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

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

	#include "ant.h"
	#include "gc.h"
	#include "utf8.h"
	#include "debug.h"
	#include "tokens.h"
	#include "common.h"
	#include "arena.h"
	#include "utils.h"
	#include "base64.h"
	#include "runtime.h"
	#include "internal.h"
	#include "sugar.h"
	#include "errors.h"
	#include "descriptors.h"

	#include "esm/remote.h"
	#include "esm/loader.h"

	#include "silver/lexer.h"
	#include "silver/compiler.h"
	#include "silver/engine.h"

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

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

	#include "modules/fs.h"
	#include "modules/timer.h"
	#include "modules/fetch.h"
	#include "modules/symbol.h"
	#include "modules/ffi.h"
	#include "modules/child_process.h"
	#include "modules/readline.h"
	#include "modules/process.h"
	#include "modules/date.h"
	#include "modules/buffer.h"
	#include "modules/collections.h"
	#include "modules/navigator.h"
	#include "modules/server.h"
	#include "modules/events.h"
	#include "modules/lmdb.h"
	#include "modules/regex.h"

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

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

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

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

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

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

	static size_t intern_count = 0;
	static size_t intern_bytes = 0;
	static interned_string_t *intern_buckets[ANT_LIMIT_SIZE_CACHE];

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

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

	typedef struct {
	jsoff_t obj_off;
	const char *intern_ptr;
	jsoff_t prop_off;
	jsoff_t tail;
	uint64_t generation;
	} intern_prop_cache_entry_t;

	static uint64_t intern_prop_cache_gen = 1;
	static intern_prop_cache_entry_t intern_prop_cache[ANT_LIMIT_SIZE_CACHE];

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

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

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

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

	typedef struct dynamic_accessors {
	jsoff_t obj_offset;
	js_getter_fn getter;
	js_setter_fn setter;
	js_deleter_fn deleter;
	js_keys_fn keys;
	UT_hash_handle hh;
	} dynamic_accessors_t;

	static proxy_data_t *proxy_registry = NULL;
	static proxy_data_t *get_proxy_data(jsval_t obj);
	static dynamic_accessors_t *accessor_registry = NULL;

	jsval_t tov(double d) {
	union { double d; jsval_t v; } u = {d};
	if (__builtin_expect(isnan(d), 0))
	return (u.v > NANBOX_PREFIX)
	? 0x7FF8000000000000ULL : u.v; // canonical NaN
	return u.v;
	}

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

	static bool is_tagged(jsval_t v) {
	return v > NANBOX_PREFIX;
	}

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

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

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

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

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

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

	const char *typestr(uint8_t t) {
	static const char *names[] = {
	[T_UNDEF] = "undefined", [T_NULL] = "object", [T_BOOL] = "boolean",
	[T_NUM] = "number", [T_BIGINT] = "bigint", [T_STR] = "string",
	[T_SYMBOL] = "symbol", [T_OBJ] = "object", [T_ARR] = "object",
	[T_FUNC] = "function", [T_CFUNC] = "function", [T_CLOSURE] = "closure",
	[T_PROMISE] = "promise", [T_GENERATOR] = "generator",
	[T_PROP] = "prop", [T_ERR] = "err", [T_TYPEDARRAY] = "typedarray",
	[T_FFI] = "ffi", [T_NTARG] = "ntarg"
	};

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

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

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

	jsval_t js_obj_to_func(jsval_t obj) {
	sv_closure_t *closure = calloc(1, sizeof(sv_closure_t));
	closure->func_obj = (vtype(obj) == T_OBJ) ? obj : mkval(T_OBJ, vdata(obj));
	return mkval(T_FUNC, (uintptr_t)closure);
	}

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

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

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

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

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

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

	typedef enum {
	NTARG_INVALID = 0,
	NTARG_NEW_TARGET = 1
	} ntarg_kind_t;

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

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

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

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

	static size_t strstring(ant_t js, jsval_t value, char buf, size_t len);
	static size_t strkey(ant_t js, jsval_t value, char buf, size_t len);

	jsoff_t vstrlen(ant_t *js, jsval_t v) {
	jsoff_t off = (jsoff_t) vdata(v);
	jsoff_t header = loadoff(js, off);
	if (header & ROPE_FLAG) {
	return offtolen(header & ~(ROPE_FLAG \| (ROPE_DEPTH_MASK << ROPE_DEPTH_SHIFT)));
	}
	return offtolen(header);
	}

	static jsval_t proxy_read_target(ant_t *js, jsval_t obj);
	static jsoff_t proxy_aware_length(ant_t *js, jsval_t obj);
	static jsval_t proxy_aware_get_elem(ant_t js, jsval_t obj, const char key, size_t key_len);
	static bool bigint_is_zero(ant_t *js, jsval_t v);

	static jsoff_t get_dense_buf(ant_t *js, jsval_t arr);
	static jsoff_t dense_length(ant_t *js, jsoff_t doff);
	static jsoff_t get_array_length(ant_t *js, jsval_t arr);
	static jsval_t arr_get(ant_t *js, jsval_t arr, jsoff_t idx);
	static bool arr_has(ant_t *js, jsval_t arr, jsoff_t idx);

	static bool streq(const char buf, size_t len, const char p, size_t n);
	static bool parse_func_params(ant_t js, uint8_t flags, int *out_count);
	static bool try_dynamic_setter(ant_t js, jsval_t obj, const char key, size_t key_len, jsval_t value);
	static jsoff_t lkp_with_setter(ant_t js, jsval_t obj, const char buf, size_t len, jsval_t setter_out, bool has_setter_out);
	static jsval_t call_proto_accessor(ant_t js, jsval_t prim, jsval_t accessor, bool has_accessor, jsval_t arg, int arg_count, bool is_setter);
	static jsval_t get_prototype_for_type(ant_t *js, uint8_t type);

	static size_t strbigint(ant_t js, jsval_t value, char buf, size_t len);
	static size_t tostr(ant_t js, jsval_t value, char buf, size_t len);
	static size_t strpromise(ant_t js, jsval_t value, char buf, size_t len);
	static jsval_t js_call_valueOf(ant_t *js, jsval_t value);
	static jsval_t js_call_toString(ant_t *js, jsval_t value);
	static jsval_t js_call_method(ant_t js, jsval_t obj, const char method, size_t method_len, jsval_t *args, int nargs);

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

	static jsval_t builtin_Object(ant_t js, jsval_t args, int nargs);
	static jsval_t builtin_promise_then(ant_t js, jsval_t args, int nargs);
	static jsval_t string_split_impl(ant_t js, jsval_t str, jsval_t args, int nargs);

	static jsval_t proxy_get(ant_t js, jsval_t proxy, const char key, size_t key_len);
	static jsval_t proxy_get_val(ant_t *js, jsval_t proxy, jsval_t key_val);
	static jsval_t proxy_set(ant_t js, jsval_t proxy, const char key, size_t key_len, jsval_t value);
	static jsval_t proxy_has(ant_t js, jsval_t proxy, const char key, size_t key_len);
	static jsval_t proxy_has_val(ant_t *js, jsval_t proxy, jsval_t key_val);
	static jsval_t proxy_delete(ant_t js, jsval_t proxy, const char key, size_t key_len);
	static jsval_t proxy_delete_val(ant_t *js, jsval_t proxy, jsval_t key_val);

	static jsval_t get_prototype_for_type(ant_t *js, uint8_t type);
	static jsval_t get_ctor_proto(ant_t js, const char name, size_t len);
	static jsoff_t lkp_interned(ant_t js, jsval_t obj, const char search_intern, size_t len);

	static const char bigint_digits(ant_t js, jsval_t v, size_t *len);

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

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

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

	return ctor;
	}

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

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

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

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

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

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

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

	static jsval_t bigint_from_u64(ant_t *js, uint64_t value) {
	char buf[32];
	size_t len = uint_to_str(buf, sizeof(buf), value);
	return js_mkbigint(js, buf, len, false);
	}

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

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

	stringify_depth--;
	}

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

	stringify_depth--;
	}

	static void scan_func_refs(ant_t *js, jsval_t value) {
	jsval_t func_obj = js_func_obj(value);

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

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

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

	stringify_depth--;
	}

	static void scan_refs(ant_t *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 wanted = (size_t)(level * 2);
	size_t n = 0;
	for (int i = 0; i < level * 2 && n < len; i++) {
	buf[n++] = ' ';
	}
	return wanted;
	}

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

	static inline bool is_sym_key_prop(ant_t *js, jsoff_t prop) {
	jsoff_t koff = get_prop_koff(js, prop);
	return koff < js->brk && (loadoff(js, koff) & 0xF) == 0;
	}

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

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

	const char get_str_prop(ant_t js, jsval_t obj, const char key, jsoff_t klen, jsoff_t out_len) {
	jsoff_t off = lkp(js, obj, key, klen);
	if (off <= 0) return NULL;
	jsval_t v = resolveprop(js, mkval(T_PROP, off));
	if (vtype(v) != T_STR) return NULL;
	return (const char *)&js->mem[vstr(js, v, out_len)];
	}

	static bool is_small_array(ant_t js, jsval_t obj, int elem_count) {
	jsoff_t length = get_array_length(js, obj);
	if (length > 64) { if (elem_count) *elem_count = (int)length; return false; }

	int count = 0; bool has_nested = false;
	for (jsoff_t i = 0; i < length; i++) {
	jsval_t val = arr_get(js, obj, i); uint8_t t = vtype(val);
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) has_nested = true;
	count++;
	}

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

	static inline bool is_array_index(const char *key, jsoff_t klen) {
	if (klen == 0 \|\| (klen > 1 && key[0] == '0')) return false;
	for (jsoff_t i = 0; i < klen; i++) {
	if (key[i] < '0' \|\| key[i] > '9') return false;
	}
	return true;
	}

	static inline bool parse_array_index(const char key, size_t klen, jsoff_t max_len, unsigned long out_idx) {
	if (klen == 0 \|\| key[0] < '0' \|\| key[0] > '9') return false;
	unsigned long parsed_idx = 0;

	for (size_t i = 0; i < klen; i++) {
	if (key[i] < '0' \|\| key[i] > '9') return false;
	parsed_idx = parsed_idx * 10 + (key[i] - '0');
	}

	if (parsed_idx >= max_len) return false;
	*out_idx = parsed_idx;
	return true;
	}

	static jsoff_t get_array_length(ant_t *js, jsval_t arr) {
	jsoff_t doff = get_dense_buf(js, arr);
	jsoff_t dense_len = doff ? dense_length(js, doff) : 0;
	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	if (off) {
	jsval_t val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(val) == T_NUM) {
	jsoff_t prop_len = (jsoff_t) tod(val);
	return prop_len > dense_len ? prop_len : dense_len;
	}
	}
	return dense_len;
	}

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

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

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

	static inline jsoff_t dense_iterable_length(ant_t *js, jsval_t obj) {
	jsoff_t doff = get_dense_buf(js, obj);
	return doff ? dense_length(js, doff) : 0;
	}

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

	push_stringify(obj);
	jsoff_t first = loadoff(js, (jsoff_t) vdata(js_as_obj(obj))) & ~(3U \| FLAGMASK);
	jsoff_t length = get_array_length(js, obj);
	jsoff_t d_len = dense_iterable_length(js, obj);
	jsoff_t iter_len = (d_len >= length) ? length : d_len;

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

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

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

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

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

	bool printed_first = false;
	for (jsoff_t i = 0; i < iter_len; i++) {
	if (printed_first) n += cpy(buf + n, REMAIN(n, len), inline_mode ? ", " : ",\n", 2);
	if (!inline_mode) n += add_indent(buf + n, REMAIN(n, len), stringify_indent);

	jsval_t val = arr_get(js, obj, i); bool found = arr_has(js, obj, i);
	n += found ? tostr(js, val, buf + n, REMAIN(n, len)) : cpy(buf + n, REMAIN(n, len), "undefined", 9);
	printed_first = true;
	}

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

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

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

	if (is_array_index(key, klen)) {
	n += tostr(js, get_prop_val(js, p), buf + n, REMAIN(n, len));
	} else {
	n += cpy(buf + n, REMAIN(n, len), key, klen);
	n += cpy(buf + n, REMAIN(n, len), ": ", 2);
	n += tostr(js, get_prop_val(js, p), buf + n, REMAIN(n, len));
	}
	printed_first = true;
	}

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

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

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

	static const date_string_spec_t kSpec = {DATE_STRING_FMT_ISO, DATE_STRING_PART_ALL};
	jsval_t iso = get_date_string(js, obj, kSpec);
	if (is_err(iso) \|\| vtype(iso) != T_STR) return cpy(buf, len, "Invalid Date", 12);

	jsoff_t slen;
	jsoff_t soff = vstr(js, iso, &slen);

	return cpy(buf, len, (const char *)&js->mem[soff], slen);
	}

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

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

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

	if (is_sym_key_prop(js, next)) {
	count++;
	next = next_prop(header);
	continue;
	}

	const char *key; jsoff_t klen;
	get_prop_key(js, next, &key, &klen);

	descriptor_entry_t *desc = lookup_descriptor(js, obj_off, key, klen);
	if (desc && !desc->enumerable) { next = next_prop(header); continue; }

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

	next = next_prop(header);
	}

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

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

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

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

	push_stringify(obj);

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

	jsval_t tag_sym = get_toStringTag_sym();
	jsoff_t tag_off = (vtype(tag_sym) == T_SYMBOL) ? lkp_sym_proto(js, obj, (jsoff_t)vdata(tag_sym)) : 0;
	bool is_map = false, is_set = false, is_arraybuffer = false;
	jsoff_t tlen = 0, toff = 0;
	const char *tag_str = NULL;
	int prop_count = 0;
	bool inline_mode = false;

	if (tag_off == 0) goto print_plain_object;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	if (count == 0) {
	n += cpy(buf + n, REMAIN(n, len), "{}", 2);
	} else {
	n += cpy(buf + n, REMAIN(n, len), "{\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, REMAIN(n, len), ",\n", 2);
	first = false;
	n += add_indent(buf + n, REMAIN(n, len), stringify_indent);

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

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

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

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

	if (count == 0) {
	n += cpy(buf + n, REMAIN(n, len), "{}", 2);
	} else {
	n += cpy(buf + n, REMAIN(n, len), "{\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, REMAIN(n, len), ",\n", 2);
	first = false;
	n += add_indent(buf + n, REMAIN(n, len), stringify_indent);
	n += tostr(js, entry->value, buf + n, REMAIN(n, len));
	}
	}
	stringify_indent--;
	n += cpy(buf + n, REMAIN(n, len), "\n", 1);
	n += add_indent(buf + n, REMAIN(n, len), stringify_indent);
	n += cpy(buf + n, REMAIN(n, len), "}", 1);
	}
	pop_stringify();
	return n;
	}

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

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

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

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

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

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

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

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

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

	continue_object_print:;

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

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

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

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

	if (is_sym_key_prop(js, next)) { next = next_prop(header); continue; }

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

	descriptor_entry_t *desc = lookup_descriptor(js, obj_off, key, klen);
	if (desc && !desc->enumerable) { next = next_prop(header); continue; }

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

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

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

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

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

	next = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header) \|\| !is_sym_key_prop(js, next)) {
	next = next_prop(header); continue;
	}

	jsoff_t sym_off = get_prop_koff(js, next);
	if (vtype(tag_sym) == T_SYMBOL && sym_off == (jsoff_t)vdata(tag_sym)) {
	next = next_prop(header); continue;
	}

	jsval_t sym = mkval(T_SYMBOL, sym_off);
	jsval_t val = loadval(js, next + (jsoff_t)(sizeof(jsoff_t) * 2));

	if (!first) n += cpy(buf + n, REMAIN(n, len), inline_mode ? ", " : ",\n", 2);
	first = false;
	if (!inline_mode) n += add_indent(buf + n, REMAIN(n, len), stringify_indent);
	n += cpy(buf + n, REMAIN(n, len), "[", 1);
	n += tostr(js, sym, buf + n, REMAIN(n, len));
	n += cpy(buf + n, REMAIN(n, len), "]: ", 3);
	n += tostr(js, val, buf + n, REMAIN(n, len));

	next = next_prop(header);
	}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	int result = snprintf(temp, sizeof(temp), "%.17g", dv);
	fix_exponent(temp, (size_t)result);
	return cpy(buf, len, temp, strlen(temp));
	}

	static inline jsoff_t assert_string_header(ant_t js, jsval_t value, jsoff_t out_off) {
	assert(vtype(value) == T_STR);
	jsoff_t off = (jsoff_t) vdata(value);
	assert(off + sizeof(jsoff_t) <= js->brk);
	jsoff_t header = loadoff(js, off);
	assert((header & 3) == T_STR);
	if (out_off) *out_off = off;
	return header;
	}

	static inline jsoff_t assert_flat_string_len(ant_t js, jsval_t value, jsoff_t out_off) {
	jsoff_t off;
	jsoff_t header = assert_string_header(js, value, &off);
	assert((header & ROPE_FLAG) == 0);
	jsoff_t len = offtolen(header);
	assert(off + sizeof(jsoff_t) + len <= js->brk);
	if (out_off) *out_off = off;
	return len;
	}

	static inline jsoff_t assert_rope_header(ant_t js, jsval_t value, jsoff_t out_off) {
	jsoff_t off;
	jsoff_t header = assert_string_header(js, value, &off);
	assert((header & ROPE_FLAG) != 0);
	assert(off + sizeof(rope_node_t) <= js->brk);
	jsoff_t payload_header = header & ~(ROPE_FLAG \| (ROPE_DEPTH_MASK << ROPE_DEPTH_SHIFT));
	assert((payload_header >> 3) > 0);
	if (out_off) *out_off = off;
	return header;
	}

	bool is_rope(ant_t *js, jsval_t value) {
	jsoff_t header = assert_string_header(js, value, NULL);
	if ((header & ROPE_FLAG) != 0) assert_rope_header(js, value, NULL);
	return (header & ROPE_FLAG) != 0;
	}

	static inline jsoff_t rope_len(ant_t *js, jsval_t value) {
	jsoff_t header = assert_rope_header(js, value, NULL);
	return offtolen(header & ~(ROPE_FLAG \| (ROPE_DEPTH_MASK << ROPE_DEPTH_SHIFT)));
	}

	static inline uint8_t rope_depth(ant_t *js, jsval_t value) {
	jsoff_t off = (jsoff_t) vdata(value);
	jsoff_t header = loadoff(js, off);
	return (uint8_t)((header >> ROPE_DEPTH_SHIFT) & ROPE_DEPTH_MASK);
	}

	static inline jsval_t rope_left(ant_t *js, jsval_t value) {
	jsoff_t off = (jsoff_t) vdata(value);
	return loadval(js, off + offsetof(rope_node_t, left));
	}

	static inline jsval_t rope_right(ant_t *js, jsval_t value) {
	jsoff_t off = (jsoff_t) vdata(value);
	return loadval(js, off + offsetof(rope_node_t, right));
	}

	static inline jsval_t rope_cached_flat(ant_t *js, jsval_t value) {
	jsoff_t off = (jsoff_t) vdata(value);
	return loadval(js, off + offsetof(rope_node_t, cached));
	}

	static inline void rope_set_cached_flat(ant_t *js, jsval_t rope, jsval_t flat) {
	jsoff_t off = (jsoff_t) vdata(rope);
	saveval(js, off + offsetof(rope_node_t, cached), flat);
	}

	static void rope_flatten_into(ant_t js, jsval_t str, char dest, jsoff_t *pos) {
	assert(vtype(str) == T_STR);

	if (!is_rope(js, str)) {
	jsoff_t soff;
	jsoff_t slen = assert_flat_string_len(js, str, &soff);
	memcpy(dest + *pos, &js->mem[soff + sizeof(jsoff_t)], slen);
	*pos += slen; return;
	}

	jsval_t cached = rope_cached_flat(js, str);
	if (vtype(cached) == T_STR && !is_rope(js, cached)) {
	jsoff_t coff;
	jsoff_t clen = assert_flat_string_len(js, cached, &coff);
	memcpy(dest + *pos, &js->mem[coff + sizeof(jsoff_t)], clen);
	*pos += clen; return;
	}

	jsval_t stack[ROPE_MAX_DEPTH + 8];
	int sp = 0; stack[sp++] = str;

	while (sp > 0) {
	jsval_t node = stack[--sp];
	assert(vtype(node) == T_STR);

	if (!is_rope(js, node)) {
	jsoff_t soff;
	jsoff_t slen = assert_flat_string_len(js, node, &soff);
	memcpy(dest + *pos, &js->mem[soff + sizeof(jsoff_t)], slen);
	*pos += slen; continue;
	}

	jsval_t c = rope_cached_flat(js, node);
	if (vtype(c) == T_STR && !is_rope(js, c)) {
	jsoff_t coff;
	jsoff_t clen = assert_flat_string_len(js, c, &coff);
	memcpy(dest + *pos, &js->mem[coff + sizeof(jsoff_t)], clen);
	*pos += clen; continue;
	}

	if (sp + 2 <= ROPE_MAX_DEPTH + 8) {
	stack[sp++] = rope_right(js, node);
	stack[sp++] = rope_left(js, node);
	}
	}
	}

	jsval_t rope_flatten(ant_t *js, jsval_t rope) {
	assert(vtype(rope) == T_STR);
	if (!is_rope(js, rope)) return rope;

	jsval_t cached = rope_cached_flat(js, rope);
	if (vtype(cached) == T_STR && !is_rope(js, cached)) return cached;

	jsoff_t total_len = rope_len(js, rope);

	char buf = (char )ant_calloc(total_len + 1);
	if (!buf) return js_mkerr(js, "oom");

	jsoff_t pos = 0;
	rope_flatten_into(js, rope, buf, &pos);
	buf[pos] = '\0';

	jsval_t flat = js_mkstr(js, buf, pos);
	free(buf);

	if (!is_err(flat)) {
	rope_set_cached_flat(js, rope, flat);
	}

	return flat;
	}

	jsoff_t vstr(ant_t js, jsval_t value, jsoff_t len) {
	jsoff_t header = assert_string_header(js, value, NULL);

	if (header & ROPE_FLAG) {
	jsval_t flat = rope_flatten(js, value);
	assert(!is_err(flat));
	value = flat;
	}

	jsoff_t off;
	jsoff_t slen = assert_flat_string_len(js, value, &off);
	if (len) *len = slen;
	return (jsoff_t) (off + sizeof(off));
	}

	static size_t strstring(ant_t 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, REMAIN(n, len), "'", 1);
	for (jsoff_t i = 0; i < slen && n < len - 1; i++) {
	char c = str[i];
	if (c == '\n') { n += cpy(buf + n, REMAIN(n, len), "\\n", 2); }
	else if (c == '\r') { n += cpy(buf + n, REMAIN(n, len), "\\r", 2); }
	else if (c == '\t') { n += cpy(buf + n, REMAIN(n, len), "\\t", 2); }
	else if (c == '\\') { n += cpy(buf + n, REMAIN(n, len), "\\\\", 2); }
	else if (c == '\'') { n += cpy(buf + n, REMAIN(n, len), "\\'", 2); }
	else { if (n < len) buf[n++] = c; }
	}
	n += cpy(buf + n, REMAIN(n, len), "'", 1);

	return n;
	}

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

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

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

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

	intern_count++;
	intern_bytes += alloc_size;

	return entry->str;
	}

	js_intern_stats_t js_intern_stats(void) {
	return (js_intern_stats_t){
	.count = intern_count,
	.bytes = intern_bytes
	};
	}

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

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

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

	// todo: make it work with bytecode NAME
	static size_t strfunc(ant_t js, jsval_t value, char buf, size_t len) {
	jsoff_t name_len = 0;
	const char *name = get_func_name(js, value, &name_len);

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

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

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

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

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

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

	if (!is_native) return n;

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

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

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

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

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

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

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

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

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

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

	case T_ERR: {
	uint64_t data = vdata(value);
	if (data != 0) {
	jsval_t obj = mkval(T_OBJ, data);
	jsval_t stack = js_get(js, obj, "stack");
	if (vtype(stack) == T_STR) {
	jsoff_t slen;
	jsoff_t off = vstr(js, stack, &slen);
	return cpy(buf, len, (const char *)&js->mem[off], slen);
	}
	}
	return ANT_COPY(buf, len, "Error");
	}

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

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

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

	js_cstr_t js_to_cstr(ant_t js, jsval_t value, char stack_buf, size_t stack_size) {
	js_cstr_t out = { .ptr = "", .len = 0, .needs_free = false };

	if (is_err(value)) {
	uint64_t data = vdata(value);
	if (data != 0) {
	jsval_t obj = mkval(T_OBJ, data);
	jsval_t stack = js_get(js, obj, "stack");
	if (vtype(stack) == T_STR) {
	jsoff_t slen;
	jsoff_t off = vstr(js, stack, &slen);
	out.ptr = (const char *)&js->mem[off];
	out.len = slen;
	return out;
	}
	}
	out.ptr = "Error";
	out.len = 5;
	return out;
	}

	if (vtype(value) == T_STR) {
	size_t len = 0;
	char *str = js_getstr(js, value, &len);
	out.ptr = str ? str : ""; out.len = len;
	return out;
	}

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

	size_t capacity = stack_size;
	char *buf = stack_buf;
	out.needs_free = false;

	if (!buf \|\| capacity == 0) {
	capacity = 64;
	buf = ant_calloc(capacity);
	if (!buf) return out;
	out.needs_free = true;
	}

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

	if (len < capacity - 1) {
	out.ptr = buf;
	out.len = len;
	return out;
	}

	size_t new_capacity = capacity * 2;
	char *next = out.needs_free
	? ant_realloc(buf, new_capacity)
	: ant_calloc(new_capacity);

	if (!next) {
	if (out.needs_free) free(buf);
	out.ptr = ""; out.len = 0;
	out.needs_free = false;
	return out;
	}

	if (!out.needs_free) {
	memcpy(next, buf, capacity);
	out.needs_free = true;
	}

	buf = next;
	capacity = new_capacity;
	}
	}

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

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

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

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

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

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

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

	const char js_str(ant_t js, jsval_t value) {
	if (is_err(value)) {
	uint64_t data = vdata(value);
	if (data != 0) {
	jsval_t obj = mkval(T_OBJ, data);
	jsval_t stack = js_get(js, obj, "stack");
	if (vtype(stack) == T_STR) {
	jsoff_t slen, off = vstr(js, stack, &slen);
	return (const char *)&js->mem[off];
	}
	}
	return "Error";
	}

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

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

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

	if (len < capacity - 1) break;

