off);
	if ((v & GCMASK) == 0) new_brk = off + esize(v & ~(GCMASK \| CONSTMASK));
	}

	if (new_brk < min_brk) new_brk = min_brk;
	js->brk = new_brk;
	}

	static void js_clear_gc_marks(struct js *js) {
	for (jsoff_t v, off = 0; off < js->brk; off += esize(v & ~(GCMASK \| CONSTMASK))) {
	v = loadoff(js, off);
	if (v & GCMASK) {
	jsoff_t size = esize(v & ~(GCMASK \| CONSTMASK));
	free_list_add(off, size, js);
	saveoff(js, off, v & ~GCMASK);
	}
	}
	}

	jsoff_t js_gc(struct js *js) {
	setlwm(js);
	if (js->nogc == (jsoff_t) ~0) return 0;

	js_mark_all_entities_for_deletion(js);
	js_unmark_used_entities(js);
	js_compact_from_end(js);

	js_clear_gc_marks(js);
	free_list_compact();

	jsoff_t freed = free_list_zero_out(js);
	if (global_free_list != NULL) utarray_clear(global_free_list);

	return freed;
	}

	static jsoff_t skiptonext(const char code, jsoff_t len, jsoff_t n, bool had_newline) {
	if (had_newline) *had_newline = false;
	while (n < len) {
	if (is_space(code[n])) {
	if (had_newline && code[n] == '\n') *had_newline = true;
	n++;
	} else if (n + 1 < len && code[n] == '/' && code[n + 1] == '/') {
	for (n += 2; n < len && code[n] != '\n';) n++;
	if (had_newline && n < len && code[n] == '\n') *had_newline = true;
	} else if (n + 3 < len && code[n] == '/' && code[n + 1] == '*') {
	for (n += 4; n < len && (code[n - 2] != '*' \|\| code[n - 1] != '/');) {
	if (had_newline && code[n] == '\n') *had_newline = true;
	n++;
	}
	} else {
	break;
	}
	}
	return n;
	}

	static bool streq(const char buf, size_t len, const char p, size_t n) {
	return n == len && memcmp(buf, p, len) == 0;
	}

	static bool is_strict_reserved(const char *buf, size_t len) {
	switch (len) {
	case 3: return streq(buf, len, "let", 3);
	case 5: return streq(buf, len, "yield", 5);
	case 6: return streq(buf, len, "static", 6) \|\| streq(buf, len, "public", 6);
	case 7: return streq(buf, len, "private", 7) \|\| streq(buf, len, "package", 7);
	case 9: return streq(buf, len, "interface", 9) \|\| streq(buf, len, "protected", 9);
	case 10: return streq(buf, len, "implements", 10);
	default: return false;
	}
	}

	static bool is_strict_restricted(const char *buf, size_t len) {
	return (len == 4 && streq(buf, len, "eval", 4)) \|\| (len == 9 && streq(buf, len, "arguments", 9));
	}

	static uint8_t parsekeyword(const char *buf, size_t len) {
	switch (buf[0]) {
	case 'a': if (streq("async", 5, buf, len)) return TOK_ASYNC; if (streq("await", 5, buf, len)) return TOK_AWAIT; if (streq("as", 2, buf, len)) return TOK_AS; break;
	case 'b': if (streq("break", 5, buf, len)) return TOK_BREAK; break;
	case 'c': if (streq("class", 5, buf, len)) return TOK_CLASS; if (streq("case", 4, buf, len)) return TOK_CASE; if (streq("catch", 5, buf, len)) return TOK_CATCH; if (streq("const", 5, buf, len)) return TOK_CONST; if (streq("continue", 8, buf, len)) return TOK_CONTINUE; break;
	case 'd': if (streq("do", 2, buf, len)) return TOK_DO; if (streq("default", 7, buf, len)) return TOK_DEFAULT; if (streq("delete", 6, buf, len)) return TOK_DELETE; break;
	case 'e': if (streq("else", 4, buf, len)) return TOK_ELSE; if (streq("export", 6, buf, len)) return TOK_EXPORT; break;
	case 'f': if (streq("for", 3, buf, len)) return TOK_FOR; if (streq("from", 4, buf, len)) return TOK_FROM; if (streq("function", 8, buf, len)) return TOK_FUNC; if (streq("finally", 7, buf, len)) return TOK_FINALLY; if (streq("false", 5, buf, len)) return TOK_FALSE; break;
	case 'g': if (streq("globalThis", 10, buf, len)) return TOK_GLOBAL_THIS; break;
	case 'i': if (streq("if", 2, buf, len)) return TOK_IF; if (streq("import", 6, buf, len)) return TOK_IMPORT; if (streq("in", 2, buf, len)) return TOK_IN; if (streq("instanceof", 10, buf, len)) return TOK_INSTANCEOF; break;
	case 'l': if (streq("let", 3, buf, len)) return TOK_LET; break;
	case 'n': if (streq("new", 3, buf, len)) return TOK_NEW; if (streq("null", 4, buf, len)) return TOK_NULL; break;
	case 'o': if (streq("of", 2, buf, len)) return TOK_OF; break;
	case 'r': if (streq("return", 6, buf, len)) return TOK_RETURN; break;
	case 's': if (streq("switch", 6, buf, len)) return TOK_SWITCH; if (streq("static", 6, buf, len)) return TOK_STATIC; break;
	case 't': if (streq("try", 3, buf, len)) return TOK_TRY; if (streq("this", 4, buf, len)) return TOK_THIS; if (streq("throw", 5, buf, len)) return TOK_THROW; if (streq("true", 4, buf, len)) return TOK_TRUE; if (streq("typeof", 6, buf, len)) return TOK_TYPEOF; break;
	case 'u': if (streq("undefined", 9, buf, len)) return TOK_UNDEF; break;
	case 'v': if (streq("var", 3, buf, len)) return TOK_VAR; if (streq("void", 4, buf, len)) return TOK_VOID; break;
	case 'w': if (streq("while", 5, buf, len)) return TOK_WHILE; if (streq("with", 4, buf, len)) return TOK_WITH; if (streq("window", 6, buf, len)) return TOK_WINDOW; break;
	case 'y': if (streq("yield", 5, buf, len)) return TOK_YIELD; break;
	}
	return TOK_IDENTIFIER;
	}

	static uint8_t parseident(const char buf, jsoff_t len, jsoff_t tlen) {
	if (is_ident_begin(buf[0])) {
	while (tlen < len && is_ident_continue(buf[tlen])) (*tlen)++;
	return parsekeyword(buf, *tlen);
	}
	return TOK_ERR;
	}

	static uint8_t next(struct js *js) {
	if (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;

	const char *buf = js->code + js->toff;
	if (js->toff >= js->clen) { js->tok = TOK_EOF; return js->tok; }

	#define TOK(T, LEN) { js->tok = T; js->tlen = (LEN); break; }
	#define LOOK(OFS, CH) js->toff + OFS < js->clen && buf[OFS] == CH

	switch (buf[0]) {
	case '?': if (LOOK(1, '?')) TOK(TOK_NULLISH, 2); if (LOOK(1, '.')) TOK(TOK_OPTIONAL_CHAIN, 2); TOK(TOK_Q, 1);
	case ':': TOK(TOK_COLON, 1);
	case '(': TOK(TOK_LPAREN, 1);
	case ')': TOK(TOK_RPAREN, 1);
	case '{': TOK(TOK_LBRACE, 1);
	case '}': TOK(TOK_RBRACE, 1);
	case '[': TOK(TOK_LBRACKET, 1);
	case ']': TOK(TOK_RBRACKET, 1);
	case ';': TOK(TOK_SEMICOLON, 1);
	case ',': TOK(TOK_COMMA, 1);
	case '!': if (LOOK(1, '=') && LOOK(2, '=')) TOK(TOK_NE, 3); if (LOOK(1, '=')) TOK(TOK_NE, 2); TOK(TOK_NOT, 1);
	case '.': if (LOOK(1, '.') && LOOK(2, '.')) TOK(TOK_REST, 3); TOK(TOK_DOT, 1);
	case '~': TOK(TOK_TILDA, 1);
	case '-': if (LOOK(1, '-')) TOK(TOK_POSTDEC, 2); if (LOOK(1, '=')) TOK(TOK_MINUS_ASSIGN, 2); TOK(TOK_MINUS, 1);
	case '+': if (LOOK(1, '+')) TOK(TOK_POSTINC, 2); if (LOOK(1, '=')) TOK(TOK_PLUS_ASSIGN, 2); TOK(TOK_PLUS, 1);
	case '': if (LOOK(1, '')) TOK(TOK_EXP, 2); if (LOOK(1, '=')) TOK(TOK_MUL_ASSIGN, 2); TOK(TOK_MUL, 1);
	case '/': if (LOOK(1, '=')) TOK(TOK_DIV_ASSIGN, 2); TOK(TOK_DIV, 1);
	case '%': if (LOOK(1, '=')) TOK(TOK_REM_ASSIGN, 2); TOK(TOK_REM, 1);
	case '&': if (LOOK(1, '&')) TOK(TOK_LAND, 2); if (LOOK(1, '=')) TOK(TOK_AND_ASSIGN, 2); TOK(TOK_AND, 1);
	case '\|': if (LOOK(1, '\|')) TOK(TOK_LOR, 2); if (LOOK(1, '=')) TOK(TOK_OR_ASSIGN, 2); TOK(TOK_OR, 1);
	case '=': if (LOOK(1, '=') && LOOK(2, '=')) TOK(TOK_EQ, 3); if (LOOK(1, '=')) TOK(TOK_EQ, 2); if (LOOK(1, '>')) TOK(TOK_ARROW, 2); TOK(TOK_ASSIGN, 1);
	case '<': if (LOOK(1, '<') && LOOK(2, '=')) TOK(TOK_SHL_ASSIGN, 3); if (LOOK(1, '<')) TOK(TOK_SHL, 2); if (LOOK(1, '=')) TOK(TOK_LE, 2); TOK(TOK_LT, 1);
	case '>': if (LOOK(1, '>') && LOOK(2, '=')) TOK(TOK_SHR_ASSIGN, 3); if (LOOK(1, '>')) TOK(TOK_SHR, 2); if (LOOK(1, '=')) TOK(TOK_GE, 2); TOK(TOK_GT, 1);
	case '^': if (LOOK(1, '=')) TOK(TOK_XOR_ASSIGN, 2); TOK(TOK_XOR, 1);
	case '`':
	js->tlen++;
	while (js->toff + js->tlen < js->clen && buf[js->tlen] != '`') {
	uint8_t increment = 1;
	if (buf[js->tlen] == '\\') {
	if (js->toff + js->tlen + 2 > js->clen) break;
	increment = 2;
	}
	js->tlen += increment;
	}
	if (buf[js->tlen] == '`') js->tok = TOK_TEMPLATE, js->tlen++;
	break;
	case '"': case '\'':
	js->tlen++;
	while (js->toff + js->tlen < js->clen && buf[js->tlen] != buf[0]) {
	uint8_t increment = 1;
	if (buf[js->tlen] == '\\') {
	if (js->toff + js->tlen + 2 > js->clen) break;
	increment = 2;
	if (buf[js->tlen + 1] == 'x') {
	if (js->toff + js->tlen + 4 > js->clen) break;
	increment = 4;
	}
	}
	js->tlen += increment;
	}
	if (buf[0] == buf[js->tlen]) js->tok = TOK_STRING, js->tlen++;
	break;
	case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': {
	if ((js->flags & F_STRICT) && buf[0] == '0' && js->toff + 1 < js->clen &&
	is_digit(buf[1]) && buf[1] != 'x' && buf[1] != 'X' && buf[1] != 'b' && buf[1] != 'B' && buf[1] != 'o' && buf[1] != 'O') {
	js->tok = TOK_ERR;
	js->tlen = 1;
	break;
	}

	char *end;
	double value = 0;
	jsoff_t numlen = 0;

	if (buf[0] == '0' && js->toff + 2 < js->clen) {
	if (buf[1] == 'b' \|\| buf[1] == 'B') {
	numlen = 2;
	while (js->toff + numlen < js->clen && (buf[numlen] == '0' \|\| buf[numlen] == '1' \|\| buf[numlen] == '_')) {
	if (buf[numlen] != '_') value = value * 2 + (buf[numlen] - '0');
	numlen++;
	}
	js->tval = tov(value);
	} else if (buf[1] == 'o' \|\| buf[1] == 'O') {
	numlen = 2;
	while (js->toff + numlen < js->clen && ((buf[numlen] >= '0' && buf[numlen] <= '7') \|\| buf[numlen] == '_')) {
	if (buf[numlen] != '_') value = value * 8 + (buf[numlen] - '0');
	numlen++;
	}
	js->tval = tov(value);
	} else if (buf[1] == 'x' \|\| buf[1] == 'X') {
	char clean[64];
	jsoff_t ci = 0;
	numlen = 0;
	while (js->toff + numlen < js->clen && (is_xdigit(buf[numlen]) \|\| buf[numlen] == 'x' \|\| buf[numlen] == 'X' \|\| buf[numlen] == '_') && ci < 63) {
	if (buf[numlen] != '_') clean[ci++] = buf[numlen];
	numlen++;
	}
	clean[ci] = '\0';
	js->tval = tov(strtod(clean, &end));
	} else {
	char clean[64];
	jsoff_t ci = 0;
	numlen = 0;
	while (js->toff + numlen < js->clen && (is_digit(buf[numlen]) \|\| buf[numlen] == '.' \|\| buf[numlen] == 'e' \|\| buf[numlen] == 'E' \|\| buf[numlen] == '+' \|\| buf[numlen] == '-' \|\| buf[numlen] == '_') && ci < 63) {
	if (numlen > 0 && (buf[numlen] == '+' \|\| buf[numlen] == '-') && buf[numlen-1] != 'e' && buf[numlen-1] != 'E') break;
	if (buf[numlen] != '_') clean[ci++] = buf[numlen];
	numlen++;
	}
	clean[ci] = '\0';
	js->tval = tov(strtod(clean, &end));
	}
	} else {
	char clean[64];
	jsoff_t ci = 0;
	numlen = 0;
	while (js->toff + numlen < js->clen && (is_digit(buf[numlen]) \|\| buf[numlen] == '.' \|\| buf[numlen] == 'e' \|\| buf[numlen] == 'E' \|\| buf[numlen] == '+' \|\| buf[numlen] == '-' \|\| buf[numlen] == '_') && ci < 63) {
	if (numlen > 0 && (buf[numlen] == '+' \|\| buf[numlen] == '-') && buf[numlen-1] != 'e' && buf[numlen-1] != 'E') break;
	if (buf[numlen] != '_') clean[ci++] = buf[numlen];
	numlen++;
	}
	clean[ci] = '\0';
	js->tval = tov(strtod(clean, &end));
	}

	if (js->toff + numlen < js->clen && buf[numlen] == 'n') {
	js->tok = TOK_BIGINT;
	js->tlen = numlen + 1;
	} else {
	TOK(TOK_NUMBER, numlen);
	}
	break;
	}
	default: js->tok = parseident(buf, js->clen - js->toff, &js->tlen); break;
	}

	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;
	}

	void 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);
	}

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

	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, int line, int col) {
	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].line = line;
	global_call_stack.frames[global_call_stack.depth].col = col;
	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_block(struct js *js, bool create_scope) {
	jsval_t res = js_mkundef();
	if (create_scope) mkscope(js);
	js->consumed = 1;
	uint8_t peek;
	while ((peek = next(js)) != TOK_EOF && peek != TOK_RBRACE && !is_err(res)) {
	uint8_t t = js->tok;
	res = js_stmt(js);
	bool is_block_tok = (t == TOK_LBRACE \|\| t == TOK_IF \|\| t == TOK_WHILE \|\|
	t == TOK_DO \|\| t == TOK_FUNC \|\| t == TOK_FOR \|\| t == TOK_IMPORT \|\|
	t == TOK_EXPORT \|\| t == TOK_SEMICOLON \|\| t == TOK_SWITCH \|\|
	t == TOK_TRY \|\| t == TOK_CLASS \|\| t == TOK_ASYNC);
	bool asi_ok = js->had_newline \|\| js->tok == TOK_SEMICOLON \|\| js->tok == TOK_RBRACE \|\| js->tok == TOK_EOF;
	if (!is_err(res) && !is_block_tok && !asi_ok) {
	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 (create_scope) delscope(js);
	return res;
	}

	static inline jsoff_t lkp_inline(struct js js, jsval_t obj, const char buf, size_t len) {
	if (len <= 63) {
	jsoff_t cached = cache_lookup((jsoff_t)vdata(obj), buf, len);
	if (cached != 0) return cached;
	}

	jsoff_t off = loadoff(js, (jsoff_t) vdata(obj)) & ~(3U \| CONSTMASK);
	while (off < js->brk && off != 0) {
	jsoff_t koff = loadoff(js, (jsoff_t) (off + sizeof(off)));
	jsoff_t klen = (loadoff(js, koff) >> 2) - 1;
	const char p = (char ) &js->mem[koff + sizeof(koff)];
	if (streq(buf, len, p, klen)) {
	if (len <= 63) cache_property((jsoff_t)vdata(obj), buf, len, off);
	return off;
	}
	off = loadoff(js, off) & ~(3U \| CONSTMASK);
	}
	return 0;
	}

	static jsoff_t lkp(struct js js, jsval_t obj, const char buf, size_t len) {
	return lkp_inline(js, obj, buf, len);
	}

	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) return js_mknull();
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));

	jsoff_t off = lkp(js, as_obj, "__proto__", 9);
	if (off == 0) {
	if (t == T_FUNC \|\| t == T_ARR) return get_prototype_for_type(js, t);
	return js_mknull();
	}

	jsval_t val = resolveprop(js, mkval(T_PROP, off));
	uint8_t vt = vtype(val);

	return (vt == T_OBJ \|\| vt == T_ARR \|\| vt == T_FUNC) ? val : 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));
	jsval_t key = js_mkstr(js, "__proto__", 9);
	jsoff_t existing = lkp(js, as_obj, "__proto__", 9);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, proto);
	} else {
	mkprop(js, as_obj, key, proto, false);
	}
	}

	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(js, js->scope, name, len);

	if (ctor_off == 0 && global_scope_stack) {
	int stack_len = utarray_len(global_scope_stack);
	for (int i = stack_len - 1; i >= 0 && ctor_off == 0; i--) {
	jsoff_t scope_off = (jsoff_t )utarray_eltptr(global_scope_stack, i);
	jsval_t scope = mkval(T_OBJ, *scope_off);
	ctor_off = lkp(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(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(js, ctor_obj, "prototype", 9);

	if (proto_off == 0) return js_mknull();
	return resolveprop(js, mkval(T_PROP, proto_off));
	}

	static 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) {
	if (streq(key, len, "__proto__", 9)) {
	uint8_t t = vtype(obj);
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	jsval_t as_obj = (t == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));
	return lkp(js, as_obj, key, len);
	}
	return 0;
	}

	jsval_t cur = obj;
	int depth = 0;
	const int MAX_PROTO_DEPTH = 32;

	while (depth < MAX_PROTO_DEPTH) {
	uint8_t t = vtype(cur);

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	jsval_t as_obj = (t == T_OBJ) ? cur : mkval(T_OBJ, vdata(cur));
	jsoff_t off = lkp(js, as_obj, key, len);
	if (off != 0) return off;

	cur = get_proto(js, cur);
	if (vtype(cur) == T_NULL \|\| vtype(cur) == T_UNDEF) break;
	depth++;
	} else if (t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_BIGINT) {
	jsval_t proto = get_prototype_for_type(js, t);
	if (vtype(proto) == T_NULL \|\| vtype(proto) == T_UNDEF) break;
	cur = proto;
	depth++;
	} else if (t == T_CFUNC) {
	jsval_t func_proto = get_ctor_proto(js, "Function", 8);
	if (vtype(func_proto) == T_OBJ \|\| vtype(func_proto) == T_ARR \|\| vtype(func_proto) == T_FUNC) {
	jsval_t as_obj = (vtype(func_proto) == T_OBJ) ? func_proto : mkval(T_OBJ, vdata(func_proto));
	jsoff_t off = lkp(js, as_obj, 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) {
	if (streq(key, key_len, "__getter", 8)) return js_mkundef();

	jsoff_t getter_off = lkp(js, obj, "__getter", 8);
	if (getter_off == 0) return js_mkundef();

	jsval_t getter_val = resolveprop(js, mkval(T_PROP, getter_off));
	if (vtype(getter_val) != T_CFUNC) return js_mkundef();

	js_getter_fn getter = (js_getter_fn)(void *)vdata(getter_val);
	jsval_t result = getter(js, obj, key, key_len);

	if (vtype(result) != T_UNDEF) {
	jsval_t key_str = js_mkstr(js, key, key_len);
	setprop(js, obj, key_str, result);
	}

	return result;
	}

	static jsval_t lookup(struct js js, const char buf, size_t len) {
	if (js->flags & F_NOEXEC) return 0;

	for (jsval_t scope = js->scope;;) {
	jsoff_t with_marker_off = lkp(js, scope, "__with_object__", 15);
	if (with_marker_off != 0) {
	jsval_t with_obj_val = resolveprop(js, mkval(T_PROP, with_marker_off));

	jsval_t with_obj = (
	vtype(with_obj_val) == T_OBJ \|\|
	vtype(with_obj_val) == T_ARR \|\|
	vtype(with_obj_val) == T_FUNC) ?
	with_obj_val : mkval(T_OBJ, vdata(with_obj_val)
	);

	jsoff_t prop_off = lkp(js, with_obj, buf, len);
	if (prop_off != 0) {
	jsval_t key = js_mkstr(js, buf, len);
	if (is_err(key)) return key;
	return mkpropref((jsoff_t)vdata(with_obj), (jsoff_t)vdata(key));
	}
	}

	jsoff_t off = lkp(js, scope, buf, len);
	if (off != 0) return mkval(T_PROP, off);
	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 off = lkp(js, root_scope, buf, len);
	if (off != 0) return mkval(T_PROP, off);
	}
	}

	if (js->flags & F_STRICT) {
	return js_mkerr_typed(js, JS_ERR_REFERENCE, "'%.*s' is not defined", (int) len, buf);
	}

	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, buf, len);
	if (is_err(key)) return key;

	jsval_t undef = js_mkundef();
	return setprop(js, global_scope, key, undef);
	}

	static jsval_t resolveprop(struct js *js, jsval_t v) {
	if (vtype(v) == T_PROPREF) {
	jsoff_t obj_off = propref_obj(v);
	jsoff_t key_off = propref_key(v);
	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)];
	jsoff_t prop_off = lkp(js, obj, key_str, len);
	if (prop_off == 0) return js_mkundef();
	return resolveprop(js, mkval(T_PROP, prop_off));
	}
	if (vtype(v) != T_PROP) return v;
	return resolveprop(js, loadval(js, (jsoff_t) (vdata(v) + sizeof(jsoff_t) * 2)));
	}

	static jsval_t assign(struct js *js, jsval_t lhs, jsval_t val) {
	if (vtype(lhs) == T_PROPREF) {
	jsoff_t obj_off = propref_obj(lhs);
	jsoff_t key_off = propref_key(lhs);
	jsval_t obj = mkval(T_OBJ, obj_off);
	jsval_t key = mkval(T_STR, key_off);
	return setprop(js, obj, key, val);
	}

	jsoff_t propoff = (jsoff_t) vdata(lhs);
	if (is_const_prop(js, propoff)) {
	return js_mkerr(js, "assignment to constant");
	}

	if (js->flags & F_STRICT) {
	jsval_t prop_val = loadval(js, (jsoff_t) (propoff + sizeof(jsoff_t) * 2));
	uint8_t prop_type = vtype(prop_val);

	if (prop_type == T_STR \|\| prop_type == T_NUM \|\| prop_type == T_BOOL \|\|
	prop_type == T_NULL \|\| prop_type == T_UNDEF) {
	return js_mkerr(js, "TypeError: cannot set property on primitive value in strict mode");
	}
	}

	saveval(js, (jsoff_t) ((vdata(lhs) & ~3U) + 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_GC_MALLOC(new_capacity);
	if (!new_buffer) return false;

	if (sb->size > 0) memcpy(new_buffer, sb->buffer, sb->size);
	if (sb->is_dynamic) ANT_GC_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) ANT_GC_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[32];
	const char *keystr;
	size_t keylen;
	if (vtype(key_val) == T_NUM) {
	snprintf(keybuf, sizeof(keybuf), "%.0f", tod(key_val));
	keystr = keybuf;
	keylen = strlen(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 {
	return js_mkerr(js, "invalid index type");
	}
	if ((vtype(obj) == T_STR \|\| vtype(obj) == T_ARR) && streq(keystr, keylen, "length", 6)) {
	if (vtype(obj) == T_STR) {
	return tov(offtolen(loadoff(js, (jsoff_t) vdata(obj))));
	}
	}
	if (vtype(obj) == T_STR) {
	if (vtype(key_val) != T_NUM) {
	return js_mkerr(js, "string indices must be numbers");
	}
	double idx_d = tod(key_val);
	if (idx_d < 0 \|\| idx_d != (double)(long)idx_d) {
	return js_mkundef();
	}
	jsoff_t idx = (jsoff_t) idx_d;
	jsoff_t str_len = offtolen(loadoff(js, (jsoff_t) vdata(obj)));
	if (idx >= str_len) {
	return js_mkundef();
	}
	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);
	}
	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR) {
	return js_mkerr(js, "cannot index non-object");
	}
	jsoff_t off = lkp(js, obj, keystr, keylen);
	if (off == 0) {
	jsval_t key = js_mkstr(js, keystr, keylen);
	jsval_t prop = setprop(js, obj, key, js_mkundef());
	return prop;
	}
	return mkval(T_PROP, off);
	}

	static jsval_t do_dot_op(struct js *js, jsval_t l, jsval_t r) {
	const char ptr = (char ) &js->code[coderefoff(r)];
	size_t plen = codereflen(r);