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

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

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

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

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

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

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

	return true;
	}

	static inline bool js_has_space(ant_t *js, size_t size) {
	return js->brk + size <= js->size;
	}

	static bool js_ensure_space(ant_t *js, size_t size) {
	if (js_has_space(js, size)) return true;
	if (js_try_grow_memory(js, size) && js_has_space(js, size)) return true;

	js->needs_gc = true;

	if (js_has_space(js, size)) return true;
	if (js_try_grow_memory(js, size) && js_has_space(js, size)) return true;

	return false;
	}

	static void js_track_allocation(ant_t *js, size_t size) {
	js->brk += (jsoff_t) size;
	js->gc_alloc_since += (jsoff_t) size;

	jsoff_t threshold = js->brk / 2;
	if (threshold < 4 * 1024 * 1024) threshold = 4 * 1024 * 1024;
	if (js->gc_alloc_since > threshold) js->needs_gc = true;
	}

	static inline jsoff_t js_alloc(ant_t *js, size_t size) {
	size = align64((jsoff_t) size);
	if (!js_ensure_space(js, size)) return ~(jsoff_t) 0;

	jsoff_t ofs = js->brk;
	js_track_allocation(js, size);

	return ofs;
	}

	static jsoff_t dense_alloc(ant_t *js, jsoff_t capacity) {
	jsoff_t size = sizeof(jsoff_t) * 2 + sizeof(jsval_t) * capacity;
	jsoff_t off = js_alloc(js, size);
	if (off == (jsoff_t)~0) return 0;

	saveoff(js, off, capacity);
	saveoff(js, off + sizeof(jsoff_t), 0);

	for (jsoff_t i = 0; i < capacity; i++) saveval(
	js, off + sizeof(jsoff_t) * 2 + sizeof(jsval_t) * i, T_EMPTY
	);

	return off;
	}

	static inline jsoff_t get_dense_buf(ant_t *js, jsval_t arr) {
	jsoff_t off = (jsoff_t) vdata(js_as_obj(arr));
	if (__builtin_expect(off >= js->brk, 0)) return 0;
	jsoff_t next = loadoff(js, off) & ~(3U \| FLAGMASK);
	if (__builtin_expect(next == 0 \|\| next >= js->brk, 0)) return 0;
	jsoff_t header = loadoff(js, next);
	if ((header & SLOTMASK) &&
	loadoff(js, next + sizeof(jsoff_t)) == (jsoff_t)SLOT_DENSE_BUF) {
	jsval_t slot = loadval(js, next + sizeof(jsoff_t) * 2);
	return (jsoff_t) tod(slot);
	}
	jsval_t slot = get_slot(js, arr, SLOT_DENSE_BUF);
	if (vtype(slot) == T_UNDEF) return 0;
	return (jsoff_t) tod(slot);
	}

	static inline jsoff_t get_dense_buf_off(ant_t *js, jsoff_t obj_off) {
	return get_dense_buf(js, mkval(T_ARR, (uint64_t)obj_off));
	}

	static inline jsoff_t dense_capacity(ant_t *js, jsoff_t doff) {
	return loadoff(js, doff);
	}

	static inline jsoff_t dense_length(ant_t *js, jsoff_t doff) {
	return loadoff(js, doff + sizeof(jsoff_t));
	}

	static inline void dense_set_length(ant_t *js, jsoff_t doff, jsoff_t len) {
	saveoff(js, doff + sizeof(jsoff_t), len);
	}

	static inline jsval_t dense_get(ant_t *js, jsoff_t doff, jsoff_t idx) {
	return loadval(js, doff + sizeof(jsoff_t) * 2 + sizeof(jsval_t) * idx);
	}

	static inline void dense_set(ant_t *js, jsoff_t doff, jsoff_t idx, jsval_t val) {
	saveval(js, doff + sizeof(jsoff_t) * 2 + sizeof(jsval_t) * idx, val);
	}

	static jsoff_t dense_grow(ant_t *js, jsval_t arr, jsoff_t needed) {
	jsoff_t doff = get_dense_buf(js, arr);
	jsoff_t old_cap = doff ? dense_capacity(js, doff) : 0;
	jsoff_t old_len = doff ? dense_length(js, doff) : 0;
	jsoff_t new_cap = old_cap ? old_cap : MAX_DENSE_INITIAL_CAP;

	while (new_cap < needed) new_cap *= 2;
	jsoff_t new_doff = dense_alloc(js, new_cap);

	if (new_doff == 0) return 0;
	if (doff && old_len > 0) memcpy(
	&js->mem[new_doff + sizeof(jsoff_t) * 2],
	&js->mem[doff + sizeof(jsoff_t) * 2],
	sizeof(jsval_t) * old_len
	);

	dense_set_length(js, new_doff, old_len);
	set_slot(js, arr, SLOT_DENSE_BUF, tov((double)new_doff));

	return new_doff;
	}

	static inline jsval_t arr_get(ant_t *js, jsval_t arr, jsoff_t idx) {
	jsoff_t doff = get_dense_buf(js, arr);

	if (doff) {
	jsoff_t len = dense_length(js, doff);
	if (idx < len) {
	jsval_t v = dense_get(js, doff, idx);
	if (!is_empty_slot(v)) return v;
	return js_mkundef();
	}
	}

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	jsoff_t prop = lkp(js, arr, idxstr, idxlen);

	return prop ? resolveprop(js, mkval(T_PROP, prop)) : js_mkundef();
	}

	static inline void arr_set(ant_t *js, jsval_t arr, jsoff_t idx, jsval_t val) {
	jsoff_t doff = get_dense_buf(js, arr);

	if (doff) {
	jsoff_t len = dense_length(js, doff);

	if (idx < len) {
	dense_set(js, doff, idx, val);
	return;
	}

	jsoff_t density_limit = len > 0 ? len * 4 : 64;
	if (idx >= density_limit) goto sparse;

	jsoff_t cap = dense_capacity(js, doff);
	if (idx >= cap) {
	doff = dense_grow(js, arr, idx + 1);
	if (doff == 0) goto sparse;
	}

	for (jsoff_t i = len; i < idx; i++) {
	jsval_t v = dense_get(js, doff, i);
	if (!is_empty_slot(v) && vtype(v) == T_UNDEF) dense_set(js, doff, i, T_EMPTY);
	}
	dense_set(js, doff, idx, val);
	dense_set_length(js, doff, idx + 1);
	return;
	}

	sparse:;
	char idxstr[24];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (uint64_t)idx);
	jsval_t key = js_mkstr(js, idxstr, idxlen);

	js_setprop(js, arr, key, val);
	}

	static inline bool arr_has(ant_t *js, jsval_t arr, jsoff_t idx) {
	jsoff_t doff = get_dense_buf(js, arr);

	if (doff) {
	jsoff_t len = dense_length(js, doff);
	if (idx < len) return !is_empty_slot(dense_get(js, doff, idx));
	}

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	return lkp(js, arr, idxstr, idxlen) != 0;
	}

	static inline void arr_del(ant_t *js, jsval_t arr, jsoff_t idx) {
	jsoff_t doff = get_dense_buf(js, arr);

	if (doff) {
	jsoff_t len = dense_length(js, doff);
	if (idx < len) dense_set(js, doff, idx, T_EMPTY);
	return;
	}

	char idxstr[16];
	uint_to_str(idxstr, sizeof(idxstr), (unsigned)idx);
	js_del(js, arr, idxstr);
	}

	static jsval_t mkentity(ant_t js, jsoff_t b, const void buf, size_t len) {
	jsoff_t ofs = js_alloc(js, len + sizeof(b));
	if (ofs == (jsoff_t) ~0) return js_mkerr(js, "oom");

	memcpy(&js->mem[ofs], &b, sizeof(b));
	if (buf != NULL) {
	size_t copy_len = ((b & 3) == T_STR && len > 0) ? len - 1 : len;
	memmove(&js->mem[ofs + sizeof(b)], buf, copy_len);
	}

	if ((b & 3) == T_STR) js->mem[ofs + sizeof(b) + len - 1] = 0;
	return mkval(b & 3, ofs);
	}

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

	static jsval_t js_mkrope(ant_t *js, jsval_t left, jsval_t right, jsoff_t total_len, uint8_t depth) {
	jsoff_t ofs = js_alloc(js, sizeof(rope_node_t));
	if (ofs == (jsoff_t) ~0) return js_mkerr(js, "oom");

	jsoff_t header = ((total_len + 1) << 3) \| T_STR \| ROPE_FLAG \| ((jsoff_t)depth << ROPE_DEPTH_SHIFT);
	jsval_t undef = js_mkundef();

	memcpy(&js->mem[ofs + offsetof(rope_node_t, header)], &header, sizeof(header));
	memcpy(&js->mem[ofs + offsetof(rope_node_t, left)], &left, sizeof(left));
	memcpy(&js->mem[ofs + offsetof(rope_node_t, right)], &right, sizeof(right));
	memcpy(&js->mem[ofs + offsetof(rope_node_t, cached)], &undef, sizeof(undef));

	return mkval(T_STR, ofs);
	}

	static bool bigint_parse_abs_u64(ant_t js, jsval_t value, uint64_t out) {
	size_t len = 0; const char *digits = bigint_digits(js, value, &len);
	uint64_t acc = 0;

	for (size_t i = 0; i < len; i++) {
	char c = digits[i];
	if (!is_digit(c)) return false;
	uint64_t digit = (uint64_t)(c - '0');
	if (acc > UINT64_MAX / 10 \|\| (acc == UINT64_MAX / 10 && digit > (UINT64_MAX % 10))) {
	return false;
	} acc = acc * 10 + digit;
	}

	*out = acc;
	return true;
	}

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

	static bool bigint_parse_u64(ant_t js, jsval_t value, uint64_t out) {
	if (bigint_IsNegative(js, value)) return false;
	return bigint_parse_abs_u64(js, value, out);
	}

	jsval_t js_mkbigint(ant_t 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 const char bigint_digits(ant_t 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;
	}

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

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

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

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

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

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

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

	static inline jsval_t bigint_pow2(ant_t *js, uint64_t bits) {
	jsval_t two = js_mkbigint(js, "2", 1, false);
	if (is_err(two)) return two;
	jsval_t exp = bigint_from_u64(js, bits);
	if (is_err(exp)) return exp;
	return bigint_exp(js, two, exp);
	}

	jsval_t bigint_shift_left(ant_t *js, jsval_t value, uint64_t shift) {
	if (shift == 0) return value;
	if (shift > 18446744073709551615ULL) return js_mkerr(js, "Shift count too large");

	size_t digits_len; const char *digits = bigint_digits(js, value, &digits_len);
	if (digits_len == 1 && digits[0] == '0') return js_mkbigint(js, "0", 1, false);
	uint64_t u64 = 0;
	if (!bigint_IsNegative(js, value) && shift < 64 && bigint_parse_u64(js, value, &u64)) {
	if (u64 <= (UINT64_MAX >> shift)) return bigint_from_u64(js, u64 << shift);
	}

	jsval_t pow = bigint_pow2(js, shift);
	if (is_err(pow)) return pow;
	return bigint_mul(js, value, pow);
	}

	jsval_t bigint_shift_right(ant_t *js, jsval_t value, uint64_t shift) {
	if (shift == 0) return value;
	if (shift > 18446744073709551615ULL) return js_mkerr(js, "Shift count too large");

	size_t digits_len; const char *digits = bigint_digits(js, value, &digits_len);
	if (digits_len == 1 && digits[0] == '0') return js_mkbigint(js, "0", 1, false);
	uint64_t u64 = 0;
	if (!bigint_IsNegative(js, value) && bigint_parse_u64(js, value, &u64)) {
	if (shift >= 64) return js_mkbigint(js, "0", 1, false);
	return bigint_from_u64(js, u64 >> shift);
	}

	if (bigint_parse_abs_u64(js, value, &u64)) {
	if (shift >= 64) return js_mkbigint(
	js, bigint_IsNegative(js, value) ? "1" : "0", 1,
	bigint_IsNegative(js, value)
	);
	uint64_t shifted = u64 >> shift;
	if (bigint_IsNegative(js, value)) {
	if ((u64 & ((1ULL << shift) - 1)) != 0) shifted += 1;
	jsval_t pos = bigint_from_u64(js, shifted);
	if (is_err(pos)) return pos;
	return bigint_neg(js, pos);
	}
	return bigint_from_u64(js, shifted);
	}

	jsval_t pow = bigint_pow2(js, shift);
	if (is_err(pow)) return pow;
	return bigint_div(js, value, pow);
	}

	jsval_t bigint_shift_right_logical(ant_t *js, jsval_t value, uint64_t shift) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "BigInts have no unsigned right shift, use >> instead");
	}

	int bigint_compare(ant_t *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(ant_t *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(ant_t 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, REMAIN(n, len), "-", 1);
	n += cpy(buf + n, REMAIN(n, len), digits, dlen);
	return n;
	}

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

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

	static jsval_t bigint_to_u64(ant_t js, jsval_t value, uint64_t out) {
	if (!bigint_parse_u64(js, value, out)) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid bits");
	}
	return js_mkundef();
	}

	jsval_t bigint_asint_bits(ant_t js, jsval_t arg, uint64_t bits_out) {
	if (vtype(arg) == T_BIGINT) {
	return bigint_to_u64(js, arg, bits_out);
	}
	double bits = js_to_number(js, arg);
	if (!isfinite(bits) \|\| bits < 0 \|\| bits != floor(bits)) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid bits");
	}
	if (bits > 18446744073709551615.0) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid bits");
	}
	*bits_out = (uint64_t)bits;
	return js_mkundef();
	}

	static jsval_t builtin_BigInt_asIntN(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "BigInt.asIntN requires 2 arguments");
	uint64_t bits = 0;
	jsval_t err = bigint_asint_bits(js, args[0], &bits);
	if (is_err(err)) return err;
	if (vtype(args[1]) != T_BIGINT) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot convert to BigInt");
	}
	if (bits == 0) return js_mkbigint(js, "0", 1, false);

	jsval_t mod = bigint_pow2(js, bits);
	if (is_err(mod)) return mod;
	jsval_t res = bigint_mod(js, args[1], mod);
	if (is_err(res)) return res;
	if (bigint_IsNegative(js, res)) {
	jsval_t adj = bigint_add(js, res, mod);
	if (is_err(adj)) return adj;
	res = adj;
	}

	jsval_t threshold = bigint_pow2(js, bits - 1);
	if (is_err(threshold)) return threshold;
	if (bigint_compare(js, res, threshold) >= 0) {
	jsval_t adj = bigint_sub(js, res, mod);
	if (is_err(adj)) return adj;
	res = adj;
	}
	return res;
	}

	static jsval_t builtin_BigInt_asUintN(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "BigInt.asUintN requires 2 arguments");
	uint64_t bits = 0;
	jsval_t err = bigint_asint_bits(js, args[0], &bits);
	if (is_err(err)) return err;
	if (vtype(args[1]) != T_BIGINT) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot convert to BigInt");
	}
	if (bits == 0) return js_mkbigint(js, "0", 1, false);

	jsval_t mod = bigint_pow2(js, bits);
	if (is_err(mod)) return mod;
	jsval_t res = bigint_mod(js, args[1], mod);
	if (is_err(res)) return res;
	if (bigint_IsNegative(js, res)) {
	jsval_t adj = bigint_add(js, res, mod);
	if (is_err(adj)) return adj;
	res = adj;
	}
	return res;
	}

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

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

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

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

	const uint32_t base = 1000000000U;
	size_t result_cap = dlen * 4 + 16;

	char result = (char )ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");

	size_t rpos = result_cap - 1;
	result[rpos] = '\0';

	size_t limb_cap = (dlen + 8) / 9 + 1;
	uint32_t limbs = (uint32_t )ant_calloc(limb_cap * sizeof(uint32_t));
	if (!limbs) { free(result); return js_mkerr(js, "oom"); }
	size_t limb_len = 1;

	for (size_t i = 0; i < dlen; i++) {
	uint64_t carry = (uint64_t)(digits[i] - '0');
	for (size_t j = 0; j < limb_len; j++) {
	uint64_t cur = (uint64_t)limbs[j] * 10 + carry;
	limbs[j] = (uint32_t)(cur % base);
	carry = cur / base;
	}
	if (carry != 0) {
	if (limb_len == limb_cap) {
	size_t new_cap = limb_cap * 2;
	uint32_t new_limbs = (uint32_t )ant_realloc(limbs, new_cap * sizeof(uint32_t));
	if (!new_limbs) { free(limbs); free(result); return js_mkerr(js, "oom"); }
	limbs = new_limbs;
	limb_cap = new_cap;
	}
	limbs[limb_len++] = (uint32_t)carry;
	}
	}

	static const char digit_map[] = "0123456789abcdefghijklmnopqrstuvwxyz";
	while (limb_len > 0 && !(limb_len == 1 && limbs[0] == 0)) {
	uint64_t remainder = 0;
	for (size_t i = limb_len; i-- > 0;) {
	uint64_t cur = (uint64_t)limbs[i] + remainder * base;
	limbs[i] = (uint32_t)(cur / (uint64_t)radix);
	remainder = cur % (uint64_t)radix;
	}

	while (limb_len > 0 && limbs[limb_len - 1] == 0) limb_len--;
	if (rpos == 0) {
	size_t new_cap = result_cap * 2;
	char new_result = (char )ant_calloc(new_cap);
	if (!new_result) { free(limbs); free(result); return js_mkerr(js, "oom"); }

	size_t used = result_cap - rpos;
	memcpy(new_result + new_cap - used, result + rpos, used);
	free(result);

	result = new_result;
	rpos = new_cap - used;
	result_cap = new_cap;
	}
	result[--rpos] = digit_map[remainder];
	}

	free(limbs);

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

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

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

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

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

	jsval_t arr_val = mkval(T_ARR, vdata(arr));
	jsoff_t doff = dense_alloc(js, MAX_DENSE_INITIAL_CAP);
	if (doff) set_slot(js, arr_val, SLOT_DENSE_BUF, tov((double)doff));

	return arr_val;
	}

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

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

	jsoff_t js_arr_len(ant_t *js, jsval_t arr) {
	if (vtype(arr) != T_ARR) return 0;
	return get_array_length(js, arr);
	}

	jsval_t js_arr_get(ant_t *js, jsval_t arr, jsoff_t idx) {
	if (vtype(arr) != T_ARR) return js_mkundef();
	return arr_get(js, arr, idx);
	}

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

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

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

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

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

	uint32_t cache_slot = (((uintptr_t)interned >> 3) ^ obj_off) & (ANT_LIMIT_SIZE_CACHE - 1);
	intern_prop_cache_entry_t *ce = &intern_prop_cache[cache_slot];
	if (ce->obj_off == obj_off && ce->intern_ptr == interned) ce->generation = 0;
	}

	jsval_t mkprop(ant_t *js, jsval_t obj, jsval_t k, jsval_t v, jsoff_t flags) {
	obj = js_as_obj(obj);
	jsoff_t koff_entity;

	if (vtype(k) == T_SYMBOL) {
	koff_entity = (jsoff_t)vdata(k);
	} else {
	jsoff_t klen; jsoff_t koff = vstr(js, k, &klen);
	koff_entity = koff - sizeof(jsoff_t);
	const char p = (char ) &js->mem[koff];
	(void)intern_string(p, klen);
	}

	jsoff_t head = (jsoff_t) vdata(obj);
	char buf[sizeof(koff_entity) + sizeof(v)];

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

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

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

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

	return prop;
	}

	static inline jsval_t mkprop_fast(ant_t *js, jsval_t obj, jsval_t k, jsval_t v, jsoff_t flags) {
	obj = js_as_obj(obj);
	jsoff_t koff_entity;
	if (vtype(k) == T_SYMBOL) {
	koff_entity = (jsoff_t)vdata(k);
	} else {
	jsoff_t klen; jsoff_t koff = vstr(js, k, &klen);
	koff_entity = koff - sizeof(jsoff_t);
	}
	jsoff_t head = (jsoff_t) vdata(obj);
	char buf[sizeof(koff_entity) + sizeof(v)];

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

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

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

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

	return prop;
	}

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

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

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

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

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

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

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

	jsoff_t new_header = new_prop_off \| (header & (3U \| FLAGMASK));
	saveoff(js, head, new_header);

	if (first_prop == 0) {
	saveoff(js, head + sizeof(jsoff_t) + sizeof(jsoff_t), new_prop_off);
	}

	return prop;
	}

	static inline jsoff_t search_slot(ant_t *js, jsval_t obj, internal_slot_t slot) {
	obj = js_as_obj(obj);
	jsoff_t off = (jsoff_t) vdata(obj);
	if (__builtin_expect(off >= js->brk, 0)) return 0;
	jsoff_t next = loadoff(js, off) & ~(3U \| FLAGMASK);
	while (next != 0 && next < js->brk) {
	jsoff_t header = loadoff(js, next);
	if ((header & SLOTMASK) == 0) return 0;
	jsoff_t koff = loadoff(js, next + sizeof(jsoff_t));
	if (koff == (jsoff_t)slot) return next;
	next = header & ~(3U \| FLAGMASK);
	}
	return 0;
	}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	return JS_NAN;
	}

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

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

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

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

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

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

	return js_mkundef();
	}

	static inline bool proto_walk_next(ant_t js, jsval_t cur, uint8_t *t, uint8_t flags) {
	uint8_t ct = *t;

	if (flags & PROTO_WALK_F_OBJECT_ONLY) {
	if (!is_object_type(*cur)) return false;
	jsval_t next = get_proto(js, *cur);
	uint8_t nt = vtype(next);
	if (nt == T_NULL \|\| nt == T_UNDEF \|\| !is_object_type(next)) return false;
	cur = next; t = nt;
	return true;
	}

	if (ct == T_OBJ \|\| ct == T_ARR \|\| ct == T_FUNC \|\| ct == T_PROMISE) {
	jsval_t as_obj = js_as_obj(*cur);
	jsval_t proto = get_slot(js, as_obj, SLOT_PROTO);

	uint8_t pt = vtype(proto);
	if (pt == T_OBJ \|\| pt == T_ARR \|\| pt == T_FUNC) {
	*cur = proto;
	*t = pt;
	return true;
	}

	if (JS_TYPE_FLAG(ct) & T_NEEDS_PROTO_FALLBACK) {
	jsval_t fallback = get_prototype_for_type(js, ct);
	uint8_t ft = vtype(fallback);
	if (ft == T_NULL \|\| ft == T_UNDEF) return false;
	*cur = fallback;
	*t = ft;
	return true;
	}

	return false;
	}

	if (ct == T_STR \|\| ct == T_NUM \|\| ct == T_BOOL \|\| ct == T_BIGINT \|\| ct == T_SYMBOL) {
	jsval_t proto = get_prototype_for_type(js, ct);
	uint8_t pt = vtype(proto);
	if (pt == T_NULL \|\| pt == T_UNDEF) return false;
	cur = proto; t = pt;
	return true;
	}

	return false;
	}

	jsval_t js_instance_proto_from_new_target(ant_t *js, jsval_t fallback_proto) {
	jsval_t instance_proto = js_mkundef();

	if (vtype(js->new_target) == T_FUNC \|\| vtype(js->new_target) == T_CFUNC) {
	jsval_t nt_obj = js_as_obj(js->new_target);
	jsoff_t nt_proto_off = lkp_interned(js, nt_obj, INTERN_PROTOTYPE, 9);
	if (nt_proto_off != 0) {
	jsval_t nt_proto = resolveprop(js, mkval(T_PROP, nt_proto_off));
	if (is_object_type(nt_proto)) instance_proto = nt_proto;
	}
	}

	if (!is_object_type(instance_proto) && is_object_type(fallback_proto)) {
	instance_proto = fallback_proto;
	} return instance_proto;
	}

	bool proto_chain_contains(ant_t *js, jsval_t obj, jsval_t proto_target) {
	if (!is_object_type(obj) \|\| !is_object_type(proto_target)) return false;
	jsval_t cur = obj; uint8_t t = vtype(cur);
	for (int depth = 0; depth < MAX_PROTO_CHAIN_DEPTH; depth++) {
	if (!proto_walk_next(js, &cur, &t, PROTO_WALK_F_OBJECT_ONLY)) break;
	if (vdata(cur) == vdata(proto_target)) return true;
	}
	return false;
	}

	static inline bool is_wrapper_ctor_target(ant_t *js, jsval_t this_val, jsval_t expected_proto) {
	if (vtype(js->new_target) == T_UNDEF) return false;
	if (vtype(this_val) != T_OBJ) return false;
	if (vtype(get_slot(js, this_val, SLOT_PRIMITIVE)) != T_UNDEF) return false;
	return proto_chain_contains(js, this_val, expected_proto);
	}

	jsval_t get_ctor_species_value(ant_t *js, jsval_t ctor) {
	if (!is_object_type(ctor) && vtype(ctor) != T_CFUNC) return js_mkundef();
	return js_get_sym(js, ctor, get_species_sym());
	}

	bool same_ctor_identity(ant_t *js, jsval_t a, jsval_t b) {
	if (vtype(a) == vtype(b) && vdata(a) == vdata(b)) return true;

	if (vtype(a) == T_FUNC && vtype(b) == T_CFUNC) {
	jsval_t c = get_slot(js, a, SLOT_CFUNC);
	return vtype(c) == T_CFUNC && vdata(c) == vdata(b);
	}

	if (vtype(a) == T_CFUNC && vtype(b) == T_FUNC) {
	jsval_t c = get_slot(js, b, SLOT_CFUNC);
	return vtype(c) == T_CFUNC && vdata(c) == vdata(a);
	}

	if (vtype(a) == T_FUNC && vtype(b) == T_FUNC) {
	jsval_t ca = get_slot(js, a, SLOT_CFUNC);
	jsval_t cb = get_slot(js, b, SLOT_CFUNC);
	if (vtype(ca) == T_CFUNC && vtype(cb) == T_CFUNC && vdata(ca) == vdata(cb)) return true;
	}

	return false;
	}

	static jsval_t array_constructor_from_receiver(ant_t *js, jsval_t receiver) {
	if (!is_object_type(receiver)) return js_mkundef();

	jsval_t species_source = receiver;
	if (is_proxy(js, species_source)) {
	species_source = proxy_read_target(js, species_source);
	}

	bool receiver_is_array = (vtype(species_source) == T_ARR);
	if (!receiver_is_array) {
	jsval_t array_proto = get_ctor_proto(js, "Array", 5);
	if (is_object_type(array_proto) && is_object_type(species_source)) {
	receiver_is_array = proto_chain_contains(js, species_source, array_proto);
	}
	}
	if (!receiver_is_array) return js_mkundef();

	jsval_t ctor = js_getprop_fallback(js, receiver, "constructor");
	if (is_err(ctor)) return ctor;

	jsval_t species = get_ctor_species_value(js, ctor);
	if (is_err(species)) return species;

	if (vtype(species) == T_NULL) return js_mkundef();
	if (vtype(species) == T_FUNC \|\| vtype(species) == T_CFUNC) return species;
	if (vtype(ctor) != T_FUNC && vtype(ctor) != T_CFUNC) return js_mkundef();

	return ctor;
	}

	static jsval_t array_alloc_from_ctor_with_length(ant_t *js, jsval_t ctor, jsoff_t length_hint) {
	if (vtype(ctor) != T_FUNC && vtype(ctor) != T_CFUNC) {
	return mkarr(js);
	}

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

	jsval_t proto = js_get(js, ctor, "prototype");
	if (is_err(proto)) return proto;
	if (is_object_type(proto)) set_proto(js, seed, proto);

	jsval_t ctor_args[1] = { tov((double)length_hint) };
	jsval_t saved_new_target = js->new_target;
	js->new_target = ctor;
	jsval_t constructed = sv_vm_call(js->vm, js, ctor, seed, ctor_args, 1, NULL, true);
	js->new_target = saved_new_target;
	if (is_err(constructed)) return constructed;

	jsval_t result = is_object_type(constructed) ? constructed : seed;
	set_slot(js, js_as_obj(result), SLOT_CTOR, ctor);
	return result;
	}

	static inline jsval_t array_alloc_from_ctor(ant_t *js, jsval_t ctor) {
	return array_alloc_from_ctor_with_length(js, ctor, 0);
	}

	static inline jsval_t array_alloc_like(ant_t *js, jsval_t receiver) {
	jsval_t ctor = array_constructor_from_receiver(js, receiver);
	if (is_err(ctor)) return ctor;
	return array_alloc_from_ctor(js, ctor);
	}

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

	static inline jsval_t check_object_extensibility(ant_t *js, jsval_t obj) {
	obj = js_as_obj(obj);
	jsoff_t obj_off_fp = (jsoff_t)vdata(obj);
	jsoff_t next = loadoff(js, obj_off_fp) & ~(3U \| FLAGMASK);

	while (next != 0 && next < js->brk) {
	jsoff_t hdr = loadoff(js, next);
	if ((hdr & SLOTMASK) == 0) break;

	jsoff_t sk = loadoff(js, next + sizeof(jsoff_t));
	jsval_t sv = loadval(js, next + sizeof(jsoff_t) * 2);

	if (sk == (jsoff_t)SLOT_FROZEN && js_truthy(js, sv)) {
	return sv_vm_is_strict(js->vm)
	? js_mkerr(js, "cannot add property to frozen object")
	: js_mkundef();
	}

	if (sk == (jsoff_t)SLOT_SEALED && js_truthy(js, sv)) {
	return sv_vm_is_strict(js->vm)
	? js_mkerr(js, "cannot add property to sealed object")
	: js_mkundef();
	}

	if (sk == (jsoff_t)SLOT_EXTENSIBLE && !js_truthy(js, sv)) {
	return sv_vm_is_strict(js->vm)
	? js_mkerr(js, "cannot add property to non-extensible object")
	: js_mkundef();
	}

	next = hdr & ~(3U \| FLAGMASK);
	}

	return js_mkundef();
	}

	static inline void update_array_length(ant_t *js, jsval_t obj, jsoff_t new_len) {
	jsoff_t len_off = lkp_interned(js, obj, INTERN_LENGTH, 6);
	jsval_t new_len_val = tov((double)new_len);

	if (len_off != 0) saveval(js, len_off + sizeof(jsoff_t) * 2, new_len_val); else {
	js_mkprop_fast(js, obj, "length", 6, new_len_val);
	}
	}

	static jsval_t js_setprop_array_fast(ant_t js, jsval_t obj, jsval_t k, jsval_t v, jsoff_t klen, const char key) {
	unsigned long idx;
	if (!parse_array_index(key, klen, (jsoff_t)-1, &idx)) return js_mkundef();

	jsoff_t doff = get_dense_buf(js, obj);
	if (doff) {
	jsoff_t cur_len = dense_length(js, doff);
	if (idx < cur_len) { dense_set(js, doff, (jsoff_t)idx, v); return v; }

	jsoff_t density_limit = cur_len > 0 ? cur_len * 4 : 64;
	if (idx >= density_limit) goto sparse;

	jsval_t extensibility_error = check_object_extensibility(js, obj);
	if (!is_undefined(extensibility_error)) return extensibility_error;

	arr_set(js, obj, (jsoff_t)idx, v);
	return v;
	}

	sparse:;
	jsoff_t cur_len = get_array_length(js, obj);
	if (idx < cur_len) return js_mkundef();

	jsval_t extensibility_error = check_object_extensibility(js, obj);
	if (!is_undefined(extensibility_error)) return extensibility_error;

	jsval_t result = mkprop_fast(js, obj, k, v, 0);
	update_array_length(js, obj, idx + 1);

	return result;
	}

	jsval_t js_setprop(ant_t *js, jsval_t obj, jsval_t k, jsval_t v) {
	uint8_t ot = vtype(obj);

	if (ot == T_STR \|\| ot == T_NUM \|\| ot == T_BOOL) {
	jsoff_t klen; jsoff_t koff = vstr(js, k, &klen);
	const char key = (char )&js->mem[koff];
	jsval_t proto = get_prototype_for_type(js, ot);
	if (is_object_type(proto)) {
	jsval_t setter = js_mkundef();
	bool has_setter = false;
	lkp_with_setter(js, proto, key, klen, &setter, &has_setter);
	if (has_setter && (vtype(setter) == T_FUNC \|\| vtype(setter) == T_CFUNC)) {
	call_proto_accessor(js, obj, setter, true, &v, 1, true);
	return v;
	}
	}
	if (sv_vm_is_strict(js->vm))
	return js_mkerr_typed(js, JS_ERR_TYPE,
	"Cannot create property '%.*s' on %s",
	(int)klen, key, typestr(ot));
	return v;
	}

	if (vtype(obj) == T_FUNC) obj = js_func_obj(obj);
	if (vtype(k) == T_SYMBOL) {
	jsoff_t sym_off = (jsoff_t)vdata(k);
	jsval_t cur = obj;

	for (int i = 0; i < MAX_PROTO_CHAIN_DEPTH; i++) {
	jsoff_t cur_off = (jsoff_t)vdata(js_as_obj(cur));
	descriptor_entry_t *sd = lookup_sym_descriptor(cur_off, sym_off);
	if (sd && sd->has_setter) {
	jsval_t setter = sd->setter;
	if (vtype(setter) == T_FUNC \|\| vtype(setter) == T_CFUNC) {
	jsval_t result = sv_vm_call(js->vm, js, setter, obj, &v, 1, NULL, false);
	if (is_err(result)) return result;
	return v;
	}
	}

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

	jsval_t proto = get_proto(js, js_as_obj(cur));
	if (!is_object_type(proto)) break;
	cur = proto;
	}

	jsoff_t existing = lkp_sym(js, obj, sym_off);

	if (existing > 0) {
	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);
	}

	if (js_truthy(js, get_slot(js, obj, SLOT_FROZEN))) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr(js, "cannot add property to frozen object");
	return js_mkundef();
	}

	return mkprop(js, obj, k, v, 0);
	}

	jsoff_t klen; jsoff_t koff = vstr(js, k, &klen);
	const char key = (char ) &js->mem[koff];

	if (vtype(obj) == T_ARR && !is_proxy(js, obj) && klen > 0 && key[0] >= '0' && key[0] <= '9') {
	jsval_t result = js_setprop_array_fast(js, obj, k, v, klen, key);
	if (vtype(result) != T_UNDEF) return result;
	}

	if (vtype(obj) == T_ARR && streq(key, klen, "length", 6)) {
	jsval_t err = validate_array_length(js, v);
	if (is_err(err)) return err;
	jsoff_t doff = get_dense_buf(js, obj);
	if (doff) {
	jsoff_t new_len_val = (jsoff_t) tod(v);
	jsoff_t cur_len = dense_length(js, doff);
	if (new_len_val < cur_len) {
	for (jsoff_t i = new_len_val; i < cur_len; i++)
	dense_set(js, doff, i, T_EMPTY);
	dense_set_length(js, doff, new_len_val);
	return v;
	} else if (new_len_val <= dense_capacity(js, doff)) {
	dense_set_length(js, doff, new_len_val);
	return v;
	}
	}
	}

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

	if (try_dynamic_setter(js, obj, key, klen, v)) return v;
	jsoff_t existing = lkp(js, obj, key, klen);

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

	if (!desc) {
	jsval_t cur = obj;
	for (int i = 0; i < MAX_PROTO_CHAIN_DEPTH && !desc; i++) {
	cur = get_proto(js, cur);
	if (vtype(cur) != T_OBJ && vtype(cur) != T_FUNC) break;
	desc = lookup_descriptor(js, (jsoff_t)vdata(js_as_obj(cur)), key, klen);
	}
	if (desc && !desc->has_setter && !desc->has_getter && desc->writable) desc = NULL;
	}

	if (!desc) goto no_descriptor;

	if (desc->has_setter) {
	jsval_t setter = desc->setter;
	uint8_t setter_type = vtype(setter);
	if (setter_type == T_FUNC \|\| setter_type == T_CFUNC) {
	js_error_site_t saved_errsite = js->errsite;
	jsval_t result = sv_vm_call(js->vm, js, setter, obj, &v, 1, NULL, false);
	js->errsite = saved_errsite;
	if (is_err(result)) return result;
	return v;
	}
	}

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

	if (!desc->writable) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr(js, "assignment to read-only property");
	return existing > 0 ? mkval(T_PROP, existing) : v;
	}

	if (existing <= 0) goto no_descriptor;
	}

	no_descriptor:
	if (existing <= 0) goto create_new;
	if (is_const_prop(js, existing)) return js_mkerr(js, "assignment to constant");

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

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

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

	jsval_t new_len = tov((double)(update_idx + 1));
	if (len_off != 0) saveval(js, len_off + sizeof(jsoff_t) * 2, new_len); else {
	mkprop(js, obj, js->length_str, new_len, 0);
	}

	done_update:
	return mkval(T_PROP, existing);

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

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

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

	int need_length_update = 0;
	unsigned long idx = 0;

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

	jsval_t result = mkprop(js, obj, k, v, 0);
	if (need_length_update) {
	jsoff_t inner_len_off = lkp_interned(js, obj, INTERN_LENGTH, 6);
	jsval_t inner_new_len = tov((double)(idx + 1));
	if (inner_len_off != 0) saveval(js, inner_len_off + sizeof(jsoff_t) * 2, inner_new_len); else {
	mkprop(js, obj, js->length_str, inner_new_len, 0);
	}
	}

	return result;
	}

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

	jsval_t js_define_own_prop(ant_t js, jsval_t obj, const char key, size_t klen, jsval_t v) {
	obj = js_as_obj(obj);
	if (is_proxy(js, obj)) {
	jsval_t result = proxy_set(js, obj, key, klen, v);
	if (is_err(result)) return result;
	return v;
	}

	if (try_dynamic_setter(js, obj, key, klen, v)) return v;
	jsoff_t existing = lkp(js, obj, key, klen);

	{
	jsoff_t obj_off = (jsoff_t)vdata(js_as_obj(obj));
	descriptor_entry_t *desc = lookup_descriptor(js, obj_off, key, klen);
	if (desc) {
	if (!desc->writable && !desc->has_setter) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr(js, "assignment to read-only property");
	return v;
	}
	if (desc->has_setter) {
	jsval_t setter = desc->setter;
	uint8_t setter_type = vtype(setter);
	if (setter_type == T_FUNC \|\| setter_type == T_CFUNC) {
	jsval_t result = sv_vm_call(js->vm, js, setter, obj, &v, 1, NULL, false);
	if (is_err(result)) return result;
	return v;
	}
	}
	}
	}

	if (existing > 0) {
	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);
	}

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

	jsval_t k = js_mkstr(js, key, klen);
	if (is_err(k)) return k;
	return mkprop(js, obj, k, v, 0);
	}

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

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

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

	#define SYM_HEAP_FIXED (sizeof(uint32_t) + sizeof(uint32_t) + sizeof(uintptr_t))
	#define SYM_FLAG_GLOBAL 1u
	#define SYM_REGISTRY_MAX 256

	static struct {
	const char *key;
	uint32_t sym_id;
	} g_sym_registry[SYM_REGISTRY_MAX];

	static size_t g_sym_registry_count = 0;
	static size_t g_sym_all_count = 0;
	static size_t g_sym_all_cap = 0;
	static jsval_t *g_sym_all = NULL;

	static void sym_table_add(jsval_t sym) {
	if (g_sym_all_count >= g_sym_all_cap) {
	size_t new_cap = g_sym_all_cap ? g_sym_all_cap * 2 : 64;
	jsval_t new_buf = realloc(g_sym_all, new_cap sizeof(jsval_t));
	if (!new_buf) return;
	g_sym_all = new_buf;
	g_sym_all_cap = new_cap;
	}
	g_sym_all[g_sym_all_count++] = sym;
	}

	jsval_t js_mksym(ant_t js, const char desc) {
	uint32_t id = (uint32_t)(++js->sym_counter);
	size_t desc_len = (desc && *desc) ? strlen(desc) : 0;
	size_t payload = SYM_HEAP_FIXED + (desc_len ? desc_len + 1 : 0);

	jsoff_t ofs = js_alloc(js, payload + sizeof(jsoff_t));
	if (ofs == (jsoff_t)~0) return js_mkerr(js, "oom");

	jsoff_t header = (jsoff_t)(payload << 4);
	memcpy(&js->mem[ofs], &header, sizeof(header));

	jsoff_t p = ofs + sizeof(jsoff_t);
	memcpy(&js->mem[p], &id, sizeof(id));
	p += sizeof(uint32_t);
	uint32_t flags = 0;
	memcpy(&js->mem[p], &flags, sizeof(flags));
	p += sizeof(uint32_t);
	uintptr_t key_ptr = 0;
	memcpy(&js->mem[p], &key_ptr, sizeof(key_ptr));
	p += sizeof(uintptr_t);

	if (desc_len) {
	memcpy(&js->mem[p], desc, desc_len);
	js->mem[p + desc_len] = '\0';
	}

	jsval_t sym = mkval(T_SYMBOL, ofs);
	sym_table_add(sym);
	return sym;
	}

	static inline uint32_t sym_get_id(ant_t *js, jsval_t v) {
	jsoff_t ofs = (jsoff_t)vdata(v);
	uint32_t id;
	memcpy(&id, &js->mem[ofs + sizeof(jsoff_t)], sizeof(id));
	return id;
	}

	static inline uint32_t sym_get_flags(ant_t *js, jsval_t v) {
	jsoff_t ofs = (jsoff_t)vdata(v);
	uint32_t flags;
	memcpy(&flags, &js->mem[ofs + sizeof(jsoff_t) + sizeof(uint32_t)], sizeof(flags));
	return flags;
	}

	static inline uintptr_t sym_get_key_ptr(ant_t *js, jsval_t v) {
	jsoff_t ofs = (jsoff_t)vdata(v);
	uintptr_t kp;
	memcpy(&kp, &js->mem[ofs + sizeof(jsoff_t) + sizeof(uint32_t) * 2], sizeof(kp));
	return kp;
	}

	static const char sym_get_desc(ant_t js, jsval_t v) {
	jsoff_t ofs = (jsoff_t)vdata(v);
	jsoff_t header;
	memcpy(&header, &js->mem[ofs], sizeof(header));
	size_t payload = (size_t)(header >> 4);
	if (payload <= SYM_HEAP_FIXED) return NULL;
	return (const char *)&js->mem[ofs + sizeof(jsoff_t) + SYM_HEAP_FIXED];
	}

	uint64_t inline js_sym_id(jsval_t sym) {
	// TODO: fix to not use the global runtime
	ant_t *js = rt->js;
	return sym_get_id(js, sym);
	}

	jsval_t js_mksym_for(ant_t js, const char key) {
	const char *interned = intern_string(key, strlen(key));

	for (size_t i = 0; i < g_sym_registry_count; i++) {
	if (g_sym_registry[i].key == interned) {
	uint32_t id = g_sym_registry[i].sym_id;
	if (id - 1 < g_sym_all_count) return g_sym_all[id - 1];
	}
	}

	jsval_t sym = js_mksym(js, key);
	if (is_err(sym)) return sym;

	jsoff_t ofs = (jsoff_t)vdata(sym);
	uint32_t flags = SYM_FLAG_GLOBAL;
	memcpy(&js->mem[ofs + sizeof(jsoff_t) + sizeof(uint32_t)], &flags, sizeof(flags));
	uintptr_t kp = (uintptr_t)interned;
	memcpy(&js->mem[ofs + sizeof(jsoff_t) + sizeof(uint32_t) * 2], &kp, sizeof(kp));

	if (g_sym_registry_count < SYM_REGISTRY_MAX) {
	uint32_t id = sym_get_id(js, sym);
	g_sym_registry[g_sym_registry_count].key = interned;
	g_sym_registry[g_sym_registry_count].sym_id = id;
	g_sym_registry_count++;
	}

	return sym;
	}

	const char *js_sym_key(jsval_t sym) {
	if (vtype(sym) != T_SYMBOL) return NULL;
	ant_t *js = rt->js;
	if (!(sym_get_flags(js, sym) & SYM_FLAG_GLOBAL)) return NULL;
	return (const char *)sym_get_key_ptr(js, sym);
	}

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

	jsval_t sym_lookup_by_id(uint32_t id) {
	if (id == 0 \|\| id - 1 >= g_sym_all_count) return (jsval_t)0;
	return g_sym_all[id - 1];
	}

	void sym_gc_update_all(void (op_val)(void , jsval_t ), void ctx) {
	for (size_t i = 0; i < g_sym_all_count; i++) {
	op_val(ctx, &g_sym_all[i]);
	}
	}

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

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

	static inline jsoff_t lkp_interned(ant_t js, jsval_t obj, const char search_intern, size_t len) {
	obj = js_as_obj(obj);
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	jsoff_t tail = loadoff(js, obj_off + sizeof(jsoff_t) * 2);

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

	if (ce->generation == intern_prop_cache_gen
	&& ce->obj_off == obj_off
	&& ce->intern_ptr == search_intern
	&& ce->tail == tail
	) return ce->prop_off;

	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	jsoff_t off = first_prop; jsoff_t result = 0;

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

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

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

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

	return result;
	}

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

	jsoff_t lkp_sym(ant_t *js, jsval_t obj, jsoff_t sym_off) {
	obj = js_as_obj(obj);
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	jsoff_t off = first_prop;

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

	jsoff_t lkp_sym_proto(ant_t *js, jsval_t obj, jsoff_t sym_off) {
	for (int i = 0; i < MAX_PROTO_CHAIN_DEPTH; i++) {
	jsoff_t off = lkp_sym(js, obj, sym_off);
	if (off != 0) return off;
	jsval_t proto = get_proto(js, js_as_obj(obj));
	if (!is_object_type(proto)) break;
	obj = proto;
	}
	return 0;
	}

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

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

	if (vtype(bound_arr) == T_ARR) {
	bound_argc = (int)get_array_length(js, bound_arr);
	} if (bound_argc <= 0) return NULL;

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

	for (int i = 0; i < bound_argc; i++) combined[i] = arr_get(js, bound_arr, (jsoff_t)i);
	for (int i = 0; i < nargs; i++) combined[bound_argc + i] = args[i];

	return combined;
	}

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

	for (jsval_t current = obj; is_object_type(current); ) {
	current = js_as_obj(current);
	jsoff_t current_off = (jsoff_t)vdata(current);
	descriptor_entry_t *desc = lookup_descriptor(js, current_off, buf, len);

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

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

	jsval_t proto = get_proto(js, current);
	if (!is_object_type(proto)) break;
	current = proto;
	}

	return 0;
	}

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

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

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

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

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

	return 0;
	}

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

	js_error_site_t saved_errsite = js->errsite;
	jsval_t result = sv_vm_call(js->vm, js, accessor, prim, arg, arg_count, NULL, false);

	bool had_throw = js->thrown_exists;
	jsval_t thrown = js->thrown_value;
	js->errsite = saved_errsite;

	if (had_throw) {
	js->thrown_exists = true;
	js->thrown_value = thrown;
	}

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

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

	if (!is_object_type(obj)) return js_mknull();
	jsval_t as_obj = js_as_obj(obj);

	jsval_t proto = get_slot(js, as_obj, SLOT_PROTO);
	if (is_object_type(proto)) return proto;

	if (t != T_OBJ) return get_prototype_for_type(js, t);
	return js_mknull();
	}

	static jsval_t get_proto(ant_t *js, jsval_t obj) {
	return js_get_proto(js, obj);
	}

	void js_set_proto(ant_t *js, jsval_t obj, jsval_t proto) {
	if (!is_object_type(obj)) return;

	jsval_t as_obj = js_as_obj(obj);
	set_slot(js, as_obj, SLOT_PROTO, proto);
	}

	static void set_proto(ant_t *js, jsval_t obj, jsval_t proto) {
	js_set_proto(js, obj, proto);
	}

	jsval_t js_get_ctor_proto(ant_t js, const char name, size_t len) {
	jsoff_t ctor_off = lkp_interned(js, js->global, intern_string(name, len), 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 = js_as_obj(ctor);
	jsoff_t proto_off = lkp_interned(js, ctor_obj, INTERN_PROTOTYPE, 9);
	if (proto_off == 0) return js_mknull();
	return resolveprop(js, mkval(T_PROP, proto_off));
	}

	static inline jsval_t get_ctor_proto(ant_t js, const char name, size_t len) {
	return js_get_ctor_proto(js, name, len);
	}

	static jsval_t get_prototype_for_type(ant_t *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);
	case T_SYMBOL: return get_ctor_proto(js, "Symbol", 6);
	default: return js_mknull();
	}}

	jsoff_t lkp_proto(ant_t js, jsval_t obj, const char key, size_t len) {
	uint8_t t = vtype(obj);
	const char *key_intern = intern_string(key, len);
	if (!key_intern) return 0;

	jsval_t cur = obj;
	int depth = 0;

	while (depth < MAX_PROTO_CHAIN_DEPTH) {
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC \|\| t == T_PROMISE) {
	jsval_t as_obj = js_as_obj(cur);
	jsoff_t off = lkp_interned(js, as_obj, key_intern, len);
	if (off != 0) return off;
	} else if (t == T_CFUNC) {
	jsval_t func_proto = get_ctor_proto(js, "Function", 8);
	uint8_t ft = vtype(func_proto);
	if (ft == T_OBJ \|\| ft == T_ARR \|\| ft == T_FUNC) {
	jsoff_t off = lkp(js, js_as_obj(func_proto), key, len);
	if (off != 0) return off;
	}
	break;
	} else if (t != T_STR && t != T_NUM && t != T_BOOL && t != T_BIGINT && t != T_SYMBOL) break;
	if (!proto_walk_next(js, &cur, &t, PROTO_WALK_F_LOOKUP)) { break; } depth++;
	}

	return 0;
	}

	static jsval_t getprop_any(ant_t js, jsval_t obj, const char key, size_t key_len) {
	uint8_t t = vtype(obj);

	if (t == T_STR && key_len == 6 && memcmp(key, "length", 6) == 0) {
	jsoff_t byte_len;
	jsoff_t str_off = vstr(js, obj, &byte_len);
	return tov(D(utf16_strlen((const char *)&js->mem[str_off], byte_len)));
	}

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

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	jsval_t as_obj = js_as_obj(obj);
	jsoff_t off = lkp(js, as_obj, key, key_len);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	off = lkp_proto(js, obj, key, key_len);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));
	}

	return js_mkundef();
	}

	static jsval_t try_dynamic_getter(ant_t js, jsval_t obj, const char key, size_t key_len) {
	jsoff_t obj_off = (jsoff_t)vdata(js_as_obj(obj));
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry \|\| !entry->getter) return js_mkundef();
	return entry->getter(js, obj, key, key_len);
	}

	static bool try_dynamic_setter(ant_t js, jsval_t obj, const char key, size_t key_len, jsval_t value) {
	jsoff_t obj_off = (jsoff_t)vdata(js_as_obj(obj));
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry \|\| !entry->setter) return false;
	return entry->setter(js, obj, key, key_len, value);
	}

	static bool try_dynamic_deleter(ant_t js, jsval_t obj, const char key, size_t key_len) {
	jsoff_t obj_off = (jsoff_t)vdata(js_as_obj(obj));
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry \|\| !entry->deleter) return false;
	return entry->deleter(js, obj, key, key_len);
	}

	static bool try_accessor_getter(ant_t js, jsval_t obj, const char key, size_t key_len, jsval_t *out) {
	jsval_t getter = js_mkundef();
	bool has_getter = false;
	lkp_with_getter(js, obj, key, key_len, &getter, &has_getter);

	jsval_t result = call_proto_accessor(js, obj, getter, has_getter, NULL, 0, false);
	if (vtype(result) != T_UNDEF) {
	*out = result;
	return true;
	}
	return false;
	}

	static bool try_accessor_setter(ant_t js, jsval_t obj, const char key, size_t key_len, jsval_t val, jsval_t *out) {
	jsval_t setter = js_mkundef();
	bool has_setter = false;

	lkp_with_setter(js, obj, key, key_len, &setter, &has_setter);
	if (!has_setter) return false;

	jsval_t result = call_proto_accessor(js, obj, setter, has_setter, &val, 1, true);
	if (is_err(result)) {
	*out = result;
	return true;
	}