	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(offtolen(loadoff(js, (jsoff_t) vdata(l))));
	}

	if (t == T_ARR && streq(ptr, plen, "length", 6)) {
	jsoff_t off = lkp(js, l, "length", 6);
	if (off == 0) return tov(0);
	return resolveprop(js, mkval(T_PROP, off));
	}

	if (t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_BIGINT) {
	jsoff_t off = lkp_proto(js, l, ptr, plen);
	if (off != 0) {
	return resolveprop(js, mkval(T_PROP, off));
	}
	return js_mkundef();
	}

	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) {
	jsval_t func_obj = mkval(T_OBJ, vdata(l));
	jsoff_t off = lkp_proto(js, l, ptr, plen);
	if (off != 0) 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) {
	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_OBJ && t != T_ARR) {
	char errbuf[256];
	jsoff_t saved_toff = js->toff;
	jsoff_t saved_tlen = js->tlen;
	js->toff = coderefoff(r);
	js->tlen = codereflen(r);
	snprintf(errbuf, sizeof(errbuf), "Cannot read properties of %s (reading '%.*s')",
	t == T_UNDEF ? "undefined" : t == T_NULL ? "null" : typestr(t),
	(int)plen, ptr);
	jsval_t err = js_mkerr(js, errbuf);
	js->toff = saved_toff;
	js->tlen = saved_tlen;
	return err;
	}

	jsoff_t own_off = lkp(js, l, ptr, plen);
	if (own_off != 0) {
	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);
	}

	jsoff_t proto_off = lkp_proto(js, l, ptr, plen);
	if (proto_off != 0) return resolveprop(js, mkval(T_PROP, proto_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;

	for (bool comma = false; next(js) != TOK_EOF; comma = true) {
	if (!comma && 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 jsval_t call_c(struct js *js,
	jsval_t (fn)(struct js , jsval_t *, int)) {
	int argc = 0;
	jsval_t target_this = peek_this();

	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)) return arg;
	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);
	if (js->brk + sizeof(elem) > js->size) return js_mkerr(js, "call oom");
	js->size -= (jsoff_t) sizeof(elem);
	memcpy(&js->mem[js->size], &elem, sizeof(elem));
	argc++;
	}
	} else {
	if (js->brk + sizeof(arg) > js->size) return js_mkerr(js, "call oom");
	js->size -= (jsoff_t) sizeof(arg);
	memcpy(&js->mem[js->size], &arg, sizeof(arg));
	argc++;
	}
	if (next(js) == TOK_COMMA) js->consumed = 1;
	}

	jsval_t saved_this = js->this_val;
	js->this_val = target_this;
	reverse((jsval_t *) &js->mem[js->size], argc);
	jsval_t res = fn(js, (jsval_t *) &js->mem[js->size], argc);
	js->this_val = saved_this;
	setlwm(js);

	js->size += (jsoff_t) sizeof(jsval_t) * (jsoff_t) argc;
	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 jsval_t call_js(struct js js, const char fn, jsoff_t fnlen, jsval_t closure_scope) {
	jsoff_t fnpos = 1;
	jsval_t saved_scope = js->scope;
	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);
	utarray_push_back(global_scope_stack, &parent_scope_offset);
	jsval_t function_scope = mkobj(js, parent_scope_offset);

	const char *caller_code = js->code;
	jsoff_t caller_clen = js->clen;
	jsoff_t caller_pos = js->pos;

	jsval_t args[64];
	int argc = 0;
	caller_pos = skiptonext(caller_code, caller_clen, caller_pos, NULL);
	while (caller_pos < caller_clen && caller_code[caller_pos] != ')' && argc < 64) {
	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 && argc < 64; i++) {
	args[argc++] = arr_get(js, arg, i);
	}
	} else {
	args[argc++] = 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;

	int argi = 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);
	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 (argi < argc) {
	v = args[argi++];
	} else if (default_len > 0) {
	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen, saved_pos = js->pos;
	js->code = &fn[default_start];
	js->clen = default_len;
	js->pos = 0;
	js->consumed = 1;
	v = js_expr(js);
	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	} else {
	v = js_mkundef();
	}
	setprop(js, function_scope, js_mkstr(js, &fn[param_name_pos], identlen), v);
	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 (argi < argc) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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[rest_param_start], rest_param_len), rest_array);
	}
	}

	js->scope = function_scope;
	if (fnpos < fnlen && fn[fnpos] == ')') fnpos++;
	fnpos = skiptonext(fn, fnlen, fnpos, NULL);
	if (fnpos < fnlen && fn[fnpos] == '{') fnpos++;
	size_t n = fnlen - fnpos - 1U;
	js->this_val = target_this;
	js->flags = F_CALL;

	jsval_t res = js_eval(js, &fn[fnpos], n);
	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);

	js->scope = saved_scope;
	return res;
	}

	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));

	jsoff_t native_off = lkp(js, func_obj, "__native_func", 13);
	if (native_off != 0) {
	jsval_t native_val = resolveprop(js, mkval(T_PROP, native_off));
	if (vtype(native_val) == T_CFUNC) {
	jsoff_t this_off = lkp(js, func_obj, "__this", 6);
	jsval_t bound_this = js_mkundef();
	if (this_off != 0) {
	bound_this = resolveprop(js, mkval(T_PROP, this_off));
	}

	jsval_t saved_this = js->this_val;
	if (vtype(bound_this) != JS_UNDEF) {
	push_this(bound_this);
	js->this_val = bound_this;
	}

	jsval_t (fn)(struct js , jsval_t , int) = (jsval_t()(struct js , jsval_t , int)) vdata(native_val);
	jsval_t result = fn(js, args, nargs);

	if (vtype(bound_this) != JS_UNDEF) {
	pop_this();
	js->this_val = saved_this;
	}

	return result;
	}
	}

	jsoff_t code_off = lkp(js, func_obj, "__code", 6);
	if (code_off == 0) return js_mkerr(js, "function has no code");
	jsval_t code_val = resolveprop(js, mkval(T_PROP, code_off));
	if (vtype(code_val) != T_STR) return js_mkerr(js, "function code not string");

	jsoff_t fnlen, fnoff = vstr(js, code_val, &fnlen);
	const char fn = (const char ) (&js->mem[fnoff]);

	jsval_t closure_scope = js_mkundef();
	jsoff_t scope_off = lkp(js, func_obj, "__scope", 7);
	if (scope_off != 0) {
	closure_scope = resolveprop(js, mkval(T_PROP, scope_off));
	}

	jsoff_t this_off = lkp(js, func_obj, "__this", 6);
	if (this_off != 0) {
	jsval_t captured_this = resolveprop(js, mkval(T_PROP, this_off));
	pop_this();
	push_this(captured_this);
	}

	return call_js_code_with_args(js, fn, fnlen, closure_scope, args, 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) {
	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;

	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);
	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) {
	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen, saved_pos = js->pos;
	uint8_t saved_consumed = js->consumed;
	js->code = &fn[default_start];
	js->clen = default_len;
	js->pos = 0;
	js->consumed = 1;
	v = js_expr(js);
	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->consumed = saved_consumed;
	} 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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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 && fn[fnpos] == '{') fnpos++;
	size_t body_len = fnlen - fnpos - 1;

	jsval_t saved_this = js->this_val;
	jsval_t target_this = peek_this();
	js->this_val = target_this;
	js->flags = F_CALL;

	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 do_call_op(struct js *js, jsval_t func, jsval_t args) {
	if (vtype(args) != T_CODEREF) return js_mkerr(js, "bad call");
	if (vtype(func) != T_FUNC && vtype(func) != T_CFUNC)
	return js_mkerr(js, "calling non-function");

	jsval_t target_this = peek_this();
	if (vtype(func) == T_FUNC && vtype(target_this) == T_OBJ) {
	jsoff_t proto_check = lkp(js, target_this, "__proto__", 9);
	if (proto_check == 0) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsoff_t proto_off = lkp(js, func_obj, "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;
	jsoff_t nogc = js->nogc;
	jsval_t res = js_mkundef();

	if (vtype(func) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsoff_t native_off = lkp(js, func_obj, "__native_func", 13);
	if (native_off != 0) {
	jsval_t native_val = resolveprop(js, mkval(T_PROP, native_off));
	if (vtype(native_val) == T_CFUNC) {
	jsval_t saved_func = js->current_func;
	js->current_func = func;
	res = call_c(js, (jsval_t()(struct js , jsval_t *, int)) vdata(native_val));
	js->current_func = saved_func;
	}
	} else {
	jsoff_t code_off = lkp(js, func_obj, "__code", 6);
	if (code_off == 0) return js_mkerr(js, "function has no code");
	jsval_t code_val = resolveprop(js, mkval(T_PROP, code_off));
	if (vtype(code_val) != T_STR) return js_mkerr(js, "function code not string");
	jsval_t closure_scope = js_mkundef();
	jsoff_t scope_off = lkp(js, func_obj, "__scope", 7);
	if (scope_off != 0) {
	closure_scope = resolveprop(js, mkval(T_PROP, scope_off));
	}
	jsoff_t fnlen, fnoff = vstr(js, code_val, &fnlen);
	const char code_str = (const char ) (&js->mem[fnoff]);
	bool is_async = false;
	jsoff_t async_off = lkp(js, func_obj, "__async", 7);
	if (async_off != 0) {
	jsval_t async_val = resolveprop(js, mkval(T_PROP, async_off));
	is_async = vtype(async_val) == T_BOOL && vdata(async_val) == 1;
	}

	jsval_t captured_this = js_mkundef();
	bool is_arrow = false;
	jsoff_t this_off = lkp(js, func_obj, "__this", 6);
	if (this_off != 0) {
	captured_this = resolveprop(js, mkval(T_PROP, this_off));
	is_arrow = true;
	}

	if (fnlen == 16 && memcmp(code_str, "__builtin_Object", 16) == 0) {
	res = call_c(js, builtin_Object);
	} else {
	int call_line = 0, call_col = 0;
	get_line_col(code, pos, &call_line, &call_col);

	static char full_func_name[256];
	const char *func_name = NULL;
	const char *this_name = NULL;

	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) {
	jsoff_t name_len, name_offset = vstr(js, 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(js, target_this, "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,
	call_line, call_col
	);

	jsval_t saved_func = js->current_func;
	js->current_func = func;
	js->nogc = (jsoff_t) (fnoff - sizeof(jsoff_t));

	if (is_arrow) {
	pop_this();
	push_this(captured_this);
	}

	jsoff_t count_off = lkp(js, func_obj, "__field_count", 13);
	if (count_off == 0 \|\| vtype(target_this) != T_OBJ) goto skip_fields;

	jsval_t count_val = resolveprop(js, mkval(T_PROP, count_off));
	if (vtype(count_val) != T_NUM) goto skip_fields;

	int field_count = (int)tod(count_val);
	jsoff_t src_off = lkp(js, func_obj, "__source", 8);
	jsoff_t fields_off = lkp(js, func_obj, "__fields", 8);
	if (src_off == 0 \|\| fields_off == 0) goto skip_fields;

	jsval_t src_val = resolveprop(js, mkval(T_PROP, src_off));
	jsval_t fields_meta = resolveprop(js, mkval(T_PROP, fields_off));
	if (vtype(src_val) != T_STR \|\| vtype(fields_meta) != T_STR) goto skip_fields;

	jsoff_t src_len, src_ptr_off = vstr(js, src_val, &src_len);
	const char source = (const char )(&js->mem[src_ptr_off]);

	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) {
	jsoff_t init_len = init_end - init_start;
	const char *init_code = &source[init_start];

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;

	js->code = init_code;
	js->clen = init_len;
	js->pos = 0;
	js->consumed = 1;

	field_val = js_expr(js);
	field_val = resolveprop(js, field_val);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	}

	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) {
	res = start_async_in_coroutine(js, code_str, fnlen, closure_scope, NULL, 0);
	pop_call_frame();
	} else {
	res = call_js(js, code_str, fnlen, closure_scope);
	pop_call_frame();
	}

	js->current_func = saved_func;
	}
	}
	} else {
	res = call_c(js, (jsval_t()(struct js , jsval_t *, int)) vdata(func));
	}

	js->code = code, js->clen = clen, js->pos = pos;
	js->flags = flags, js->tok = tok, js->nogc = nogc;
	js->consumed = 1;
	return res;
	}

	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 = resolveprop(js, lhs), r = resolveprop(js, rhs);
	setlwm(js);

	if (is_err(l)) return l;
	if (is_err(r)) return r;
	if (is_assign(op) && vtype(lhs) != T_PROP && vtype(lhs) != T_PROPREF) return js_mkerr(js, "bad lhs");

	switch (op) {
	case TOK_TYPEOF: return js_mkstr(js, typestr(vtype(r)), strlen(typestr(vtype(r))));
	case TOK_VOID: return js_mkundef();
	case TOK_INSTANCEOF: return do_instanceof(js, l, r);
	case TOK_IN: return do_in(js, l, r);
	case TOK_CALL: return do_call_op(js, l, r);
	case TOK_BRACKET: return do_bracket_op(js, l, rhs);
	case TOK_ASSIGN: return assign(js, lhs, r);
	case TOK_DOT: return do_dot_op(js, l, r);
	case TOK_OPTIONAL_CHAIN: return do_optional_chain_op(js, l, r);
	case TOK_POSTINC: {
	if (vtype(lhs) != T_PROP) return js_mkerr(js, "bad lhs for ++");
	do_assign_op(js, TOK_PLUS_ASSIGN, lhs, tov(1)); return l;
	}
	case TOK_POSTDEC: {
	if (vtype(lhs) != T_PROP) return js_mkerr(js, "bad lhs for --");
	do_assign_op(js, TOK_MINUS_ASSIGN, lhs, tov(1)); return l;
	}
	case TOK_NOT: return mkval(T_BOOL, !js_truthy(js, r));
	case TOK_UMINUS:
	if (vtype(r) == T_BIGINT) return bigint_neg(js, r);
	break;
	case TOK_UPLUS:
	if (vtype(r) == T_BIGINT) return js_mkerr(js, "Cannot convert BigInt to number");
	break;
	}
	if (is_assign(op)) return do_assign_op(js, op, lhs, r);
	if (op == TOK_EQ \|\| op == TOK_NE) {
	bool eq = false;
	if (vtype(l) == vtype(r)) {
	if (vtype(l) == T_STR) {
	jsoff_t n1, off1 = vstr(js, l, &n1);
	jsoff_t n2, off2 = vstr(js, r, &n2);
	eq = n1 == n2 && memcmp(&js->mem[off1], &js->mem[off2], n1) == 0;
	} else if (vtype(l) == T_NUM) {
	eq = tod(l) == tod(r);
	} else if (vtype(l) == T_BOOL) {
	eq = vdata(l) == vdata(r);
	} else if (vtype(l) == T_BIGINT) {
	eq = bigint_compare(js, l, r) == 0;
	} else {
	eq = vdata(l) == vdata(r);
	}
	} else if ((vtype(l) == T_BIGINT && vtype(r) == T_NUM) \|\|
	(vtype(l) == T_NUM && vtype(r) == T_BIGINT)) {
	double num_val = vtype(l) == T_NUM ? tod(l) : tod(r);
	jsval_t bigint_val = vtype(l) == 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);
	jsval_t num_as_bigint = mkbigint(js, buf, strlen(buf), neg);
	eq = bigint_compare(js, bigint_val, num_as_bigint) == 0;
	}
	}
	return mkval(T_BOOL, op == TOK_EQ ? eq : !eq);
	}
	if (vtype(l) == T_BIGINT \|\| vtype(r) == T_BIGINT) {
	if (vtype(l) != T_BIGINT \|\| vtype(r) != T_BIGINT) {
	return js_mkerr(js, "Cannot mix BigInt and other types");
	}
	switch (op) {
	case TOK_PLUS: return bigint_add(js, l, r);
	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);
	case TOK_LT: return mkval(T_BOOL, bigint_compare(js, l, r) < 0);
	case TOK_GT: return mkval(T_BOOL, bigint_compare(js, l, r) > 0);
	case TOK_LE: return mkval(T_BOOL, bigint_compare(js, l, r) <= 0);
	case TOK_GE: return mkval(T_BOOL, bigint_compare(js, l, r) >= 0);
	default: return js_mkerr(js, "unsupported BigInt operation");
	}
	}
	if (op == TOK_PLUS && (vtype(l) == T_STR \|\| vtype(r) == T_STR \|\| vtype(l) == T_ARR \|\| vtype(r) == T_ARR)) {
	jsval_t l_str = l, r_str = r;

	if (vtype(l) == T_ARR) {
	char buf[1024];
	size_t len = array_to_string(js, l, buf, sizeof(buf));
	l_str = js_mkstr(js, buf, len);
	if (is_err(l_str)) return l_str;
	} else if (vtype(l) != T_STR) {
	const char *str = js_str(js, l);
	l_str = js_mkstr(js, str, strlen(str));
	if (is_err(l_str)) return l_str;
	}

	if (vtype(r) == T_ARR) {
	char buf[1024];
	size_t len = array_to_string(js, r, buf, sizeof(buf));
	r_str = js_mkstr(js, buf, len);
	if (is_err(r_str)) return r_str;
	} else if (vtype(r) != T_STR) {
	const char *str = js_str(js, r);
	r_str = js_mkstr(js, str, strlen(str));
	if (is_err(r_str)) return r_str;
	}

	return do_string_op(js, op, l_str, r_str);
	}
	if (vtype(l) == T_STR && vtype(r) == T_STR) {
	return do_string_op(js, op, l, r);
	}

	double a = 0.0, b = 0.0;

	if (vtype(l) == T_NUM) {
	a = tod(l);
	} else if (vtype(l) == T_STR) {
	jsoff_t slen, off = vstr(js, l, &slen);
	char *endptr;
	char temp[256];
	size_t copy_len = slen < sizeof(temp) - 1 ? slen : sizeof(temp) - 1;
	memcpy(temp, &js->mem[off], copy_len);
	temp[copy_len] = '\0';
	a = strtod(temp, &endptr);
	if (endptr == temp \|\| *endptr != '\0') a = NAN;
	} else if (vtype(l) == T_BOOL) {
	a = vdata(l) ? 1.0 : 0.0;
	} else if (vtype(l) == T_NULL) {
	a = 0.0;
	} else if (vtype(l) == T_UNDEF) {
	a = NAN;
	} else if (vtype(l) == T_ARR) {
	a = NAN;
	} else {
	a = NAN;
	}

	if (vtype(r) == T_NUM) {
	b = tod(r);
	} else if (vtype(r) == T_STR) {
	jsoff_t slen, off = vstr(js, r, &slen);
	char *endptr;
	char temp[256];
	size_t copy_len = slen < sizeof(temp) - 1 ? slen : sizeof(temp) - 1;
	memcpy(temp, &js->mem[off], copy_len);
	temp[copy_len] = '\0';
	b = strtod(temp, &endptr);
	if (endptr == temp \|\| *endptr != '\0') b = NAN;
	} else if (vtype(r) == T_BOOL) {
	b = vdata(r) ? 1.0 : 0.0;
	} else if (vtype(r) == T_NULL) {
	b = 0.0;
	} else if (vtype(r) == T_UNDEF) {
	b = NAN;
	} else if (vtype(r) == T_ARR) {
	b = NAN;
	} else {
	b = NAN;
	}

	switch (op) {
	case TOK_DIV: return tov(a / b);
	case TOK_REM: return tov(a - b * ((double) (long) (a / b)));
	case TOK_MUL: return tov(a * b);
	case TOK_PLUS: return tov(a + b);
	case TOK_MINUS: return tov(a - b);
	case TOK_EXP: return tov(pow(a, b));
	case TOK_XOR: return tov((double)((long) a ^ (long) b));
	case TOK_AND: return tov((double)((long) a & (long) b));
	case TOK_OR: return tov((double)((long) a \| (long) b));
	case TOK_UMINUS: return tov(-b);
	case TOK_UPLUS: return tov(b);
	case TOK_TILDA: return tov((double)(~(long) b));
	case TOK_SHL: return tov((double)((long) a << (long) b));
	case TOK_SHR: return tov((double)((long) a >> (long) b));
	case TOK_DOT: return do_dot_op(js, l, r);
	case TOK_OPTIONAL_CHAIN: return do_optional_chain_op(js, l, r);
	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);
	default: 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;
	uint8_t *out = &js->mem[js->brk + sizeof(jsoff_t)];
	size_t out_len = 0;

	if (js->brk + sizeof(jsoff_t) + part_len > js->size)
	return js_mkerr(js, "oom");

	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 ${");

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;

	js->code = (const char *)&in[expr_start];
	js->clen = n - expr_start;
	js->pos = 0;
	js->consumed = 1;

	jsval_t expr_result = js_expr(js);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;

	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();

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen, saved_pos = js->pos;
	uint8_t saved_tok = js->tok;

	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++;
	}

	uint8_t *out = &js->mem[js->brk + sizeof(jsoff_t)];
	size_t out_len = 0;
	if (js->brk + sizeof(jsoff_t) + (n - part_start) > js->size) return js_mkerr(js, "oom");

	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 ${");

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen, saved_pos = js->pos;
	uint8_t saved_tok = js->tok, saved_consumed = js->consumed;

	js->code = (const char *)&in[expr_start];
	js->clen = n - expr_start;
	js->pos = 0;
	js->consumed = 1;

	jsval_t expr_result = resolveprop(js, js_expr(js));

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;

	if (is_err(expr_result)) return 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->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	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];
	uint8_t *out = &js->mem[js->brk + sizeof(jsoff_t)];
	size_t n1 = 0, n2 = 0;
	if (js->brk + sizeof(jsoff_t) + js->tlen > js->size)
	return js_mkerr(js, "oom");
	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] == '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] == '\\') {
	out[n1++] = '\\';
	} else {
	return js_mkerr(js, "bad str literal");
	}
	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 mkbigint(js, start, len, neg);
	}

	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) {
	jsval_t val = js_expr(js);
	if (exe) {
	if (is_err(val)) return val;
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	jsval_t res = setprop(js, arr, key, resolveprop(js, val));
	if (is_err(res)) return res;
	}
	idx++;
	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);
	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;
	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;
	}

	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));

	return regexp_obj;
	}

	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;