	*out = val;
	return true;
	}

	jsval_t resolveprop(ant_t *js, jsval_t v) {
	if (vtype(v) != T_PROP) return v;
	return resolveprop(js, loadval(js, (jsoff_t) (vdata(v) + sizeof(jsoff_t) * 2)));
	}

	typedef struct {
	char *buffer;
	size_t capacity;
	size_t size;
	bool is_dynamic;
	} string_builder_t;

	static void string_builder_init(string_builder_t sb, char static_buf, size_t static_cap) {
	sb->buffer = static_buf;
	sb->capacity = static_cap;
	sb->size = 0;
	sb->is_dynamic = false;
	}

	static bool string_builder_append(string_builder_t sb, const char data, size_t len) {
	if (sb->size + len > sb->capacity) {
	size_t new_capacity = sb->capacity ? sb->capacity * 2 : 256;
	while (new_capacity < sb->size + len) new_capacity *= 2;

	char new_buffer = (char )ant_calloc(new_capacity);
	if (!new_buffer) return false;

	if (sb->size > 0) memcpy(new_buffer, sb->buffer, sb->size);
	if (sb->is_dynamic) free(sb->buffer);

	sb->buffer = new_buffer;
	sb->capacity = new_capacity;
	sb->is_dynamic = true;
	}

	if (len > 0) {
	memcpy(sb->buffer + sb->size, data, len);
	sb->size += len;
	}

	return true;
	}

	static jsval_t string_builder_finalize(ant_t js, string_builder_t sb) {
	jsval_t result = js_mkstr(js, sb->buffer, sb->size);
	if (sb->is_dynamic && sb->buffer) free(sb->buffer);
	return result;
	}

	jsoff_t str_len_fast(ant_t *js, jsval_t str) {
	if (vtype(str) != T_STR) return 0;
	if (is_rope(js, str)) return rope_len(js, str);
	return assert_flat_string_len(js, str, NULL);
	}

	jsval_t do_string_op(ant_t *js, uint8_t op, jsval_t l, jsval_t r) {
	if (op == TOK_PLUS) {
	jsoff_t n1 = str_len_fast(js, l);
	jsoff_t n2 = str_len_fast(js, r);
	jsoff_t total_len = n1 + n2;

	if (n2 == 0) return l;
	if (n1 == 0) return r;

	uint8_t left_depth = (vtype(l) == T_STR && is_rope(js, l)) ? rope_depth(js, l) : 0;
	uint8_t right_depth = (vtype(r) == T_STR && is_rope(js, r)) ? rope_depth(js, r) : 0;
	uint8_t new_depth = (left_depth > right_depth ? left_depth : right_depth) + 1;

	if (new_depth >= ROPE_MAX_DEPTH \|\| total_len >= ROPE_FLATTEN_THRESHOLD) {
	jsval_t flat_l = l, flat_r = r;
	if (is_rope(js, l)) flat_l = rope_flatten(js, l);
	if (is_err(flat_l)) return flat_l;
	if (is_rope(js, r)) flat_r = rope_flatten(js, r);
	if (is_err(flat_r)) return flat_r;

	jsoff_t off1, off2, len1, len2;
	off1 = vstr(js, flat_l, &len1);
	off2 = vstr(js, flat_r, &len2);

	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], len1) \|\|
	!string_builder_append(&sb, (char *)&js->mem[off2], len2)
	) return js_mkerr(js, "string concatenation failed");

	return string_builder_finalize(js, &sb);
	}

	return js_mkrope(js, l, r, total_len, new_depth);
	}

	jsoff_t n1, off1 = vstr(js, l, &n1);
	jsoff_t n2, off2 = vstr(js, r, &n2);

	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");
	}


	typedef enum { ITER_CONTINUE, ITER_BREAK, ITER_ERROR } iter_action_t;
	typedef iter_action_t (iter_callback_t)(ant_t js, jsval_t value, void ctx, jsval_t out);
	static jsval_t iter_foreach(ant_t js, jsval_t iterable, iter_callback_t cb, void ctx);


	static bool js_try_call_method(ant_t js, jsval_t obj, const char method, size_t method_len, jsval_t args, int nargs, jsval_t out_result) {
	jsval_t getter = js_mkundef(); bool has_getter = false;
	jsoff_t off = lkp_with_getter(js, obj, method, method_len, &getter, &has_getter);

	jsval_t fn;
	if (has_getter) {
	fn = call_proto_accessor(js, obj, getter, true, NULL, 0, false);
	if (is_err(fn)) { *out_result = fn; return true; }
	} else if (off != 0) {
	fn = resolveprop(js, mkval(T_PROP, off));
	} else return false;

	uint8_t ft = vtype(fn);
	if (ft != T_FUNC && ft != T_CFUNC) return false;

	jsval_t saved_this = js->this_val;
	js->this_val = obj;

	jsval_t result;
	if (ft == T_CFUNC) result = ((jsval_t ()(ant_t , jsval_t *, int))vdata(fn))(js, args, nargs);
	else result = sv_vm_call(js->vm, js, fn, obj, args, nargs, NULL, false);

	bool had_throw = js->thrown_exists;
	jsval_t thrown = js->thrown_value;

	js->this_val = saved_this;
	if (had_throw) {
	js->thrown_exists = true;
	js->thrown_value = thrown;
	}

	*out_result = result;
	return true;
	}

	static jsval_t js_call_method(ant_t js, jsval_t obj, const char method, size_t method_len, jsval_t *args, int nargs) {
	jsval_t result;
	if (!js_try_call_method(js, obj, method, method_len, args, nargs, &result)) return js_mkundef();
	return result;
	}

	static jsval_t js_call_toString(ant_t *js, jsval_t value) {
	jsval_t result = js_call_method(js, value, "toString", 8, NULL, 0);

	if (is_err(result)) return result;
	if (vtype(result) == T_STR) return result;

	uint8_t rtype = vtype(result);
	if (rtype == T_UNDEF) {
	goto fallback;
	}

	if (rtype != T_OBJ && rtype != T_ARR && rtype != T_FUNC) {
	char buf[256];
	size_t len = tostr(js, result, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	fallback:;
	char buf[4096];
	size_t len = tostr(js, value, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	static jsval_t js_call_valueOf(ant_t *js, jsval_t value) {
	jsval_t result = js_call_method(js, value, "valueOf", 7, NULL, 0);
	if (vtype(result) == T_UNDEF) return value;
	return result;
	}

	static inline bool is_primitive(jsval_t v) {
	uint8_t t = vtype(v);
	return t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_NULL \|\| t == T_UNDEF \|\| t == T_SYMBOL \|\| t == T_BIGINT;
	}

	static jsval_t try_exotic_to_primitive(ant_t *js, jsval_t value, int hint) {
	jsval_t tp_sym = get_toPrimitive_sym();
	if (vtype(tp_sym) != T_SYMBOL) return mkval(T_UNDEF, 0);
	jsoff_t tp_off = lkp_sym_proto(js, value, (jsoff_t)vdata(tp_sym));
	if (tp_off == 0) return mkval(T_UNDEF, 0);

	jsval_t tp_fn = resolveprop(js, mkval(T_PROP, tp_off));
	uint8_t ft = vtype(tp_fn);

	if (ft == T_UNDEF) return mkval(T_UNDEF, 0);
	if (ft != T_FUNC && ft != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Symbol.toPrimitive is not a function");
	}

	const char *hint_str = hint == 1 ? "string" : (hint == 2 ? "number" : "default");
	jsval_t hint_arg = js_mkstr(js, hint_str, strlen(hint_str));
	jsval_t result = sv_vm_call(js->vm, js, tp_fn, value, &hint_arg, 1, NULL, false);

	if (is_err(result) \|\| is_primitive(result)) return result;
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot convert object to primitive value");
	}

	static jsval_t try_ordinary_to_primitive(ant_t *js, jsval_t value, int hint) {
	static const char *names[] = {"valueOf", "toString"};
	static const size_t lens[] = {7, 8};

	int first = (hint == 1);
	jsval_t result;

	for (int i = 0; i < 2; i++) {
	int idx = first ^ i;
	if (js_try_call_method(js, value, names[idx], lens[idx], NULL, 0, &result))
	if (is_err(result) \|\| is_primitive(result)) return result;
	}

	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot convert object to primitive value");
	}

	jsval_t js_to_primitive(ant_t *js, jsval_t value, int hint) {
	if (is_primitive(value)) return value;
	if (!is_object_type(value)) return value;

	jsval_t result = try_exotic_to_primitive(js, value, hint);
	if (vtype(result) != T_UNDEF) return result;

	return try_ordinary_to_primitive(js, value, hint);
	}

	bool strict_eq_values(ant_t *js, jsval_t l, jsval_t r) {
	uint8_t t = vtype(l);
	if (t != vtype(r)) return false;
	if (t == T_STR) {
	jsoff_t n1, n2, off1 = vstr(js, l, &n1), off2 = vstr(js, r, &n2);
	return n1 == n2 && memcmp(&js->mem[off1], &js->mem[off2], n1) == 0;
	}
	if (t == T_NUM) return tod(l) == tod(r);
	if (t == T_BIGINT) return bigint_compare(js, l, r) == 0;
	return vdata(l) == vdata(r);
	}

	jsval_t coerce_to_str(ant_t *js, jsval_t v) {
	if (vtype(v) == T_STR) return v;

	if (is_object_type(v)) {
	jsval_t prim = js_to_primitive(js, v, 1);
	if (is_err(prim)) return prim;
	if (vtype(prim) == T_STR) return prim;
	return js_tostring_val(js, prim);
	}

	return js_tostring_val(js, v);
	}

	jsval_t coerce_to_str_concat(ant_t *js, jsval_t v) {
	if (vtype(v) == T_STR) return v;

	if (is_object_type(v)) {
	jsval_t prim = js_to_primitive(js, v, 0);
	if (is_err(prim)) return prim;
	if (vtype(prim) == T_STR) return prim;
	return js_tostring_val(js, prim);
	}

	return js_tostring_val(js, v);
	}

	static void unlink_prop(ant_t *js, jsoff_t obj_off, jsoff_t prop_off, jsoff_t prev_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~FLAGMASK;
	jsoff_t target = prev_off ? prev_off : obj_off;
	jsoff_t current = loadoff(js, target);

	saveoff(js, target, (deleted_next & ~3ULL) \| (current & (FLAGMASK \| 3ULL)));
	jsoff_t tail = loadoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t));

	if (tail == prop_off) {
	saveoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t), prev_off);
	}

	invalidate_prop_cache(js, obj_off, prop_off);
	js->needs_gc = true;
	}

	static jsval_t check_frozen_sealed(ant_t js, jsval_t obj, const char action) {
	if (js_truthy(js, get_slot(js, obj, SLOT_FROZEN))) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr(js, "cannot %s property of frozen object", action);
	return js_false;
	}
	if (js_truthy(js, get_slot(js, obj, SLOT_SEALED))) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr(js, "cannot %s property of sealed object", action);
	return js_false;
	}
	return js_mkundef();
	}

	jsval_t js_delete_prop(ant_t js, jsval_t obj, const char key, size_t len) {
	obj = js_as_obj(obj);
	if (is_proxy(js, obj)) {
	jsval_t result = proxy_delete(js, obj, key, len);
	return is_err(result) ? result : js_bool(js_truthy(js, result));
	}

	jsval_t err = check_frozen_sealed(js, obj, "delete");
	if (vtype(err) != T_UNDEF) return err;

	jsoff_t obj_off = (jsoff_t)vdata(js_as_obj(obj));

	if (is_arr_off(js, obj_off)) {
	jsoff_t doff = get_dense_buf_off(js, obj_off);
	unsigned long del_idx;
	if (doff && parse_array_index(key, len, dense_length(js, doff), &del_idx)) {
	arr_del(js, mkval(T_ARR, (uint64_t)obj_off), (jsoff_t)del_idx);
	return js_true;
	}
	}

	jsoff_t prop_off = lkp(js, obj, key, len);
	if (prop_off == 0) {
	try_dynamic_deleter(js, obj, key, len);
	return js_true;
	}

	if (is_nonconfig_prop(js, prop_off)) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr_typed(js, JS_ERR_TYPE, "cannot delete non-configurable property");
	return js_false;
	}

	descriptor_entry_t *desc = lookup_descriptor(js, obj_off, key, len);
	if (desc && !desc->configurable) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr_typed(js, JS_ERR_TYPE, "cannot delete non-configurable property");
	return js_false;
	}

	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	if (first_prop == prop_off) {
	unlink_prop(js, obj_off, prop_off, 0);
	return js_true;
	}
	for (jsoff_t prev = first_prop; prev != 0; ) {
	jsoff_t next_prop = loadoff(js, prev) & ~(3U \| FLAGMASK);
	if (next_prop == prop_off) {
	unlink_prop(js, obj_off, prop_off, prev);
	return js_true;
	}
	prev = next_prop;
	}
	return js_true;
	}

	jsval_t js_delete_sym_prop(ant_t *js, jsval_t obj, jsval_t sym) {
	obj = js_as_obj(obj);
	if (is_proxy(js, obj)) {
	jsval_t result = proxy_delete_val(js, obj, sym);
	return is_err(result) ? result : js_bool(js_truthy(js, result));
	}

	jsval_t err = check_frozen_sealed(js, obj, "delete");
	if (vtype(err) != T_UNDEF) return err;

	jsoff_t obj_off = (jsoff_t)vdata(obj);
	jsoff_t sym_off = (jsoff_t)vdata(sym);
	jsoff_t prop_off = lkp_sym(js, obj, sym_off);
	if (prop_off == 0) return js_true;

	if (is_nonconfig_prop(js, prop_off)) {
	if (sv_vm_is_strict(js->vm)) return js_mkerr_typed(js, JS_ERR_TYPE, "cannot delete non-configurable property");
	return js_false;
	}

	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	if (first_prop == prop_off) {
	unlink_prop(js, obj_off, prop_off, 0);
	return js_true;
	}
	for (jsoff_t prev = first_prop; prev != 0; ) {
	jsoff_t np = loadoff(js, prev) & ~(3U \| FLAGMASK);
	if (np == prop_off) {
	unlink_prop(js, obj_off, prop_off, prev);
	return js_true;
	}
	prev = np;
	}
	return js_true;
	}

	static jsval_t iter_call_noargs_with_this(ant_t *js, jsval_t this_val, jsval_t method) {
	jsval_t result = sv_vm_call(js->vm, js, method, this_val, NULL, 0, NULL, false);
	return result;
	}

	static jsval_t iter_close_iterator(ant_t *js, jsval_t iterator) {
	jsoff_t return_off = lkp_proto(js, iterator, "return", 6);
	if (return_off == 0) return js_mkundef();
	jsval_t return_method = loadval(js, return_off + sizeof(jsoff_t) * 2);
	if (vtype(return_method) != T_FUNC && vtype(return_method) != T_CFUNC) {
	return js_mkerr(js, "iterator.return is not a function");
	}
	return iter_call_noargs_with_this(js, iterator, return_method);
	}

	static jsval_t iter_foreach(ant_t js, jsval_t iterable, iter_callback_t cb, void ctx) {
	jsval_t iter_sym = get_iterator_sym();
	jsoff_t iter_prop = (vtype(iter_sym) == T_SYMBOL) ? lkp_sym_proto(js, iterable, (jsoff_t)vdata(iter_sym)) : 0;
	if (iter_prop == 0) return js_mkerr(js, "not iterable");

	jsval_t iter_method = loadval(js, iter_prop + sizeof(jsoff_t) * 2);
	jsval_t iterator = iter_call_noargs_with_this(js, iterable, iter_method);
	if (is_err(iterator)) return iterator;

	jshdl_t h_iterator = js_root(js, iterator);
	jsval_t out = js_mkundef();

	while (true) {
	jsval_t cur_iter = js_deref(js, h_iterator);
	jsoff_t next_off = lkp_proto(js, cur_iter, "next", 4);
	if (next_off == 0) { js_unroot(js, h_iterator); return js_mkerr(js, "iterator.next is not a function"); }

	jsval_t next_method = loadval(js, next_off + sizeof(jsoff_t) * 2);
	if (vtype(next_method) != T_FUNC && vtype(next_method) != T_CFUNC) {
	js_unroot(js, h_iterator);
	return js_mkerr(js, "iterator.next is not a function");
	}

	cur_iter = js_deref(js, h_iterator);
	jsval_t result = iter_call_noargs_with_this(js, cur_iter, next_method);
	if (is_err(result)) { js_unroot(js, h_iterator); return result; }

	jsoff_t done_off = lkp(js, result, "done", 4);
	jsval_t done_val = done_off ? loadval(js, done_off + sizeof(jsoff_t) * 2) : js_mkundef();
	if (js_truthy(js, done_val)) break;

	jsoff_t value_off = lkp(js, result, "value", 5);
	jsval_t value = value_off ? loadval(js, value_off + sizeof(jsoff_t) * 2) : js_mkundef();

	iter_action_t action = cb(js, value, ctx, &out);
	if (action == ITER_BREAK) {
	jsval_t close_result = iter_close_iterator(js, cur_iter);
	if (is_err(close_result)) { js_unroot(js, h_iterator); return close_result; }
	break;
	}
	if (action == ITER_ERROR) {
	jsval_t close_result = iter_close_iterator(js, cur_iter);
	js_unroot(js, h_iterator);
	if (is_err(close_result)) return close_result;
	return out;
	}
	}

	js_unroot(js, h_iterator);
	return out;
	}

	jsval_t js_symbol_to_string(ant_t *js, jsval_t sym) {
	const char *desc = js_sym_desc(js, sym);
	if (!desc) return js_mkstr(js, "Symbol()", 8);

	size_t desc_len = strlen(desc);
	size_t total = 7 + desc_len + 1;

	char stack_buf[128];
	char *buf = (total + 1 <= sizeof(stack_buf)) ? stack_buf : malloc(total + 1);
	if (!buf) return js_mkerr(js, "out of memory");

	memcpy(buf, "Symbol(", 7);
	memcpy(buf + 7, desc, desc_len);
	buf[7 + desc_len] = ')';
	buf[total] = '\0';

	jsval_t result = js_mkstr(js, buf, total);
	if (buf != stack_buf) free(buf);
	return result;
	}

	static jsval_t builtin_String(ant_t js, jsval_t args, int nargs) {
	jsval_t sval;

	if (nargs == 0) {
	sval = js_mkstr(js, "", 0);
	} else if (vtype(args[0]) == T_STR) {
	sval = args[0];
	} else if (vtype(args[0]) == T_SYMBOL) {
	sval = js_symbol_to_string(js, args[0]);
	if (is_err(sval)) return sval;
	} else {
	sval = coerce_to_str(js, args[0]);
	if (is_err(sval)) return sval;
	}

	jsval_t string_proto = js_get_ctor_proto(js, "String", 6);
	if (is_wrapper_ctor_target(js, js->this_val, string_proto)) {
	set_slot(js, js->this_val, SLOT_PRIMITIVE, sval);
	jsoff_t slen;
	vstr(js, sval, &slen);
	js_setprop(js, js->this_val, js->length_str, tov((double)slen));
	js_set_descriptor(js, js->this_val, "length", 6, 0);
	}
	return sval;
	}

	static jsval_t builtin_Number_isNaN(ant_t 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(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t arg = args[0];

	if (vtype(arg) != T_NUM) return mkval(T_BOOL, 0);

	double val = tod(arg);
	return mkval(T_BOOL, isfinite(val) ? 1 : 0);
	}

	static jsval_t builtin_global_isNaN(ant_t 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(ant_t 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_eval(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkundef();
	jsval_t code = args[0];
	if (vtype(code) != T_STR) return code;
	jsoff_t code_len = 0;
	jsoff_t code_off = vstr(js, code, &code_len);
	const char code_str = (const char )&js->mem[code_off];
	return js_eval_bytecode_eval_with_strict(js, code_str, (size_t)code_len, false);
	}

	static jsval_t builtin_Number_isInteger(ant_t 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(ant_t 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(ant_t js, jsval_t args, int nargs) {
	jsval_t nval = tov(nargs > 0 ? js_to_number(js, args[0]) : 0.0);
	jsval_t number_proto = js_get_ctor_proto(js, "Number", 6);
	if (is_wrapper_ctor_target(js, js->this_val, number_proto)) {
	set_slot(js, js->this_val, SLOT_PRIMITIVE, nval);
	}
	return nval;
	}

	static jsval_t builtin_Boolean(ant_t js, jsval_t args, int nargs) {
	jsval_t bval = mkval(T_BOOL, nargs > 0 && js_truthy(js, args[0]) ? 1 : 0);
	jsval_t boolean_proto = js_get_ctor_proto(js, "Boolean", 7);
	if (is_wrapper_ctor_target(js, js->this_val, boolean_proto)) {
	set_slot(js, js->this_val, SLOT_PRIMITIVE, bval);
	}
	return bval;
	}

	static jsval_t builtin_Object(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0 \|\| vtype(args[0]) == T_NULL \|\| vtype(args[0]) == T_UNDEF) {
	jsval_t obj_proto = js_get_ctor_proto(js, "Object", 6);
	if (is_unboxed_obj(js, js->this_val, obj_proto)) return js->this_val;
	return js_mkobj(js);
	}

	jsval_t arg = args[0];
	uint8_t t = vtype(arg);

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) return arg;
	if (t == T_STR \|\| t == T_NUM \|\| t == T_BOOL \|\| t == T_BIGINT) {
	jsval_t wrapper = js_mkobj(js);
	if (is_err(wrapper)) return wrapper;
	set_slot(js, wrapper, SLOT_PRIMITIVE, arg);
	jsval_t proto = get_prototype_for_type(js, t);
	if (vtype(proto) == T_OBJ) set_proto(js, wrapper, proto);
	return wrapper;
	}

	return arg;
	}

	static jsval_t builtin_function_empty(ant_t , jsval_t , int);

	static jsval_t build_dynamic_function(ant_t js, jsval_t args, int nargs, bool is_async) {
	if (nargs == 0) {
	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) return func_obj;

	set_func_code_ptr(js, func_obj, "(){}", 4);
	if (is_async) {
	set_slot(js, func_obj, SLOT_ASYNC, js_true);
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);
	} else {
	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	jsval_t instance_proto = js_instance_proto_from_new_target(js, func_proto);
	if (is_object_type(instance_proto)) set_proto(js, func_obj, instance_proto);
	}
	set_slot(js, func_obj, SLOT_CFUNC, js_mkfun(builtin_function_empty));

	jsval_t func = js_obj_to_func(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++) {
	args[i] = coerce_to_str(js, args[i]);
	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 = coerce_to_str(js, args[nargs - 1]);
	if (is_err(body)) return body;
	total_len += vstrlen(js, body);
	total_len += 1;

	char code_buf = (char )malloc(total_len + 1);
	if (!code_buf) return js_mkerr(js, "oom");
	size_t pos = 0;

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

	jsval_t func_obj = mkobj(js, 0);
	if (is_err(func_obj)) { free(code_buf); return func_obj; }

	sv_func_t *compiled = sv_compile_function(js, code_buf, pos, is_async);
	if (!compiled) {
	free(code_buf);
	return js_mkerr_typed(js, JS_ERR_SYNTAX, "invalid function body");
	}

	sv_closure_t *closure = calloc(1, sizeof(sv_closure_t));
	closure->func = compiled;
	closure->bound_this = js_mkundef();
	closure->call_flags = 0;
	closure->func_obj = func_obj;

	size_t params_len = (size_t)(pos - 2) - (size_t)body_len - 2;
	const char *async_prefix = is_async ? "async " : "";
	size_t async_len = is_async ? 6 : 0;
	size_t display_len = async_len + 19 + params_len + 5 + (size_t)body_len + 2;
	char display = (char )malloc(display_len + 1);
	if (!display) { free(code_buf); return js_mkerr(js, "oom"); }
	size_t n = 0;

	memcpy(display + n, async_prefix, async_len); n += async_len;
	memcpy(display + n, "function anonymous(", 19); n += 19;
	memcpy(display + n, code_buf + 1, params_len); n += params_len;
	memcpy(display + n, "\n) {\n", 5); n += 5;
	memcpy(display + n, code_buf + 1 + params_len + 2, (size_t)body_len); n += (size_t)body_len;
	memcpy(display + n, "\n}", 2); n += 2;
	display[n] = '\0';
	set_func_code(js, func_obj, display, display_len);
	free(display);
	free(code_buf);

	if (is_async) {
	set_slot(js, func_obj, SLOT_ASYNC, js_true);
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, func_obj, async_proto);
	} else {
	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	jsval_t instance_proto = js_instance_proto_from_new_target(js, func_proto);
	if (is_object_type(instance_proto)) set_proto(js, func_obj, instance_proto);
	}

	jsval_t func = mkval(T_FUNC, (uintptr_t)closure);
	jsval_t proto_setup = setup_func_prototype(js, func);
	if (is_err(proto_setup)) return proto_setup;
	return func;
	}

	static jsval_t builtin_Function(ant_t js, jsval_t args, int nargs) {
	return build_dynamic_function(js, args, nargs, false);
	}

	static jsval_t builtin_AsyncFunction(ant_t js, jsval_t args, int nargs) {
	return build_dynamic_function(js, args, nargs, true);
	}

	static jsval_t builtin_function_empty(ant_t js, jsval_t args, int nargs) {
	(void)js; (void)args; (void)nargs;
	return js_mkundef();
	}

	static jsval_t builtin_function_call(ant_t 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];
	}

	return sv_vm_call(js->vm, js, func, this_arg, call_args, call_nargs, NULL, false);
	}

	static int extract_array_args(ant_t js, jsval_t arr, jsval_t *out_args) {
	int len = (int) get_array_length(js, arr);
	if (len <= 0) return 0;

	jsval_t args_out = (jsval_t )ant_calloc(sizeof(jsval_t) * len);
	if (!args_out) return 0;

	for (int i = 0; i < len; i++) {
	args_out[i] = arr_get(js, arr, (jsoff_t)i);
	}

	*out_args = args_out;
	return len;
	}

	static jsval_t builtin_function_toString(ant_t js, jsval_t args, int nargs) {
	jsval_t func = js->this_val;
	uint8_t t = vtype(func);

	if (t != T_FUNC && t != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Function.prototype.toString requires that 'this' be a Function");
	}

	if (t == T_CFUNC) return ANT_STRING("function() { [native code] }");

	jsval_t func_obj = js_func_obj(func);
	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);

	if (vtype(cfunc_slot) == T_CFUNC) {
	jsoff_t name_len = 0;
	const char *name = get_func_name(js, func, &name_len);
	if (name && name_len > 0) {
	size_t total = 9 + name_len + 21 + 1;
	char *buf = ant_calloc(total);
	size_t n = 0;
	n += cpy(buf + n, total - n, "function ", 9);
	n += cpy(buf + n, total - n, name, name_len);
	n += cpy(buf + n, total - n, "() { [native code] }", 20);
	jsval_t result = js_mkstr(js, buf, n);
	free(buf);
	return result;
	}
	return ANT_STRING("function() { [native code] }");
	}

	jsval_t code_val = get_slot(js, func_obj, SLOT_CODE);
	jsval_t len_val = get_slot(js, func_obj, SLOT_CODE_LEN);

	if (vtype(code_val) == T_CFUNC && vtype(len_val) == T_NUM) {
	const char code = (const char )(uintptr_t)vdata(code_val);
	size_t code_len = (size_t)tod(len_val);

	if (code && code_len > 0) {
	jsval_t async_slot = get_slot(js, func_obj, SLOT_ASYNC);
	jsval_t arrow_slot = get_slot(js, func_obj, SLOT_ARROW);

	bool is_async = (async_slot == js_true);
	bool is_arrow = (arrow_slot == js_true);

	if (is_arrow) {
	const char *paren_end = memchr(code, ')', code_len);
	if (!paren_end) goto fallback_arrow;

	size_t params_len = paren_end - code + 1;
	const char *body = paren_end + 1;
	size_t body_len = code_len - params_len;

	size_t len = (is_async ? 6 : 0) + params_len + 4 + body_len + 1;
	char *buf = ant_calloc(len);
	size_t n = 0;

	if (is_async) n += cpy(buf + n, REMAIN(n, len), "async ", 6);
	n += cpy(buf + n, REMAIN(n, len), code, params_len);
	n += cpy(buf + n, REMAIN(n, len), " => ", 4);
	n += cpy(buf + n, REMAIN(n, len), body, body_len);

	jsval_t result = js_mkstr(js, buf, n);
	free(buf);
	return result;
	fallback_arrow:;
	}

	return js_mkstr(js, code, code_len);
	}
	}

	sv_closure_t *cl = js_func_closure(func);
	if (cl->func != NULL) {
	sv_func_t *fn = cl->func;
	if (fn && fn->source && fn->source_end > fn->source_start) {
	int start = fn->source_start;
	int end = fn->source_end;
	if (start >= 0 && end <= fn->source_len && end > start)
	return js_mkstr(js, fn->source + start, (size_t)(end - start));
	}
	}

	char buf[256];
	size_t len = strfunc(js, func, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	static jsval_t builtin_function_apply(ant_t js, jsval_t args, int nargs) {
	jsval_t func = js->this_val;
	if (vtype(func) != T_FUNC && vtype(func) != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Function.prototype.apply requires that 'this' be a Function");
	}

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

	if (nargs > 1) {
	jsval_t arg_array = args[1];
	uint8_t t = vtype(arg_array);
	if (t == T_ARR \|\| t == T_OBJ) {
	call_nargs = extract_array_args(js, arg_array, &call_args);
	} else if (t != T_UNDEF && t != T_NULL) {}
	}

	jsval_t result = sv_vm_call(js->vm, js, func, this_arg, call_args, call_nargs, NULL, false);
	if (call_args) free(call_args);
	return result;
	}

	static jsval_t builtin_function_bind(ant_t js, jsval_t args, int nargs) {
	jsval_t func = js->this_val;

	if (vtype(func) != T_FUNC && vtype(func) != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "bind requires a function");
	}

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

	int bound_argc = (nargs > 1) ? nargs - 1 : 0;
	jsval_t *bound_args = (bound_argc > 0) ? &args[1] : NULL;

	int orig_length = 0;
	jsval_t target_func_obj;
	if (vtype(func) == T_CFUNC) {
	orig_length = 0;
	} else {
	target_func_obj = js_func_obj(func);
	jsoff_t len_off = lkp_interned(js, target_func_obj, INTERN_LENGTH, 6);
	if (len_off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, len_off));
	if (vtype(len_val) == T_NUM) {
	orig_length = (int) tod(len_val);
	}
	}
	}

	int bound_length = orig_length - bound_argc;
	if (bound_length < 0) bound_length = 0;

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

	set_slot(js, bound_func, SLOT_CFUNC, func);
	set_slot(js, bound_func, SLOT_BOUND_THIS, this_arg);

	if (bound_argc > 0) {
	jsval_t bound_arr = mkarr(js);
	for (int i = 0; i < bound_argc; i++) arr_set(js, bound_arr, (jsoff_t)i, bound_args[i]);
	set_slot(js, bound_func, SLOT_BOUND_ARGS, bound_arr);
	}

	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, bound_func, func_proto);

	jsval_t bound = js_obj_to_func(bound_func);
	js_setprop(js, bound_func, js->length_str, tov((double) bound_length));

	jsval_t proto_setup = setup_func_prototype(js, bound);
	if (is_err(proto_setup)) return proto_setup;

	return bound;
	}

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

	jsval_t code_val = get_slot(js, func_obj, SLOT_CODE);
	if (vtype(code_val) == T_STR \|\| vtype(code_val) == T_CFUNC) {
	set_slot(js, bound_func, SLOT_CODE, code_val);
	set_slot(js, bound_func, SLOT_CODE_LEN, get_slot(js, func_obj, SLOT_CODE_LEN));
	}

	sv_closure_t *orig = js_func_closure(func);
	sv_closure_t *bound_closure = calloc(1, sizeof(sv_closure_t));
	bound_closure->func = orig->func;
	bound_closure->upvalues = orig->upvalues;
	bound_closure->bound_this = this_arg;
	bound_closure->func_obj = bound_func;
	bound_closure->call_flags = orig->call_flags;
	if (bound_argc > 0)
	bound_closure->call_flags \|= SV_CALL_HAS_BOUND_ARGS;

	jsval_t async_slot = get_slot(js, func_obj, SLOT_ASYNC);
	if (vtype(async_slot) == T_BOOL && vdata(async_slot) == 1) {
	set_slot(js, bound_func, SLOT_ASYNC, js_true);
	}

	jsval_t target_proto = get_proto(js, func);
	if (is_object_type(target_proto)) {
	set_proto(js, bound_func, target_proto);
	} else if (vtype(async_slot) == T_BOOL && vdata(async_slot) == 1) {
	jsval_t async_proto = get_slot(js, js_glob(js), SLOT_ASYNC_PROTO);
	if (vtype(async_proto) == T_FUNC) set_proto(js, bound_func, async_proto);
	} else {
	jsval_t func_proto = get_slot(js, js_glob(js), SLOT_FUNC_PROTO);
	if (vtype(func_proto) == T_FUNC) set_proto(js, bound_func, func_proto);
	}

	jsval_t data_slot = get_slot(js, func_obj, SLOT_DATA);
	if (vtype(data_slot) != T_UNDEF) {
	set_slot(js, bound_func, SLOT_DATA, data_slot);
	}

	set_slot(js, bound_func, SLOT_TARGET_FUNC, func);
	set_slot(js, bound_func, SLOT_BOUND_THIS, this_arg);

	if (bound_argc > 0) {
	jsval_t bound_arr = mkarr(js);
	for (int i = 0; i < bound_argc; i++) arr_set(js, bound_arr, (jsoff_t)i, bound_args[i]);
	set_slot(js, bound_func, SLOT_BOUND_ARGS, bound_arr);
	}

	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);
	if (vtype(cfunc_slot) == T_CFUNC) {
	set_slot(js, bound_func, SLOT_CFUNC, cfunc_slot);
	}

	js_setprop(js, bound_func, js->length_str, tov((double) bound_length));

	jsval_t bound = mkval(T_FUNC, (uintptr_t)bound_closure);
	jsval_t proto_setup = setup_func_prototype(js, bound);
	if (is_err(proto_setup)) return proto_setup;

	return bound;
	}

	static jsval_t builtin_Array(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = mkarr(js);
	if (is_err(arr)) return arr;

	if (nargs == 1 && vtype(args[0]) == T_NUM) {
	jsval_t err = validate_array_length(js, args[0]);
	if (is_err(err)) return err;
	jsoff_t new_len = (jsoff_t)tod(args[0]);
	jsoff_t doff = get_dense_buf(js, arr);
	if (doff && new_len <= 1024) {
	if (new_len > dense_capacity(js, doff)) doff = dense_grow(js, arr, new_len);
	if (doff) dense_set_length(js, doff, new_len);
	}
	update_array_length(js, arr, new_len);
	} else if (nargs > 0) {
	for (int i = 0; i < nargs; i++) arr_set(js, arr, (jsoff_t)i, args[i]);
	}

	jsval_t array_proto = get_ctor_proto(js, "Array", 5);
	jsval_t instance_proto = js_instance_proto_from_new_target(js, array_proto);

	if (is_object_type(instance_proto)) set_proto(js, arr, instance_proto);
	if (vtype(js->new_target) == T_FUNC \|\| vtype(js->new_target) == T_CFUNC) {
	set_slot(js, arr, SLOT_CTOR, js->new_target);
	}

	return arr;
	}

	static jsval_t builtin_Error(ant_t js, jsval_t args, int nargs) {
	bool is_new = (vtype(js->new_target) != T_UNDEF);
	jsval_t this_val = js->this_val;

	jsval_t target = is_new ? js->new_target : js->current_func;
	jsval_t name = ANT_STRING("Error");

	if (vtype(target) == T_FUNC) {
	jsoff_t off = lkp(js, js_func_obj(target), "name", 4);
	if (off) name = resolveprop(js, mkval(T_PROP, off));
	}

	if (!is_new) {
	this_val = js_mkobj(js);
	jsoff_t proto_off = lkp_interned(js, js_func_obj(js->current_func), INTERN_PROTOTYPE, 9);
	if (proto_off) set_proto(js, this_val, resolveprop(js, mkval(T_PROP, proto_off)));
	else set_proto(js, this_val, get_ctor_proto(js, "Error", 5));
	}

	if (nargs > 0) {
	jsval_t msg = args[0];
	if (vtype(msg) != T_STR) {
	const char *str = js_str(js, msg);
	msg = js_mkstr(js, str, strlen(str));
	}
	js_mkprop_fast(js, this_val, "message", 7, msg);
	}

	if (nargs > 1 && vtype(args[1]) == T_OBJ) {
	jsoff_t cause_off = lkp(js, args[1], "cause", 5);
	if (cause_off) js_mkprop_fast(js, this_val, "cause", 5, resolveprop(js, mkval(T_PROP, cause_off)));
	}

	js_mkprop_fast(js, this_val, "name", 4, name);
	set_slot(js, this_val, SLOT_ERROR_BRAND, js_true);

	return this_val;
	}

	static jsval_t builtin_Error_toString(ant_t js, jsval_t args, int nargs) {
	jsval_t this_val = js_getthis(js);

	jsval_t name = js_get(js, this_val, "name");
	if (vtype(name) == T_UNDEF) name = js_mkstr(js, "Error", 5);
	else if (vtype(name) != T_STR) {
	const char *s = js_str(js, name);
	name = js_mkstr(js, s, strlen(s));
	}

	jsval_t msg = js_get(js, this_val, "message");
	if (vtype(msg) == T_UNDEF) msg = js_mkstr(js, "", 0);
	else if (vtype(msg) != T_STR) {
	const char *s = js_str(js, msg);
	msg = js_mkstr(js, s, strlen(s));
	}

	jsoff_t name_len, msg_len;
	jsoff_t name_off = vstr(js, name, &name_len);
	jsoff_t msg_off = vstr(js, msg, &msg_len);

	const char name_str = (const char )&js->mem[name_off];
	const char msg_str = (const char )&js->mem[msg_off];

	if (name_len == 0) return msg;
	if (msg_len == 0) return name;

	size_t total = (size_t)(name_len + 2 + msg_len);
	char *buf = malloc(total + 1);
	if (!buf) return js_mkerr(js, "out of memory");

	memcpy(buf, name_str, (size_t)name_len);
	buf[name_len] = ':';
	buf[name_len + 1] = ' ';
	memcpy(buf + name_len + 2, msg_str, (size_t)msg_len);
	buf[total] = '\0';

	jsval_t result = js_mkstr(js, buf, total);
	free(buf);
	return result;
	}

	static jsval_t builtin_AggregateError(ant_t js, jsval_t args, int nargs) {
	bool is_new = (vtype(js->new_target) != T_UNDEF);
	jsval_t this_val = js->this_val;

	if (!is_new) {
	this_val = js_mkobj(js);
	jsoff_t proto_off = lkp_interned(js, js_func_obj(js->current_func), INTERN_PROTOTYPE, 9);
	if (proto_off) set_proto(js, this_val, resolveprop(js, mkval(T_PROP, proto_off)));
	else set_proto(js, this_val, get_ctor_proto(js, "AggregateError", 14));
	}

	jsval_t errors = nargs > 0 ? args[0] : mkarr(js);
	if (vtype(errors) != T_ARR) errors = mkarr(js);
	js_mkprop_fast(js, this_val, "errors", 6, errors);

	if (nargs > 1 && vtype(args[1]) != T_UNDEF) {
	jsval_t msg = args[1];
	if (vtype(msg) != T_STR) {
	const char *str = js_str(js, msg);
	msg = js_mkstr(js, str, strlen(str));
	}
	js_mkprop_fast(js, this_val, "message", 7, msg);
	}

	if (nargs > 2 && vtype(args[2]) == T_OBJ) {
	jsoff_t cause_off = lkp(js, args[2], "cause", 5);
	if (cause_off) js_mkprop_fast(js, this_val, "cause", 5, resolveprop(js, mkval(T_PROP, cause_off)));
	}

	js_mkprop_fast(js, this_val, "name", 4, ANT_STRING("AggregateError"));
	set_slot(js, this_val, SLOT_ERROR_BRAND, js_true);

	return this_val;
	}

	static jsval_t builtin_Math_abs(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(fabs(x));
	}

	static jsval_t builtin_Math_acos(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(acos(x));
	}

	static jsval_t builtin_Math_acosh(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(acosh(x));
	}

	static jsval_t builtin_Math_asin(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(asin(x));
	}

	static jsval_t builtin_Math_asinh(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(asinh(x));
	}

	static jsval_t builtin_Math_atan(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(atan(x));
	}

	static jsval_t builtin_Math_atanh(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(atanh(x));
	}

	static jsval_t builtin_Math_atan2(ant_t js, jsval_t args, int nargs) {
	double y = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	double x = (nargs < 2) ? JS_NAN : js_to_number(js, args[1]);
	if (isnan(y) \|\| isnan(x)) return tov(JS_NAN);
	return tov(atan2(y, x));
	}

	static jsval_t builtin_Math_cbrt(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(cbrt(x));
	}

	static jsval_t builtin_Math_ceil(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(ceil(x));
	}

	static jsval_t builtin_Math_clz32(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(32);
	double x = js_to_number(js, args[0]);
	if (isnan(x) \|\| isinf(x)) return tov(32);
	uint32_t n = (uint32_t) x;
	if (n == 0) return tov(32);
	int count = 0;
	while ((n & 0x80000000U) == 0) { count++; n <<= 1; }
	return tov((double) count);
	}

	static jsval_t builtin_Math_cos(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(cos(x));
	}

	static jsval_t builtin_Math_cosh(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(cosh(x));
	}

	static jsval_t builtin_Math_exp(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(exp(x));
	}

	static jsval_t builtin_Math_expm1(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(expm1(x));
	}

	static jsval_t builtin_Math_floor(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(floor(x));
	}

	static jsval_t builtin_Math_fround(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov((double)(float)x);
	}

	static jsval_t builtin_Math_hypot(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return tov(0.0);
	double sum = 0.0;
	for (int i = 0; i < nargs; i++) {
	double v = js_to_number(js, args[i]);
	if (isnan(v)) return tov(JS_NAN);
	sum += v * v;
	}
	return tov(sqrt(sum));
	}

	static int32_t toInt32(double d) {
	if (isnan(d) \|\| isinf(d) \|\| d == 0) return 0;
	double int_val = trunc(d);
	double two32 = (double)(1ULL << 32);
	double two31 = (double)(1ULL << 31);
	double mod_val = fmod(int_val, two32);
	if (mod_val < 0) mod_val += two32;
	if (mod_val >= two31) mod_val -= two32;
	return (int32_t)mod_val;
	}

	static jsval_t builtin_Math_imul(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return tov(0);
	int32_t a = toInt32(js_to_number(js, args[0]));
	int32_t b = toInt32(js_to_number(js, args[1]));
	return tov((double)((int32_t)((uint32_t)a * (uint32_t)b)));
	}

	static jsval_t builtin_Math_log(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log(x));
	}

	static jsval_t builtin_Math_log1p(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log1p(x));
	}

	static jsval_t builtin_Math_log10(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log10(x));
	}

	static jsval_t builtin_Math_log2(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(log2(x));
	}

	static jsval_t builtin_Math_max(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return tov(JS_NEG_INF);
	double max_val = JS_NEG_INF;
	for (int i = 0; i < nargs; i++) {
	double v = js_to_number(js, args[i]);
	if (isnan(v)) return tov(JS_NAN);
	if (v > max_val) max_val = v;
	}
	return tov(max_val);
	}

	static jsval_t builtin_Math_min(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return tov(JS_INF);
	double min_val = JS_INF;
	for (int i = 0; i < nargs; i++) {
	double v = js_to_number(js, args[i]);
	if (isnan(v)) return tov(JS_NAN);
	if (v < min_val) min_val = v;
	}
	return tov(min_val);
	}

	static jsval_t builtin_Math_pow(ant_t js, jsval_t args, int nargs) {
	double base = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	double exp = (nargs < 2) ? JS_NAN : js_to_number(js, args[1]);
	if (isnan(base) \|\| isnan(exp)) return tov(JS_NAN);
	return tov(pow(base, exp));
	}

	static bool random_seeded = false;

	static jsval_t builtin_Math_random(ant_t js, jsval_t args, int nargs) {
	if (!random_seeded) {
	srand((unsigned int) time(NULL));
	random_seeded = true;
	}
	return tov((double) rand() / ((double) RAND_MAX + 1.0));
	}

	static jsval_t builtin_Math_round(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x) \|\| isinf(x)) return tov(x);
	return tov(floor(x + 0.5));
	}

	static jsval_t builtin_Math_sign(ant_t js, jsval_t args, int nargs) {
	double v = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(v)) return tov(JS_NAN);
	if (v > 0) return tov(1.0);
	if (v < 0) return tov(-1.0);
	return tov(v);
	}

	static jsval_t builtin_Math_sin(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(sin(x));
	}

	static jsval_t builtin_Math_sinh(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(sinh(x));
	}

	static jsval_t builtin_Math_sqrt(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(sqrt(x));
	}

	static jsval_t builtin_Math_tan(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(tan(x));
	}

	static jsval_t builtin_Math_tanh(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(tanh(x));
	}

	static jsval_t builtin_Math_trunc(ant_t js, jsval_t args, int nargs) {
	double x = (nargs < 1) ? JS_NAN : js_to_number(js, args[0]);
	if (isnan(x)) return tov(JS_NAN);
	return tov(trunc(x));
	}

	typedef jsval_t (*dynamic_kv_mapper_fn)(
	ant_t *js,
	jsval_t key,
	jsval_t val
	);

	static jsval_t iterate_dynamic_keys(ant_t js, jsval_t obj, dynamic_accessors_t acc, dynamic_kv_mapper_fn mapper) {
	jsval_t keys_arr = acc->keys(js, obj);
	jsval_t arr = mkarr(js);
	jsoff_t len = get_array_length(js, keys_arr);

	for (jsoff_t i = 0; i < len; i++) {
	jsval_t key_val = arr_get(js, keys_arr, i);
	if (vtype(key_val) != T_STR) continue;
	jsoff_t klen; jsoff_t str_off = vstr(js, key_val, &klen);
	const char key = (const char )&js->mem[str_off];
	jsval_t val = acc->getter(js, obj, key, klen);
	js_arr_push(js, arr, mapper ? mapper(js, key_val, val) : val);
	}

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

	static jsval_t builtin_object_is(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return js_false;

	jsval_t x = args[0];
	jsval_t y = args[1];

	uint8_t tx = vtype(x);
	uint8_t ty = vtype(y);
	if (tx != ty) return js_false;

	if (tx == T_UNDEF \|\| tx == T_NULL) return js_true;

	if (tx == T_NUM) {
	double dx = tod(x);
	double dy = tod(y);
	if (isnan(dx) && isnan(dy)) return js_true;
	if (dx == 0.0 && dy == 0.0) {
	bool x_neg = (1.0 / dx) < 0;
	bool y_neg = (1.0 / dy) < 0;
	return x_neg == y_neg ? js_true : js_false;
	}
	return dx == dy ? js_true : js_false;
	}

	if (tx == T_BOOL) return vdata(x) == vdata(y) ? js_true : js_false;

	return x == y ? js_true : js_false;
	}

	enum obj_enum_mode {
	OBJ_ENUM_KEYS,
	OBJ_ENUM_VALUES,
	OBJ_ENUM_ENTRIES
	};

	static jsval_t map_to_entry(ant_t *js, jsval_t key, jsval_t val) {
	jsval_t pair = mkarr(js);
	arr_set(js, pair, 0, key);
	arr_set(js, pair, 1, val);
	return mkval(T_ARR, vdata(pair));
	}

	static jsval_t object_enum(ant_t *js, jsval_t obj, enum obj_enum_mode mode) {
	bool is_arr = (vtype(obj) == T_ARR);
	if (vtype(obj) == T_FUNC) obj = js_func_obj(obj);

	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *acc = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), acc);
	if (acc && acc->keys) {
	if (mode == OBJ_ENUM_KEYS && !acc->getter) return acc->keys(js, obj);
	if (acc->getter) {
	dynamic_kv_mapper_fn mapper = (mode == OBJ_ENUM_ENTRIES) ? map_to_entry : NULL;
	return iterate_dynamic_keys(js, obj, acc, mapper);
	}
	}

	jsval_t arr = mkarr(js);
	jsoff_t idx = 0;

	if (is_arr) {
	jsoff_t doff = get_dense_buf_off(js, obj_off);
	if (doff) {
	jsoff_t dense_len = dense_length(js, doff);
	for (jsoff_t i = 0; i < dense_len; i++) {
	jsval_t v = dense_get(js, doff, i);
	if (is_empty_slot(v)) continue;
	char idxstr[16]; size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t key_val = js_mkstr(js, idxstr, idxlen);
	if (mode == OBJ_ENUM_KEYS) arr_set(js, arr, idx, key_val);
	else if (mode == OBJ_ENUM_VALUES) arr_set(js, arr, idx, v);
	else arr_set(js, arr, idx, map_to_entry(js, key_val, v));
	idx++;
	}
	}
	}

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

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

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

	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;
	if (is_arr && is_array_index(key, klen)) {
	jsoff_t doff = get_dense_buf_off(js, obj_off);
	if (doff) {
	unsigned long pidx = 0;
	for (jsoff_t ci = 0; ci < klen; ci++) pidx = pidx * 10 + (key[ci] - '0');
	if (pidx < dense_length(js, doff)) continue;
	}
	}

	bool should_include = true;
	descriptor_entry_t *desc = lookup_descriptor(js, obj_off, key, klen);
	if (desc) should_include = desc->enumerable;

	if (should_include) {
	jsval_t key_val = js_mkstr(js, key, klen);
	if (mode == OBJ_ENUM_KEYS) arr_set(js, arr, idx, key_val);
	else if (mode == OBJ_ENUM_VALUES) arr_set(js, arr, idx, val);
	else arr_set(js, arr, idx, map_to_entry(js, key_val, val));
	idx++;
	}
	}

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

	static jsval_t builtin_object_keys(ant_t 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 (is_proxy(js, obj)) {
	proxy_data_t *data = get_proxy_data(obj);
	if (!data) return mkarr(js);
	if (data->revoked)
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot perform 'ownKeys' on a proxy that has been revoked");

	jsoff_t trap_off = lkp(js, data->handler, "ownKeys", 7);
	if (!trap_off) return object_enum(js, data->target, OBJ_ENUM_KEYS);

	jsval_t trap = resolveprop(js, mkval(T_PROP, trap_off));
	uint8_t ft = vtype(trap);
	if (ft != T_FUNC && ft != T_CFUNC) return object_enum(js, data->target, OBJ_ENUM_KEYS);

	jsval_t trap_args[1] = { data->target };
	jsval_t result = sv_vm_call(js->vm, js, trap, data->handler, trap_args, 1, NULL, false);
	if (is_err(result)) return result;
	if (vtype(result) != T_ARR)
	return js_mkerr_typed(js, JS_ERR_TYPE, "ownKeys trap must return an array");

	jsoff_t len = get_array_length(js, result);
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t ki = arr_get(js, result, i);
	if (vtype(ki) != T_STR && vtype(ki) != T_SYMBOL)
	return js_mkerr_typed(js, JS_ERR_TYPE, "ownKeys trap result must contain only strings or symbols");
	jsoff_t ki_len; jsoff_t ki_off = vstr(js, ki, &ki_len);
	for (jsoff_t j = 0; j < i; j++) {
	jsval_t kj = arr_get(js, result, j);
	jsoff_t kj_len; jsoff_t kj_off = vstr(js, kj, &kj_len);
	if (ki_len == kj_len && memcmp(&js->mem[ki_off], &js->mem[kj_off], ki_len) == 0)
	return js_mkerr_typed(js, JS_ERR_TYPE, "ownKeys trap result must not contain duplicate entries");
	}
	}
	return result;
	}

	return object_enum(js, obj, OBJ_ENUM_KEYS);
	}

	static jsval_t for_in_keys_add(ant_t *js, jsval_t out, jsval_t seen, jsval_t key) {
	if (vtype(key) != T_STR) return js_mkundef();

	jsoff_t key_len = 0;
	jsoff_t key_off = vstr(js, key, &key_len);
	const char key_ptr = (const char )&js->mem[key_off];

	if (is_internal_prop(key_ptr, key_len))
	return js_mkundef();
	if (lkp(js, seen, key_ptr, key_len) != 0)
	return js_mkundef();

	jsval_t mark = setprop_cstr(js, seen, key_ptr, key_len, js_true);
	if (is_err(mark)) return mark;

	js_arr_push(js, out, key);
	return js_mkundef();
	}

	static jsval_t for_in_keys_add_string_indices(ant_t *js, jsval_t out, jsval_t seen, jsval_t str) {
	jsoff_t slen = vstrlen(js, str);
	for (jsoff_t i = 0; i < slen; i++) {
	char idx[16];
	size_t idx_len = uint_to_str(idx, sizeof(idx), (uint64_t)i);
	jsval_t key = js_mkstr(js, idx, idx_len);
	jsval_t r = for_in_keys_add(js, out, seen, key);
	if (is_err(r)) return r;
	}
	return js_mkundef();
	}

	jsval_t js_for_in_keys(ant_t *js, jsval_t obj) {
	uint8_t t = vtype(obj);
	jsval_t out = mkarr(js);
	if (t == T_NULL \|\| t == T_UNDEF) return out;

	jsval_t seen = mkobj(js, 0);
	jshdl_t h_out = js_root(js, out);
	jshdl_t h_seen = js_root(js, seen);
	jsval_t result = js_mkundef();

	if (t == T_STR) {
	result = for_in_keys_add_string_indices(js, js_deref(js, h_out), js_deref(js, h_seen), obj);
	goto done;
	}

	if (t == T_OBJ) {
	jsval_t prim = get_slot(js, obj, SLOT_PRIMITIVE);
	if (vtype(prim) == T_STR) {
	result = for_in_keys_add_string_indices(js, js_deref(js, h_out), js_deref(js, h_seen), prim);
	if (is_err(result)) goto done;
	}
	}