	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 = loadoff(js, (jsoff_t) vdata(src_obj)) & ~(3U \| CONSTMASK);

	while (next_prop < js->brk && next_prop != 0) {
	jsoff_t koff = loadoff(js, next_prop + (jsoff_t) sizeof(next_prop));
	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 + (jsoff_t) (sizeof(next_prop) + sizeof(koff)));

	next_prop = loadoff(js, next_prop) & ~(3U \| CONSTMASK);

	if (streq(prop_key, klen, "__proto__", 9)) continue;
	if (klen > 7 && memcmp(prop_key, "__desc_", 7) == 0) 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;
	}

	if (js->tok == TOK_IDENTIFIER) {
	id_off = js->toff;
	id_len = js->tlen;
	if (exe) key = js_mkstr(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) key = js_mkstr(js, js->code + js->toff, js->tlen);
	} 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 {
	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 {
	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_computed && id_len > 0 && 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 str = js_mkstr(js, &js->code[pos], js->pos - pos);
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	jsval_t code_key = js_mkstr(js, "__code", 6);
	setprop(js, func_obj, code_key, str);
	jsval_t name_key = js_mkstr(js, "name", 4);
	setprop(js, func_obj, name_key, key);
	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	setprop(js, func_obj, scope_key, js->scope);
	jsval_t val = mkval(T_FUNC, (unsigned long) vdata(func_obj));
	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 resolved_val = resolveprop(js, val);

	if (vtype(resolved_val) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(resolved_val));
	jsoff_t name_prop = lkp(js, func_obj, "name", 4);
	if (name_prop == 0) {
	jsval_t name_key = js_mkstr(js, "name", 4);
	if (!is_err(name_key)) setprop(js, func_obj, name_key, key);
	}
	}

	jsval_t res = setprop(js, obj, key, resolved_val);
	if (is_err(res)) return res;
	}
	}

	if (next(js) == TOK_RBRACE) break;
	EXPECT(TOK_COMMA, );
	}

	EXPECT(TOK_RBRACE, );
	return obj;
	}

	static bool parse_func_params(struct js js, uint8_t flags, int *out_count) {
	const char *param_names[32];
	size_t param_lens[32];
	int param_count = 0;

	for (bool comma = false; next(js) != TOK_EOF; comma = true) {
	if (!comma && next(js) == TOK_RPAREN) break;

	bool is_rest = false;
	if (next(js) == TOK_REST) {
	is_rest = true;
	js->consumed = 1;
	next(js);
	}

	if (next(js) != TOK_IDENTIFIER) {
	if (flags) js->flags = *flags;
	js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected");
	return false;
	}

	const char *param_name = &js->code[js->toff];
	size_t param_len = js->tlen;

	if ((js->flags & F_STRICT) && is_strict_restricted(param_name, param_len)) {
	if (flags) js->flags = *flags;
	js_mkerr_typed(js, JS_ERR_SYNTAX, "cannot use '%.*s' as parameter name in strict mode", (int) param_len, param_name);
	return false;
	}

	if (js->flags & F_STRICT) {
	for (int i = 0; i < param_count; i++) {
	if (param_lens[i] == param_len && memcmp(param_names[i], param_name, param_len) == 0) {
	if (flags) js->flags = *flags;
	js_mkerr_typed(js, JS_ERR_SYNTAX, "duplicate parameter name '%.*s' in strict mode", (int) param_len, param_name);
	return false;
	}
	}
	}

	if (param_count < 32) {
	param_names[param_count] = param_name;
	param_lens[param_count] = param_len;
	param_count++;
	}

	js->consumed = 1;

	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	int depth = 0;
	bool done = false;
	while (!done && next(js) != TOK_EOF) {
	uint8_t tok = next(js);
	if (depth == 0 && (tok == TOK_RPAREN \|\| tok == TOK_COMMA)) {
	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) {
	depth--;
	js->consumed = 1;
	} else {
	js->consumed = 1;
	}
	}
	}

	if (is_rest && next(js) != TOK_RPAREN) {
	if (flags) js->flags = *flags;
	js_mkerr_typed(js, JS_ERR_SYNTAX, "rest parameter must be last");
	return false;
	}
	if (next(js) == TOK_RPAREN) break;

	if (next(js) != TOK_COMMA) {
	if (flags) js->flags = *flags;
	js_mkerr_typed(js, JS_ERR_SYNTAX, "parse error");
	return false;
	}
	js->consumed = 1;
	}
	if (out_count) *out_count = param_count;
	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;
	jsval_t str = js_mkstr(js, &js->code[pos], js->pos - pos);
	js->consumed = 1;
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;
	jsval_t res2 = setprop(js, func_obj, code_key, str);
	if (is_err(res2)) return res2;

	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;

	if (is_async) {
	jsval_t async_key = js_mkstr(js, "__async", 7);
	if (is_err(async_key)) return async_key;
	jsval_t res_async = setprop(js, func_obj, async_key, js_mktrue());
	if (is_err(res_async)) return res_async;
	}

	if (name_len > 0) {
	jsval_t name_key = js_mkstr(js, "name", 4);
	if (is_err(name_key)) return name_key;
	jsval_t name_val = js_mkstr(js, &js->code[name_off], name_len);
	if (is_err(name_val)) return name_val;
	jsval_t res3 = setprop(js, func_obj, name_key, name_val);
	if (is_err(res3)) return res3;
	}

	if (!(flags & F_NOEXEC)) {
	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;
	jsval_t res4 = setprop(js, func_obj, scope_key, js->scope);
	if (is_err(res4)) return res4;
	}

	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_literal(struct js *js) {
	next(js);
	setlwm(js);
	if (js->maxcss > 0 && js->css > js->maxcss) return js_mkerr(js, "C stack");
	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_literal(js);
	case TOK_DIV: return js_regex_literal(js);
	case TOK_FUNC: return js_func_literal(js, false);
	case TOK_ASYNC: {
	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) {
	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");
	} 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;
	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 = js->pos;
	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 str = js_mkstr(js, fn_str, fn_pos);
	free(fn_str);
	if (is_err(str)) return str;
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;
	jsval_t res = setprop(js, func_obj, code_key, str);
	if (is_err(res)) return res;
	jsval_t async_key = js_mkstr(js, "__async", 7);
	if (is_err(async_key)) return async_key;
	jsval_t res_async = setprop(js, func_obj, async_key, js_mktrue());
	if (is_err(res_async)) return res_async;
	if (!(flags & F_NOEXEC)) {
	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;
	jsval_t res2 = setprop(js, func_obj, scope_key, js->scope);
	if (is_err(res2)) return res2;
	}
	return mkval(T_FUNC, (unsigned long) vdata(func_obj));
	}
	return mkcoderef((jsoff_t) id_start, (jsoff_t) id_len);
	}
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "unexpected token after async");
	}

	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;

	case TOK_WINDOW:
	case TOK_GLOBAL_THIS: return js_glob(js);

	case TOK_OF:
	case TOK_WITH:
	case TOK_TYPEOF:
	case TOK_FROM:
	case TOK_VOID:
	case TOK_DELETE:
	case TOK_IMPORT:
	case TOK_IDENTIFIER:
	case TOK_CATCH:
	case TOK_TRY:
	case TOK_FINALLY: return mkcoderef((jsoff_t) js->toff, (jsoff_t) js->tlen);

	default: return js_mkerr_typed(js, JS_ERR_SYNTAX, "bad expr");
	}
	}

	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);
	if (tok == TOK_RPAREN \|\| tok == TOK_RBRACE \|\| tok == TOK_SEMICOLON \|\|
	tok == TOK_COMMA \|\| tok == TOK_EOF) {
	body_end_actual = js->toff;
	} else {
	body_end_actual = 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 str = js_mkstr(js, fn_str, fn_pos);
	free(fn_str);
	if (is_err(str)) return str;

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;

	jsval_t res = setprop(js, func_obj, code_key, str);
	if (is_err(res)) return res;

	if (is_async) {
	jsval_t async_key = js_mkstr(js, "__async", 7);
	if (is_err(async_key)) return async_key;
	jsval_t res_async = setprop(js, func_obj, async_key, js_mktrue());
	if (is_err(res_async)) return res_async;
	}

	if (!(flags & F_NOEXEC)) {
	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;
	jsval_t res2 = setprop(js, func_obj, scope_key, js->scope);
	if (is_err(res2)) return res2;

	jsval_t this_key = js_mkstr(js, "__this", 6);
	if (is_err(this_key)) return this_key;
	jsval_t res3 = setprop(js, func_obj, this_key, js->this_val);
	if (is_err(res3)) return res3;
	}

	return mkval(T_FUNC, (unsigned long) vdata(func_obj));
	}

	static jsval_t js_group(struct js *js) {
	if (next(js) == TOK_LPAREN) {
	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) {
	if (js->tok != TOK_IDENTIFIER && js->tok != TOK_COMMA && js->tok != TOK_REST &&
	js->tok != TOK_ASSIGN && js->tok != TOK_NUMBER && js->tok != TOK_STRING &&
	js->tok != TOK_TRUE && js->tok != TOK_FALSE && js->tok != TOK_NULL &&
	js->tok != TOK_UNDEF && js->tok != TOK_LBRACKET && js->tok != TOK_RBRACKET &&
	js->tok != TOK_LBRACE && js->tok != TOK_RBRACE && js->tok != TOK_DOT &&
	js->tok != TOK_PLUS && js->tok != TOK_MINUS && js->tok != TOK_MUL && js->tok != TOK_DIV) {
	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;
	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, false);
	} else {
	jsval_t v = js_expr(js);
	if (is_err(v)) return v;
	while (next(js) == TOK_COMMA) {
	js->consumed = 1;
	v = js_expr(js);
	if (is_err(v)) return v;
	}
	if (next(js) != TOK_RPAREN) return js_mkerr_typed(js, JS_ERR_SYNTAX, ") expected");
	js->consumed = 1;
	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;
	jsval_t result = js_tagged_template(js, tag_func);
	return result;
	}
	res = lookup(js, &js->code[coderefoff(res)], codereflen(res));
	}
	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;
	return js_tagged_template(js, 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) {
	obj = res;
	} else {
	obj = resolveprop(js, res);
	}
	if (op == TOK_OPTIONAL_CHAIN && (vtype(obj) == T_NULL \|\| vtype(obj) == T_UNDEF)) {
	js_group(js);
	res = js_mkundef();
	} else {
	res = do_op(js, op, res, js_group(js));
	}
	} 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;
	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();
	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->consumed = 1;
	res = do_op(js, js->tok, res, 0);
	}
	return res;
	}

	static jsval_t js_unary(struct js *js) {
	if (next(js) == TOK_NEW) {
	js->consumed = 1;
	jsval_t obj = mkobj(js, 0);
	jsval_t saved_this = js->this_val;
	js->this_val = obj;
	jsval_t result = js_postfix(js);
	jsval_t constructed_obj = js->this_val;
	js->this_val = saved_this;
	if (vtype(result) == T_OBJ \|\| vtype(result) == T_ARR \|\| vtype(result) == T_PROMISE \|\| vtype(result) == T_FUNC) return result;
	return constructed_obj;
	} else if (next(js) == TOK_DELETE) {
	js->consumed = 1;
	jsoff_t save_pos = js->pos;
	uint8_t save_tok = js->tok;
	jsval_t operand = js_postfix(js);
	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)];
	jsoff_t prop_off = lkp(js, obj, key_str, len);
	if (prop_off == 0) return js_mktrue();
	if (is_const_prop(js, prop_off)) {
	return js_mkerr(js, "cannot delete constant property");
	}
	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| CONSTMASK \| GCMASK);
	if (first_prop == prop_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~(GCMASK \| CONSTMASK);
	jsoff_t current = loadoff(js, obj_off);
	saveoff(js, obj_off, (deleted_next & ~3U) \| (current & (GCMASK \| CONSTMASK \| 3U)));
	saveoff(js, prop_off, loadoff(js, prop_off) \| GCMASK);
	invalidate_obj_cache(obj_off);
	js_gc(js);
	return js_mktrue();
	}
	jsoff_t prev = first_prop;
	while (prev != 0) {
	jsoff_t next_prop = loadoff(js, prev) & ~(3U \| CONSTMASK \| GCMASK);
	if (next_prop == prop_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~(GCMASK \| CONSTMASK);
	jsoff_t current = loadoff(js, prev);
	saveoff(js, prev, (deleted_next & ~3U) \| (current & (GCMASK \| CONSTMASK \| 3U)));
	saveoff(js, prop_off, loadoff(js, prop_off) \| GCMASK);
	invalidate_obj_cache(obj_off);
	js_gc(js);
	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_const_prop(js, prop_off)) {
	return js_mkerr(js, "cannot delete constant property");
	}

	jsoff_t owner_obj_off = 0;
	jsoff_t 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 & ~(GCMASK \| CONSTMASK);
	jsoff_t n = esize(cleaned);
	if ((cleaned & 3) == T_OBJ) {
	jsoff_t first_prop = cleaned & ~3U;
	if (first_prop == prop_off) {
	owner_obj_off = off;
	is_first_prop = true;
	break;
	}
	jsoff_t cur_prop = first_prop;
	while (cur_prop != 0 && cur_prop < js->brk) {
	jsoff_t next = loadoff(js, cur_prop) & ~(GCMASK \| CONSTMASK \| 3U);
	if (next == prop_off) {
	owner_obj_off = off;
	prev_prop_off = cur_prop;
	break;
	}
	cur_prop = next;
	}
	if (owner_obj_off != 0) break;
	}
	off += n;
	}

	if (owner_obj_off != 0) {
	if (is_first_prop) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~(GCMASK \| CONSTMASK);
	jsoff_t current = loadoff(js, owner_obj_off);
	saveoff(js, owner_obj_off, (deleted_next & ~3U) \| (current & (GCMASK \| CONSTMASK \| 3U)));
	} else {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~(GCMASK \| CONSTMASK);
	jsoff_t current = loadoff(js, prev_prop_off);
	saveoff(js, prev_prop_off, (deleted_next & ~3U) \| (current & (GCMASK \| CONSTMASK \| 3U)));
	}
	saveoff(js, prop_off, loadoff(js, prop_off) \| GCMASK);
	invalidate_obj_cache(owner_obj_off);
	js_gc(js);
	}
	(void) save_pos;
	(void) save_tok;
	return js_mktrue();
	} else if (next(js) == TOK_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;
	}

	jsval_t p_obj = mkval(T_OBJ, vdata(resolved));
	jsoff_t state_off = lkp(js, p_obj, "__state", 7);
	if (state_off == 0) return js_mkerr(js, "invalid promise state");

	int state = (int)tod(resolveprop(js, mkval(T_PROP, state_off)));

	if (state != 0) {
	jsoff_t val_off = lkp(js, p_obj, "__value", 7);
	if (val_off == 0) return js_mkerr(js, "invalid promise value");
	jsval_t val = resolveprop(js, mkval(T_PROP, val_off));
	if (state == 1) {
	return val;
	} else if (state == 2) {
	return js_throw(js, val);
	}
	}

	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 = false;
	coro->is_ready = false;

	jsval_t resume_obj = mkobj(js, 0);
	setprop(js, resume_obj, js_mkstr(js, "__native_func", 13), js_mkfun(resume_coroutine_wrapper));
	setprop(js, resume_obj, js_mkstr(js, "__coroutine", 11), tov((double)(uintptr_t)coro));
	jsval_t resume_fn = mkval(T_FUNC, vdata(resume_obj));

	jsval_t reject_obj = mkobj(js, 0);
	setprop(js, reject_obj, js_mkstr(js, "__native_func", 13), js_mkfun(reject_coroutine_wrapper));
	setprop(js, reject_obj, js_mkstr(js, "__coroutine", 11), tov((double)(uintptr_t)coro));
	jsval_t reject_fn = mkval(T_FUNC, vdata(reject_obj));

	jsval_t then_args[] = { resume_fn, reject_fn };
	jsval_t saved_this = js->this_val;
	js->this_val = resolved;
	(void)builtin_promise_then(js, then_args, 2);
	js->this_val = saved_this;

	uint8_t saved_flags = js->flags;
	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;

	mco_result mco_res = mco_yield(current_mco);
	js->flags = saved_flags;
	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;

	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();

	if (is_error) {
	return js_throw(js, result);
	}
	return result;
	} else if (next(js) == TOK_POSTINC \|\| js->tok == TOK_POSTDEC) {
	uint8_t op = js->tok;
	js->consumed = 1;
	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, "bad expr");
	}
	return do_op(js, op == TOK_POSTINC ? TOK_PLUS : TOK_MINUS, resolved, tov(1));
	} else if (next(js) == TOK_NOT \|\| js->tok == TOK_TILDA \|\| js->tok == TOK_TYPEOF \|\|
	js->tok == TOK_VOID \|\| js->tok == TOK_MINUS \|\| js->tok == TOK_PLUS) {
	uint8_t t = js->tok;
	if (t == TOK_MINUS) t = TOK_UMINUS;
	if (t == TOK_PLUS) t = TOK_UPLUS;
	js->consumed = 1;
	return do_op(js, t, js_mkundef(), js_unary(js));
	} else {
	return js_postfix(js);
	}
	}

	static jsval_t js_exp(struct js *js) {
	jsval_t base = js_unary(js);
	if (is_err(base)) return base;
	if (next(js) == TOK_EXP) {
	js->consumed = 1;
	jsval_t exponent = js_exp(js);
	if (is_err(exponent)) return exponent;
	return do_op(js, TOK_EXP, base, exponent);
	}
	return base;
	}

	static jsval_t js_mul_div_rem(struct js *js) {
	LTR_BINOP(js_exp, (next(js) == TOK_MUL \|\| js->tok == TOK_DIV \|\| js->tok == TOK_REM));
	}

	static jsval_t js_plus_minus(struct js *js) {
	LTR_BINOP(js_mul_div_rem, (next(js) == TOK_PLUS \|\| js->tok == TOK_MINUS));
	}

	static jsval_t js_shifts(struct js *js) {
	LTR_BINOP(js_plus_minus,
	(next(js) == TOK_SHR \|\| next(js) == TOK_SHL \|\|
	next(js) == TOK_ZSHR));
	}

	static jsval_t js_comparison(struct js *js) {
	LTR_BINOP(js_shifts,
	(next(js) == TOK_LT \|\| next(js) == TOK_LE \|\|
	next(js) == TOK_GT \|\| next(js) == TOK_GE \|\|
	next(js) == TOK_INSTANCEOF \|\| next(js) == TOK_IN));
	}

	static jsval_t js_equality(struct js *js) {
	LTR_BINOP(js_comparison, (next(js) == TOK_EQ \|\| next(js) == TOK_NE));
	}

	static jsval_t js_bitwise_and(struct js *js) {
	LTR_BINOP(js_equality, (next(js) == TOK_AND));
	}

	static jsval_t js_bitwise_xor(struct js *js) {
	LTR_BINOP(js_bitwise_and, (next(js) == TOK_XOR));
	}

	static jsval_t js_bitwise_or(struct js *js) {
	LTR_BINOP(js_bitwise_xor, (next(js) == TOK_OR));
	}

	static jsval_t js_nullish_coalesce(struct js *js) {
	jsval_t res = js_bitwise_or(js);
	if (is_err(res)) return res;
	uint8_t flags = js->flags;
	while (next(js) == TOK_NULLISH) {
	js->consumed = 1;
	res = resolveprop(js, res);
	uint8_t res_type = vtype(res);
	if (res_type != T_NULL && res_type != T_UNDEF) {
	js->flags \|= F_NOEXEC;
	}
	if (js->flags & F_NOEXEC) {
	js_nullish_coalesce(js);
	} else {
	res = js_nullish_coalesce(js);
	}
	}
	js->flags = flags;
	return res;
	}

	static jsval_t js_logical_and(struct js *js) {
	jsval_t res = js_nullish_coalesce(js);
	if (is_err(res)) return res;
	uint8_t flags = js->flags;
	while (next(js) == TOK_LAND) {
	js->consumed = 1;
	res = resolveprop(js, res);
	if (!js_truthy(js, res)) js->flags \|= F_NOEXEC;
	if (js->flags & F_NOEXEC) {
	js_logical_and(js);
	} else {
	res = js_logical_and(js);
	}
	}
	js->flags = flags;
	return res;
	}

	static jsval_t js_logical_or(struct js *js) {
	jsval_t res = js_logical_and(js);
	if (is_err(res)) return res;
	uint8_t flags = js->flags;
	while (next(js) == TOK_LOR) {
	js->consumed = 1;
	res = resolveprop(js, res);
	if (js_truthy(js, res)) js->flags \|= F_NOEXEC;
	if (js->flags & F_NOEXEC) {
	js_logical_or(js);
	} else {
	res = js_logical_or(js);
	}
	}
	js->flags = flags;
	return res;
	}

	static jsval_t js_ternary(struct js *js) {
	jsval_t res = js_logical_or(js);
	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 = 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 str = js_mkstr(js, fn_str, fn_pos);
	free(fn_str);
	if (is_err(str)) return str;

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;

	jsval_t res2 = setprop(js, func_obj, code_key, str);
	if (is_err(res2)) return res2;

	if (!(flags & F_NOEXEC)) {
	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;
	jsval_t res3 = setprop(js, func_obj, scope_key, js->scope);
	if (is_err(res3)) return res3;
	}

	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)) {
	uint8_t op = js->tok;
	js->consumed = 1;
	jsval_t rhs = js_assignment(js);
	if (is_err(rhs)) return rhs;
	res = do_op(js, op, res, rhs);
	}

	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;

	typedef struct {
	jsoff_t src_off;
	jsoff_t src_len;
	jsoff_t var_off;
	jsoff_t var_len;
	jsoff_t default_off;
	jsoff_t default_len;
	} DestructProp;
	DestructProp props[32];
	int prop_count = 0;

	while (next(js) != TOK_RBRACE && next(js) != TOK_EOF && prop_count < 32) {
	EXPECT(TOK_IDENTIFIER, );
	props[prop_count].src_off = js->toff;
	props[prop_count].src_len = js->tlen;
	props[prop_count].var_off = js->toff;
	props[prop_count].var_len = js->tlen;
	props[prop_count].default_off = 0;
	props[prop_count].default_len = 0;
	js->consumed = 1;

	if (next(js) == TOK_COLON) {
	js->consumed = 1;
	EXPECT(TOK_IDENTIFIER, );
	props[prop_count].var_off = js->toff;
	props[prop_count].var_len = js->tlen;
	js->consumed = 1;
	}

	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	props[prop_count].default_off = js->pos;
	uint8_t saved_flags = js->flags;
	js->flags \|= F_NOEXEC;
	jsval_t default_expr = js_expr(js);
	js->flags = saved_flags;
	if (is_err(default_expr)) return default_expr;
	props[prop_count].default_len = js->pos - props[prop_count].default_off;
	}

	prop_count++;

	if (next(js) == TOK_RBRACE) break;
	EXPECT(TOK_COMMA, );
	}

	EXPECT(TOK_RBRACE, );

	jsval_t v = js_mkundef();
	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	v = js_expr(js);
	if (is_err(v)) return v;
	} else {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "destructuring requires assignment");
	}

	if (exe) {
	jsval_t obj = resolveprop(js, v);
	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR) {
	return js_mkerr(js, "cannot destructure non-object");
	}

	for (int i = 0; i < prop_count; i++) {
	const char *var_name = &js->code[props[i].var_off];
	jsoff_t var_len = props[i].var_len;

	const char *src_name = &js->code[props[i].src_off];
	jsoff_t src_len = props[i].src_len;

	if (lkp(js, js->scope, var_name, var_len) > 0) {
	return js_mkerr(js, "'%.*s' already declared", (int) var_len, var_name);
	}

	jsoff_t prop_off = lkp(js, obj, src_name, src_len);
	jsval_t prop_val = js_mkundef();

	if (prop_off > 0) {
	prop_val = resolveprop(js, mkval(T_PROP, prop_off));
	}

	if (vtype(prop_val) == T_UNDEF && props[i].default_len > 0) {
	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen, saved_pos = js->pos;
	uint8_t saved_tok = js->tok, saved_consumed = js->consumed;

	js->code = &js->code[props[i].default_off - (js->code - saved_code)];
	js->clen = props[i].default_len;
	js->pos = 0;
	js->consumed = 1;

	prop_val = js_expr(js);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;

	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);
	if (is_err(x)) return x;
	}
	}
	} else {
	EXPECT(TOK_IDENTIFIER, );
	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();
	js->consumed = 1;
	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	v = js_expr(js);
	if (is_err(v)) return v;
	}
	if (exe) {
	if (lkp(js, js->scope, name, nlen) > 0) return js_mkerr(js, "'%.*s' already declared", (int) nlen, name);
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, name, nlen), resolveprop(js, v), is_const);
	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_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);
	js->consumed = 1;
	EXPECT(TOK_IDENTIFIER, );
	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;
	for (bool comma = false; next(js) != TOK_EOF; comma = true) {
	if (!comma && next(js) == TOK_RPAREN) break;

	bool is_rest = false;
	if (next(js) == TOK_REST) {
	is_rest = true;
	js->consumed = 1;
	next(js);
	}

	if (next(js) != TOK_IDENTIFIER) return js_mkerr_typed(js, JS_ERR_SYNTAX, "identifier expected");
	param_count++;
	js->consumed = 1;

	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	int depth = 0;
	bool done = false;
	while (!done && next(js) != TOK_EOF) {
	uint8_t tok = next(js);
	if (depth == 0 && (tok == TOK_RPAREN \|\| tok == TOK_COMMA)) {
	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) {
	depth--;
	js->consumed = 1;
	} else {
	js->consumed = 1;
	}
	}
	}

	if (is_rest && next(js) != TOK_RPAREN) {
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "rest parameter must be last");
	}
	if (next(js) == TOK_RPAREN) break;
	EXPECT(TOK_COMMA, );
	}
	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 str = js_mkstr(js, &js->code[pos], js->pos - pos);
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;
	jsval_t res2 = setprop(js, func_obj, code_key, str);
	if (is_err(res2)) return res2;
	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;
	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;
	jsval_t res3 = setprop(js, func_obj, name_key, name_val);
	if (is_err(res3)) return res3;
	if (exe) {
	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;
	jsval_t res4 = setprop(js, func_obj, scope_key, js->scope);
	if (is_err(res4)) return res4;
	}
	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) {
	if (lkp(js, js->scope, name, nlen) > 0)
	return js_mkerr(js, "'%.*s' already declared", (int) nlen, name);
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, name, nlen), func, false);
	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(TOK_IDENTIFIER, );
	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 str = js_mkstr(js, &js->code[pos], js->pos - pos);
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;
	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;
	jsval_t res2 = setprop(js, func_obj, code_key, str);
	if (is_err(res2)) return res2;
	jsval_t async_key = js_mkstr(js, "__async", 7);
	if (is_err(async_key)) return async_key;
	jsval_t res_async = setprop(js, func_obj, async_key, js_mktrue());
	if (is_err(res_async)) return res_async;
	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;
	jsval_t res3 = setprop(js, func_obj, name_key, name_val);
	if (is_err(res3)) return res3;
	if (exe) {
	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;
	jsval_t res4 = setprop(js, func_obj, scope_key, js->scope);
	if (is_err(res4)) return res4;
	}
	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) {
	if (lkp(js, js->scope, name, nlen) > 0)
	return js_mkerr(js, "'%.*s' already declared", (int) nlen, name);
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, name, nlen), func, false);
	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;
	}

	static jsval_t js_if(struct js *js) {
	js->consumed = 1;
	EXPECT(TOK_LPAREN, );
	jsval_t res = js_mkundef(), cond = resolveprop(js, js_expr(js));
	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;
	}

	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;
	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;
	jsoff_t var_name_off = 0, var_name_len = 0;
	bool is_const_var = false;
	bool is_var_decl = false;
	bool is_let_loop = false;
	jsoff_t let_var_off = 0, let_var_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_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(js);
	if (is_err2(&v, &res)) goto done;
	}
	} else if (next(js) == TOK_SEMICOLON) {
	} else {
	v = js_expr(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;
	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);
	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR && vtype(obj) != T_FUNC) {
	res = js_mkerr(js, "for-in requires object");
	goto done;
	}

	jsval_t iter_obj = obj;
	if (vtype(obj) == T_FUNC) {
	iter_obj = mkval(T_OBJ, vdata(obj));
	}

	jsoff_t prop_off = loadoff(js, (jsoff_t) vdata(iter_obj)) & ~(3U \| CONSTMASK);

	while (prop_off < js->brk && prop_off != 0) {
	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 should_skip = streq(key, klen, "__proto__", 9);

	if (!should_skip && klen > 7 && key[0] == '_' && key[1] == '_' &&
	key[2] == 'd' && key[3] == 'e' && key[4] == 's' && key[5] == 'c' && key[6] == '_') {
	should_skip = true;
	}

	if (!should_skip) {
	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, iter_obj, desc_key, strlen(desc_key));
	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	jsoff_t enumerable_off = lkp(js, desc_obj, "enumerable", 10);
	if (enumerable_off != 0) {
	jsval_t enumerable_val = resolveprop(js, mkval(T_PROP, enumerable_off));
	if (!js_truthy(js, enumerable_val)) {
	should_skip = true;
	}
	}
	}
	}
	}

	if (!should_skip) {
	jsval_t key_str = js_mkstr(js, key, klen);

	const char *var_name = &js->code[var_name_off];
	jsoff_t existing = lkp(js, js->scope, var_name, var_name_len);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, key_str);
	} else {
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, var_name, var_name_len), key_str, is_const_var);
	if (is_err(x)) {
	res = x;
	goto done;
	}
	}

	js->pos = body_start;
	js->consumed = 1;
	js->flags = (flags & ~F_NOEXEC) \| F_LOOP;
	v = js_block_or_stmt(js);
	if (is_err(v)) {
	res = v;
	goto done;
	}

	if (js->flags & F_BREAK) break;
	if (js->flags & F_RETURN) {
	res = v;
	goto done;
	}
	}

	prop_off = loadoff(js, prop_off) & ~(3U \| CONSTMASK);
	}
	}

	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;
	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);

	if (itype == T_ARR) {
	jsoff_t next_prop = loadoff(js, (jsoff_t) vdata(iterable)) & ~(3U \| CONSTMASK);
	jsoff_t length = 0;
	jsoff_t scan = next_prop;

	while (scan < js->brk && scan != 0) {
	jsoff_t koff = loadoff(js, scan + (jsoff_t) sizeof(scan));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];

	if (streq(key, klen, "length", 6)) {
	jsval_t val = loadval(js, scan + (jsoff_t) (sizeof(scan) + sizeof(koff)));
	if (vtype(val) == T_NUM) length = (jsoff_t) tod(val);
	break;
	}
	scan = loadoff(js, scan) & ~(3U \| CONSTMASK);
	}

	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;
	jsval_t val = js_mkundef();

	while (prop < js->brk && prop != 0) {
	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)];
	if (streq(key, klen, idx, idxlen)) {
	val = loadval(js, prop + (jsoff_t) (sizeof(prop) + sizeof(koff)));
	break;
	}
	prop = loadoff(js, prop) & ~(3U \| CONSTMASK);
	}

	const char *var_name = &js->code[var_name_off];
	jsoff_t existing = lkp(js, js->scope, var_name, var_name_len);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, val);
	} else {
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, var_name, var_name_len), val, is_const_var);
	if (is_err(x)) {
	res = x;
	goto done;
	}
	}

	js->pos = body_start;
	js->consumed = 1;
	js->flags = (flags & ~F_NOEXEC) \| F_LOOP;
	v = js_block_or_stmt(js);
	if (is_err(v)) {
	res = v;
	goto done;
	}

	if (js->flags & F_BREAK) break;
	if (js->flags & F_RETURN) {
	res = v;
	goto done;
	}
	}
	} else if (itype == T_STR) {
	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);

	const char *var_name = &js->code[var_name_off];
	jsoff_t existing = lkp(js, js->scope, var_name, var_name_len);
	if (existing > 0) {
	saveval(js, existing + sizeof(jsoff_t) * 2, char_str);
	} else {
	jsval_t x = mkprop(js, js->scope, js_mkstr(js, var_name, var_name_len), char_str, is_const_var);
	if (is_err(x)) {
	res = x;
	goto done;
	}
	}

	js->pos = body_start;
	js->consumed = 1;
	js->flags = (flags & ~F_NOEXEC) \| F_LOOP;
	v = js_block_or_stmt(js);
	if (is_err(v)) {
	res = v;
	goto done;
	}

	if (js->flags & F_BREAK) break;
	if (js->flags & F_RETURN) {
	res = v;
	goto done;
	}
	}
	} else {
	res = js_mkerr(js, "for-of requires iterable");
	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(js);
	if (is_err2(&v, &res)) goto done;
	}
	if (!expect(js, TOK_RPAREN, &res)) goto done;
	pos3 = js->pos;
	v = js_block_or_stmt(js);
	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;
	}

	jsval_t iter_scope = js_mkundef();
	jsval_t loop_var_val = js_mkundef();
	if (is_let_loop && let_var_len > 0) {
	jsoff_t var_off = lkp(js, js->scope, &js->code[let_var_off], let_var_len);
	if (var_off != 0) {
	loop_var_val = resolveprop(js, mkval(T_PROP, var_off));
	}
	mkscope(js);
	iter_scope = js->scope;
	jsval_t var_key = js_mkstr(js, &js->code[let_var_off], let_var_len);
	mkprop(js, js->scope, var_key, loop_var_val, false);
	}

	js->pos = pos3, js->consumed = 1, js->flags \|= F_LOOP;
	v = js_block_or_stmt(js);
	if (is_err2(&v, &res)) {
	if (vtype(iter_scope) != T_UNDEF) delscope(js);
	goto done;
	}

	if (is_let_loop && let_var_len > 0) {
	jsoff_t iter_var_off = lkp(js, iter_scope, &js->code[let_var_off], let_var_len);
	if (iter_var_off != 0) {
	loop_var_val = resolveprop(js, mkval(T_PROP, iter_var_off));
	}
	delscope(js);
	jsoff_t outer_var_off = lkp(js, js->scope, &js->code[let_var_off], let_var_len);
	if (outer_var_off != 0) {
	saveval(js, outer_var_off + sizeof(jsoff_t) * 2, loop_var_val);
	}
	}

	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(js);
	if (is_err2(&v, &res)) goto done;
	}
	}
	js->pos = pos4, js->tok = TOK_SEMICOLON, js->consumed = 0;
	done:
	if (exe) delscope(js);
	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| 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;

	js->consumed = 1;
	if (!expect(js, TOK_LPAREN, &res)) return res;

	jsoff_t cond_start = js->pos;
	js->flags \|= F_NOEXEC;
	v = js_expr(js);
	if (is_err(v)) return v;

	if (!expect(js, TOK_RPAREN, &res)) return res;

	jsoff_t body_start = js->pos;
	v = js_block_or_stmt(js);
	if (is_err(v)) return v;
	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;

	v = js_block_or_stmt(js);
	if (is_err(v)) {
	res = v;
	break;
	}

	if (js->flags & F_BREAK) {
	break;
	}

	if (js->flags & F_RETURN) {
	res = v;
	break;
	}
	}
	}

	js->pos = body_end;
	js->tok = TOK_SEMICOLON;
	js->consumed = 0;

	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| 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;

	js->consumed = 1;

	jsoff_t body_start = js->pos;
	bool is_block = (next(js) == TOK_LBRACE);
	js->flags \|= F_NOEXEC;
	v = js_block_or_stmt(js);
	if (is_err(v)) return v;

	if (is_block && next(js) == TOK_RBRACE) {
	js->consumed = 1;
	}
	(void) js->pos;

	if (!expect(js, TOK_WHILE, &res)) return res;
	if (!expect(js, TOK_LPAREN, &res)) return res;

	jsoff_t cond_start = js->pos;
	v = js_expr(js);
	if (is_err(v)) return v;

	if (!expect(js, TOK_RPAREN, &res)) return res;
	jsoff_t cond_end = js->pos;

	if (exe) {
	do {
	js->pos = body_start;
	js->consumed = 1;
	js->flags = (flags & ~F_NOEXEC) \| F_LOOP;

	v = js_block_or_stmt(js);
	if (is_err(v)) {
	res = v;
	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));
	}

	js->pos = cond_end;
	js->consumed = 1;

	uint8_t preserve = 0;
	if (js->flags & F_RETURN) {
	preserve = js->flags & (F_RETURN \| 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;
	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, false);
	}

	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';
	} 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);
	} 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);
	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 jsval_t js_break(struct js *js) {
	if (js->flags & F_NOEXEC) {
	} else {
	if (!(js->flags & (F_LOOP \| F_SWITCH))) return js_mkerr(js, "not in loop or switch");
	js->flags \|= F_BREAK \| F_NOEXEC;
	}
	js->consumed = 1;
	return js_mkundef();
	}

	static jsval_t js_continue(struct js *js) {
	if (js->flags & F_NOEXEC) {
	} else {
	if (!(js->flags & F_LOOP)) return js_mkerr(js, "not in loop");
	js->flags \|= F_NOEXEC;
	}
	js->consumed = 1;
	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) {
	res = resolveprop(js, js_expr(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 = mkentity(js, 0 \| T_OBJ, &parent_scope_offset, sizeof(parent_scope_offset));

	jsval_t with_marker = js_mkstr(js, "__with_object__", 15);
	jsval_t with_ref = mkprop(js, with_scope, with_marker, with_obj, false);
	if (is_err(with_ref)) return with_ref;

	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_decl(struct js *js) {
	uint8_t exe = !(js->flags & F_NOEXEC);
	js->consumed = 1;
	EXPECT(TOK_IDENTIFIER, );
	js->consumed = 0;

	jsoff_t class_name_off = js->toff, class_name_len = js->tlen;
	char class_name = (char ) &js->code[class_name_off];
	js->consumed = 1;

	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(TOK_IDENTIFIER, );
	super_off = js->toff;
	super_len = js->tlen;
	js->consumed = 1;
	}

	EXPECT(TOK_LBRACE, );
	jsoff_t class_body_start = js->pos;
	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;
	jsoff_t field_start, field_end;
	} MethodInfo;

	MethodInfo methods[32];
	int method_count = 0;

	uint8_t class_tok;
	while ((class_tok = next(js)) != TOK_RBRACE && class_tok != TOK_EOF && method_count < 32) {
	bool is_async_method = false;
	bool is_static_member = 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;
	}
	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;

	methods[method_count].name_off = method_name_off;
	methods[method_count].name_len = method_name_len;
	methods[method_count].is_static = is_static_member;
	methods[method_count].is_async = false;
	methods[method_count].is_field = true;
	methods[method_count].field_start = field_start;
	methods[method_count].field_end = field_end;
	methods[method_count].fn_start = 0;
	methods[method_count].fn_end = 0;
	method_count++;
	continue;
	}

	if (next(js) == TOK_SEMICOLON \|\| (next(js) != TOK_LPAREN && next(js) == TOK_IDENTIFIER)) {
	if (next(js) == TOK_SEMICOLON) js->consumed = 1;
	methods[method_count].name_off = method_name_off;
	methods[method_count].name_len = method_name_len;
	methods[method_count].is_static = is_static_member;
	methods[method_count].is_async = false;
	methods[method_count].is_field = true;
	methods[method_count].field_start = 0;
	methods[method_count].field_end = 0;
	methods[method_count].fn_start = 0;
	methods[method_count].fn_end = 0;
	method_count++;
	continue;
	}

	EXPECT(TOK_LPAREN, js->flags = save_flags);
	jsoff_t method_params_start = js->pos - 1;
	for (bool comma = false; next(js) != TOK_EOF; comma = true) {
	if (!comma && next(js) == TOK_RPAREN) break;
	EXPECT(TOK_IDENTIFIER, js->flags = save_flags);
	js->consumed = 1;

	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	int depth = 0;
	bool done = false;
	while (!done && next(js) != TOK_EOF) {
	uint8_t tok = next(js);
	if (depth == 0 && (tok == TOK_RPAREN \|\| tok == TOK_COMMA)) {
	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) {
	depth--;
	js->consumed = 1;
	} else {
	js->consumed = 1;
	}
	}
	}

	if (next(js) == TOK_RPAREN) break;
	EXPECT(TOK_COMMA, js->flags = save_flags);
	}
	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 {
	methods[method_count].name_off = method_name_off;
	methods[method_count].name_len = method_name_len;
	methods[method_count].fn_start = method_params_start;
	methods[method_count].fn_end = method_body_end;
	methods[method_count].is_async = is_async_method;
	methods[method_count].is_static = is_static_member;
	methods[method_count].is_field = false;
	methods[method_count].field_start = 0;
	methods[method_count].field_end = 0;
	method_count++;
	}
	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(js, super_obj, "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));
	if (super_len > 0) {
	jsval_t super_key = js_mkstr(js, "super", 5);
	if (is_err(super_key)) return super_key;
	jsval_t res_super = setprop(js, func_scope, super_key, super_constructor);
	if (is_err(res_super)) return res_super;
	}

	for (int i = 0; i < method_count; i++) {
	if (methods[i].is_static) continue;
	if (methods[i].is_field) continue;

	jsval_t method_name = js_mkstr(js, &js->code[methods[i].name_off], methods[i].name_len);
	if (is_err(method_name)) return method_name;

	jsoff_t mlen = methods[i].fn_end - methods[i].fn_start;
	jsval_t method_code = js_mkstr(js, &js->code[methods[i].fn_start], mlen);
	if (is_err(method_code)) return method_code;

	jsval_t method_obj = mkobj(js, 0);
	if (is_err(method_obj)) return method_obj;

	jsval_t mcode_key = js_mkstr(js, "__code", 6);
	if (is_err(mcode_key)) return mcode_key;
	jsval_t mres = setprop(js, method_obj, mcode_key, method_code);
	if (is_err(mres)) return mres;

	if (methods[i].is_async) {
	jsval_t async_key = js_mkstr(js, "__async", 7);
	if (is_err(async_key)) return async_key;
	jsval_t async_val = mkval(T_BOOL, 1);
	jsval_t res_async = setprop(js, method_obj, async_key, async_val);
	if (is_err(res_async)) return res_async;
	}

	jsval_t mscope_key = js_mkstr(js, "__scope", 7);
	if (is_err(mscope_key)) return mscope_key;
	jsval_t mscope_res = setprop(js, method_obj, mscope_key, func_scope);
	if (is_err(mscope_res)) return mscope_res;

	jsval_t method_func = mkval(T_FUNC, (unsigned long) vdata(method_obj));
	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;

	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;
	jsval_t ctor_str = js_mkstr(js, &js->code[constructor_params_start], code_len);
	if (is_err(ctor_str)) return ctor_str;

	jsval_t res2 = setprop(js, func_obj, code_key, ctor_str);
	if (is_err(res2)) return res2;
	} else {
	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;
	jsval_t default_ctor;
	if (super_len > 0) {
	default_ctor = js_mkstr(js, "(...args){super(...args);}", 26);
	} else {
	default_ctor = js_mkstr(js, "(){}", 4);
	}
	if (is_err(default_ctor)) return default_ctor;
	jsval_t res2 = setprop(js, func_obj, code_key, default_ctor);
	if (is_err(res2)) return res2;
	}

	int field_count = 0;
	for (int i = 0; i < method_count; i++) {
	if (methods[i].is_static) continue;
	if (methods[i].is_field) field_count++;
	}

	if (field_count > 0) {
	size_t metadata_size = field_count * sizeof(jsoff_t) * 4;
	jsoff_t meta_len = (jsoff_t) (metadata_size + 1);
	jsoff_t meta_header = (jsoff_t) ((meta_len << 2) \| 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 (int i = 0; i < method_count; i++) {
	if (methods[i].is_static) continue;
	if (!methods[i].is_field) continue;

	metadata[meta_idx * 4 + 0] = methods[i].name_off;
	metadata[meta_idx * 4 + 1] = methods[i].name_len;
	metadata[meta_idx * 4 + 2] = methods[i].field_start;
	metadata[meta_idx * 4 + 3] = methods[i].field_end;
	meta_idx++;
	}

	js->mem[meta_off + sizeof(meta_header) + metadata_size] = 0;
	jsval_t fields_meta = mkval(T_STR, meta_off);

	jsval_t fields_key = js_mkstr(js, "__fields", 8);
	if (is_err(fields_key)) return fields_key;
	jsval_t res_fields = setprop(js, func_obj, fields_key, fields_meta);
	if (is_err(res_fields)) return res_fields;

	jsval_t count_key = js_mkstr(js, "__field_count", 13);
	if (is_err(count_key)) return count_key;
	jsval_t res_count = setprop(js, func_obj, count_key, tov((double)field_count));
	if (is_err(res_count)) return res_count;

	jsval_t src_key = js_mkstr(js, "__source", 8);
	if (is_err(src_key)) return src_key;
	jsval_t src_ref = js_mkstr(js, js->code, js->clen);
	if (is_err(src_ref)) return src_ref;
	jsval_t res_src = setprop(js, func_obj, src_key, src_ref);
	if (is_err(res_src)) return res_src;
	}

	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;
	jsval_t res3 = setprop(js, func_obj, scope_key, func_scope);
	if (is_err(res3)) return res3;

	jsval_t name_key = js_mkstr(js, "name", 4);
	if (is_err(name_key)) return name_key;
	jsval_t name_val = js_mkstr(js, class_name, class_name_len);
	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));
	if (lkp(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, false);
	if (is_err(x)) return x;

	for (int i = 0; i < method_count; i++) {
	if (!methods[i].is_static) continue;

	jsval_t member_name = js_mkstr(js, &js->code[methods[i].name_off], methods[i].name_len);
	if (is_err(member_name)) return member_name;

	if (methods[i].is_field) {
	jsval_t field_val = js_mkundef();
	if (methods[i].field_start > 0 && methods[i].field_end > methods[i].field_start) {
	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	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;

	jsoff_t field_len = methods[i].field_end - methods[i].field_start;
	js->code = &saved_code[methods[i].field_start];
	js->clen = field_len;
	js->pos = 0;
	js->consumed = 1;

	field_val = js_expr(js);
	field_val = resolveprop(js, field_val);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	js->toff = saved_toff;
	js->tlen = saved_tlen;
	}
	jsval_t set_res = setprop(js, func_obj, member_name, field_val);
	if (is_err(set_res)) return set_res;
	} else {
	jsoff_t mlen = methods[i].fn_end - methods[i].fn_start;
	jsval_t method_code = js_mkstr(js, &js->code[methods[i].fn_start], mlen);
	if (is_err(method_code)) return method_code;

	jsval_t method_obj = mkobj(js, 0);
	if (is_err(method_obj)) return method_obj;

	jsval_t mcode_key = js_mkstr(js, "__code", 6);
	if (is_err(mcode_key)) return mcode_key;
	jsval_t mres = setprop(js, method_obj, mcode_key, method_code);
	if (is_err(mres)) return mres;

	jsval_t mscope_key = js_mkstr(js, "__scope", 7);
	if (is_err(mscope_key)) return mscope_key;
	jsval_t mscope_res = setprop(js, method_obj, mscope_key, func_scope);
	if (is_err(mscope_res)) return mscope_res;

	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;
	}
	}

	(void) class_body_start;
	return constructor;
	}

	(void) class_body_start;
	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) {
	if ((js->flags & F_CALL) && global_scope_stack && utarray_len(global_scope_stack) > 0) {
	jsoff_t scope_off = (jsoff_t )utarray_eltptr(global_scope_stack, 0);
	if (scope_off && scope_off != 0) return mkval(T_OBJ, scope_off);
	}

	jsval_t scope = js->scope;
	while (vdata(upper(js, scope)) != 0) {
	scope = upper(js, scope);
	}
	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(TOK_IDENTIFIER, );
	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();
	js->consumed = 1;
	if (next(js) == TOK_ASSIGN) {
	js->consumed = 1;
	v = js_expr(js);
	if (is_err(v)) return v;
	}

	if (exe) {
	jsoff_t existing_off = lkp(js, var_scope, name, nlen);
	if (existing_off > 0) {
	jsval_t key_val = js_mkstr(js, name, nlen);
	if (!is_err(v) && vtype(v) != T_UNDEF) {
	setprop(js, var_scope, key_val, resolveprop(js, v));
	}
	} else {
	jsval_t x = mkprop(js, var_scope, js_mkstr(js, name, nlen), resolveprop(js, v), false);
	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) 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;
	if (next(js) == TOK_FUNC) {
	*res = js_func_decl_async(js);
	return;
	}
	*res = js_mkerr_typed(js, JS_ERR_SYNTAX, "async must be followed by function");
	}

	static jsval_t js_stmt(struct js *js) {
	jsval_t res;
	if (js->brk > js->gct) js_gc(js);
	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_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_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 builtin_String(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkstr(js, "", 0);
	jsval_t arg = args[0];
	if (vtype(arg) == T_STR) return arg;
	const char *str = js_str(js, arg);
	return js_mkstr(js, str, strlen(str));
	}