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	jsval_t own_keys = object_enum(js, obj, OBJ_ENUM_KEYS);
	if (is_err(own_keys)) {
	result = own_keys;
	goto done;
	}
	if (vtype(own_keys) == T_ARR) {
	jshdl_t h_own = js_root(js, own_keys);
	jsoff_t own_len = js_arr_len(js, js_deref(js, h_own));
	for (jsoff_t i = 0; i < own_len; i++) {
	jsval_t key = js_arr_get(js, js_deref(js, h_own), i);
	result = for_in_keys_add(js, js_deref(js, h_out), js_deref(js, h_seen), key);
	if (is_err(result)) {
	js_unroot(js, h_own);
	goto done;
	}
	}
	js_unroot(js, h_own);
	}
	}

	done:
	if (is_err(result)) {
	js_unroot(js, h_seen);
	js_unroot(js, h_out);
	return result;
	}
	jsval_t ret = js_deref(js, h_out);
	js_unroot(js, h_seen);
	js_unroot(js, h_out);
	return ret;
	}

	static jsval_t builtin_object_values(ant_t 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);
	return object_enum(js, obj, OBJ_ENUM_VALUES);
	}

	static jsval_t builtin_object_entries(ant_t 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);
	return object_enum(js, obj, OBJ_ENUM_ENTRIES);
	}

	static jsval_t builtin_object_getPrototypeOf(ant_t 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 (is_object_type(obj)) return get_proto(js, obj);

	return js_mknull();
	}

	static jsval_t builtin_object_setPrototypeOf(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "Object.setPrototypeOf requires 2 arguments");

	jsval_t obj = args[0];
	jsval_t proto = args[1];

	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	return js_mkerr(js, "Object.setPrototypeOf: first argument must be an object");
	}

	uint8_t pt = vtype(proto);
	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC && pt != T_NULL) {
	return js_mkerr(js, "Object.setPrototypeOf: prototype must be an object or null");
	}

	for (jsval_t cur = proto; pt != T_NULL && vtype(cur) != T_NULL; cur = get_proto(js, cur)) {
	if (vdata(js_as_obj(cur)) == vdata(js_as_obj(obj))) return js_mkerr(js, "Cyclic __proto__ value");
	}

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

	static jsval_t builtin_proto_getter(ant_t js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	uint8_t t = vtype(this_val);

	if (t == T_UNDEF \|\| t == T_NULL) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot read property '__proto__' of %s", typestr(t));
	}

	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	return get_proto(js, this_val);
	}

	return get_prototype_for_type(js, t);
	}

	static jsval_t builtin_proto_setter(ant_t js, jsval_t args, int nargs) {
	jsval_t this_val = js->this_val;
	uint8_t t = vtype(this_val);

	if (t == T_UNDEF \|\| t == T_NULL) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot set property '__proto__' of %s", typestr(t));
	}

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	return js_mkundef();
	}

	if (nargs == 0) return js_mkundef();

	jsval_t proto = args[0];
	uint8_t pt = vtype(proto);

	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC && pt != T_NULL) {
	return js_mkundef();
	}

	for (jsval_t cur = proto; pt != T_NULL && vtype(cur) == T_OBJ; cur = get_proto(js, cur)) {
	if (vdata(cur) == vdata(this_val)) return js_mkundef();
	}

	set_proto(js, this_val, proto);
	return js_mkundef();
	}

	static jsval_t builtin_object_create(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkerr(js, "Object.create requires a prototype argument");

	jsval_t proto = args[0];
	uint8_t pt = vtype(proto);

	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC && pt != T_NULL) {
	return js_mkerr(js, "Object.create: prototype must be an object or null");
	}

	jsval_t obj = js_mkobj(js);
	if (pt == T_NULL) {
	set_proto(js, obj, js_mknull());
	} else set_proto(js, obj, proto);

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

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

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsoff_t klen = offtolen(loadoff(js, koff));
	const char key = (char ) &js->mem[koff + sizeof(koff)];
	jsval_t descriptor = resolveprop(js, mkval(T_PROP, next));

	if (vtype(descriptor) == T_OBJ) {
	jsoff_t val_off = lkp(js, descriptor, "value", 5);
	if (val_off != 0) {
	jsval_t val = resolveprop(js, mkval(T_PROP, val_off));
	jsval_t key_str = js_mkstr(js, key, klen);
	js_setprop(js, obj, key_str, val);
	}
	}

	next = next_prop(header);
	}
	}

	return obj;
	}

	static jsval_t builtin_object_hasOwn(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return mkval(T_BOOL, 0);

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t == T_NULL \|\| t == T_UNDEF) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot convert undefined or null to object");
	}

	jsval_t key = args[1];
	if (vtype(key) != T_STR) {
	key = js_tostring_val(js, key);
	if (is_err(key)) return key;
	}

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return mkval(T_BOOL, 0);

	jsval_t as_obj = js_as_obj(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_groupBy(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr_typed(js, JS_ERR_TYPE, "Object.groupBy requires 2 arguments");

	jsval_t items = args[0];
	jsval_t callback = args[1];

	if (vtype(callback) != T_FUNC && vtype(callback) != T_CFUNC)
	return js_mkerr_typed(js, JS_ERR_TYPE, "callback is not a function");

	jsval_t result = js_mkobj(js);
	set_proto(js, result, js_mknull());

	jsoff_t len = get_array_length(js, items);
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t val = arr_get(js, items, i);
	jsval_t cb_args[2] = { val, tov((double)i) };
	jsval_t key = sv_vm_call(js->vm, js, callback, js_mkundef(), cb_args, 2, NULL, false);
	if (is_err(key)) return key;

	jsval_t key_str = js_tostring_val(js, key);
	if (is_err(key_str)) return key_str;

	jsoff_t klen;
	jsoff_t koff = vstr(js, key_str, &klen);
	const char kptr = (char )&js->mem[koff];

	jsoff_t grp_off = lkp(js, result, kptr, klen);
	jsval_t group;
	if (grp_off) {
	group = resolveprop(js, mkval(T_PROP, grp_off));
	} else {
	group = mkarr(js);
	js_setprop(js, result, key_str, group);
	}
	js_arr_push(js, group, val);
	}

	return result;
	}

	static jsval_t builtin_object_defineProperty(ant_t 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");
	}

	bool sym_key = (vtype(prop) == T_SYMBOL);
	if (!sym_key && vtype(prop) != T_STR) {
	char buf[64];
	size_t len = tostr(js, prop, buf, sizeof(buf));
	prop = js_mkstr(js, buf, len);
	}

	if (vtype(descriptor) != T_OBJ) {
	return js_mkerr(js, "Property descriptor must be an object");
	}

	jsval_t as_obj = js_as_obj(obj);

	jsoff_t prop_len = 0;
	const char *prop_str = NULL;
	jsoff_t sym_off = 0;

	if (sym_key) {
	sym_off = (jsoff_t)vdata(prop);
	const char *desc = js_sym_desc(js, prop);
	prop_str = desc ? desc : "symbol";
	prop_len = (jsoff_t)strlen(prop_str);
	} else {
	jsoff_t prop_off = vstr(js, prop, &prop_len);
	prop_str = (char *) &js->mem[prop_off];
	if (streq(prop_str, prop_len, STR_PROTO, STR_PROTO_LEN)) {
	return js_mkerr(js, "Cannot define " STR_PROTO " property");
	}
	}

	bool has_value = false, has_get = false, has_set = false, has_writable = false;
	jsval_t value = js_mkundef();
	bool writable = false, enumerable = false, configurable = false;

	jsoff_t value_off = lkp(js, descriptor, "value", 5);
	if (value_off != 0) {
	has_value = true;
	value = resolveprop(js, mkval(T_PROP, value_off));
	}

	jsoff_t get_off = lkp_interned(js, descriptor, INTERN_GET, 3);
	if (get_off != 0) {
	has_get = true;
	jsval_t getter = resolveprop(js, mkval(T_PROP, get_off));
	if (vtype(getter) != T_FUNC && vtype(getter) != T_UNDEF) {
	return js_mkerr(js, "Getter must be a function");
	}
	}

	jsoff_t set_off = lkp_interned(js, descriptor, INTERN_SET, 3);
	if (set_off != 0) {
	has_set = true;
	jsval_t setter = resolveprop(js, mkval(T_PROP, set_off));
	if (vtype(setter) != T_FUNC && vtype(setter) != T_UNDEF) {
	return js_mkerr(js, "Setter must be a function");
	}
	}

	if ((has_value \|\| has_writable) && (has_get \|\| has_set)) {
	return js_mkerr(js, "Invalid property descriptor. Cannot both specify accessors and a value or writable attribute");
	}

	jsoff_t writable_off = lkp(js, descriptor, "writable", 8);
	if (writable_off != 0) {
	has_writable = true;
	jsval_t w_val = resolveprop(js, mkval(T_PROP, writable_off));
	writable = js_truthy(js, w_val);
	}

	jsoff_t enumerable_off = lkp(js, descriptor, "enumerable", 10);
	if (enumerable_off != 0) {
	jsval_t e_val = resolveprop(js, mkval(T_PROP, enumerable_off));
	enumerable = js_truthy(js, e_val);
	}

	jsoff_t configurable_off = lkp(js, descriptor, "configurable", 12);
	if (configurable_off != 0) {
	jsval_t c_val = resolveprop(js, mkval(T_PROP, configurable_off));
	configurable = js_truthy(js, c_val);
	}

	jsoff_t existing_off = sym_key ? lkp_sym(js, as_obj, sym_off) : lkp(js, as_obj, prop_str, prop_len);

	if (existing_off == 0) {
	if (js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN)))
	return js_mkerr(js, "Cannot define property %.*s, object is not extensible", (int)prop_len, prop_str);
	if (js_truthy(js, get_slot(js, as_obj, SLOT_SEALED)))
	return js_mkerr(js, "Cannot define property %.*s, object is not extensible", (int)prop_len, prop_str);
	if (get_slot(js, as_obj, SLOT_EXTENSIBLE) == js_false)
	return js_mkerr(js, "Cannot define property %.*s, object is not extensible", (int)prop_len, prop_str);
	}

	if (has_get \|\| has_set) {
	int desc_flags =
	(enumerable ? JS_DESC_E : 0) \|
	(configurable ? JS_DESC_C : 0);

	if (!sym_key) {
	if (has_get && has_set) {
	jsval_t getter = resolveprop(js, mkval(T_PROP, get_off));
	jsval_t setter = resolveprop(js, mkval(T_PROP, set_off));
	js_set_accessor_desc(js, as_obj, prop_str, prop_len, getter, setter, desc_flags);
	} else if (has_get) {
	jsval_t getter = resolveprop(js, mkval(T_PROP, get_off));
	js_set_getter_desc(js, as_obj, prop_str, prop_len, getter, desc_flags);
	} else {
	jsval_t setter = resolveprop(js, mkval(T_PROP, set_off));
	js_set_setter_desc(js, as_obj, prop_str, prop_len, setter, desc_flags);
	}
	}
	} else {
	int desc_flags =
	(writable ? JS_DESC_W : 0) \|
	(enumerable ? JS_DESC_E : 0) \|
	(configurable ? JS_DESC_C : 0);

	if (!sym_key) js_set_descriptor(js, as_obj, prop_str, prop_len, desc_flags);

	if (existing_off > 0) {
	bool is_frozen = js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN));
	bool is_nonconfig = is_nonconfig_prop(js, existing_off) \|\| is_frozen;
	bool is_readonly = is_const_prop(js, existing_off) \|\| is_frozen;

	if (is_nonconfig) {
	if (configurable) return js_mkerr(js,
	"Cannot redefine property %.*s: cannot change configurable from false to true",
	(int)prop_len, prop_str
	);

	if (is_readonly && has_writable && writable) return js_mkerr(js,
	"Cannot redefine property %.*s: cannot change writable from false to true",
	(int)prop_len, prop_str
	);
	}

	if (is_readonly && has_value) return js_mkerr(js, "Cannot assign to read-only property '%.*s'", (int)prop_len, prop_str);
	if (has_value) saveval(js, existing_off + sizeof(jsoff_t) * 2, value);

	if (!writable \|\| !configurable) {
	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| FLAGMASK)) == existing_off) {
	jsoff_t flags = 0;
	if (!writable) flags \|= CONSTMASK;
	if (!configurable) flags \|= NONCONFIGMASK;
	saveoff(js, head, firstprop \| flags);
	} else {
	jsoff_t prop_header = loadoff(js, existing_off);
	jsoff_t flags = 0;
	if (!writable) flags \|= CONSTMASK;
	if (!configurable) flags \|= NONCONFIGMASK;
	saveoff(js, existing_off, prop_header \| flags);
	}
	}
	} else {
	if (!has_value) value = js_mkundef();
	jsval_t prop_key = sym_key ? prop : js_mkstr(js, prop_str, prop_len);
	jsoff_t flags = (writable ? 0 : CONSTMASK) \| (configurable ? 0 : NONCONFIGMASK);
	mkprop(js, as_obj, prop_key, value, flags);
	}
	}

	return obj;
	}

	static jsval_t builtin_object_defineProperties(ant_t js, jsval_t args, int nargs) {
	if (nargs < 2) return js_mkerr(js, "Object.defineProperties requires 2 arguments");

	jsval_t obj = args[0];
	jsval_t props = args[1];

	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) {
	return js_mkerr(js, "Object.defineProperties called on non-object");
	}

	if (vtype(props) != T_OBJ) {
	return js_mkerr(js, "Property descriptors must be an object");
	}

	jsval_t props_obj = props;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(props_obj)) & ~(3U \| FLAGMASK);

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

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

	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	jsval_t prop_key = js_mkstr(js, key, klen);
	jsval_t define_args[3] = { obj, prop_key, descriptor };
	jsval_t result = builtin_object_defineProperty(js, define_args, 3);
	if (is_err(result)) return result;
	}

	return obj;
	}

	static jsval_t builtin_object_assign(ant_t 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 = js_as_obj(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 = js_as_obj(source);
	jsoff_t next = loadoff(js, (jsoff_t) vdata(src_obj)) & ~(3U \| FLAGMASK);

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

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

	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	bool should_copy = true;
	jsoff_t src_obj_off = (jsoff_t)vdata(src_obj);

	descriptor_entry_t *desc = lookup_descriptor(js, src_obj_off, key, klen);
	if (desc) should_copy = desc->enumerable;

	if (should_copy) {
	jsval_t key_str = js_mkstr(js, key, klen);
	js_setprop(js, as_obj, key_str, val);
	}
	}
	}

	return target;
	}

	static jsval_t builtin_object_freeze(ant_t 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 = js_as_obj(obj);

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

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

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

	jsoff_t cur_prop = next;
	next = next_prop(header);
	if (is_internal_prop(key, klen)) continue;

	jsoff_t freeze_flags = CONSTMASK \| NONCONFIGMASK;
	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| FLAGMASK)) == cur_prop) {
	saveoff(js, head, firstprop \| freeze_flags);
	} else {
	jsoff_t prop_header = loadoff(js, cur_prop);
	saveoff(js, cur_prop, prop_header \| freeze_flags);
	}

	js_set_descriptor(js, as_obj, key, klen, JS_DESC_E);
	}

	set_slot(js, as_obj, SLOT_FROZEN, js_true);
	return obj;
	}

	static jsval_t builtin_object_isFrozen(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return js_true;

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_true;
	jsval_t as_obj = js_as_obj(obj);

	return js_bool(js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN)));
	}

	static jsval_t builtin_object_seal(ant_t 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 = js_as_obj(obj);

	set_slot(js, as_obj, SLOT_SEALED, js_true);
	jsoff_t next = loadoff(js, (jsoff_t) vdata(as_obj)) & ~(3U \| FLAGMASK);

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

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

	jsoff_t cur_prop = next;
	next = next_prop(header);

	if (is_internal_prop(key, klen)) continue;

	jsoff_t head = (jsoff_t) vdata(as_obj);
	jsoff_t firstprop = loadoff(js, head);
	if ((firstprop & ~(3U \| FLAGMASK)) == cur_prop) {
	saveoff(js, head, firstprop \| NONCONFIGMASK);
	} else {
	jsoff_t prop_header = loadoff(js, cur_prop);
	saveoff(js, cur_prop, prop_header \| NONCONFIGMASK);
	}

	js_set_descriptor(js, as_obj, key, klen, JS_DESC_W \| JS_DESC_E);
	}

	return obj;
	}

	static jsval_t builtin_object_isSealed(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return js_true;

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_true;
	jsval_t as_obj = js_as_obj(obj);

	if (js_truthy(js, get_slot(js, as_obj, SLOT_SEALED))) return js_true;
	if (js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN))) return js_true;

	return js_false;
	}

	static jsval_t builtin_object_fromEntries(ant_t 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 = get_array_length(js, iterable);
	if (len == 0) return result;

	for (jsoff_t i = 0; i < len; i++) {
	jsval_t entry = arr_get(js, iterable, i);
	if (vtype(entry) != T_ARR && vtype(entry) != T_OBJ) continue;

	jsval_t key = arr_get(js, entry, 0);
	if (is_undefined(key)) continue;
	jsval_t val = arr_get(js, entry, 1);

	if (vtype(key) != T_STR) {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}

	js_setprop(js, result, key, val);
	}

	return result;
	}

	static jsval_t builtin_object_getOwnPropertyDescriptor(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkundef();

	jsval_t obj = args[0];
	jsval_t key = args[1];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_mkundef();

	const char *key_str;
	jsoff_t key_len;

	bool is_sym = (vtype(key) == T_SYMBOL);
	if (is_sym) {
	const char *d = js_sym_desc(js, key);
	key_str = d ? d : "symbol";
	key_len = (jsoff_t)strlen(key_str);
	} else if (vtype(key) == T_STR) {
	jsoff_t key_off = vstr(js, key, &key_len);
	key_str = (char *) &js->mem[key_off];
	} else {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	jsoff_t key_off = vstr(js, key, &key_len);
	key_str = (char *) &js->mem[key_off];
	}

	jsval_t as_obj = js_as_obj(obj);
	jsoff_t obj_off = (jsoff_t)vdata(as_obj);

	descriptor_entry_t *desc = is_sym
	? lookup_sym_descriptor(obj_off, (jsoff_t)vdata(key))
	: lookup_descriptor(js, obj_off, key_str, key_len);

	jsoff_t prop_off = is_sym ? lkp_sym(js, as_obj, (jsoff_t)vdata(key)) : lkp(js, as_obj, key_str, key_len);
	if (prop_off == 0 && !desc) {
	return js_mkundef();
	}

	jsval_t result = js_mkobj(js);

	if (desc && (desc->has_getter \|\| desc->has_setter)) {
	if (desc->has_getter) {
	js_setprop(js, result, js_mkstr(js, "get", 3), desc->getter);
	}
	if (desc->has_setter) {
	js_setprop(js, result, js_mkstr(js, "set", 3), desc->setter);
	}
	js_setprop(js, result, js_mkstr(js, "enumerable", 10), js_bool(desc->enumerable));
	js_setprop(js, result, js_mkstr(js, "configurable", 12), js_bool(desc->configurable));
	} else {
	if (prop_off != 0) {
	jsval_t prop_val = resolveprop(js, mkval(T_PROP, prop_off));
	js_setprop(js, result, js_mkstr(js, "value", 5), prop_val);
	}
	js_setprop(js, result, js_mkstr(js, "writable", 8), desc ? (js_bool(desc->writable)) : js_true);
	js_setprop(js, result, js_mkstr(js, "enumerable", 10), desc ? (js_bool(desc->enumerable)) : js_true);
	js_setprop(js, result, js_mkstr(js, "configurable", 12), desc ? (js_bool(desc->configurable)) : js_true);
	}

	return result;

	return js_mkundef();
	}

	static inline bool own_prop_names_is_dense_shadow(
	ant_t *js, jsoff_t obj_off,
	const char *key, jsoff_t key_len
	) {
	jsoff_t doff = get_dense_buf_off(js, obj_off);
	if (!doff) return false;

	jsoff_t dense_len = dense_length(js, doff);
	if (dense_len <= 0 \|\| !is_array_index(key, key_len)) return false;

	unsigned long dense_idx = 0;
	return parse_array_index(key, (size_t)key_len, dense_len, &dense_idx);
	}

	static jsval_t builtin_object_getOwnPropertyNames(ant_t 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 = js_func_obj(obj);

	jsoff_t obj_off = (jsoff_t)vdata(obj);
	bool is_arr_obj = (vtype(obj) == T_ARR);

	jsval_t arr = mkarr(js);
	jsoff_t idx = 0;

	if (is_arr_obj) {
	for (jsoff_t i = 0;; i++) {
	jsoff_t doff = get_dense_buf_off(js, obj_off);
	if (!doff) break;

	jsoff_t dense_len = dense_length(js, doff);
	if (i >= dense_len) break;

	jsval_t v = dense_get(js, doff, i);
	if (is_empty_slot(v)) continue;

	char idxstr[16]; size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	arr_set(js, arr, idx++, js_mkstr(js, idxstr, idxlen));
	}}

	jsoff_t next = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0) {
	jsoff_t prop = next;
	jsoff_t header = loadoff(js, prop);
	next = next_prop(header);
	if (is_slot_prop(header) \|\| is_sym_key_prop(js, prop)) continue;

	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 (is_internal_prop(key, klen)) continue;
	if (is_arr_obj && own_prop_names_is_dense_shadow(js, obj_off, key, klen)) continue;
	arr_set(js, arr, idx++, js_mkstr(js, key, klen));
	}

	if (is_arr_obj) arr_set(js, arr, idx++, js->length_str);
	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_object_getOwnPropertySymbols(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return mkarr(js);
	jsval_t obj = args[0];

	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return mkarr(js);
	if (t == T_FUNC) obj = js_func_obj(obj);

	jsval_t arr = mkarr(js); jsoff_t idx = 0;
	jsoff_t next = loadoff(js, (jsoff_t)vdata(obj)) & ~(3U \| FLAGMASK);

	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (!is_slot_prop(header) && is_sym_key_prop(js, next)) {
	arr_set(js, arr, idx++, mkval(T_SYMBOL, get_prop_koff(js, next)));
	}
	next = next_prop(header);
	}

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

	static jsval_t builtin_object_isExtensible(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return js_true;

	jsval_t obj = args[0];
	uint8_t t = vtype(obj);