	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 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 NAN;
	if (vtype(arg) == T_STR) {
	jsoff_t len;
	jsoff_t off = vstr(js, arg, &len);
	const char str = (char ) &js->mem[off];
	while (str == ' ' \|\| str == '\t' \|\| str == '\n' \|\| str == '\r') str++;
	if (*str == '\0') return 0.0;
	char *end;
	double val = strtod(str, &end);
	while (end == ' ' \|\| end == '\t' \|\| end == '\n' \|\| end == '\r') end++;
	if (end == str \|\| *end != '\0') return NAN;
	return val;
	}
	return NAN;
	}

	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) {
	if (nargs == 0) return tov(0.0);
	jsval_t arg = args[0];

	if (vtype(arg) == T_NUM) return arg;
	if (vtype(arg) == T_BOOL) {
	return tov(vdata(arg) ? 1.0 : 0.0);
	} else if (vtype(arg) == T_STR) {
	jsoff_t len;
	jsoff_t off = vstr(js, arg, &len);
	const char str = (char ) &js->mem[off];
	while (str == ' ' \|\| str == '\t' \|\| str == '\n' \|\| str == '\r') str++;
	if (*str == '\0') return tov(0.0);
	char *end;
	double val = strtod(str, &end);
	while (end == ' ' \|\| end == '\t' \|\| end == '\n' \|\| end == '\r') end++;
	if (end == str \|\| *end != '\0') return tov(NAN);
	return tov(val);
	} else if (vtype(arg) == T_NULL \|\| vtype(arg) == T_UNDEF) {
	return tov(0.0);
	}

	return tov(0.0);
	}

	static jsval_t builtin_Boolean(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 0);
	return mkval(T_BOOL, js_truthy(js, args[0]) ? 1 : 0);
	}

	static jsval_t builtin_Object(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkobj(js);
	jsval_t arg = args[0];
	if (vtype(arg) == T_NULL \|\| vtype(arg) == T_UNDEF) {
	return js_mkobj(js);
	}
	return arg;
	}

	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];

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_tok = js->tok;
	uint8_t saved_consumed = js->consumed;
	uint8_t saved_flags = js->flags;

	jsval_t result = js_eval(js, code_str, code_len);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	js->flags = saved_flags;

	return result;
	}

	static jsval_t builtin_Function(struct js js, jsval_t args, int nargs) {
	if (nargs == 0) {
	jsval_t code_str = js_mkstr(js, "(){}", 4);
	if (is_err(code_str)) return code_str;

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;

	jsval_t res = setprop(js, func_obj, code_key, code_str);
	if (is_err(res)) return res;

	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;

	res = setprop(js, func_obj, scope_key, js_glob(js));
	if (is_err(res)) return res;

	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;

	jsval_t code_str = js_mkstr(js, NULL, total_len);
	if (is_err(code_str)) return code_str;

	jsoff_t code_len, code_off = vstr(js, code_str, &code_len);
	char code_ptr = (char )&js->mem[code_off];
	size_t pos = 0;

	code_ptr[pos++] = '(';

	for (int i = 0; i < nargs - 1; i++) {
	jsoff_t param_len, param_off = vstr(js, args[i], &param_len);
	memcpy(code_ptr + pos, &js->mem[param_off], param_len);
	pos += param_len;
	if (i < nargs - 2) {
	code_ptr[pos++] = ',';
	}
	}

	code_ptr[pos++] = ')';
	code_ptr[pos++] = '{';

	jsoff_t body_len, body_off = vstr(js, body, &body_len);
	memcpy(code_ptr + pos, &js->mem[body_off], body_len);
	pos += body_len;

	code_ptr[pos++] = '}';

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	jsval_t code_key = js_mkstr(js, "__code", 6);
	if (is_err(code_key)) return code_key;

	jsval_t res = setprop(js, func_obj, code_key, code_str);
	if (is_err(res)) return res;

	jsval_t scope_key = js_mkstr(js, "__scope", 7);
	if (is_err(scope_key)) return scope_key;

	res = setprop(js, func_obj, scope_key, js_glob(js));
	if (is_err(res)) return res;

	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_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(js, arr, "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_GC_MALLOC(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_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(js, "apply requires a function");
	}

	jsval_t this_arg = (nargs > 0) ? args[0] : js_mkundef();
	jsval_t *call_args = NULL;
	int call_nargs = 0;

	if (nargs > 1 && vtype(args[1]) == T_ARR) {
	call_nargs = extract_array_args(js, args[1], &call_args);
	}

	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) ANT_GC_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(js, "bind requires a function");
	}

	jsval_t this_arg = (nargs > 0) ? args[0] : js_mkundef();

	if (vtype(func) == T_CFUNC) {
	jsval_t bound_func = mkobj(js, 0);
	if (is_err(bound_func)) return bound_func;

	setprop(js, bound_func, js_mkstr(js, "__native_func", 13), func);
	setprop(js, bound_func, js_mkstr(js, "__this", 6), this_arg);

	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;
	}

	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsval_t bound_func = mkobj(js, 0);
	if (is_err(bound_func)) return bound_func;

	jsoff_t code_off = lkp(js, func_obj, "__code", 6);
	if (code_off != 0) {
	jsval_t code_val = resolveprop(js, mkval(T_PROP, code_off));
	setprop(js, bound_func, js_mkstr(js, "__code", 6), code_val);
	}

	jsoff_t scope_off = lkp(js, func_obj, "__scope", 7);
	if (scope_off != 0) {
	jsval_t scope_val = resolveprop(js, mkval(T_PROP, scope_off));
	setprop(js, bound_func, js_mkstr(js, "__scope", 7), scope_val);
	}

	jsoff_t async_off = lkp(js, func_obj, "__async", 7);
	if (async_off != 0) {
	jsval_t async_val = resolveprop(js, mkval(T_PROP, async_off));
	setprop(js, bound_func, js_mkstr(js, "__async", 7), async_val);
	}

	setprop(js, bound_func, js_mkstr(js, "__this", 6), this_arg);

	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) {
	jsoff_t len = (jsoff_t) tod(args[0]);
	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double) len);
	setprop(js, arr, len_key, len_val);
	} else {
	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%d", i);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, arr, key, args[i]);
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double) nargs);
	setprop(js, arr, len_key, len_val);
	}

	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_Error(struct js js, jsval_t args, int nargs) {
	jsval_t err_obj = js->this_val;
	bool use_this = (vtype(err_obj) == T_OBJ);

	if (!use_this) {
	err_obj = mkobj(js, 0);
	}

	jsval_t message = js_mkstr(js, "", 0);
	if (nargs > 0) {
	if (vtype(args[0]) == T_STR) {
	message = args[0];
	} else {
	const char *str = js_str(js, args[0]);
	message = js_mkstr(js, str, strlen(str));
	}
	}

	jsval_t message_key = js_mkstr(js, "message", 7);
	setprop(js, err_obj, message_key, message);

	jsval_t name_key = js_mkstr(js, "name", 4);
	jsval_t name_val = js_mkstr(js, "Error", 5);
	setprop(js, err_obj, name_key, name_val);

	return err_obj;
	}

	#define DEFINE_ERROR_BUILTIN(name, name_str, name_len) \
	static jsval_t builtin_##name(struct js js, jsval_t args, int nargs) { \
	jsval_t err_obj = js->this_val; \
	bool use_this = (vtype(err_obj) == T_OBJ); \
	if (!use_this) err_obj = mkobj(js, 0); \
	jsval_t message = js_mkstr(js, "", 0); \
	if (nargs > 0) { \
	if (vtype(args[0]) == T_STR) { \
	message = args[0]; \
	} else { \
	const char *str = js_str(js, args[0]); \
	message = js_mkstr(js, str, strlen(str)); \
	} \
	} \
	setprop(js, err_obj, js_mkstr(js, "message", 7), message); \
	setprop(js, err_obj, js_mkstr(js, "name", 4), js_mkstr(js, name_str, name_len)); \
	return err_obj; \
	}

	DEFINE_ERROR_BUILTIN(EvalError, "EvalError", 9)
	DEFINE_ERROR_BUILTIN(RangeError, "RangeError", 10)
	DEFINE_ERROR_BUILTIN(ReferenceError, "ReferenceError", 14)
	DEFINE_ERROR_BUILTIN(SyntaxError, "SyntaxError", 11)
	DEFINE_ERROR_BUILTIN(TypeError, "TypeError", 9)
	DEFINE_ERROR_BUILTIN(URIError, "URIError", 8)
	DEFINE_ERROR_BUILTIN(InternalError, "InternalError", 13)

	#undef DEFINE_ERROR_BUILTIN

	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 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;
	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;
	}

	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));

	return regexp_obj;
	}

	static jsval_t builtin_Date(struct js js, jsval_t args, int nargs) {
	jsval_t date_obj = js->this_val;
	bool use_this = (vtype(date_obj) == T_OBJ);

	if (!use_this) {
	date_obj = mkobj(js, 0);
	}

	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 {
	timestamp_ms = 0;
	}

	jsval_t time_key = js_mkstr(js, "__time", 6);
	jsval_t time_val = tov(timestamp_ms);
	setprop(js, date_obj, time_key, time_val);

	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 double date_get_time(struct js *js, jsval_t this_val) {
	jsoff_t time_off = lkp(js, this_val, "__time", 6);
	if (time_off == 0) return NAN;
	jsval_t time_val = resolveprop(js, mkval(T_PROP, time_off));
	if (vtype(time_val) != T_NUM) return 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(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(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(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(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(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(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(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(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(js, "Invalid Date");
	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_Math_abs(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(fabs(tod(args[0])));
	}

	static jsval_t builtin_Math_acos(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(acos(tod(args[0])));
	}

	static jsval_t builtin_Math_acosh(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(acosh(tod(args[0])));
	}

	static jsval_t builtin_Math_asin(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(asin(tod(args[0])));
	}

	static jsval_t builtin_Math_asinh(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(asinh(tod(args[0])));
	}

	static jsval_t builtin_Math_atan(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(atan(tod(args[0])));
	}

	static jsval_t builtin_Math_atanh(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(atanh(tod(args[0])));
	}

	static jsval_t builtin_Math_atan2(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 2 \|\| vtype(args[0]) != T_NUM \|\| vtype(args[1]) != T_NUM) return tov(NAN);
	return tov(atan2(tod(args[0]), tod(args[1])));
	}

	static jsval_t builtin_Math_cbrt(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(cbrt(tod(args[0])));
	}

	static jsval_t builtin_Math_ceil(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(ceil(tod(args[0])));
	}

	static jsval_t builtin_Math_clz32(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(32);
	uint32_t n = (uint32_t) tod(args[0]);
	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) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(cos(tod(args[0])));
	}

	static jsval_t builtin_Math_cosh(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(cosh(tod(args[0])));
	}

	static jsval_t builtin_Math_exp(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(exp(tod(args[0])));
	}

	static jsval_t builtin_Math_expm1(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(expm1(tod(args[0])));
	}

	static jsval_t builtin_Math_floor(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(floor(tod(args[0])));
	}

	static jsval_t builtin_Math_fround(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov((double)(float)tod(args[0]));
	}

	static jsval_t builtin_Math_hypot(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs == 0) return tov(0.0);
	double sum = 0.0;
	for (int i = 0; i < nargs; i++) {
	if (vtype(args[i]) != T_NUM) return tov(NAN);
	double v = tod(args[i]);
	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) {
	(void) js;
	if (nargs < 2) return tov(0);
	int32_t a = toInt32(tod(args[0]));
	int32_t b = toInt32(tod(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) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(log(tod(args[0])));
	}

	static jsval_t builtin_Math_log1p(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(log1p(tod(args[0])));
	}

	static jsval_t builtin_Math_log10(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(log10(tod(args[0])));
	}

	static jsval_t builtin_Math_log2(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(log2(tod(args[0])));
	}

	static jsval_t builtin_Math_max(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs == 0) return tov(-INFINITY);
	double max_val = -INFINITY;
	for (int i = 0; i < nargs; i++) {
	if (vtype(args[i]) != T_NUM) return tov(NAN);
	double v = tod(args[i]);
	if (isnan(v)) return tov(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) {
	(void) js;
	if (nargs == 0) return tov(INFINITY);
	double min_val = INFINITY;
	for (int i = 0; i < nargs; i++) {
	if (vtype(args[i]) != T_NUM) return tov(NAN);
	double v = tod(args[i]);
	if (isnan(v)) return tov(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) {
	(void) js;
	if (nargs < 2 \|\| vtype(args[0]) != T_NUM \|\| vtype(args[1]) != T_NUM) return tov(NAN);
	return tov(pow(tod(args[0]), tod(args[1])));
	}

	static bool random_seeded = false;

	static jsval_t builtin_Math_random(struct js js, jsval_t args, int nargs) {
	(void) js;
	(void) args;
	(void) 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) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	double x = tod(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) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	double v = tod(args[0]);
	if (isnan(v)) return tov(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) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(sin(tod(args[0])));
	}

	static jsval_t builtin_Math_sinh(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(sinh(tod(args[0])));
	}

	static jsval_t builtin_Math_sqrt(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(sqrt(tod(args[0])));
	}

	static jsval_t builtin_Math_tan(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(tan(tod(args[0])));
	}

	static jsval_t builtin_Math_tanh(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(tanh(tod(args[0])));
	}

	static jsval_t builtin_Math_trunc(struct js js, jsval_t args, int nargs) {
	(void) js;
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(NAN);
	return tov(trunc(tod(args[0])));
	}

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

	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);

	if (streq(key, klen, "__proto__", 9)) continue;
	if (klen > 7 && memcmp(key, "__desc_", 7) == 0) continue;

	bool should_include = true;
	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, obj, desc_key, strlen(desc_key));

	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	jsoff_t enum_off = lkp(js, desc_obj, "enumerable", 10);
	if (enum_off != 0) {
	jsval_t enum_val = resolveprop(js, mkval(T_PROP, enum_off));
	should_include = js_truthy(js, enum_val);
	}
	}
	}

	if (should_include) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t idx_key = js_mkstr(js, idxstr, strlen(idxstr));
	jsval_t key_val = js_mkstr(js, key, klen);
	setprop(js, arr, idx_key, key_val);
	idx++;
	}
	}

	for (jsoff_t i = 0; i < idx / 2; i++) {
	jsoff_t j = idx - 1 - i;
	char istr[16], jstr[16];
	snprintf(istr, sizeof(istr), "%u", (unsigned) i);
	snprintf(jstr, sizeof(jstr), "%u", (unsigned) j);
	jsoff_t ioff = lkp(js, arr, istr, strlen(istr));
	jsoff_t joff = lkp(js, arr, jstr, strlen(jstr));
	jsval_t iv = loadval(js, ioff + sizeof(jsoff_t) * 2);
	jsval_t jv = loadval(js, joff + sizeof(jsoff_t) * 2);
	saveval(js, ioff + sizeof(jsoff_t) * 2, jv);
	saveval(js, joff + sizeof(jsoff_t) * 2, iv);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double) idx);
	setprop(js, arr, len_key, 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 \| CONSTMASK);

	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);

	if (streq(key, klen, "__proto__", 9)) continue;
	if (klen > 7 && memcmp(key, "__desc_", 7) == 0) continue;

	bool should_include = true;
	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, obj, desc_key, strlen(desc_key));

	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	jsoff_t enum_off = lkp(js, desc_obj, "enumerable", 10);
	if (enum_off != 0) {
	jsval_t enum_val = resolveprop(js, mkval(T_PROP, enum_off));
	should_include = js_truthy(js, enum_val);
	}
	}
	}

	if (should_include) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t idx_key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, arr, idx_key, val);
	idx++;
	}
	}

	for (jsoff_t i = 0; i < idx / 2; i++) {
	jsoff_t j = idx - 1 - i;
	char istr[16], jstr[16];
	snprintf(istr, sizeof(istr), "%u", (unsigned) i);
	snprintf(jstr, sizeof(jstr), "%u", (unsigned) j);
	jsoff_t ioff = lkp(js, arr, istr, strlen(istr));
	jsoff_t joff = lkp(js, arr, jstr, strlen(jstr));
	jsval_t iv = loadval(js, ioff + sizeof(jsoff_t) * 2);
	jsval_t jv = loadval(js, joff + sizeof(jsoff_t) * 2);
	saveval(js, ioff + sizeof(jsoff_t) * 2, jv);
	saveval(js, joff + sizeof(jsoff_t) * 2, iv);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double) idx);
	setprop(js, arr, len_key, 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 \| CONSTMASK);

	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);

	if (streq(key, klen, "__proto__", 9)) continue;
	if (klen > 7 && memcmp(key, "__desc_", 7) == 0) continue;

	bool should_include = true;
	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, obj, desc_key, strlen(desc_key));

	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	jsoff_t enum_off = lkp(js, desc_obj, "enumerable", 10);
	if (enum_off != 0) {
	jsval_t enum_val = resolveprop(js, mkval(T_PROP, enum_off));
	should_include = js_truthy(js, enum_val);
	}
	}
	}

	if (should_include) {
	jsval_t pair = mkarr(js);
	jsval_t key_val = js_mkstr(js, key, klen);
	setprop(js, pair, js_mkstr(js, "0", 1), key_val);
	setprop(js, pair, js_mkstr(js, "1", 1), val);
	setprop(js, pair, js_mkstr(js, "length", 6), tov(2.0));

	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t idx_key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, arr, idx_key, mkval(T_ARR, vdata(pair)));
	idx++;
	}
	}

	for (jsoff_t i = 0; i < idx / 2; i++) {
	jsoff_t j = idx - 1 - i;
	char istr[16], jstr[16];
	snprintf(istr, sizeof(istr), "%u", (unsigned) i);
	snprintf(jstr, sizeof(jstr), "%u", (unsigned) j);
	jsoff_t ioff = lkp(js, arr, istr, strlen(istr));
	jsoff_t joff = lkp(js, arr, jstr, strlen(jstr));
	jsval_t iv = loadval(js, ioff + sizeof(jsoff_t) * 2);
	jsval_t jv = loadval(js, joff + sizeof(jsoff_t) * 2);
	saveval(js, ioff + sizeof(jsoff_t) * 2, jv);
	saveval(js, joff + sizeof(jsoff_t) * 2, iv);
	}

	jsval_t len_key = js_mkstr(js, "length", 6);
	jsval_t len_val = tov((double) idx);
	setprop(js, arr, len_key, 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");
	}

	if (pt != T_NULL) {
	jsval_t cur = proto;
	int depth = 0;
	while (vtype(cur) != T_NULL && depth < 32) {
	if (vdata(cur) == vdata(obj)) return js_mkerr(js, "Cyclic __proto__ value");
	cur = get_proto(js, cur);
	depth++;
	}
	}

	set_proto(js, obj, proto);
	return obj;
	}

	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, proto);
	}

	if (nargs >= 2 && vtype(args[1]) == T_OBJ) {
	jsval_t props = args[1];
	jsoff_t next = loadoff(js, (jsoff_t) vdata(props)) & ~(3U \| CONSTMASK);

	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);
	}
	}

	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_STR) {
	return js_mkerr(js, "Property key must be a string");
	}

	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, "__proto__", 9)) {
	return js_mkerr(js, "Cannot define __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(js, descriptor, "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(js, descriptor, "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 (existing_off > 0) {
	if (is_const_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);
	}

	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)prop_len, prop_str);
	jsval_t desc_key_str = js_mkstr(js, desc_key, strlen(desc_key));
	jsval_t desc_obj = js_mkobj(js);
	setprop(js, desc_obj, js_mkstr(js, "writable", 8), mkval(T_BOOL, writable ? 1 : 0));
	setprop(js, desc_obj, js_mkstr(js, "enumerable", 10), mkval(T_BOOL, enumerable ? 1 : 0));
	setprop(js, desc_obj, js_mkstr(js, "configurable", 12), mkval(T_BOOL, configurable ? 1 : 0));
	setprop(js, as_obj, desc_key_str, desc_obj);

	if (!configurable) {
	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| CONSTMASK)) == existing_off) {
	saveoff(js, head, firstprop \| CONSTMASK);
	}
	}
	} else {
	if (has_get \|\| has_set) {
	return js_mkerr(js, "Accessor properties not fully supported");
	}

	if (!has_value) {
	value = js_mkundef();
	}

	jsval_t prop_key = js_mkstr(js, prop_str, prop_len);
	bool mark_const = (!writable \|\| !configurable);
	mkprop(js, as_obj, prop_key, value, mark_const);

	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)prop_len, prop_str);
	jsval_t desc_key_str = js_mkstr(js, desc_key, strlen(desc_key));
	jsval_t desc_obj = js_mkobj(js);
	setprop(js, desc_obj, js_mkstr(js, "writable", 8), mkval(T_BOOL, writable ? 1 : 0));
	setprop(js, desc_obj, js_mkstr(js, "enumerable", 10), mkval(T_BOOL, enumerable ? 1 : 0));
	setprop(js, desc_obj, js_mkstr(js, "configurable", 12), mkval(T_BOOL, configurable ? 1 : 0));
	setprop(js, as_obj, desc_key_str, desc_obj);
	}

	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 \| CONSTMASK);

	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);

	if (streq(key, klen, "__proto__", 9)) continue;
	if (klen > 7 && memcmp(key, "__desc_", 7) == 0) continue;

	bool should_copy = true;
	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, src_obj, desc_key, strlen(desc_key));

	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	jsoff_t enum_off = lkp(js, desc_obj, "enumerable", 10);
	if (enum_off != 0) {
	jsval_t enum_val = resolveprop(js, mkval(T_PROP, enum_off));
	should_copy = js_truthy(js, enum_val);
	}
	}
	}

	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));

	setprop(js, as_obj, js_mkstr(js, "__frozen__", 10), js_mktrue());
	jsoff_t next = loadoff(js, (jsoff_t) vdata(as_obj)) & ~(3U \| CONSTMASK);

	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);

	if (streq(key, klen, "__proto__", 9)) continue;
	if (streq(key, klen, "__frozen__", 10)) continue;
	if (streq(key, klen, "__sealed__", 10)) continue;
	if (klen > 7 && memcmp(key, "__desc_", 7) == 0) continue;

	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| CONSTMASK)) == cur_prop) {
	saveoff(js, head, firstprop \| CONSTMASK);
	} else {
	jsoff_t prev = head;
	jsoff_t scan = firstprop & ~(3U \| CONSTMASK);
	while (scan < js->brk && scan != 0) {
	if (scan == cur_prop) {
	jsoff_t prev_val = loadoff(js, prev);
	saveoff(js, prev, prev_val \| CONSTMASK);
	break;
	}
	prev = scan;
	scan = loadoff(js, scan) & ~(3U \| CONSTMASK);
	}
	}

	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, as_obj, desc_key, strlen(desc_key));
	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	setprop(js, desc_obj, js_mkstr(js, "writable", 8), js_mkfalse());
	setprop(js, desc_obj, js_mkstr(js, "configurable", 12), js_mkfalse());
	}
	} else {
	jsval_t desc_key_str = js_mkstr(js, desc_key, strlen(desc_key));
	jsval_t desc_obj = js_mkobj(js);
	setprop(js, desc_obj, js_mkstr(js, "writable", 8), js_mkfalse());
	setprop(js, desc_obj, js_mkstr(js, "enumerable", 10), js_mktrue());
	setprop(js, desc_obj, js_mkstr(js, "configurable", 12), js_mkfalse());
	setprop(js, as_obj, desc_key_str, desc_obj);
	}
	}

	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));

	jsoff_t frozen_off = lkp(js, as_obj, "__frozen__", 10);
	if (frozen_off != 0) {
	jsval_t frozen_val = resolveprop(js, mkval(T_PROP, frozen_off));
	if (js_truthy(js, frozen_val)) return js_mktrue();
	}

	return 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));

	setprop(js, as_obj, js_mkstr(js, "__sealed__", 10), js_mktrue());
	jsoff_t next = loadoff(js, (jsoff_t) vdata(as_obj)) & ~(3U \| CONSTMASK);

	while (next < js->brk && next != 0) {
	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 = loadoff(js, next) & ~(3U \| CONSTMASK);

	if (streq(key, klen, "__proto__", 9)) continue;
	if (streq(key, klen, "__frozen__", 10)) continue;
	if (streq(key, klen, "__sealed__", 10)) continue;
	if (klen > 7 && memcmp(key, "__desc_", 7) == 0) continue;

	char desc_key[128];
	snprintf(desc_key, sizeof(desc_key), "__desc_%.*s", (int)klen, key);
	jsoff_t desc_off = lkp(js, as_obj, desc_key, strlen(desc_key));
	if (desc_off != 0) {
	jsval_t desc_obj = resolveprop(js, mkval(T_PROP, desc_off));
	if (vtype(desc_obj) == T_OBJ) {
	setprop(js, desc_obj, js_mkstr(js, "configurable", 12), js_mkfalse());
	}
	} else {
	jsval_t desc_key_str = js_mkstr(js, desc_key, strlen(desc_key));
	jsval_t desc_obj = js_mkobj(js);
	setprop(js, desc_obj, js_mkstr(js, "writable", 8), js_mktrue());
	setprop(js, desc_obj, js_mkstr(js, "enumerable", 10), js_mktrue());
	setprop(js, desc_obj, js_mkstr(js, "configurable", 12), js_mkfalse());
	setprop(js, as_obj, desc_key_str, desc_obj);
	}
	}

	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));

	jsoff_t sealed_off = lkp(js, as_obj, "__sealed__", 10);
	if (sealed_off != 0) {
	jsval_t sealed_val = resolveprop(js, mkval(T_PROP, sealed_off));
	if (js_truthy(js, sealed_val)) return js_mktrue();
	}

	jsoff_t frozen_off = lkp(js, as_obj, "__frozen__", 10);
	if (frozen_off != 0) {
	jsval_t frozen_val = resolveprop(js, mkval(T_PROP, frozen_off));
	if (js_truthy(js, frozen_val)) 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(js, iterable, "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_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_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;
	jsoff_t tag_off = lkp(js, check_obj, "@@toStringTag", 13);
	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_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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) len);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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 off = lkp(js, arr, "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);
	}

	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) len);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, arr, key, val);

	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, 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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) len);

	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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);

	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(js, arr, "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 >= 1 && vtype(args[0]) == T_NUM) {
	double d = tod(args[0]);
	if (d < 0) {
	start = (jsoff_t) (d + len < 0 ? 0 : d + len);
	} else {
	start = (jsoff_t) (d > len ? len : d);
	}
	}

	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d < 0) {
	end = (jsoff_t) (d + len < 0 ? 0 : d + len);
	} else {
	end = (jsoff_t) (d > len ? len : 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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) result_idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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(js, arr, "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);
	char result[1024] = "";
	size_t result_len = 0;

	for (jsoff_t i = 0; i < len; i++) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));

	if (i > 0 && result_len + sep_len < sizeof(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 < sizeof(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 < sizeof(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 < sizeof(result)) {
	memcpy(result + result_len, boolstr, bool_len);
	result_len += bool_len;
	}
	}
	}
	}
	return js_mkstr(js, result, result_len);
	}

	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 off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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 mkval(T_BOOL, 1);
	} else if (vtype(elem) == T_BOOL && vdata(elem) == vdata(search)) {
	return mkval(T_BOOL, 1);
	} else if (vtype(elem) == T_STR) {
	jsoff_t elem_len, elem_off_str = vstr(js, elem, &elem_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	if (elem_len == search_len && memcmp(&js->mem[elem_off_str], &js->mem[search_off], elem_len) == 0) {
	return mkval(T_BOOL, 1);
	}
	} else if ((vtype(elem) == T_OBJ \|\| vtype(elem) == T_ARR \|\| vtype(elem) == T_FUNC) && vdata(elem) == vdata(search)) {
	return mkval(T_BOOL, 1);
	}
	}
	}
	}
	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");
	}

	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "every requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));

	jsval_t elem = js_mkundef();
	if (elem_off != 0) {
	elem = resolveprop(js, mkval(T_PROP, elem_off));
	}

	jsval_t call_args[3] = { elem, tov((double)i), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);

	if (is_err(result)) return result;

	if (!js_truthy(js, result)) {
	return mkval(T_BOOL, 0);
	}
	}

	return mkval(T_BOOL, 1);
	}

	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 off = lkp(js, arr, "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 / 2; i++) {
	jsoff_t j = len - 1 - i;
	char idx_i[16], idx_j[16];
	snprintf(idx_i, sizeof(idx_i), "%u", (unsigned) i);
	snprintf(idx_j, sizeof(idx_j), "%u", (unsigned) j);

	jsoff_t off_i = lkp(js, arr, idx_i, strlen(idx_i));
	jsoff_t off_j = lkp(js, arr, idx_j, strlen(idx_j));

	jsval_t val_i = off_i ? resolveprop(js, mkval(T_PROP, off_i)) : js_mkundef();
	jsval_t val_j = off_j ? resolveprop(js, mkval(T_PROP, off_j)) : js_mkundef();

	jsval_t key_i = js_mkstr(js, idx_i, strlen(idx_i));
	jsval_t key_j = js_mkstr(js, idx_j, strlen(idx_j));
	setprop(js, arr, key_i, val_j);
	setprop(js, arr, key_j, val_i);
	}

	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");
	}

	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "map requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));

	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;

	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, result, key, mapped);
	}

	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_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");
	}

	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "filter requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));

	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 test = call_js_with_args(js, callback, call_args, 3);
	if (is_err(test)) return test;

	if (js_truthy(js, test)) {
	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, 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_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");
	}

	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "reduce requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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_idx = 0;
	jsval_t accumulator;

	if (nargs >= 2) {
	accumulator = args[1];
	} else {
	if (len == 0) return js_mkerr(js, "reduce of empty array with no initial value");
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", 0u);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	accumulator = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	start_idx = 1;
	}

	for (jsoff_t i = start_idx; i < len; i++) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));

	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 void flat_helper(struct js js, jsval_t arr, jsval_t result, jsoff_t result_idx, int depth) {
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));

	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, elem_off));
	if (depth > 0 && (vtype(elem) == T_ARR \|\| vtype(elem) == T_OBJ)) {
	flat_helper(js, elem, result, result_idx, depth - 1);
	} 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, elem);
	(*result_idx)++;
	}
	}
	}
	}

	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, 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, 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(js, arg, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arg, idxstr, strlen(idxstr));
	if (elem_off != 0) {
	jsval_t elem = resolveprop(js, mkval(T_PROP, 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, 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, arg);
	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_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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, arr, key, value);
	}

	return arr;
	}

	static jsval_t builtin_array_find(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, "find called on non-array");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "find requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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 result = call_js_with_args(js, callback, call_args, 3);
	if (is_err(result)) return result;
	if (js_truthy(js, result)) return elem;
	}
	return js_mkundef();
	}

	static jsval_t builtin_array_findIndex(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, "findIndex called on non-array");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "findIndex requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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 result = call_js_with_args(js, callback, call_args, 3);
	if (is_err(result)) return result;
	if (js_truthy(js, result)) return tov((double)i);
	}
	return tov(-1);
	}

	static jsval_t builtin_array_findLast(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, "findLast called on non-array");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "findLast requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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 = len; i > 0; i--) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned)(i - 1));
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t call_args[3] = { elem, tov((double)(i - 1)), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);
	if (is_err(result)) return result;
	if (js_truthy(js, result)) return elem;
	}
	return js_mkundef();
	}

	static jsval_t builtin_array_findLastIndex(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, "findLastIndex called on non-array");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "findLastIndex requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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 = len; i > 0; i--) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned)(i - 1));
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t call_args[3] = { elem, tov((double)(i - 1)), arr };
	jsval_t result = call_js_with_args(js, callback, call_args, 3);
	if (is_err(result)) return result;
	if (js_truthy(js, result)) return tov((double)(i - 1));
	}
	return tov(-1);
	}

	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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(js, mapped, "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 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");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "forEach requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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 result = call_js_with_args(js, callback, call_args, 3);
	if (is_err(result)) return result;
	}
	return js_mkundef();
	}

	static int js_compare_values(struct js *js, jsval_t a, jsval_t b, jsval_t compareFn) {
	if (vtype(compareFn) == T_FUNC) {
	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;
	}
	const char *sa = js_str(js, a);
	const char *sb = js_str(js, b);
	return strcmp(sa, sb);
	}

	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned)(len - 1));
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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(js, arr, "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)));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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");
	}
	if (nargs == 0 \|\| vtype(args[0]) != T_FUNC) {
	return js_mkerr(js, "some requires a function argument");
	}

	jsval_t callback = args[0];
	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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 result = call_js_with_args(js, callback, call_args, 3);
	if (is_err(result)) return result;
	if (js_truthy(js, result)) return mkval(T_BOOL, 1);
	}
	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;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) {
	return js_mkerr(js, "sort called on non-array");
	}

	jsval_t compareFn = (nargs >= 1 && vtype(args[0]) == T_FUNC) ? args[0] : js_mkundef();

	jsoff_t off = lkp(js, arr, "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++) {
	for (jsoff_t j = i + 1; j < len; j++) {
	char idx_i[16], idx_j[16];
	snprintf(idx_i, sizeof(idx_i), "%u", (unsigned) i);
	snprintf(idx_j, sizeof(idx_j), "%u", (unsigned) j);

	jsoff_t off_i = lkp(js, arr, idx_i, strlen(idx_i));
	jsoff_t off_j = lkp(js, arr, idx_j, strlen(idx_j));
	jsval_t val_i = off_i ? resolveprop(js, mkval(T_PROP, off_i)) : js_mkundef();
	jsval_t val_j = off_j ? resolveprop(js, mkval(T_PROP, off_j)) : js_mkundef();

	if (js_compare_values(js, val_i, val_j, compareFn) > 0) {
	jsval_t key_i = js_mkstr(js, idx_i, strlen(idx_i));
	jsval_t key_j = js_mkstr(js, idx_j, strlen(idx_j));
	setprop(js, arr, key_i, val_j);
	setprop(js, arr, key_j, val_i);
	}
	}
	}
	return arr;
	}

	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned)(start + i));
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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)));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned)(start + i));
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	temp[i] = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	}

	for (int i = 0; i < count; i++) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned)(target + i));
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, arr, key, temp[i]);
	}

	free(temp);
	return arr;
	}

	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");
	}

	jsoff_t off = lkp(js, arr, "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 src[16], dst[16];
	snprintf(src, sizeof(src), "%u", (unsigned)(len - 1 - i));
	snprintf(dst, sizeof(dst), "%u", (unsigned) i);
	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, 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_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 compareFn = (nargs >= 1 && vtype(args[0]) == T_FUNC) ? args[0] : js_mkundef();

	jsoff_t off = lkp(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	setprop(js, result, key, elem);
	}
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, result, len_key, tov((double) len));

	for (jsoff_t i = 0; i < len; i++) {
	for (jsoff_t j = i + 1; j < len; j++) {
	char idx_i[16], idx_j[16];
	snprintf(idx_i, sizeof(idx_i), "%u", (unsigned) i);
	snprintf(idx_j, sizeof(idx_j), "%u", (unsigned) j);

	jsoff_t off_i = lkp(js, result, idx_i, strlen(idx_i));
	jsoff_t off_j = lkp(js, result, idx_j, strlen(idx_j));
	jsval_t val_i = off_i ? resolveprop(js, mkval(T_PROP, off_i)) : js_mkundef();
	jsval_t val_j = off_j ? resolveprop(js, mkval(T_PROP, off_j)) : js_mkundef();

	if (js_compare_values(js, val_i, val_j, compareFn) > 0) {
	jsval_t key_i = js_mkstr(js, idx_i, strlen(idx_i));
	jsval_t key_j = js_mkstr(js, idx_j, strlen(idx_j));
	setprop(js, result, key_i, val_j);
	setprop(js, result, key_j, val_i);
	}
	}
	}
	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");
	}

	jsoff_t off = lkp(js, arr, "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 result = mkarr(js);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	for (int i = 0; i < start; i++) {
	char src[16], dst[16];
	snprintf(src, sizeof(src), "%u", (unsigned) i);
	snprintf(dst, sizeof(dst), "%u", (unsigned) result_idx);
	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, result, key, elem);
	result_idx++;
	}

	for (int i = 0; i < insertCount; i++) {
	char dst[16];
	snprintf(dst, sizeof(dst), "%u", (unsigned) result_idx);
	jsval_t key = js_mkstr(js, dst, strlen(dst));
	setprop(js, result, key, args[2 + i]);
	result_idx++;
	}

	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) result_idx);
	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, 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_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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsval_t elem;
	if ((jsoff_t)idx == i) {
	elem = args[1];
	} else {
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	}
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	jsval_t elem = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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(js, arr, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, arr, idxstr, strlen(idxstr));
	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, strlen(idxstr));
	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_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];
	snprintf(idxstr, sizeof(idxstr), "%u", (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, strlen(idxstr));
	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(js, src, "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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsoff_t elem_off = lkp(js, src, idxstr, strlen(idxstr));
	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, strlen(idxstr));
	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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) i);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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 = 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);
	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	for (jsoff_t i = 0; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) {
	return tov((double) i);
	}
	}

	return tov(-1);
	}

	static jsval_t builtin_string_substring(struct js js, jsval_t args, int nargs) {
	jsval_t str = 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;

	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	double d = tod(args[0]);
	start = (jsoff_t) (d < 0 ? 0 : (d > str_len ? str_len : d));
	}

	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	end = (jsoff_t) (d < 0 ? 0 : (d > str_len ? str_len : 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_split(struct js js, jsval_t args, int nargs) {
	jsval_t str = 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;
	if (nargs == 0 \|\| vtype(args[0]) != T_STR) {
	jsval_t key = js_mkstr(js, "0", 1);
	setprop(js, arr, key, str);
	jsval_t len_key = js_mkstr(js, "length", 6);
	setprop(js, arr, len_key, tov(1));
	return mkval(T_ARR, vdata(arr));
	}

	jsval_t sep = args[0];
	jsoff_t sep_len, sep_off = vstr(js, sep, &sep_len);
	const char sep_ptr = (char ) &js->mem[sep_off];
	jsoff_t idx = 0;
	jsoff_t start = 0;

	if (sep_len == 0) {
	for (jsoff_t i = 0; i < str_len; i++) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	jsval_t part = js_mkstr(js, str_ptr + i, 1);
	setprop(js, arr, key, part);
	idx++;
	}
	} else {
	for (jsoff_t i = 0; i <= str_len - sep_len; i++) {
	if (memcmp(str_ptr + i, sep_ptr, sep_len) == 0) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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 (start <= str_len) {
	char idxstr[16];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	jsval_t part = js_mkstr(js, str_ptr + start, str_len - start);
	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));
	}

	static jsval_t builtin_string_slice(struct js js, jsval_t args, int nargs) {
	jsval_t str = js->this_val;
	if (vtype(str) != T_STR) return js_mkerr(js, "slice 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;

	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	double d = tod(args[0]);
	if (d < 0) {
	start = (jsoff_t) (d + str_len < 0 ? 0 : d + str_len);
	} else {
	start = (jsoff_t) (d > str_len ? str_len : d);
	}
	}
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d < 0) {
	end = (jsoff_t) (d + str_len < 0 ? 0 : d + str_len);
	} else {
	end = (jsoff_t) (d > str_len ? str_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 = 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];

	if (search_len == 0) return mkval(T_BOOL, 1);
	for (jsoff_t i = 0; 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 = 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 = 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 str = js->this_val;
	if (vtype(str) != T_STR) return js_mkerr(js, "replace called on non-string");
	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[256];
	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 < sizeof(pattern_buf) - 1 ? plen : sizeof(pattern_buf) - 1;
	memcpy(pattern_buf, &js->mem[poff], pattern_len);
	pattern_buf[pattern_len] = '\0';

	jsoff_t flags_off = lkp(js, search, "flags", 5);
	if (flags_off == 0) goto not_regex;

	jsval_t flags_val = resolveprop(js, mkval(T_PROP, flags_off));
	if (vtype(flags_val) != T_STR) 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) return str;
	jsoff_t repl_off;
	repl_off = vstr(js, replacement, &repl_len);
	repl_ptr = (char *) &js->mem[repl_off];
	}

	char result[4096];
	jsoff_t result_len = 0;

	if (is_regex) {
	regex_t regex;
	int cflags = REG_EXTENDED;

	if (regcomp(&regex, pattern_buf, cflags) != 0) {
	return js_mkerr(js, "invalid regex pattern");
	}

	char str_buf[4096];
	if (str_len >= sizeof(str_buf)) {
	regfree(&regex);
	return js_mkerr(js, "string too long");
	}
	memcpy(str_buf, str_ptr, str_len);
	str_buf[str_len] = '\0';

	jsoff_t pos = 0;
	bool replaced = false;

	while (pos < str_len) {
	regmatch_t match;
	int ret = regexec(&regex, str_buf + pos, 1, &match, 0);

	if (ret == 0 && match.rm_so >= 0) {
	jsoff_t before_len = (jsoff_t)match.rm_so;
	if (result_len + before_len < sizeof(result)) {
	memcpy(result + result_len, str_buf + pos, before_len);
	result_len += before_len;
	}

	jsoff_t match_len = (jsoff_t)(match.rm_eo - match.rm_so);

	if (is_func_replacement) {
	jsval_t match_str = js_mkstr(js, str_buf + pos + match.rm_so, match_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) {
	regfree(&regex);
	return cb_result;
	}

	if (vtype(cb_result) == T_STR) {
	jsoff_t cb_len, cb_off = vstr(js, cb_result, &cb_len);
	if (result_len + cb_len < sizeof(result)) {
	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));
	if (result_len + n < sizeof(result)) {
	memcpy(result + result_len, numbuf, n);
	result_len += (jsoff_t)n;
	}
	}
	} else {
	if (result_len + repl_len < sizeof(result)) {
	memcpy(result + result_len, repl_ptr, repl_len);
	result_len += repl_len;
	}
	}

	if (match.rm_eo == 0) {
	if (pos < str_len && result_len < sizeof(result)) {
	result[result_len++] = str_buf[pos];
	}
	pos++;
	} else {
	pos += (jsoff_t)match.rm_eo;
	}

	replaced = true;

	if (!global_flag) break;
	} else {
	break;
	}
	}

	if (pos < str_len && result_len + (str_len - pos) < sizeof(result)) {
	memcpy(result + result_len, str_buf + pos, str_len - pos);
	result_len += str_len - pos;
	}

	regfree(&regex);
	return replaced ? js_mkstr(js, result, result_len) : str;

	} else {
	if (vtype(search) != T_STR) 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) return str;

	for (jsoff_t i = 0; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) {
	if (result_len + i < sizeof(result)) {
	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) return cb_result;

	if (vtype(cb_result) == T_STR) {
	jsoff_t cb_len, cb_off = vstr(js, cb_result, &cb_len);
	if (result_len + cb_len < sizeof(result)) {
	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));
	if (result_len + n < sizeof(result)) {
	memcpy(result + result_len, numbuf, n);
	result_len += (jsoff_t)n;
	}
	}
	} else {
	if (result_len + repl_len < sizeof(result)) {
	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 && result_len + after_len < sizeof(result)) {
	memcpy(result + result_len, str_ptr + after_start, after_len);
	result_len += after_len;
	}
	return js_mkstr(js, result, result_len);
	}
	}
	return str;
	}
	}

	static jsval_t builtin_string_template(struct js js, jsval_t args, int nargs) {
	jsval_t str = 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];

	char result[2048];
	jsoff_t result_len = 0;
	jsoff_t i = 0;

	while (i < str_len && result_len < sizeof(result) - 1) {
	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);
	if (result_len + val_len < sizeof(result)) {
	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);
	if (result_len + num_len < sizeof(result)) {
	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);
	if (result_len + bool_len < sizeof(result)) {
	memcpy(result + result_len, boolstr, bool_len);
	result_len += bool_len;
	}
	}
	} else {
	}
	i = end + 2;
	continue;
	}
	}
	result[result_len++] = str_ptr[i++];
	}
	return js_mkstr(js, result, result_len);
	}

	static jsval_t builtin_string_charCodeAt(struct js js, jsval_t args, int nargs) {
	jsval_t str = js->this_val;
	if (vtype(str) != T_STR) return js_mkerr(js, "charCodeAt called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return tov(-NAN);

	double idx_d = tod(args[0]);
	if (idx_d < 0 \|\| idx_d != (double)(long)idx_d) return tov(-NAN);

	jsoff_t idx = (jsoff_t) idx_d;
	jsoff_t str_len = offtolen(loadoff(js, (jsoff_t) vdata(str)));

	if (idx >= str_len) return tov(-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_toLowerCase(struct js js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = 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 = 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 = 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_repeat(struct js js, jsval_t args, int nargs) {
	jsval_t str = 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 = 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 = 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 = js->this_val;
	if (vtype(str) != T_STR) return js_mkerr(js, "charAt called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return js_mkstr(js, "", 0);

	double idx_d = tod(args[0]);
	if (idx_d < 0 \|\| idx_d != (double)(long)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 = js->mem[str_off + idx];

	return js_mkstr(js, &ch, 1);
	}

	static jsval_t builtin_number_toString(struct js js, jsval_t args, int nargs) {
	jsval_t num = 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 = 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++] = 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 = js->this_val;
	if (vtype(num) != T_NUM) return js_mkerr(js, "toFixed called on non-number");

	int digits = 0;
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	digits = (int) tod(args[0]);
	if (digits < 0) digits = 0;
	if (digits > 20) digits = 20;
	}

	char buf[64];
	snprintf(buf, sizeof(buf), "%.*f", digits, tod(num));
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_number_toPrecision(struct js js, jsval_t args, int nargs) {
	jsval_t num = js->this_val;
	if (vtype(num) != T_NUM) return js_mkerr(js, "toPrecision called on non-number");

	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) {
	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 = 1;
	if (precision > 21) precision = 21;

	char buf[64];
	snprintf(buf, sizeof(buf), "%.*g", precision, tod(num));
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_number_toExponential(struct js js, jsval_t args, int nargs) {
	jsval_t num = js->this_val;
	if (vtype(num) != T_NUM) return js_mkerr(js, "toExponential called on non-number");

	int digits = 6;
	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	digits = (int) tod(args[0]);
	if (digits < 0) digits = 0;
	if (digits > 20) digits = 20;
	}

	char buf[64];
	snprintf(buf, sizeof(buf), "%.*e", digits, tod(num));
	char *e = strchr(buf, 'e');
	if (e && (e[1] == '+' \|\| e[1] == '-') && e[2] == '0' && e[3] != '\0') {
	memmove(e + 2, e + 3, strlen(e + 3) + 1);
	}
	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_parseInt(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(-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 = 10;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	radix = (int) tod(args[1]);
	if (radix < 2 \|\| radix > 36) return tov(-NAN);
	}

	jsoff_t i = 0;
	while (i < str_len && is_space(str[i])) i++;

	if (i >= str_len) return tov(-NAN);

	int sign = 1;
	if (str[i] == '-') {
	sign = -1;
	i++;
	} else if (str[i] == '+') {
	i++;
	}

	if (radix == 16 && i + 1 < str_len && str[i] == '0' && (str[i + 1] == 'x' \|\| str[i + 1] == 'X')) {
	i += 2;
	}

	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(-NAN);

	return tov(sign * result);
	}

	static jsval_t builtin_parseFloat(struct js js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(-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(-NAN);

	char *end;
	double result = strtod(&str[i], &end);

	if (end == &str[i]) return tov(-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_GC_MALLOC(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);
	ANT_GC_FREE(out);
	return result;
	}

	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_GC_MALLOC(out_len + 1);
	if (!out) return js_mkerr(js, "out of memory");

	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
	};