	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return js_true;
	jsval_t as_obj = js_as_obj(obj);

	if (js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN))) return js_false;
	if (js_truthy(js, get_slot(js, as_obj, SLOT_SEALED))) return js_false;

	jsval_t ext_slot = get_slot(js, as_obj, SLOT_EXTENSIBLE);
	if (vtype(ext_slot) != T_UNDEF) return js_bool(js_truthy(js, ext_slot));

	return js_true;
	}

	static jsval_t builtin_object_preventExtensions(ant_t 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 = js_as_obj(obj);

	set_slot(js, as_obj, SLOT_EXTENSIBLE, js_false);
	return obj;
	}

	static jsval_t builtin_object_hasOwnProperty(ant_t 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);
	jsval_t as_obj = js_as_obj(obj);

	if (vtype(key) == T_SYMBOL) {
	jsoff_t off = lkp_sym(js, as_obj, (jsoff_t)vdata(key));
	return mkval(T_BOOL, off != 0 ? 1 : 0);
	}

	const char *key_str = NULL;
	jsoff_t key_len = 0;
	if (vtype(key) != T_STR) {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}
	jsoff_t key_off = vstr(js, key, &key_len);
	key_str = (char *) &js->mem[key_off];

	if (t == T_ARR && streq(key_str, key_len, "length", 6)) return mkval(T_BOOL, 1);
	if (t == T_ARR && is_array_index(key_str, key_len)) {
	unsigned long idx;
	if (parse_array_index(key_str, key_len, get_array_length(js, obj), &idx)) {
	return mkval(T_BOOL, arr_has(js, obj, (jsoff_t)idx) ? 1 : 0);
	}
	}

	jsoff_t off = lkp(js, as_obj, key_str, key_len);
	if (off != 0) return mkval(T_BOOL, 1);
	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(as_obj), key_str, key_len);
	return mkval(T_BOOL, (desc && (desc->has_getter \|\| desc->has_setter)) ? 1 : 0);
	}

	static jsval_t builtin_object_isPrototypeOf(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return mkval(T_BOOL, 0);

	jsval_t proto_obj = resolveprop(js, js->this_val);
	jsval_t obj = args[0];

	uint8_t obj_type = vtype(obj);
	if (obj_type != T_OBJ && obj_type != T_ARR && obj_type != T_FUNC) return mkval(T_BOOL, 0);

	uint8_t proto_type = vtype(proto_obj);
	if (proto_type != T_OBJ && proto_type != T_ARR && proto_type != T_FUNC) return mkval(T_BOOL, 0);
	jsoff_t proto_data = (jsoff_t)vdata(js_as_obj(proto_obj));

	jsval_t current = get_proto(js, obj);
	while (!is_undefined(current) && !is_null(current)) {
	uint8_t cur_type = vtype(current);
	if (cur_type != T_OBJ && cur_type != T_ARR && cur_type != T_FUNC) break;
	if ((jsoff_t)vdata(js_as_obj(current)) == proto_data) return mkval(T_BOOL, 1);
	current = get_proto(js, current);
	}

	return mkval(T_BOOL, 0);
	}

	static jsval_t builtin_object_propertyIsEnumerable(ant_t 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);
	jsval_t as_obj = js_as_obj(obj);

	if (vtype(key) == T_SYMBOL) {
	jsoff_t off = lkp_sym(js, as_obj, (jsoff_t)vdata(key));
	return mkval(T_BOOL, off != 0 ? 1 : 0);
	}

	const char *key_str = NULL;
	jsoff_t key_len = 0;
	if (vtype(key) != T_STR) {
	char buf[64];
	size_t n = tostr(js, key, buf, sizeof(buf));
	key = js_mkstr(js, buf, n);
	}
	jsoff_t key_off = vstr(js, key, &key_len);
	key_str = (char *) &js->mem[key_off];

	if (t == T_ARR && streq(key_str, key_len, "length", 6)) {
	return mkval(T_BOOL, 0);
	}

	if (t == T_ARR) {
	jsoff_t doff = get_dense_buf(js, obj);
	if (doff) {
	unsigned long idx;
	if (parse_array_index(key_str, key_len, dense_length(js, doff), &idx)) {
	return mkval(T_BOOL, !is_empty_slot(dense_get(js, doff, (jsoff_t)idx)) ? 1 : 0);
	}
	}
	}

	jsoff_t off = lkp(js, as_obj, key_str, key_len);
	if (off == 0) return mkval(T_BOOL, 0);

	jsoff_t obj_off = (jsoff_t)vdata(as_obj);
	descriptor_entry_t *desc = lookup_descriptor(js, obj_off, key_str, key_len);
	if (desc) {
	return mkval(T_BOOL, desc->enumerable ? 1 : 0);
	}

	return mkval(T_BOOL, 1);
	}

	static jsval_t builtin_object_toString(ant_t 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);

	const char *tag = NULL;
	jsoff_t tag_len = 0;

	jsval_t tag_sym = get_toStringTag_sym();
	if (vtype(tag_sym) == T_SYMBOL) {
	jsoff_t sym_off = (jsoff_t)vdata(tag_sym);
	jsoff_t tag_off = 0;
	if (is_object_type(obj)) {
	tag_off = lkp_sym_proto(js, obj, sym_off);
	} else {
	jsval_t proto = get_prototype_for_type(js, t);
	if (is_object_type(proto)) {
	tag_off = lkp_sym_proto(js, proto, sym_off);
	}
	}
	if (tag_off != 0) {
	jsval_t tag_val = resolveprop(js, mkval(T_PROP, tag_off));
	if (vtype(tag_val) == T_STR) {
	jsoff_t str_off = vstr(js, tag_val, &tag_len);
	tag = (const char *)&js->mem[str_off];
	}
	}
	}

	if (!tag) {
	if (is_object_type(obj) && get_slot(js, obj, SLOT_ERROR_BRAND) == js_true) {
	tag = "Error"; tag_len = 5;
	} else switch (t) {
	case T_UNDEF: tag = "Undefined"; tag_len = 9; break;
	case T_NULL: tag = "Null"; tag_len = 4; break;
	case T_BOOL: tag = "Boolean"; tag_len = 7; break;
	case T_NUM: tag = "Number"; tag_len = 6; break;
	case T_STR: tag = "String"; tag_len = 6; break;
	case T_ARR: tag = "Array"; tag_len = 5; break;
	case T_FUNC: tag = "Function"; tag_len = 8; break;
	case T_CFUNC: tag = "Function"; tag_len = 8; break;
	case T_ERR: tag = "Error"; tag_len = 5; break;
	case T_BIGINT: tag = "BigInt"; tag_len = 6; break;
	case T_PROMISE: tag = "Promise"; tag_len = 7; break;
	case T_OBJ: tag = "Object"; tag_len = 6; break;
	default: tag = "Unknown"; tag_len = 7; break;
	}
	}

	char static_buf[64];
	string_builder_t sb;

	string_builder_init(&sb, static_buf, sizeof(static_buf));
	string_builder_append(&sb, "[object ", 8);
	string_builder_append(&sb, tag, tag_len);
	string_builder_append(&sb, "]", 1);

	return string_builder_finalize(js, &sb);
	}

	static jsval_t builtin_object_valueOf(ant_t js, jsval_t args, int nargs) {
	return js->this_val;
	}

	static jsval_t builtin_object_toLocaleString(ant_t js, jsval_t args, int nargs) {
	return js_call_toString(js, js->this_val);
	}

	static inline bool is_callable(jsval_t v) {
	uint8_t t = vtype(v);
	return t == T_FUNC \|\| t == T_CFUNC;
	}

	static inline jsval_t require_callback(ant_t js, jsval_t args, int nargs, const char *name) {
	if (nargs == 0 \|\| !is_callable(args[0]))
	return js_mkerr(js, "%s requires a function argument", name);
	return args[0];
	}

	static jsval_t array_shallow_copy(ant_t *js, jsval_t arr, jsoff_t len) {
	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff) {
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t v = dense_get(js, doff, i);
	arr_set(js, result, i, v);
	}
	return result;
	}

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	if (key_len == 0 \|\| key[0] > '9' \|\| key[0] < '0') continue;
	js_mkprop_fast(js, result, key, key_len, val);
	}

	js_prop_iter_end(&iter);
	js_mkprop_fast(js, result, "length", 6, tov((double)len));
	return result;
	}

	static jsval_t builtin_array_push(ant_t 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");
	}

	if (is_proxy(js, arr)) {
	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;
	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}
	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	js_setprop(js, arr, key, args[i]);
	len++;
	}

	jsval_t len_val = tov((double) len);
	js_setprop(js, arr, js->length_str, len_val);
	return len_val;
	}

	jsoff_t len = get_array_length(js, arr);

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff) {
	for (int i = 0; i < nargs; i++) {
	jsoff_t cap = dense_capacity(js, doff);
	if (len >= cap) {
	doff = dense_grow(js, arr, len + 1);
	if (doff == 0) return js_mkerr(js, "oom");
	}
	dense_set(js, doff, len, args[i]);
	len++;
	dense_set_length(js, doff, len);
	}
	return tov((double) len);
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);

	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);
	js_mkprop_fast(js, arr, idxstr, idxlen, args[i]); len++;
	}

	jsval_t new_len = tov((double) len);
	if (off != 0) saveval(js, off + sizeof(jsoff_t) * 2, new_len);
	else js_mkprop_fast(js, arr, "length", 6, new_len);

	return new_len;
	}

	void js_arr_push(ant_t *js, jsval_t arr, jsval_t val) {
	arr = resolveprop(js, arr);
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ) return;

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff) {
	jsoff_t len = dense_length(js, doff);
	jsoff_t cap = dense_capacity(js, doff);
	if (len >= cap) {
	doff = dense_grow(js, arr, len + 1);
	if (doff == 0) return;
	}
	dense_set(js, doff, len, val);
	dense_set_length(js, doff, len + 1);
	return;
	}

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

	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);
	js_mkprop_fast(js, arr, idxstr, idxlen, val);

	if (len_off != 0) saveval(js, len_off + sizeof(jsoff_t) * 2, tov((double)(len + 1)));
	else js_mkprop_fast(js, arr, "length", 6, tov((double)(len + 1)));
	}

	static jsval_t builtin_array_pop(ant_t 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, "pop called on non-array");
	}

	if (is_proxy(js, arr)) {
	jsoff_t len = proxy_aware_length(js, arr);
	if (len == 0) {
	js_setprop(js, arr, js->length_str, tov(0.0));
	return js_mkundef();
	}
	len--;
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);
	jsval_t result = proxy_aware_get_elem(js, arr, idxstr, idxlen);
	js_setprop(js, arr, js->length_str, tov((double) len));
	js->needs_gc = true;
	return result;
	}

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff) {
	jsoff_t len = dense_length(js, doff);
	if (len == 0) return js_mkundef();
	len--;
	jsval_t result = dense_get(js, doff, len);
	if (is_empty_slot(result)) result = js_mkundef();
	dense_set(js, doff, len, T_EMPTY);
	dense_set_length(js, doff, len);
	return result;
	}

	jsoff_t off = lkp_interned(js, arr, INTERN_LENGTH, 6);
	jsoff_t len = 0;

	if (off != 0) {
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	if (vtype(len_val) == T_NUM) len = (jsoff_t) tod(len_val);
	}

	if (len == 0) return js_mkundef();
	len--; char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)len);

	jsoff_t arr_off = (jsoff_t)vdata(js_as_obj(arr));
	jsoff_t tail = loadoff(js, arr_off + sizeof(jsoff_t) * 2);
	jsoff_t elem_off = 0;

	if (tail != 0 && tail < js->brk) {
	jsoff_t tail_hdr = loadoff(js, tail);
	if ((tail_hdr & SLOTMASK) == 0) {
	jsoff_t tail_koff = loadoff(js, tail + sizeof(jsoff_t));
	jsoff_t tail_klen = offtolen(loadoff(js, tail_koff));
	const char tail_key = (char )&js->mem[tail_koff + sizeof(jsoff_t)];
	if (tail_klen == idxlen && memcmp(tail_key, idxstr, idxlen) == 0) elem_off = tail;
	}
	}

	if (elem_off == 0) elem_off = lkp(js, arr, idxstr, idxlen);
	jsval_t result = js_mkundef();
	if (elem_off != 0) result = resolveprop(js, mkval(T_PROP, elem_off));

	if (off != 0) {
	saveval(js, off + sizeof(jsoff_t) * 2, tov((double) len));
	} else js_setprop(js, arr, js->length_str, tov((double) len));

	js->needs_gc = true;
	return result;
	}

	static jsval_t builtin_array_slice(ant_t 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 len = get_array_length(js, arr);

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

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

	if (start > end) start = end;
	jsval_t result = array_alloc_like(js, arr);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	for (jsoff_t i = start; i < end; i++) {
	jsval_t elem = arr_get(js, arr, i);
	arr_set(js, result, result_idx, elem);
	result_idx++;
	}

	return result;
	}

	static jsval_t builtin_array_join(ant_t 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 len = get_array_length(js, arr);

	if (len == 0) return js_mkstr(js, "", 0);

	size_t capacity = 1024;
	size_t result_len = 0;
	char result = (char )ant_calloc(capacity);
	if (!result) return js_mkerr(js, "oom");

	for (jsoff_t i = 0; i < len; i++) {
	if (i > 0) {
	if (result_len + sep_len >= capacity) {
	capacity = (result_len + sep_len + 1) * 2;
	char new_result = (char )ant_realloc(result, capacity);
	if (!new_result) return js_mkerr(js, "oom");
	result = new_result;
	}
	memcpy(result + result_len, sep, sep_len);
	result_len += sep_len;
	}

	{
	jsval_t elem = arr_get(js, arr, i);
	uint8_t et = vtype(elem);
	if (et == T_NULL \|\| et == T_UNDEF) continue;

	const char *elem_str = NULL;
	size_t elem_len = 0;
	char numstr[64];
	jsval_t str_val = js_mkundef();

	if (et == T_STR) {
	jsoff_t soff, slen;
	soff = vstr(js, elem, &slen);
	elem_str = (const char *)&js->mem[soff];
	elem_len = slen;
	} else if (et == T_NUM) {
	snprintf(numstr, sizeof(numstr), "%g", tod(elem));
	elem_str = numstr;
	elem_len = strlen(numstr);
	} else if (et == T_BOOL) {
	elem_str = vdata(elem) ? "true" : "false";
	elem_len = strlen(elem_str);
	} else if (et == T_ARR \|\| et == T_OBJ \|\| et == T_FUNC \|\| et == T_BIGINT) {
	str_val = to_string_val(js, elem);

	if (is_err(str_val)) {
	free(result);
	return str_val;
	}

	if (vtype(str_val) == T_STR) {
	jsoff_t soff, slen;
	soff = vstr(js, str_val, &slen);
	elem_str = (const char *)&js->mem[soff];
	elem_len = slen;
	}
	}


	if (elem_str && elem_len > 0) {
	if (result_len + elem_len >= capacity) {
	capacity = (result_len + elem_len + 1) * 2;
	char new_result = (char )ant_realloc(result, capacity);
	if (!new_result) { free(result); return js_mkerr(js, "oom"); }
	result = new_result;
	}
	memcpy(result + result_len, elem_str, elem_len);
	result_len += elem_len;
	}
	}
	}

	jsval_t ret = js_mkstr(js, result, result_len);
	free(result); return ret;
	}

	static jsval_t builtin_array_includes(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "includes called on non-array");

	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	jsoff_t len = get_array_length(js, arr);
	if (len == 0) return mkval(T_BOOL, 0);

	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++) {
	jsval_t val = arr_get(js, arr, i);
	if (vtype(val) == T_NUM && vtype(search) == T_NUM && isnan(tod(val)) && isnan(tod(search))) return mkval(T_BOOL, 1);
	if (strict_eq_values(js, val, search)) return mkval(T_BOOL, 1);
	}

	return mkval(T_BOOL, 0);
	}

	static jsval_t builtin_array_every(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "every called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "every");
	if (is_err(callback)) return callback;
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();

	jsoff_t len = get_array_length(js, arr);

	for (jsoff_t i = 0; i < len; i++) {
	if (!arr_has(js, arr, i)) continue;
	jsval_t val = arr_get(js, arr, i);
	jsval_t call_args[3] = { val, tov((double)i), arr };
	jsval_t result = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);
	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_forEach(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "forEach called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "forEach");
	if (is_err(callback)) return callback;
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();

	jsoff_t len = get_array_length(js, arr);

	for (jsoff_t i = 0; i < len; i++) {
	if (!arr_has(js, arr, i)) continue;
	jsval_t val = arr_get(js, arr, i);
	jsval_t call_args[3] = { val, tov((double)i), arr };
	jsval_t result = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);
	if (is_err(result)) return result;
	}

	return js_mkundef();
	}

	static jsval_t builtin_array_reverse(ant_t 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");

	if (is_proxy(js, arr)) {
	jsoff_t len = proxy_aware_length(js, arr);
	if (len <= 1) return arr;
	jsval_t read_from = proxy_read_target(js, arr);
	jsoff_t lower = 0;
	while (lower < len / 2) {
	jsoff_t upper_idx = len - lower - 1;
	bool lower_exists = arr_has(js, read_from, lower);
	bool upper_exists = arr_has(js, read_from, upper_idx);
	jsval_t lower_val = lower_exists ? arr_get(js, read_from, lower) : js_mkundef();
	jsval_t upper_val = upper_exists ? arr_get(js, read_from, upper_idx) : js_mkundef();
	if (lower_exists && upper_exists) {
	char s1[16]; size_t l1 = uint_to_str(s1, sizeof(s1), (unsigned)lower);
	js_setprop(js, arr, js_mkstr(js, s1, l1), upper_val);
	char s2[16]; size_t l2 = uint_to_str(s2, sizeof(s2), (unsigned)upper_idx);
	js_setprop(js, arr, js_mkstr(js, s2, l2), lower_val);
	} else if (upper_exists) {
	char s[16]; size_t l = uint_to_str(s, sizeof(s), (unsigned)lower);
	js_setprop(js, arr, js_mkstr(js, s, l), upper_val);
	} else if (lower_exists) {
	char s[16]; size_t l = uint_to_str(s, sizeof(s), (unsigned)upper_idx);
	js_setprop(js, arr, js_mkstr(js, s, l), lower_val);
	} lower++;
	} return arr;
	}

	jsoff_t len = get_array_length(js, arr);
	if (len <= 1) return arr;

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff) {
	for (jsoff_t i = 0; i < len / 2; i++) {
	jsval_t a = dense_get(js, doff, i);
	jsval_t b = dense_get(js, doff, len - 1 - i);
	dense_set(js, doff, i, b);
	dense_set(js, doff, len - 1 - i, a);
	}
	return arr;
	}

	jsval_t vals = malloc(len sizeof(jsval_t));
	jsoff_t offs = malloc(len sizeof(jsoff_t));
	if (!vals \|\| !offs) { free(vals); free(offs); return js_mkerr(js, "out of memory"); }

	jsoff_t count = 0;
	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	unsigned long parsed_idx;
	if (!parse_array_index(key, key_len, len, &parsed_idx) \|\| count >= len) continue;

	vals[count] = val;
	offs[count] = iter.off;
	count++;
	}
	js_prop_iter_end(&iter);

	for (jsoff_t i = 0; i < count / 2; i++) {
	jsval_t tmp = vals[i];
	vals[i] = vals[count - 1 - i];
	vals[count - 1 - i] = tmp;
	}

	for (jsoff_t i = 0; i < count; i++) {
	saveval(js, offs[i] + sizeof(jsoff_t) * 2, vals[i]);
	}

	free(vals);
	free(offs);
	return arr;
	}

	static jsval_t builtin_array_map(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "map called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "map");
	if (is_err(callback)) return callback;
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();

	jsoff_t len = get_array_length(js, arr);
	jsval_t result = array_alloc_like(js, arr);
	if (is_err(result)) return result;

	for (jsoff_t i = 0; i < len; i++) {
	if (!arr_has(js, arr, i)) continue;
	jsval_t val = arr_get(js, arr, i);
	jsval_t call_args[3] = { val, tov((double)i), arr };
	jsval_t mapped = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);
	if (is_err(mapped)) return mapped;
	arr_set(js, result, i, mapped);
	}

	return result;
	}

	static jsval_t builtin_array_filter(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "filter called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "filter");
	if (is_err(callback)) return callback;
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();

	jsoff_t len = get_array_length(js, arr);
	jsval_t result = array_alloc_like(js, arr);
	if (is_err(result)) return result;

	jsoff_t result_idx = 0;

	for (jsoff_t i = 0; i < len; i++) {
	if (!arr_has(js, arr, i)) continue;
	jsval_t val = arr_get(js, arr, i);
	jsval_t call_args[3] = { val, tov((double)i), arr };
	jsval_t test = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);

	if (is_err(test)) return test;
	if (js_truthy(js, test)) { arr_set(js, result, result_idx, val); result_idx++; }
	}

	return result;
	}

	static jsval_t builtin_array_reduce(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "reduce called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "reduce");
	if (is_err(callback)) return callback;
	bool has_initial = (nargs >= 2);

	jsoff_t len = get_array_length(js, arr);

	jsval_t accumulator = has_initial ? args[1] : js_mkundef();
	bool first = !has_initial;

	for (jsoff_t i = 0; i < len; i++) {
	if (!arr_has(js, arr, i)) continue;
	jsval_t val = arr_get(js, arr, i);
	if (first) { accumulator = val; first = false; continue; }
	jsval_t call_args[4] = { accumulator, val, tov((double)i), arr };
	accumulator = sv_vm_call(js->vm, js, callback, js_mkundef(), call_args, 4, NULL, false);
	if (is_err(accumulator)) return accumulator;
	}

	if (first) return js_mkerr(js, "reduce of empty array with no initial value");
	return accumulator;
	}

	static void flat_helper(ant_t js, jsval_t arr, jsval_t result, jsoff_t result_idx, int depth) {
	jsoff_t len = get_array_length(js, arr);
	if (len == 0) return;

	for (jsoff_t i = 0; i < len; i++) {
	if (!arr_has(js, arr, i)) continue;
	jsval_t val = arr_get(js, arr, i);

	if (depth > 0 && (vtype(val) == T_ARR \|\| vtype(val) == T_OBJ)) {
	flat_helper(js, val, result, result_idx, depth - 1);
	} else { arr_set(js, result, result_idx, val); (result_idx)++; }
	}
	}

	static jsval_t builtin_array_flat(ant_t 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 = array_alloc_like(js, arr);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	flat_helper(js, arr, result, &result_idx, depth);
	return result;
	}

	static jsval_t builtin_array_concat(ant_t 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 = array_alloc_like(js, arr);
	if (is_err(result)) return result;

	jsoff_t result_idx = 0;
	for (int a = -1; a < nargs; a++) {
	jsval_t arg = (a < 0) ? arr : args[a];
	bool spreadable = false;

	if (vtype(arg) == T_ARR \|\| vtype(arg) == T_OBJ) {
	bool array_default_spreadable = (vtype(arg) == T_ARR);
	if (!array_default_spreadable && is_proxy(js, arg)) {
	jsval_t target = proxy_read_target(js, arg);
	array_default_spreadable = (vtype(target) == T_ARR);
	}

	jsval_t spread_val = js_get_sym(js, arg, get_isConcatSpreadable_sym());
	if (is_err(spread_val)) return spread_val;
	if (vtype(spread_val) == T_UNDEF) spreadable = array_default_spreadable;
	else spreadable = js_truthy(js, spread_val);
	}

	if (spreadable) {
	jsoff_t arg_len = 0;
	jsval_t len_val = js_get(js, arg, "length");
	if (is_err(len_val)) return len_val;
	if (vtype(len_val) == T_NUM && tod(len_val) > 0) arg_len = (jsoff_t)tod(len_val);

	for (jsoff_t i = 0; i < arg_len; i++) {
	char idxstr[32];
	uint_to_str(idxstr, sizeof(idxstr), (uint64_t)i);
	jsval_t elem = js_get(js, arg, idxstr);
	if (is_err(elem)) return elem;
	arr_set(js, result, result_idx, elem);
	result_idx++;
	}
	} else {
	arr_set(js, result, result_idx, arg);
	result_idx++;
	}
	}

	return result;
	}

	static jsval_t builtin_array_at(ant_t 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 len = get_array_length(js, arr);

	int idx = (int) tod(args[0]);
	if (idx < 0) idx = (int)len + idx;
	if (idx < 0 \|\| (jsoff_t)idx >= len) return js_mkundef();

	return arr_get(js, arr, (jsoff_t)idx);
	}

	static jsval_t builtin_array_fill(ant_t 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 len = proxy_aware_length(js, arr);

	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++) {
	arr_set(js, arr, i, value);
	}

	return arr;
	}

	static jsval_t array_find_impl(ant_t js, jsval_t args, int nargs, bool return_index, const char *name) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "%s called on non-array", name);

	jsval_t callback = require_callback(js, args, nargs, name);
	if (is_err(callback)) return callback;
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();

	jsoff_t len = get_array_length(js, arr);
	if (len == 0) return return_index ? tov(-1) : js_mkundef();

	for (jsoff_t i = 0; i < len; i++) {
	jsval_t val = arr_get(js, arr, i);

	jsval_t call_args[3] = { val, tov((double)i), arr };
	jsval_t result = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);

	if (is_err(result)) return result;
	if (js_truthy(js, result)) return return_index ? tov((double)i) : val;
	}

	return return_index ? tov(-1) : js_mkundef();
	}

	static jsval_t builtin_array_find(ant_t js, jsval_t args, int nargs) {
	return array_find_impl(js, args, nargs, false, "find");
	}

	static jsval_t builtin_array_findIndex(ant_t js, jsval_t args, int nargs) {
	return array_find_impl(js, args, nargs, true, "findIndex");
	}

	static jsval_t array_find_last_impl(ant_t js, jsval_t args, int nargs, bool return_index, const char *name) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "%s called on non-array", name);

	jsval_t callback = require_callback(js, args, nargs, name);
	if (is_err(callback)) return callback;
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();

	jsoff_t len = get_array_length(js, arr);
	if (len == 0) return return_index ? tov(-1) : js_mkundef();

	for (jsoff_t i = len; i > 0; i--) {
	jsval_t val = arr_get(js, arr, i - 1);

	jsval_t call_args[3] = { val, tov((double)(i - 1)), arr };
	jsval_t result = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);

	if (is_err(result)) return result;
	if (js_truthy(js, result)) return return_index ? tov((double)(i - 1)) : val;
	}

	return return_index ? tov(-1) : js_mkundef();
	}

	static jsval_t builtin_array_findLast(ant_t js, jsval_t args, int nargs) {
	return array_find_last_impl(js, args, nargs, false, "findLast");
	}

	static jsval_t builtin_array_findLastIndex(ant_t js, jsval_t args, int nargs) {
	return array_find_last_impl(js, args, nargs, true, "findLastIndex");
	}

	static jsval_t builtin_array_flatMap(ant_t 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];
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();
	jsoff_t len = get_array_length(js, arr);

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;
	jsoff_t result_idx = 0;

	for (jsoff_t i = 0; i < len; i++) {
	jsval_t elem = arr_get(js, arr, i);
	jsval_t call_args[3] = { elem, tov((double)i), arr };
	jsval_t mapped = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);
	if (is_err(mapped)) return mapped;

	if (vtype(mapped) == T_ARR \|\| vtype(mapped) == T_OBJ) {
	jsoff_t m_len = get_array_length(js, mapped);
	for (jsoff_t j = 0; j < m_len; j++) {
	jsval_t m_elem = arr_get(js, mapped, j);
	arr_set(js, result, result_idx, m_elem);
	result_idx++;
	}
	} else {
	arr_set(js, result, result_idx, mapped);
	result_idx++;
	}
	}

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

	static const char js_tostring(ant_t js, jsval_t v) {
	if (vtype(v) == T_STR) {
	jsoff_t slen, off = vstr(js, v, &slen);
	return (const char *)&js->mem[off];
	}
	return js_str(js, v);
	}

	static int js_compare_values(ant_t *js, jsval_t a, jsval_t b, jsval_t compareFn) {
	uint8_t t = vtype(compareFn);
	if (t == T_FUNC \|\| t == T_CFUNC) {
	jsval_t call_args[2] = { a, b };
	jsval_t result = sv_vm_call(js->vm, js, compareFn, js_mkundef(), call_args, 2, NULL, false);
	if (vtype(result) == T_NUM) return (int)tod(result);
	return 0;
	}

	if (vtype(a) == T_STR && vtype(b) == T_STR) {
	jsoff_t len_a, len_b;
	const char sa = (const char )&js->mem[vstr(js, a, &len_a)];
	const char sb = (const char )&js->mem[vstr(js, b, &len_b)];
	return strcmp(sa, sb);
	}

	const char *sa = js_tostring(js, a);
	size_t len = strlen(sa);

	char *copy = alloca(len + 1);
	memcpy(copy, sa, len + 1);

	return strcmp(copy, js_tostring(js, b));
	}

	static jsval_t builtin_array_indexOf(ant_t 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 len = get_array_length(js, arr);

	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++) {
	jsval_t elem = arr_get(js, arr, i);
	if (vtype(elem) == T_UNDEF && !arr_has(js, arr, i)) continue;
	if (strict_eq_values(js, elem, search)) return tov((double)i);
	}
	return tov(-1);
	}

	static jsval_t builtin_array_lastIndexOf(ant_t 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 len = get_array_length(js, arr);

	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--) {
	jsval_t elem = arr_get(js, arr, (jsoff_t)i);
	if (vtype(elem) == T_UNDEF && !arr_has(js, arr, (jsoff_t)i)) continue;
	if (strict_eq_values(js, elem, search)) return tov((double)i);
	}
	return tov(-1);
	}

	static jsval_t builtin_array_reduceRight(ant_t 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 len = get_array_length(js, arr);

	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");
	accumulator = arr_get(js, arr, len - 1);
	start_idx = (int)len - 2;
	}

	for (int i = start_idx; i >= 0; i--) {
	jsval_t elem = arr_get(js, arr, (jsoff_t)i);
	jsval_t call_args[4] = { accumulator, elem, tov((double)i), arr };
	accumulator = sv_vm_call(js->vm, js, callback, js_mkundef(), call_args, 4, NULL, false);
	if (is_err(accumulator)) return accumulator;
	}

	return accumulator;
	}

	static jsval_t builtin_array_shift(ant_t 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 len = proxy_aware_length(js, arr);
	if (len == 0) return js_mkundef();