	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)) {
	ANT_GC_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);
	ANT_GC_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) {
	jsval_t prom_obj = mkval(T_OBJ, vdata(value));
	jsoff_t state_off = lkp(js, prom_obj, "__state", 7);
	int state = 0;
	if (state_off != 0) {
	jsval_t val = resolveprop(js, mkval(T_PROP, state_off));
	if (vtype(val) == T_NUM) state = (int)tod(val);
	}

	if (state == 0) {
	return (size_t)snprintf(buf, len, "Promise { <pending> }");
	}

	jsoff_t value_off = lkp(js, prom_obj, "__value", 7);
	if (value_off == 0) {
	const char *s = (state == 1) ? "<fulfilled>" : "<rejected>";
	return (size_t)snprintf(buf, len, "Promise { %s }", s);
	}

	jsval_t prom_val = resolveprop(js, mkval(T_PROP, value_off));
	char value_buf[256];
	size_t value_len = tostr(js, prom_val, value_buf, sizeof(value_buf));
	if (value_len >= sizeof(value_buf)) value_len = sizeof(value_buf) - 1;
	value_buf[value_len] = '\0';

	if (state == 1) {
	return (size_t)snprintf(buf, len, "Promise { %s }", value_buf);
	} else {
	return (size_t)snprintf(buf, len, "Promise { <rejected> %s }", value_buf);
	}
	}

	static jsval_t mkpromise(struct js *js) {
	jsval_t obj = mkobj(js, 0);
	if (is_err(obj)) return obj;
	setprop(js, obj, js_mkstr(js, "__state", 7), tov(0.0));
	setprop(js, obj, js_mkstr(js, "__value", 7), js_mkundef());
	setprop(js, obj, js_mkstr(js, "__handlers", 10), mkarr(js));
	return mkval(T_PROMISE, vdata(obj));
	}

	static jsval_t builtin_trigger_handler_wrapper(struct js js, jsval_t args, int nargs);

	static void trigger_handlers(struct js *js, jsval_t p) {
	jsval_t wrapper_obj = mkobj(js, 0);
	setprop(js, wrapper_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_trigger_handler_wrapper));
	setprop(js, wrapper_obj, js_mkstr(js, "promise", 7), p);
	jsval_t wrapper_fn = mkval(T_FUNC, vdata(wrapper_obj));
	queue_microtask(js, wrapper_fn);
	}

	static jsval_t builtin_trigger_handler_wrapper(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t p = js_get(js, me, "promise");
	if (vtype(p) != T_PROMISE) return js_mkundef();

	jsval_t p_obj = mkval(T_OBJ, vdata(p));
	jsoff_t state_off = lkp(js, p_obj, "__state", 7);
	int state = (int)tod(resolveprop(js, mkval(T_PROP, state_off)));

	jsoff_t val_off = lkp(js, p_obj, "__value", 7);
	jsval_t val = resolveprop(js, mkval(T_PROP, val_off));

	jsoff_t handlers_off = lkp(js, p_obj, "__handlers", 10);
	jsval_t handlers_arr = resolveprop(js, mkval(T_PROP, handlers_off));

	jsoff_t len_off = lkp(js, handlers_arr, "length", 6);
	int len = (int)tod(resolveprop(js, mkval(T_PROP, len_off)));

	for (int i = 0; i < len; i += 3) {
	char idx1[16], idx2[16], idx3[16];
	snprintf(idx1, sizeof(idx1), "%d", i);
	snprintf(idx2, sizeof(idx2), "%d", i+1);
	snprintf(idx3, sizeof(idx3), "%d", i+2);

	jsval_t onFulfilled = resolveprop(js, js_get(js, handlers_arr, idx1));
	jsval_t onRejected = resolveprop(js, js_get(js, handlers_arr, idx2));
	jsval_t nextPromise = resolveprop(js, js_get(js, handlers_arr, idx3));

	jsval_t handler = (state == 1) ? onFulfilled : 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 args[] = { val };
	res = js_call(js, handler, args, 1);
	}

	if (is_err(res)) {
	jsval_t err_str = js_mkstr(js, js->errmsg, strlen(js->errmsg));
	reject_promise(js, nextPromise, err_str);
	} else {
	resolve_promise(js, nextPromise, res);
	}
	} else {
	if (state == 1) resolve_promise(js, nextPromise, val);
	else reject_promise(js, nextPromise, val);
	}
	}
	setprop(js, p_obj, js_mkstr(js, "__handlers", 10), mkarr(js));
	return js_mkundef();
	}

	static void resolve_promise(struct js *js, jsval_t p, jsval_t val) {
	jsval_t p_obj = mkval(T_OBJ, vdata(p));
	jsoff_t state_off = lkp(js, p_obj, "__state", 7);
	if (state_off == 0) {
	return;
	}
	jsval_t state_val = resolveprop(js, mkval(T_PROP, state_off));
	if ((int)tod(state_val) != 0) {
	return;
	}

	if (vtype(val) == T_PROMISE) {
	if (vdata(val) == vdata(p)) {
	jsval_t err = js_mkerr(js, "TypeError: Chaining cycle");
	reject_promise(js, p, err);
	return;
	}
	jsval_t res_obj = mkobj(js, 0);
	setprop(js, res_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_resolve_internal));
	setprop(js, res_obj, js_mkstr(js, "promise", 7), p);
	jsval_t res_fn = mkval(T_FUNC, vdata(res_obj));

	jsval_t rej_obj = mkobj(js, 0);
	setprop(js, rej_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_reject_internal));
	setprop(js, rej_obj, js_mkstr(js, "promise", 7), p);
	jsval_t rej_fn = mkval(T_FUNC, vdata(rej_obj));

	jsval_t 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) {
	jsval_t saved_this = js->this_val;
	js->this_val = val;
	js_call(js, then_prop, args, 2);
	js->this_val = saved_this;
	return;
	}
	}

	setprop(js, p_obj, js_mkstr(js, "__state", 7), tov(1.0));
	setprop(js, p_obj, js_mkstr(js, "__value", 7), val);
	trigger_handlers(js, p);
	}

	static void reject_promise(struct js *js, jsval_t p, jsval_t val) {
	jsval_t p_obj = mkval(T_OBJ, vdata(p));
	jsoff_t state_off = lkp(js, p_obj, "__state", 7);
	if (state_off == 0) return;
	jsval_t state_val = resolveprop(js, mkval(T_PROP, state_off));
	if ((int)tod(state_val) != 0) return;

	setprop(js, p_obj, js_mkstr(js, "__state", 7), tov(2.0));
	setprop(js, p_obj, js_mkstr(js, "__value", 7), val);
	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 = js_get(js, me, "promise");
	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 = js_get(js, me, "promise");
	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_executor_wrapper(struct js js, jsval_t args, int nargs);

	static jsval_t builtin_Promise(struct js js, jsval_t args, int nargs) {
	jsval_t p = mkpromise(js);
	jsval_t res_obj = mkobj(js, 0);
	setprop(js, res_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_resolve_internal));
	setprop(js, res_obj, js_mkstr(js, "promise", 7), p);
	jsval_t res_fn = mkval(T_FUNC, vdata(res_obj));
	jsval_t rej_obj = mkobj(js, 0);
	setprop(js, rej_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_reject_internal));
	setprop(js, rej_obj, js_mkstr(js, "promise", 7), p);
	jsval_t rej_fn = mkval(T_FUNC, vdata(rej_obj));
	if (nargs > 0) {
	jsval_t wrapper_obj = mkobj(js, 0);
	setprop(js, wrapper_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_promise_executor_wrapper));
	setprop(js, wrapper_obj, js_mkstr(js, "executor", 8), args[0]);
	setprop(js, wrapper_obj, js_mkstr(js, "resolve", 7), res_fn);
	setprop(js, wrapper_obj, js_mkstr(js, "reject", 6), rej_fn);
	jsval_t wrapper_fn = mkval(T_FUNC, vdata(wrapper_obj));
	queue_microtask(js, wrapper_fn);
	}
	return p;
	}

	static jsval_t builtin_promise_executor_wrapper(struct js js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t executor = js_get(js, me, "executor");
	jsval_t res_fn = js_get(js, me, "resolve");
	jsval_t rej_fn = js_get(js, me, "reject");
	jsval_t exec_args[] = { res_fn, rej_fn };
	js_call(js, executor, exec_args, 2);
	return js_mkundef();
	}

	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 onFulfilled = nargs > 0 ? args[0] : js_mkundef();
	jsval_t onRejected = nargs > 1 ? args[1] : js_mkundef();
	jsval_t p_obj = mkval(T_OBJ, vdata(p));
	jsval_t handlers = resolveprop(js, js_get(js, p_obj, "__handlers"));
	jsval_t push_args[] = { onFulfilled, onRejected, nextP };
	jsval_t saved_this = js->this_val;
	js->this_val = handlers;
	builtin_array_push(js, push_args, 3);
	js->this_val = saved_this;
	jsoff_t state_off = lkp(js, p_obj, "__state", 7);
	int state = (int)tod(resolveprop(js, mkval(T_PROP, state_off)));
	if (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 builtin_promise_finally(struct js js, jsval_t args, int nargs) {
	jsval_t fn = nargs > 0 ? args[0] : js_mkundef();
	jsval_t args_then[] = { fn, 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 res = js_call(js, fn, NULL, 0);
	if (is_err(res)) {
	jsval_t err_str = js_mkstr(js, js->errmsg, strlen(js->errmsg));
	jsval_t rej_args[] = { err_str };
	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 = js_get(js, me, "__coroutine");
	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 = js_get(js, me, "__coroutine");

	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 = js_get(js, tracker, "promise");
	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 = js_get(js, tracker, "promise");

	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(js, arr, "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));
	setprop(js, tracker, js_mkstr(js, "promise", 7), 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);
	setprop(js, resolve_obj, js_mkstr(js, "__native_func", 13), 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);
	setprop(js, reject_obj, js_mkstr(js, "__native_func", 13), 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(js, arr, "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);
	setprop(js, resolve_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_resolve_internal));
	setprop(js, resolve_obj, js_mkstr(js, "promise", 7), result_promise);
	jsval_t resolve_fn = mkval(T_FUNC, vdata(resolve_obj));

	jsval_t reject_obj = mkobj(js, 0);
	setprop(js, reject_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_reject_internal));
	setprop(js, reject_obj, js_mkstr(js, "promise", 7), 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;
	}

	jsval_t item_obj = mkval(T_OBJ, vdata(item));
	jsoff_t state_off = lkp(js, item_obj, "__state", 7);
	int state = (int)tod(resolveprop(js, mkval(T_PROP, state_off)));

	if (state == 1) {
	jsoff_t val_off = lkp(js, item_obj, "__value", 7);
	jsval_t val = resolveprop(js, mkval(T_PROP, val_off));
	resolve_promise(js, result_promise, val);
	return result_promise;
	} else if (state == 2) {
	jsoff_t val_off = lkp(js, item_obj, "__value", 7);
	jsval_t val = resolveprop(js, mkval(T_PROP, val_off));
	reject_promise(js, result_promise, val);
	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 do_instanceof(struct js *js, jsval_t l, jsval_t r) {
	uint8_t ltype = vtype(l);

	if (vtype(r) != T_FUNC) {
	// handle legacy T_CFUNC
	if (vtype(r) == 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(js, func_obj, "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) {
	if (vtype(l) != T_STR) {
	return js_mkerr(js, "left operand of 'in' must be string");
	}

	if (vtype(r) != T_OBJ && vtype(r) != T_ARR && vtype(r) != T_FUNC) {
	return js_mkerr(js, "right operand of 'in' must be object");
	}

	jsoff_t prop_len;
	jsoff_t prop_off = vstr(js, l, &prop_len);
	const char prop_name = (char ) &js->mem[prop_off];

	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);
	return realpath(path, 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, ".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;
	}

	cleanup_ext:
	free(base_ext);
	cleanup:
	free(base_copy);
	return result;
	}

	static bool esm_is_json(const char *path) {
	size_t len = strlen(path);
	return len > 5 && strcmp(path + len - 5, ".json") == 0;
	}

	static bool esm_is_text(const char *path) {
	size_t len = strlen(path);
	return (len > 4 && strcmp(path + len - 4, ".txt") == 0) \|\|
	(len > 3 && strcmp(path + len - 3, ".md") == 0) \|\|
	(len > 5 && strcmp(path + len - 5, ".html") == 0) \|\|
	(len > 4 && strcmp(path + len - 4, ".css") == 0);
	}

	static bool esm_is_image(const char *path) {
	size_t len = strlen(path);
	return (len > 4 && strcmp(path + len - 4, ".png") == 0) \|\|
	(len > 4 && strcmp(path + len - 4, ".jpg") == 0) \|\|
	(len > 5 && strcmp(path + len - 5, ".jpeg") == 0) \|\|
	(len > 4 && strcmp(path + len - 4, ".gif") == 0) \|\|
	(len > 4 && strcmp(path + len - 4, ".svg") == 0) \|\|
	(len > 5 && strcmp(path + len - 5, ".webp") == 0);
	}

	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) {
	char *canonical_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->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);
	free(current);
	}
	global_module_cache.count = 0;
	}

	static jsval_t esm_load_json(struct js js, const char path) {
	FILE *fp = fopen(path, "rb");
	if (!fp) return js_mkerr(js, "Cannot open JSON file: %s", path);

	fseek(fp, 0, SEEK_END);
	long size = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	char content = (char )malloc(size + 1);
	if (!content) {
	fclose(fp);
	return js_mkerr(js, "OOM loading JSON");
	}

	fread(content, 1, size, fp);
	fclose(fp);
	content[size] = '\0';

	jsval_t result = js_eval(js, content, size);
	free(content);

	return result;
	}

	static jsval_t esm_load_text(struct js js, const char path) {
	FILE *fp = fopen(path, "rb");
	if (!fp) return js_mkerr(js, "Cannot open text file: %s", path);

	fseek(fp, 0, SEEK_END);
	long size = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	char content = (char )malloc(size + 1);
	if (!content) {
	fclose(fp);
	return js_mkerr(js, "OOM loading text");
	}

	fread(content, 1, size, fp);
	fclose(fp);
	content[size] = '\0';

	jsval_t result = js_mkstr(js, content, size);
	free(content);

	return result;
	}

	static jsval_t esm_load_image(struct js js, const char path) {
	FILE *fp = fopen(path, "rb");
	if (!fp) return js_mkerr(js, "Cannot open image file: %s", path);

	fseek(fp, 0, SEEK_END);
	long size = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	unsigned char content = (unsigned char )malloc(size);
	if (!content) {
	fclose(fp);
	return js_mkerr(js, "OOM loading image");
	}

	fread(content, 1, size, fp);
	fclose(fp);

	jsval_t obj = mkobj(js, 0);
	jsval_t data_arr = mkarr(js);

	for (long i = 0; i < size; i++) {
	char idx[16];
	snprintf(idx, sizeof(idx), "%ld", 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(content);
	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;
	}

	jsval_t ns = mkobj(js, 0);
	setprop(js, ns, js_mkstr(js, "default", 7), json_val);
	mod->namespace_obj = ns;
	mod->default_export = json_val;
	mod->is_loaded = true;
	mod->is_loading = false;
	return ns;
	}

	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;
	}

	jsval_t ns = mkobj(js, 0);
	setprop(js, ns, js_mkstr(js, "default", 7), text_val);
	mod->namespace_obj = ns;
	mod->default_export = text_val;
	mod->is_loaded = true;
	mod->is_loading = false;
	return ns;
	}

	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;
	}

	jsval_t ns = mkobj(js, 0);
	setprop(js, ns, js_mkstr(js, "default", 7), img_val);
	mod->namespace_obj = ns;
	mod->default_export = img_val;
	mod->is_loaded = true;
	mod->is_loading = false;
	return ns;
	}

	FILE *fp = fopen(mod->resolved_path, "rb");
	if (!fp) {
	mod->is_loading = false;
	return js_mkerr(js, "Cannot open module: %s", mod->resolved_path);
	}

	fseek(fp, 0, SEEK_END);
	long size = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	char content = (char )malloc(size + 1);
	if (!content) {
	fclose(fp);
	mod->is_loading = false;
	return js_mkerr(js, "OOM loading module");
	}

	fread(content, 1, size, fp);
	fclose(fp);
	content[size] = '\0';

	jsval_t ns = mkobj(js, 0);
	mod->namespace_obj = ns;

	jsval_t glob = js_glob(js);
	jsval_t module_scope = js_get(js, glob, "__esm_module_scope");
	jsval_t prev_module = module_scope;
	js_set(js, glob, "__esm_module_scope", ns);

	const char *prev_filename = js->filename;
	jsval_t saved_scope = js->scope;

	js_set_filename(js, mod->resolved_path);
	mkscope(js);

	jsval_t result = js_eval(js, content, size);

	free(content);

	js->scope = saved_scope;
	js_set_filename(js, prev_filename);
	js_set(js, glob, "__esm_module_scope", prev_module);

	if (is_err(result)) {
	mod->is_loading = false;
	return result;
	}

	jsoff_t default_off = lkp(js, ns, "default", 7);
	if (default_off != 0) {
	mod->default_export = resolveprop(js, mkval(T_PROP, default_off));
	}

	mod->is_loaded = true;
	mod->is_loading = false;

	return ns;
	}

	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;
	jsoff_t spec_off = vstr(js, args[0], &spec_len);
	const char specifier = (char )&js->mem[spec_off];

	ant_library_t *lib = find_library(specifier, spec_len);
	if (lib) {
	jsval_t lib_obj = lib->init_fn(js);
	if (is_err(lib_obj)) return builtin_Promise_reject(js, &lib_obj, 1);
	jsval_t promise_args[] = { lib_obj };
	return builtin_Promise_resolve(js, promise_args, 1);
	}

	const char *base_path = js->filename ? js->filename : ".";
	char *resolved_path = esm_resolve_path(specifier, base_path);
	if (!resolved_path) {
	return js_mkerr(js, "Cannot resolve module: %.*s", (int)spec_len, specifier);
	}

	esm_module_t *mod = esm_find_module(resolved_path);
	if (!mod) {
	mod = esm_create_module(specifier, resolved_path);
	if (!mod) {
	free(resolved_path);
	return js_mkerr(js, "Cannot create module");
	}
	}

	jsval_t ns = esm_load_module(js, mod);
	free(resolved_path);

	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");
	}

	jsoff_t spec_len;
	jsoff_t spec_off = vstr(js, args[0], &spec_len);
	const char specifier = (char )&js->mem[spec_off];

	const char *base_path = js->filename ? js->filename : ".";
	char *resolved_path = esm_resolve_path(specifier, base_path);
	if (!resolved_path) {
	return js_mkerr(js, "Cannot resolve module: %.*s", (int)spec_len, specifier);
	}

	size_t url_len = strlen(resolved_path) + 8;
	char *url = malloc(url_len);
	if (!url) {
	free(resolved_path);
	return js_mkerr(js, "oom");
	}

	snprintf(url, url_len, "file://%s", resolved_path);
	free(resolved_path);

	jsval_t result = js_mkstr(js, url, strlen(url));
	free(url);

	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;

	size_t url_len = strlen(filename) + 8;
	char *url = malloc(url_len);
	if (url) {
	snprintf(url, url_len, "file://%s", filename);
	jsval_t url_val = js_mkstr(js, url, strlen(url));
	if (!is_err(url_val)) setprop(js, import_meta, js_mkstr(js, "url", 3), url_val);
	free(url);
	}

	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);

	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;
	jsoff_t spec_off = vstr(js, spec, &spec_len);
	const char specifier = (char )&js->mem[spec_off];

	jsval_t ns = js_mkundef();
	ant_library_t *lib = find_library(specifier, spec_len);
	if (lib) {
	ns = lib->init_fn(js);
	} else {
	const char *base_path = js->filename ? js->filename : ".";
	char *resolved_path = esm_resolve_path(specifier, base_path);
	if (!resolved_path) {
	return js_mkerr(js, "Cannot resolve module: %.*s", (int)spec_len, specifier);
	}

	esm_module_t *mod = esm_find_module(resolved_path);
	if (!mod) {
	mod = esm_create_module(specifier, resolved_path);
	if (!mod) {
	free(resolved_path);
	return js_mkerr(js, "Cannot create module");
	}
	}

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	jsoff_t saved_pos = js->pos;

	ns = esm_load_module(js, mod);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;

	free(resolved_path);
	}

	js->consumed = 1; next(js); js->consumed = 0;
	if (is_err(ns)) return ns;

	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;

	EXPECT(TOK_FROM, );
	EXPECT(TOK_STRING, );

	jsval_t spec = js_str_literal(js);

	jsoff_t spec_len;
	jsoff_t spec_off = vstr(js, spec, &spec_len);
	const char specifier = (char )&js->mem[spec_off];

	jsval_t ns = js_mkundef();
	ant_library_t *lib = find_library(specifier, spec_len);
	if (lib) {
	ns = lib->init_fn(js);
	} else {
	const char *base_path = js->filename ? js->filename : ".";
	char *resolved_path = esm_resolve_path(specifier, base_path);
	if (!resolved_path) {
	return js_mkerr(js, "Cannot resolve module: %.*s", (int)spec_len, specifier);
	}

	esm_module_t *mod = esm_find_module(resolved_path);
	if (!mod) {
	mod = esm_create_module(specifier, resolved_path);
	if (!mod) {
	free(resolved_path);
	return js_mkerr(js, "Cannot create module");
	}
	}

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	jsoff_t saved_pos = js->pos;

	ns = esm_load_module(js, mod);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;

	free(resolved_path);
	}

	js->consumed = 1; next(js); js->consumed = 0;
	if (is_err(ns)) return ns;

	jsoff_t default_off = lkp(js, ns, "default", 7);
	jsval_t default_val = default_off != 0 ? resolveprop(js, mkval(T_PROP, default_off)) : js_mkundef();

	setprop(js, js->scope, js_mkstr(js, default_name, default_len), default_val);
	return js_mkundef();
	}

	if (next(js) == TOK_LBRACE) {
	js->consumed = 1;

	typedef struct {
	const char *import_name;
	size_t import_len;
	const char *local_name;
	size_t local_len;
	} import_binding_t;

	import_binding_t bindings[64];
	int binding_count = 0;

	while (next(js) != TOK_RBRACE && binding_count < 64) {
	EXPECT(TOK_IDENTIFIER, );
	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;
	EXPECT(TOK_IDENTIFIER, );
	local_name = &js->code[js->toff];
	local_len = js->tlen;
	js->consumed = 1;
	}

	bindings[binding_count].import_name = import_name;
	bindings[binding_count].import_len = import_len;
	bindings[binding_count].local_name = local_name;
	bindings[binding_count].local_len = local_len;
	binding_count++;

	if (next(js) == TOK_COMMA) js->consumed = 1;
	}

	EXPECT(TOK_RBRACE, );
	EXPECT(TOK_FROM, );
	EXPECT(TOK_STRING, );

	jsval_t spec = js_str_literal(js);
	jsoff_t spec_len;

	jsoff_t spec_off = vstr(js, spec, &spec_len);
	const char specifier = (char )&js->mem[spec_off];

	jsval_t ns = js_mkundef();
	ant_library_t *lib = find_library(specifier, spec_len);
	if (lib) {
	ns = lib->init_fn(js);
	} else {
	const char *base_path = js->filename ? js->filename : ".";
	char *resolved_path = esm_resolve_path(specifier, base_path);
	if (!resolved_path) return js_mkerr(js, "Cannot resolve module: %.*s", (int)spec_len, specifier);

	esm_module_t *mod = esm_find_module(resolved_path);
	if (!mod) {
	mod = esm_create_module(specifier, resolved_path);
	if (!mod) {
	free(resolved_path);
	return js_mkerr(js, "Cannot create module");
	}
	}

	const char *saved_code = js->code;
	jsoff_t saved_clen = js->clen;
	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;
	jsval_t saved_scope = js->scope;

	ns = esm_load_module(js, mod);

	js->code = saved_code;
	js->clen = saved_clen;
	js->pos = saved_pos;
	js->tok = saved_tok;
	js->consumed = saved_consumed;
	js->toff = saved_toff;
	js->tlen = saved_tlen;
	js->scope = saved_scope;

	free(resolved_path);
	}

	js->consumed = 1;
	next(js);
	js->consumed = 0;

	if (is_err(ns)) return ns;

	for (int i = 0; i < binding_count; i++) {
	jsoff_t prop_off = lkp(js, ns, bindings[i].import_name, bindings[i].import_len);
	jsval_t imported_val = prop_off != 0 ? resolveprop(js, mkval(T_PROP, prop_off)) : js_mkundef();

	setprop(js, js->scope, js_mkstr(js, bindings[i].local_name, bindings[i].local_len), imported_val);
	}

	return js_mkundef();
	}

	return js_mkerr(js, "Invalid import statement");
	}

	static jsval_t js_export_stmt(struct js *js) {
	js->consumed = 1;

	jsval_t glob = js_glob(js);
	jsval_t module_ns = js_get(js, glob, "__esm_module_scope");

	if (vtype(module_ns) != T_OBJ) {
	module_ns = mkobj(js, 0);
	js_set(js, glob, "__esm_module_scope", module_ns);
	}

	if (next(js) == TOK_DEFAULT) {
	js->consumed = 1;
	jsval_t value = js_assignment(js);
	if (is_err(value)) return value;

	setprop(js, module_ns, js_mkstr(js, "default", 7), resolveprop(js, value));
	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);
	setprop(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, 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, module_ns, name_val, cls);
	}
	}

	return cls;
	}

	if (next(js) == TOK_LBRACE) {
	js->consumed = 1;

	while (next(js) != TOK_RBRACE) {
	EXPECT(TOK_IDENTIFIER, );
	const char *local_name = &js->code[js->toff];
	size_t local_len = js->tlen;
	js->consumed = 1;

	const char *export_name = local_name;
	size_t export_len = local_len;

	if (next(js) == TOK_AS) {
	js->consumed = 1;
	EXPECT(TOK_IDENTIFIER, );
	export_name = &js->code[js->toff];
	export_len = js->tlen;
	js->consumed = 1;
	}

	jsval_t local_val = lookup(js, local_name, local_len);
	if (is_err(local_val)) return local_val;

	setprop(js, module_ns, js_mkstr(js, export_name, export_len), resolveprop(js, local_val));
	if (next(js) == TOK_COMMA) js->consumed = 1;
	}

	EXPECT(TOK_RBRACE, );
	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_GC_MALLOC(sizeof(map_entry_t *));
	if (!map_head) return js_mkerr(js, "out of memory");
	*map_head = NULL;

	jsval_t map_ptr = mkval(T_NUM, (size_t)map_head);
	jsval_t map_key = js_mkstr(js, "__map", 5);
	setprop(js, map_obj, map_key, 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_GC_MALLOC(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_GC_MALLOC(sizeof(set_entry_t *));
	if (!set_head) return js_mkerr(js, "out of memory");
	*set_head = NULL;

	jsval_t set_ptr = mkval(T_NUM, (size_t)set_head);
	jsval_t set_key = js_mkstr(js, "__set", 5);
	setprop(js, set_obj, set_key, 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_GC_MALLOC(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) {
	jsoff_t map_off = lkp(js, obj, "__map", 5);
	if (map_off == 0) return NULL;
	jsval_t map_val = resolveprop(js, mkval(T_PROP, map_off));
	if (vtype(map_val) != T_NUM) return NULL;
	return (map_entry_t**)(size_t)vdata(map_val);
	}

	static set_entry_t** get_set_from_obj(struct js *js, jsval_t obj) {
	jsoff_t set_off = lkp(js, obj, "__set", 5);
	if (set_off == 0) return NULL;
	jsval_t set_val = resolveprop(js, mkval(T_PROP, set_off));
	if (vtype(set_val) != T_NUM) return NULL;
	return (set_entry_t**)(size_t)vdata(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_GC_MALLOC(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);
	ANT_GC_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);
	ANT_GC_FREE(entry);
	}
	*map_ptr = NULL;

	return js_mkundef();
	}

	static jsval_t map_size(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 tov(0);

	size_t count = HASH_COUNT(*map_ptr);
	return tov((double)count);
	}

	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_GC_MALLOC(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);
	ANT_GC_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);
	ANT_GC_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_GC_MALLOC(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_GC_MALLOC(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_GC_MALLOC(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_GC_MALLOC(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 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_GC_MALLOC(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);
	ANT_GC_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_GC_MALLOC(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);
	ANT_GC_FREE(entry);
	return mkval(T_BOOL, 1);
	}
	return mkval(T_BOOL, 0);
	}

	struct js js_create(void buf, size_t len) {
	ANT_GC_INIT();
	init_free_list();

	struct js *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->lwm = js->size;
	js->gct = js->size / 2;
	js->this_val = js->scope;
	js->errmsg_size = 4096;
	js->errmsg = (char *)malloc(js->errmsg_size);
	if (js->errmsg) js->errmsg[0] = '\0';

	jsval_t glob = js->scope;
	jsval_t object_proto = js_mkobj(js);
	setprop(js, object_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_object_toString));
	setprop(js, object_proto, js_mkstr(js, "hasOwnProperty", 14), js_mkfun(builtin_object_hasOwnProperty));

	jsval_t function_proto = js_mkobj(js);
	set_proto(js, function_proto, object_proto);
	setprop(js, function_proto, js_mkstr(js, "call", 4), js_mkfun(builtin_function_call));
	setprop(js, function_proto, js_mkstr(js, "apply", 5), js_mkfun(builtin_function_apply));
	setprop(js, function_proto, js_mkstr(js, "bind", 4), js_mkfun(builtin_function_bind));

	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));

	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, "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, "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, "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, "trim", 4), js_mkfun(builtin_string_trim));
	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));

	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));

	jsval_t boolean_proto = js_mkobj(js);
	set_proto(js, boolean_proto, object_proto);

	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, js_mkstr(js, "name", 4), js_mkstr(js, "Error", 5));
	setprop(js, error_proto, js_mkstr(js, "message", 7), js_mkstr(js, "", 0));

	jsval_t evalerror_proto = js_mkobj(js);
	set_proto(js, evalerror_proto, error_proto);
	setprop(js, evalerror_proto, js_mkstr(js, "name", 4), js_mkstr(js, "EvalError", 9));

	jsval_t rangeerror_proto = js_mkobj(js);
	set_proto(js, rangeerror_proto, error_proto);
	setprop(js, rangeerror_proto, js_mkstr(js, "name", 4), js_mkstr(js, "RangeError", 10));

	jsval_t referenceerror_proto = js_mkobj(js);
	set_proto(js, referenceerror_proto, error_proto);
	setprop(js, referenceerror_proto, js_mkstr(js, "name", 4), js_mkstr(js, "ReferenceError", 14));

	jsval_t syntaxerror_proto = js_mkobj(js);
	set_proto(js, syntaxerror_proto, error_proto);
	setprop(js, syntaxerror_proto, js_mkstr(js, "name", 4), js_mkstr(js, "SyntaxError", 11));

	jsval_t typeerror_proto = js_mkobj(js);
	set_proto(js, typeerror_proto, error_proto);
	setprop(js, typeerror_proto, js_mkstr(js, "name", 4), js_mkstr(js, "TypeError", 9));

	jsval_t urierror_proto = js_mkobj(js);
	set_proto(js, urierror_proto, error_proto);
	setprop(js, urierror_proto, js_mkstr(js, "name", 4), js_mkstr(js, "URIError", 8));

	jsval_t internalerror_proto = js_mkobj(js);
	set_proto(js, internalerror_proto, error_proto);
	setprop(js, internalerror_proto, js_mkstr(js, "name", 4), js_mkstr(js, "InternalError", 13));

	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, "toISOString", 11), js_mkfun(builtin_Date_toISOString));
	setprop(js, date_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_Date_toString));

	jsval_t regexp_proto = js_mkobj(js);
	set_proto(js, regexp_proto, object_proto);

	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, "@@toStringTag", 13), js_mkstr(js, "Map", 3));

	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, "@@toStringTag", 13), js_mkstr(js, "Set", 3));

	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 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);
	setprop(js, obj_func_obj, js_mkstr(js, "__code", 6), js_mkstr(js, "__builtin_Object", 16));
	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, "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, "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);
	setprop(js, func_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_Function));
	setprop(js, func_ctor_obj, js_mkstr(js, "prototype", 9), function_proto);
	setprop(js, glob, js_mkstr(js, "Function", 8), mkval(T_FUNC, vdata(func_ctor_obj)));

	jsval_t str_ctor_obj = mkobj(js, 0);
	set_proto(js, str_ctor_obj, function_proto);
	setprop(js, str_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_String));
	setprop(js, str_ctor_obj, js_mkstr(js, "prototype", 9), string_proto);
	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);

	setprop(js, number_ctor_obj, js_mkstr(js, "__native_func", 13), 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(INFINITY));
	setprop(js, number_ctor_obj, js_mkstr(js, "NEGATIVE_INFINITY", 17), tov(-INFINITY));
	setprop(js, number_ctor_obj, js_mkstr(js, "NaN", 3), tov(NAN));
	setprop(js, number_ctor_obj, js_mkstr(js, "EPSILON", 7), tov(2.220446049250313e-16));

	setprop(js, number_ctor_obj, js_mkstr(js, "prototype", 9), number_proto);
	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);
	setprop(js, bool_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_Boolean));
	setprop(js, bool_ctor_obj, js_mkstr(js, "prototype", 9), boolean_proto);
	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);
	setprop(js, arr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_Array));
	setprop(js, arr_ctor_obj, js_mkstr(js, "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, 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);
	setprop(js, map_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_Map));
	setprop(js, map_ctor_obj, js_mkstr(js, "prototype", 9), map_proto);
	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);
	setprop(js, set_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_Set));
	setprop(js, set_ctor_obj, js_mkstr(js, "prototype", 9), set_proto_obj);
	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);
	setprop(js, weakmap_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_WeakMap));
	setprop(js, weakmap_ctor_obj, js_mkstr(js, "prototype", 9), weakmap_proto);
	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);
	setprop(js, weakset_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_WeakSet));
	setprop(js, weakset_ctor_obj, js_mkstr(js, "prototype", 9), weakset_proto);
	setprop(js, glob, js_mkstr(js, "WeakSet", 7), mkval(T_FUNC, vdata(weakset_ctor_obj)));

	jsval_t err_ctor_obj = mkobj(js, 0);
	set_proto(js, err_ctor_obj, function_proto);
	setprop(js, err_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_Error));
	setprop(js, err_ctor_obj, js_mkstr(js, "prototype", 9), error_proto);
	setprop(js, glob, js_mkstr(js, "Error", 5), mkval(T_FUNC, vdata(err_ctor_obj)));

	jsval_t evalerr_ctor_obj = mkobj(js, 0);
	set_proto(js, evalerr_ctor_obj, function_proto);
	setprop(js, evalerr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_EvalError));
	setprop(js, evalerr_ctor_obj, js_mkstr(js, "prototype", 9), evalerror_proto);
	setprop(js, glob, js_mkstr(js, "EvalError", 9), mkval(T_FUNC, vdata(evalerr_ctor_obj)));

	jsval_t rangeerr_ctor_obj = mkobj(js, 0);
	set_proto(js, rangeerr_ctor_obj, function_proto);
	setprop(js, rangeerr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_RangeError));
	setprop(js, rangeerr_ctor_obj, js_mkstr(js, "prototype", 9), rangeerror_proto);
	setprop(js, glob, js_mkstr(js, "RangeError", 10), mkval(T_FUNC, vdata(rangeerr_ctor_obj)));

	jsval_t referr_ctor_obj = mkobj(js, 0);
	set_proto(js, referr_ctor_obj, function_proto);
	setprop(js, referr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_ReferenceError));
	setprop(js, referr_ctor_obj, js_mkstr(js, "prototype", 9), referenceerror_proto);
	setprop(js, glob, js_mkstr(js, "ReferenceError", 14), mkval(T_FUNC, vdata(referr_ctor_obj)));

	jsval_t syntaxerr_ctor_obj = mkobj(js, 0);
	set_proto(js, syntaxerr_ctor_obj, function_proto);
	setprop(js, syntaxerr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_SyntaxError));
	setprop(js, syntaxerr_ctor_obj, js_mkstr(js, "prototype", 9), syntaxerror_proto);
	setprop(js, glob, js_mkstr(js, "SyntaxError", 11), mkval(T_FUNC, vdata(syntaxerr_ctor_obj)));

	jsval_t typeerr_ctor_obj = mkobj(js, 0);
	set_proto(js, typeerr_ctor_obj, function_proto);
	setprop(js, typeerr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_TypeError));
	setprop(js, typeerr_ctor_obj, js_mkstr(js, "prototype", 9), typeerror_proto);
	setprop(js, glob, js_mkstr(js, "TypeError", 9), mkval(T_FUNC, vdata(typeerr_ctor_obj)));

	jsval_t urierr_ctor_obj = mkobj(js, 0);
	set_proto(js, urierr_ctor_obj, function_proto);
	setprop(js, urierr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_URIError));
	setprop(js, urierr_ctor_obj, js_mkstr(js, "prototype", 9), urierror_proto);
	setprop(js, glob, js_mkstr(js, "URIError", 8), mkval(T_FUNC, vdata(urierr_ctor_obj)));

	jsval_t internerr_ctor_obj = mkobj(js, 0);
	set_proto(js, internerr_ctor_obj, function_proto);
	setprop(js, internerr_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_InternalError));
	setprop(js, internerr_ctor_obj, js_mkstr(js, "prototype", 9), internalerror_proto);
	setprop(js, glob, js_mkstr(js, "InternalError", 13), mkval(T_FUNC, vdata(internerr_ctor_obj)));

	jsval_t regex_ctor_obj = mkobj(js, 0);
	set_proto(js, regex_ctor_obj, function_proto);
	setprop(js, regex_ctor_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_RegExp));
	setprop(js, regex_ctor_obj, js_mkstr(js, "prototype", 9), regexp_proto);
	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);
	setprop(js, date_ctor_obj, js_mkstr(js, "__native_func", 13), 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, "prototype", 9), date_proto);
	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);
	setprop(js, p_ctor_obj, js_mkstr(js, "__native_func", 13), 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, "prototype", 9), promise_proto);
	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);
	setprop(js, bigint_ctor_obj, js_mkstr(js, "__native_func", 13), 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));
	setprop(js, bigint_ctor_obj, js_mkstr(js, "prototype", 9), bigint_proto);
	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(NAN));
	setprop(js, glob, js_mkstr(js, "Infinity", 8), tov(INFINITY));

	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);

	setprop(js, import_obj, js_mkstr(js, "__native_func", 13), js_mkfun(builtin_import));
	setprop(js, glob, js_mkstr(js, "import", 6), mkval(T_FUNC, vdata(import_obj)));
	setprop(js, glob, js_mkstr(js, "__esm_module_scope", 18), js_mkundef());

	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 = 1024 * 1024;
	if (max_size == 0 \|\| max_size < initial_size) max_size = 512 * 1024 * 1024;

	void *buf = ANT_GC_MALLOC(initial_size);
	if (buf == NULL) return NULL;

	struct js *js = js_create(buf, initial_size);
	if (js == NULL) {
	ANT_GC_FREE(buf);
	return NULL;
	}

	js->owns_mem = true;
	js->max_size = (jsoff_t) max_size;

	return js;
	}

	void js_destroy(struct js *js) {
	if (js == NULL) return;
	esm_cleanup_module_cache();

	if (js->errmsg) {
	free(js->errmsg);
	js->errmsg = NULL;
	}

	if (js->owns_mem) {
	ANT_GC_FREE((void )((uint8_t )js - 0));
	}
	}

	double js_getnum(jsval_t value) { return tod(value); }
	int js_getbool(jsval_t value) { return vdata(value) & 1 ? 1 : 0; }

	void js_setgct(struct js *js, size_t gct) { js->gct = (jsoff_t) gct; }
	void js_setmaxcss(struct js *js, size_t max) { js->maxcss = (jsoff_t) max; }
	void js_set_filename(struct js js, const char filename) { js->filename = filename; }

	jsval_t js_mktrue(void) { return mkval(T_BOOL, 1); }
	jsval_t js_mkfalse(void) { return mkval(T_BOOL, 0); }
	jsval_t js_mkundef(void) { return mkval(T_UNDEF, 0); }
	jsval_t js_mknull(void) { return mkval(T_NULL, 0); }
	jsval_t js_mknum(double value) { return tov(value); }
	jsval_t js_mkobj(struct js *js) { return mkobj(js, 0); }
	jsval_t js_glob(struct js *js) { (void) js; return mkval(T_OBJ, 0); }
	jsval_t js_mkfun(jsval_t (fn)(struct js , jsval_t , int)) { return mkval(T_CFUNC, (size_t) (void ) fn); }
	jsval_t js_getthis(struct js *js) { return js->this_val; }
	jsval_t js_getcurrentfunc(struct js *js) { return js->current_func; }

	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)) {
	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, false);
	}
	} 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)) {
	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, 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));
	}

	if (vtype(obj) == T_PROMISE) {
	jsval_t prom_obj = mkval(T_OBJ, vdata(obj));
	jsoff_t off = lkp(js, prom_obj, key, key_len);
	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(js, promise_proto, key, key_len);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	}
	return js_mkundef();
	}

	if (vtype(obj) != 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;
	}

	return off == 0 ? js_mkundef() : resolveprop(js, mkval(T_PROP, off));
	}

	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 \| CONSTMASK);
	while (next < js->brk && next != 0) {
	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));
	jsoff_t klen = offtolen(loadoff(js, koff));

	char key = (char ) &js->mem[koff + sizeof(koff)];
	setprop(js, dst, js_mkstr(js, key, klen), val);
	next = loadoff(js, next) & ~(3U \| CONSTMASK);
	}
	}

	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_OBJ:
	case T_ARR: return JS_OBJ;
	case T_FUNC: return JS_FUNC;
	default: return JS_PRIV;
	}
	}

	void js_stats(struct js js, size_t total, size_t lwm, size_t css) {
	if (total) *total = js->size;
	if (lwm) *lwm = js->lwm;
	if (css) *css = js->css;
	}

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

	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;
	}

	jsval_t js_eval(struct js js, const char buf, size_t len) {
	jsval_t res = js_mkundef();
	if (len == (size_t) ~0U) len = strlen(buf);
	js->consumed = 1;
	js->tok = TOK_ERR;
	js->code = buf;
	js->clen = (jsoff_t) len;
	js->pos = 0;
	js->cstk = &res;

	uint8_t saved_tok = js->tok;
	jsoff_t saved_pos = js->pos;
	uint8_t saved_consumed = js->consumed;
	js->consumed = 1;

	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;
	}
	}

	js->tok = saved_tok;
	js->pos = saved_pos;
	js->consumed = saved_consumed;

	while (next(js) != TOK_EOF && !is_err(res)) {
	res = js_stmt(js);
	if (js->flags & F_RETURN) break;
	}
	return res;
	}

	jsval_t js_call(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);
	} else if (vtype(func) == T_FUNC) {
	jsval_t func_obj = mkval(T_OBJ, vdata(func));
	jsoff_t native_off = lkp(js, func_obj, "__native_func", 13);
	if (native_off != 0) {
	jsval_t native_val = resolveprop(js, mkval(T_PROP, native_off));
	if (vtype(native_val) == T_CFUNC) {
	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(native_val);
	jsval_t res = fn(js, args, nargs);
	js->current_func = saved_func;
	return res;
	}
	}
	jsoff_t code_off = lkp(js, func_obj, "__code", 6);

	if (code_off == 0) return js_mkerr(js, "function has no code");
	jsval_t code_val = resolveprop(js, mkval(T_PROP, code_off));
	if (vtype(code_val) != T_STR) return js_mkerr(js, "function code not string");
	jsoff_t fnlen, fnoff = vstr(js, code_val, &fnlen);
	const char fn = (const char ) (&js->mem[fnoff]);

	jsoff_t async_off = lkp(js, func_obj, "__async", 7);
	bool is_async = false;
	if (async_off != 0) {
	jsval_t async_val = resolveprop(js, mkval(T_PROP, async_off));
	is_async = vtype(async_val) == T_BOOL && vdata(async_val) == 1;
	}

	if (is_async) {
	jsval_t closure_scope = js_mkundef();
	jsoff_t scope_off = lkp(js, func_obj, "__scope", 7);
	if (scope_off != 0) {
	closure_scope = resolveprop(js, mkval(T_PROP, scope_off));
	}
	return start_async_in_coroutine(js, fn, fnlen, closure_scope, args, nargs);
	}

	jsoff_t fnpos = 1;

	jsval_t saved_scope = js->scope;
	jsoff_t scope_off = lkp(js, func_obj, "__scope", 7);
	if (scope_off != 0) {
	jsval_t closure_scope = resolveprop(js, mkval(T_PROP, scope_off));
	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;
	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);
	if (tok != TOK_IDENTIFIER) break;

	if (is_rest) {
	rest_param_start = fnpos;
	rest_param_len = identlen;
	fnpos = skiptonext(fn, fnlen, fnpos + identlen, NULL);
	break;
	}

	jsval_t v = arg_idx < nargs ? args[arg_idx] : js_mkundef();
	setprop(js, js->scope, js_mkstr(js, &fn[fnpos], identlen), v);
	arg_idx++;
	fnpos = skiptonext(fn, fnlen, fnpos + identlen, NULL);
	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];
	snprintf(idxstr, sizeof(idxstr), "%u", (unsigned) idx);
	jsval_t key = js_mkstr(js, idxstr, strlen(idxstr));
	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, js->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 && fn[fnpos] == '{') fnpos++;
	size_t body_len = fnlen - fnpos - 1;

	jsval_t saved_this = js->this_val;
	js->this_val = js_glob(js);

	js->flags = F_CALL;
	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;
	delscope(js);
	js->scope = saved_scope;

	return res;
	}
	return js_mkerr(js, "not a function");
	}

	js_prop_iter_t js_prop_iter_begin(struct js *js, jsval_t obj) {
	js_prop_iter_t iter = {0};
	iter.obj = obj;
	iter.js_internal = (void *)js;

	if (vtype(obj) == T_OBJ \|\| vtype(obj) == T_ARR \|\| vtype(obj) == T_FUNC) {
	jsval_t check_obj = (vtype(obj) == T_FUNC) ? mkval(T_OBJ, vdata(obj)) : obj;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(check_obj)) & ~(3U \| CONSTMASK);
	iter.current = (void *)(uintptr_t)next;
	}

	return iter;
	}

	bool js_prop_iter_next(js_prop_iter_t iter, const char key, size_t key_len, jsval_t *value) {
	if (!iter \|\| !iter->js_internal) return false;

	struct js js = (struct js )iter->js_internal;
	jsoff_t next = (jsoff_t)(uintptr_t)iter->current;

	if (next >= js->brk \|\| next == 0) return false;

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	if (key) {
	jsoff_t klen = offtolen(loadoff(js, koff));
	key = (const char ) &js->mem[koff + sizeof(koff)];
	if (key_len) *key_len = klen;
	}

	if (value) *value = val;

	iter->current = (void *)(uintptr_t)(loadoff(js, next) & ~(3U \| CONSTMASK));
	return true;
	}

	void js_prop_iter_end(js_prop_iter_t *iter) {
	if (iter) {
	iter->current = NULL;
	iter->js_internal = 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); }

	#ifdef JS_DUMP
	void js_dump(struct js *js) {
	jsoff_t off = 0, v;
	printf("JS size %u, brk %u, lwm %u, css %u, nogc %u\n", js->size, js->brk, js->lwm, (unsigned) js->css, js->nogc);
	while (off < js->brk) {
	memcpy(&v, &js->mem[off], sizeof(v));
	printf(" %5u: ", off);
	jsoff_t cleaned = v & ~(GCMASK \| CONSTMASK);
	if ((cleaned & 3U) == T_OBJ) {
	printf("OBJ %u %u%s\n", cleaned & ~3U, loadoff(js, (jsoff_t) (off + sizeof(off))), (v & CONSTMASK) ? " [CONST]" : "");
	} else if ((cleaned & 3U) == T_PROP) {
	jsoff_t koff = loadoff(js, (jsoff_t) (off + sizeof(v)));
	jsval_t val = loadval(js, (jsoff_t) (off + sizeof(v) + sizeof(v)));
	printf("PROP next %u, koff %u vtype %d vdata %lu%s\n", cleaned & ~3U, koff, vtype(val), (unsigned long) vdata(val), (v & CONSTMASK) ? " [CONST]" : "");
	} else if ((cleaned & 3) == T_STR) {
	jsoff_t len = offtolen(cleaned);
	printf("STR %u [%.*s]\n", len, (int) len, js->mem + off + sizeof(v));
	} else {
	printf("???\n");
	break;
	}
	off += esize(v & ~(GCMASK \| CONSTMASK));
	}
	}
	#endif

	void js_set_getter(struct js *js, jsval_t obj, js_getter_fn getter) {
	if (vtype(obj) != T_OBJ) return;
	jsval_t getter_val = mkval(T_CFUNC, (size_t)(void *)getter);
	js_set(js, obj, "__getter", getter_val);
	}

	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->filename) {
	fprintf(stream, "%s:%d:%d", frame->filename, frame->line, frame->col);
	} else fprintf(stream, "<unknown>");

	fprintf(stream, "\x1b[0m)\n");
	}
	}
	}

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