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff && !is_proxy(js, arr)) {
	jsoff_t d_len = dense_length(js, doff);
	if (d_len == 0) return js_mkundef();
	jsval_t first = dense_get(js, doff, 0);
	if (is_empty_slot(first)) first = js_mkundef();
	memmove(&js->mem[doff + sizeof(jsoff_t) * 2],
	&js->mem[doff + sizeof(jsoff_t) * 2 + sizeof(jsval_t)],
	sizeof(jsval_t) * (d_len - 1));
	dense_set(js, doff, d_len - 1, T_EMPTY);
	dense_set_length(js, doff, d_len - 1);
	return first;
	}

	jsval_t read_from = is_proxy(js, arr) ? proxy_read_target(js, arr) : arr;
	jsval_t first = arr_get(js, read_from, 0);

	for (jsoff_t i = 1; i < len; i++) {
	if (arr_has(js, read_from, i)) {
	jsval_t elem = arr_get(js, read_from, i);
	char dst[16];
	size_t dstlen = uint_to_str(dst, sizeof(dst), (unsigned)(i - 1));
	js_setprop(js, arr, js_mkstr(js, dst, dstlen), elem);
	}
	}

	js_setprop(js, arr, js->length_str, tov((double)(len - 1)));
	js->needs_gc = true;

	return first;
	}

	static jsval_t builtin_array_unshift(ant_t 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 len = proxy_aware_length(js, arr);

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff && !is_proxy(js, arr)) {
	jsoff_t d_len = dense_length(js, doff);
	jsoff_t new_len = d_len + nargs;
	jsoff_t cap = dense_capacity(js, doff);
	if (new_len > cap) {
	doff = dense_grow(js, arr, new_len);
	if (doff == 0) return js_mkerr(js, "oom");
	}
	memmove(&js->mem[doff + sizeof(jsoff_t) * 2 + sizeof(jsval_t) * nargs],
	&js->mem[doff + sizeof(jsoff_t) * 2],
	sizeof(jsval_t) * d_len);
	for (int i = 0; i < nargs; i++)
	dense_set(js, doff, (jsoff_t)i, args[i]);
	dense_set_length(js, doff, new_len);
	return tov((double) new_len);
	}

	jsval_t read_from = is_proxy(js, arr) ? proxy_read_target(js, arr) : arr;

	for (int i = (int)len - 1; i >= 0; i--) {
	if (arr_has(js, read_from, (jsoff_t)i)) {
	jsval_t elem = arr_get(js, read_from, (jsoff_t)i);
	char dst[16];
	size_t dstlen = uint_to_str(dst, sizeof(dst), (unsigned)(i + nargs));
	js_setprop(js, arr, js_mkstr(js, dst, dstlen), elem);
	}
	}

	for (int i = 0; i < nargs; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	js_setprop(js, arr, key, args[i]);
	}

	jsoff_t new_len = len + nargs;
	js_setprop(js, arr, js->length_str, tov((double) new_len));

	return tov((double) new_len);
	}

	static jsval_t builtin_array_some(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "some called on non-array");

	jsval_t callback = require_callback(js, args, nargs, "some");
	if (is_err(callback)) return callback;
	jsval_t this_arg = (nargs >= 2) ? args[1] : js_mkundef();

	jsoff_t len = get_array_length(js, arr);
	if (len == 0) return mkval(T_BOOL, 0);

	for (jsoff_t i = 0; i < len; i++) {
	if (!arr_has(js, arr, i)) continue;
	jsval_t val = arr_get(js, arr, i);

	jsval_t call_args[3] = { val, tov((double)i), arr };
	jsval_t result = sv_vm_call(js->vm, js, callback, this_arg, call_args, 3, NULL, false);

	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(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	jsval_t compareFn = js_mkundef();
	jsval_t vals = NULL, keys = NULL, temp_vals = NULL, temp_keys = NULL;
	jsoff_t *offs = NULL;
	jsoff_t count = 0, undef_count = 0, len = 0;

	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "sort called on non-array");

	if (nargs >= 1) {
	uint8_t t = vtype(args[0]);
	if (t == T_FUNC \|\| t == T_CFUNC) compareFn = args[0];
	else if (t != T_UNDEF) return js_mkerr_typed(js, JS_ERR_TYPE, "compareFn must be a function or undefined");
	}

	len = get_array_length(js, arr);
	if (len == 0) return arr;

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff) {
	vals = malloc(len * sizeof(jsval_t));
	if (!vals) goto oom;
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t v = dense_get(js, doff, i);
	if (is_empty_slot(v) \|\| vtype(v) == T_UNDEF) undef_count++;
	else vals[count++] = v;
	}
	} else {
	vals = malloc(len * sizeof(jsval_t));
	offs = malloc(len * sizeof(jsoff_t));
	if (!vals \|\| !offs) goto oom;

	ant_iter_t iter = js_prop_iter_begin(js, arr);
	const char *key;
	size_t key_len;
	jsval_t val;

	while (js_prop_iter_next(&iter, &key, &key_len, &val)) {
	if (key_len == 0 \|\| key[0] > '9' \|\| key[0] < '0') continue;

	unsigned idx = 0;
	bool valid = true;
	for (size_t i = 0; i < key_len && valid; i++) {
	if (key[i] < '0' \|\| key[i] > '9') valid = false;
	else idx = idx * 10 + (key[i] - '0');
	}
	if (!valid \|\| idx >= len \|\| (count + undef_count) >= len) continue;

	offs[count + undef_count] = iter.off;
	if (vtype(val) == T_UNDEF) undef_count++;
	else vals[count++] = val;
	}

	js_prop_iter_end(&iter);
	}
	if (count <= 1) goto writeback;

	bool use_keys = (vtype(compareFn) == T_UNDEF);
	if (use_keys) {
	keys = malloc(count * sizeof(jsval_t));
	if (!keys) goto oom;
	for (jsoff_t i = 0; i < count; i++) {
	const char *s = js_tostring(js, vals[i]);
	keys[i] = js_mkstr(js, s, strlen(s));
	}
	}

	temp_vals = malloc(count * sizeof(jsval_t));
	if (use_keys) temp_keys = malloc(count * sizeof(jsval_t));
	if (!temp_vals \|\| (use_keys && !temp_keys)) goto oom;

	for (jsoff_t width = 1; width < count; width *= 2) {
	for (jsoff_t left = 0; left < count; left += width * 2) {
	jsoff_t mid = left + width;
	jsoff_t right = (mid + width < count) ? mid + width : count;
	if (mid >= count) break;

	jsoff_t i = left, j = mid, k = 0;
	while (i < mid && j < right) {
	int cmp;
	if (use_keys) {
	jsoff_t len_a, len_b;
	const char sa = (const char )&js->mem[vstr(js, keys[i], &len_a)];
	const char sb = (const char )&js->mem[vstr(js, keys[j], &len_b)];
	cmp = strcmp(sa, sb);
	} else {
	cmp = js_compare_values(js, vals[i], vals[j], compareFn);
	}
	if (cmp <= 0) {
	temp_vals[k] = vals[i];
	if (use_keys) temp_keys[k] = keys[i];
	k++; i++;
	} else {
	temp_vals[k] = vals[j];
	if (use_keys) temp_keys[k] = keys[j];
	k++; j++;
	}
	}
	while (i < mid) {
	temp_vals[k] = vals[i];
	if (use_keys) temp_keys[k] = keys[i];
	k++; i++;
	}
	while (j < right) {
	temp_vals[k] = vals[j];
	if (use_keys) temp_keys[k] = keys[j];
	k++; j++;
	}

	memcpy(&vals[left], temp_vals, k * sizeof(jsval_t));
	if (use_keys) memcpy(&keys[left], temp_keys, k * sizeof(jsval_t));
	}
	}

	writeback:
	if (doff) {
	for (jsoff_t i = 0; i < count; i++) dense_set(js, doff, i, vals[i]);
	for (jsoff_t i = count; i < count + undef_count; i++) dense_set(js, doff, i, js_mkundef());
	for (jsoff_t i = count + undef_count; i < len; i++) dense_set(js, doff, i, T_EMPTY);
	} else {
	for (jsoff_t i = 0; i < count; i++)
	saveval(js, offs[i] + sizeof(jsoff_t) * 2, vals[i]);
	for (jsoff_t i = 0; i < undef_count; i++)
	saveval(js, offs[count + i] + sizeof(jsoff_t) * 2, js_mkundef());
	}

	free(temp_keys);
	free(temp_vals);
	free(keys);
	free(vals);
	free(offs);
	return arr;

	oom:
	free(temp_keys);
	free(temp_vals);
	free(keys);
	free(vals);
	free(offs);
	return js_mkerr(js, "out of memory");
	}

	static jsval_t builtin_array_splice(ant_t 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 len = proxy_aware_length(js, arr);
	jsval_t read_from = is_proxy(js, arr) ? proxy_read_target(js, arr) : arr;

	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 = array_alloc_like(js, arr);
	if (is_err(removed)) return removed;

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff && !is_proxy(js, arr)) {
	for (int i = 0; i < deleteCount; i++) {
	jsval_t elem = arr_get(js, arr, (jsoff_t)(start + i));
	arr_set(js, removed, (jsoff_t)i, elem);
	}

	jsoff_t d_len = dense_length(js, doff);
	int shift = insertCount - deleteCount;
	jsoff_t new_len = (jsoff_t)((int)d_len + shift);

	if (shift != 0) {
	if (new_len > dense_capacity(js, doff)) {
	doff = dense_grow(js, arr, new_len);
	if (doff == 0) return js_mkerr(js, "oom");
	}
	jsoff_t move_start = (jsoff_t)(start + deleteCount);
	jsoff_t move_dest = (jsoff_t)(start + insertCount);
	jsoff_t move_count = d_len - move_start;
	if (move_count > 0) memmove(
	&js->mem[doff + sizeof(jsoff_t) * 2 + sizeof(jsval_t) * move_dest],
	&js->mem[doff + sizeof(jsoff_t) * 2 + sizeof(jsval_t) * move_start],
	sizeof(jsval_t) * move_count
	);
	}

	for (int i = 0; i < insertCount; i++)
	dense_set(js, doff, (jsoff_t)(start + i), args[2 + i]);

	if (shift < 0) {
	for (jsoff_t i = new_len; i < d_len; i++)
	dense_set(js, doff, i, T_EMPTY);
	}

	dense_set_length(js, doff, new_len);
	if (deleteCount > 0) js->needs_gc = true;
	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, read_from, 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));
	js_setprop(js, removed, key, elem);
	}
	}

	js_setprop(js, removed, js->length_str, 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, read_from, 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));
	js_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, read_from, 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));
	js_setprop(js, arr, key, elem);
	}
	}

	for (int i = 0; i < insertCount; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)(start + i));
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	js_setprop(js, arr, key, args[2 + i]);
	}

	js_setprop(js, arr, js->length_str, tov((double)((int)len + shift)));
	if (deleteCount > 0) js->needs_gc = true;

	return removed;
	}

	static jsval_t builtin_array_copyWithin(ant_t 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 len = proxy_aware_length(js, arr);
	jsval_t read_from = is_proxy(js, arr) ? proxy_read_target(js, arr) : arr;

	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;
	if (count <= 0) return arr;

	jsoff_t doff = get_dense_buf(js, arr);
	if (doff && !is_proxy(js, arr)) {
	if (start < target) {
	for (int i = count - 1; i >= 0; i--) {
	jsval_t v = dense_get(js, doff, (jsoff_t)(start + i));
	dense_set(js, doff, (jsoff_t)(target + i), is_empty_slot(v) ? js_mkundef() : v);
	}
	} else {
	for (int i = 0; i < count; i++) {
	jsval_t v = dense_get(js, doff, (jsoff_t)(start + i));
	dense_set(js, doff, (jsoff_t)(target + i), is_empty_slot(v) ? js_mkundef() : v);
	}
	}
	return arr;
	}

	jsval_t temp = (jsval_t )malloc(count * sizeof(jsval_t));
	for (int i = 0; i < count; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)(start + i));
	jsoff_t elem_off = lkp(js, read_from, idxstr, idxlen);
	temp[i] = elem_off ? resolveprop(js, mkval(T_PROP, elem_off)) : js_mkundef();
	}

	for (int i = 0; i < count; i++) {
	char idxstr[16];
	size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)(target + i));
	jsval_t key = js_mkstr(js, idxstr, idxlen);
	js_setprop(js, arr, key, temp[i]);
	}

	free(temp);
	return arr;
	}

	static jsval_t builtin_array_toSorted(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "toSorted called on non-array");

	jsval_t result = array_shallow_copy(js, arr, get_array_length(js, arr));
	if (is_err(result)) return result;

	jsval_t saved_this = js->this_val;
	js->this_val = result;
	jsval_t sorted = builtin_array_sort(js, args, nargs);
	js->this_val = saved_this;

	if (is_err(sorted)) return sorted;
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_toReversed(ant_t js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "toReversed called on non-array");

	jsval_t result = array_shallow_copy(js, arr, get_array_length(js, arr));
	if (is_err(result)) return result;

	jsval_t saved_this = js->this_val;
	js->this_val = result;
	jsval_t reversed = builtin_array_reverse(js, NULL, 0);
	js->this_val = saved_this;

	if (is_err(reversed)) return reversed;
	return mkval(T_ARR, vdata(result));
	}

	static jsval_t builtin_array_toSpliced(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR && vtype(arr) != T_OBJ)
	return js_mkerr(js, "toSpliced called on non-array");

	jsval_t result = array_shallow_copy(js, arr, get_array_length(js, arr));
	if (is_err(result)) return result;

	jsval_t saved_this = js->this_val;
	js->this_val = result;
	builtin_array_splice(js, args, nargs);
	js->this_val = saved_this;

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

	static jsval_t builtin_array_with(ant_t 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 len = get_array_length(js, arr);

	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++) {
	jsval_t elem = ((jsoff_t)idx == i) ? args[1] : arr_get(js, arr, i);
	arr_set(js, result, i, elem);
	}

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

	static jsval_t builtin_array_keys(ant_t 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 len = get_array_length(js, arr);

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	for (jsoff_t i = 0; i < len; i++) {
	arr_set(js, result, i, tov((double) i));
	}

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

	static jsval_t builtin_array_values(ant_t 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 len = get_array_length(js, arr);

	jsval_t result = mkarr(js);
	if (is_err(result)) return result;

	for (jsoff_t i = 0; i < len; i++) {
	arr_set(js, result, i, arr_get(js, arr, i));
	}

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

	static jsval_t builtin_array_entries(ant_t 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 len = get_array_length(js, arr);

	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;

	jsval_t elem = arr_get(js, arr, i);

	arr_set(js, entry, 0, tov((double) i));
	arr_set(js, entry, 1, elem);

	arr_set(js, result, i, mkval(T_ARR, vdata(entry)));
	}

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

	static jsval_t builtin_array_toString(ant_t js, jsval_t args, int nargs) {
	jsval_t arr = js->this_val;

	jsval_t join_result;
	if (js_try_call_method(js, arr, "join", 4, NULL, 0, &join_result)) {
	if (is_err(join_result)) return join_result;
	return join_result;
	}

	return builtin_object_toString(js, args, nargs);
	}

	static jsval_t builtin_array_toLocaleString(ant_t js, jsval_t args, int nargs) {
	(void) args;
	(void) nargs;
	jsval_t arr = js->this_val;
	if (vtype(arr) != T_ARR) return js_mkerr(js, "toLocaleString called on non-array");

	jsoff_t len = get_array_length(js, arr);
	if (len == 0) return js_mkstr(js, "", 0);

	char *result = NULL;
	size_t result_len = 0, result_cap = 256;
	result = (char *)ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");

	for (jsoff_t i = 0; i < len; i++) {
	if (i > 0) {
	if (result_len + 1 >= result_cap) {
	result_cap *= 2;
	char new_result = (char )ant_calloc(result_cap);
	if (!new_result) { free(result); return js_mkerr(js, "oom"); }
	memcpy(new_result, result, result_len);
	free(result);
	result = new_result;
	}
	result[result_len++] = ',';
	}

	if (!arr_has(js, arr, i)) continue;
	jsval_t elem = arr_get(js, arr, i);
	if (vtype(elem) == T_NULL \|\| vtype(elem) == T_UNDEF) continue;

	char buf[64];
	size_t elem_len = tostr(js, elem, buf, sizeof(buf));

	if (result_len + elem_len >= result_cap) {
	while (result_len + elem_len >= result_cap) result_cap *= 2;
	char new_result = (char )ant_calloc(result_cap);
	if (!new_result) { free(result); return js_mkerr(js, "oom"); }
	memcpy(new_result, result, result_len);
	free(result);
	result = new_result;
	}
	memcpy(result + result_len, buf, elem_len);
	result_len += elem_len;
	}

	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	}

	static jsval_t builtin_Array_isArray(ant_t 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);
	}

	typedef struct {
	jsval_t write_target;
	jsval_t result;
	jsval_t mapFn;
	jsval_t mapThis;
	jsoff_t index;
	} array_from_iter_ctx_t;

	static iter_action_t array_from_iter_cb(ant_t js, jsval_t value, void ctx, jsval_t *out) {
	array_from_iter_ctx_t fctx = (array_from_iter_ctx_t )ctx;
	jsval_t elem = value;

	if (is_callable(fctx->mapFn)) {
	jsval_t call_args[2] = { elem, tov((double)fctx->index) };
	elem = sv_vm_call(js->vm, js, fctx->mapFn, fctx->mapThis, call_args, 2, NULL, false);
	if (is_err(elem)) { *out = elem; return ITER_ERROR; }
	}

	if (vtype(fctx->write_target) == T_ARR) arr_set(js, fctx->write_target, fctx->index, elem);
	else {
	char idxstr[16]; size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)fctx->index);
	js_setprop(js, fctx->write_target, js_mkstr(js, idxstr, idxlen), elem);
	}

	fctx->index++;
	return ITER_CONTINUE;
	}

	static jsval_t builtin_Array_from(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return mkarr(js);

	jsval_t src = args[0];
	jsval_t mapFn = (nargs >= 2 && is_callable(args[1])) ? args[1] : js_mkundef();
	jsval_t mapThis = (nargs >= 3) ? args[2] : js_mkundef();

	jsval_t ctor = js->this_val;
	bool use_ctor = (vtype(ctor) == T_FUNC \|\| vtype(ctor) == T_CFUNC);
	jsval_t result = use_ctor ? array_alloc_from_ctor_with_length(js, ctor, 0) : mkarr(js);
	if (is_err(result)) return result;

	bool result_is_proxy = is_proxy(js, result);
	jsval_t write_target = result_is_proxy ? proxy_read_target(js, result) : result;
	jsval_t iter_sym = get_iterator_sym();

	if (vtype(src) == T_STR) {
	if (is_rope(js, src)) { src = rope_flatten(js, src); if (is_err(src)) return src; }
	jsoff_t slen = str_len_fast(js, src);
	array_from_iter_ctx_t ctx = { write_target, result, mapFn, mapThis, 0 };
	for (jsoff_t i = 0; i < slen; ) {
	jsoff_t off = vstr(js, src, NULL);
	utf8proc_int32_t cp;
	jsoff_t cb_len = (jsoff_t)utf8_next((const utf8proc_uint8_t *)&js->mem[off + i], (utf8proc_ssize_t)(slen - i), &cp);
	jsval_t ch = js_mkstr(js, (char *)&js->mem[off + i], cb_len);

	jsval_t out;
	iter_action_t act = array_from_iter_cb(js, ch, &ctx, &out);

	if (act == ITER_ERROR) return out;
	i += cb_len;
	}
	if (vtype(result) != T_ARR) js_setprop(js, result, js->length_str, tov((double)ctx.index));
	} else if (vtype(src) == T_ARR) {
	jsoff_t iter_off = (vtype(iter_sym) == T_SYMBOL) ? lkp_sym_proto(js, src, (jsoff_t)vdata(iter_sym)) : 0;
	bool default_iter = iter_off != 0 && vtype(loadval(js, iter_off + sizeof(jsoff_t) * 2)) == T_CFUNC;

	if (default_iter) {
	array_from_iter_ctx_t ctx = { write_target, result, mapFn, mapThis, 0 };
	jsoff_t len = get_array_length(js, src);
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t unused;
	iter_action_t act = array_from_iter_cb(js, arr_get(js, src, i), &ctx, &unused);
	if (act == ITER_ERROR) return unused;
	}
	if (vtype(result) != T_ARR) js_setprop(js, result, js->length_str, tov((double)len));
	} else {
	array_from_iter_ctx_t ctx = { write_target, result, mapFn, mapThis, 0 };
	jsval_t iter_result = iter_foreach(js, src, array_from_iter_cb, &ctx);
	if (is_err(iter_result)) return iter_result;
	if (vtype(result) != T_ARR) js_setprop(js, result, js->length_str, tov((double)ctx.index));
	}
	} else {
	jsoff_t iter_prop = (vtype(iter_sym) == T_SYMBOL) ? lkp_sym_proto(js, src, (jsoff_t)vdata(iter_sym)) : 0;

	if (iter_prop != 0) {
	array_from_iter_ctx_t ctx = { write_target, result, mapFn, mapThis, 0 };
	jsval_t iter_result = iter_foreach(js, src, array_from_iter_cb, &ctx);
	if (is_err(iter_result)) return iter_result;
	if (vtype(result) != T_ARR) js_setprop(js, result, js->length_str, tov((double)ctx.index));
	} else if (vtype(src) == T_OBJ) {
	array_from_iter_ctx_t ctx = { write_target, result, mapFn, mapThis, 0 };
	jsoff_t len = get_array_length(js, src);
	for (jsoff_t i = 0; i < len; i++) {
	jsval_t unused;
	iter_action_t act = array_from_iter_cb(js, arr_get(js, src, i), &ctx, &unused);
	if (act == ITER_ERROR) return unused;
	}
	if (vtype(result) != T_ARR) js_setprop(js, result, js->length_str, tov((double)len));
	}
	}

	if (!use_ctor) return mkval(T_ARR, vdata(result));
	return result;
	}

	static jsval_t builtin_Array_of(ant_t js, jsval_t args, int nargs) {
	jsval_t ctor = js->this_val;
	bool use_ctor = (vtype(ctor) == T_FUNC \|\| vtype(ctor) == T_CFUNC);
	jsval_t arr = use_ctor ? array_alloc_from_ctor_with_length(js, ctor, (jsoff_t)nargs) : mkarr(js);
	if (is_err(arr)) return arr;

	bool arr_is_proxy = is_proxy(js, arr);
	jsval_t write_target = arr_is_proxy ? proxy_read_target(js, arr) : arr;

	for (int i = 0; i < nargs; i++) {
	if (vtype(write_target) == T_ARR) arr_set(js, write_target, (jsoff_t)i, args[i]);
	else {
	char idxstr[16]; size_t idxlen = uint_to_str(idxstr, sizeof(idxstr), (unsigned)i);
	js_setprop(js, write_target, js_mkstr(js, idxstr, idxlen), args[i]);
	}
	}

	if (vtype(arr) != T_ARR) js_setprop(js, arr, js->length_str, tov((double) nargs));
	if (!use_ctor) return mkval(T_ARR, vdata(arr));

	return arr;
	}

	static jsval_t builtin_string_indexOf(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "indexOf called on non-string");
	if (nargs == 0) return tov(-1);

	jsval_t search = args[0];
	if (vtype(search) != T_STR) return tov(-1);

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);

	jsoff_t start = 0;
	double dstr_len = D(str_len);
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double pos = tod(args[1]);
	if (pos < 0) pos = 0;
	if (pos > dstr_len) pos = dstr_len;
	start = (jsoff_t) pos;
	}

	if (search_len == 0) return tov(D(start));
	if (start + search_len > str_len) return tov(-1);

	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	for (jsoff_t i = start; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) return tov(D(i));
	}
	return tov(-1);
	}

	static jsval_t builtin_string_substring(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "substring called on non-string");
	jsoff_t byte_len, str_off = vstr(js, str, &byte_len);
	const char str_ptr = (char ) &js->mem[str_off];
	size_t utf16_len = utf16_strlen(str_ptr, byte_len);
	jsoff_t start = 0, end = (jsoff_t)utf16_len;
	double dstr_len2 = D(utf16_len);

	if (nargs >= 1 && vtype(args[0]) == T_NUM) {
	double d = tod(args[0]);
	start = (jsoff_t) (d < 0 ? 0 : (d > dstr_len2 ? dstr_len2 : d));
	}

	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	end = (jsoff_t) (d < 0 ? 0 : (d > dstr_len2 ? dstr_len2 : d));
	}

	if (start > end) {
	jsoff_t tmp = start;
	start = end;
	end = tmp;
	}

	size_t byte_start, byte_end;
	utf16_range_to_byte_range(str_ptr, byte_len, start, end, &byte_start, &byte_end);
	return js_mkstr(js, str_ptr + byte_start, byte_end - byte_start);
	}

	static jsval_t builtin_string_substr(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "substr called on non-string");
	jsoff_t byte_len, str_off = vstr(js, str, &byte_len);
	const char str_ptr = (char ) &js->mem[str_off];
	size_t utf16_len = utf16_strlen(str_ptr, byte_len);

	if (nargs < 1) return js_mkstr(js, str_ptr, byte_len);

	double d_start = tod(args[0]);
	jsoff_t start;
	if (d_start < 0) {
	start = (jsoff_t)((double)utf16_len + d_start);
	if ((int)start < 0) start = 0;
	} else {
	start = (jsoff_t)d_start;
	}
	if (start > (jsoff_t)utf16_len) start = (jsoff_t)utf16_len;

	jsoff_t len = (jsoff_t)utf16_len - start;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d < 0) d = 0;
	len = (jsoff_t)d;
	}
	if (start + len > (jsoff_t)utf16_len) len = (jsoff_t)utf16_len - start;

	size_t byte_start, byte_end;
	utf16_range_to_byte_range(str_ptr, byte_len, start, start + len, &byte_start, &byte_end);
	return js_mkstr(js, str_ptr + byte_start, byte_end - byte_start);
	}

	static jsval_t string_split_impl(ant_t js, jsval_t str, jsval_t args, int nargs) {
	if (vtype(str) != T_STR) return js_mkerr(js, "split called on non-string");
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	jsval_t arr = mkarr(js);

	if (is_err(arr)) return arr;

	uint32_t limit = UINT32_MAX;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double d = tod(args[1]);
	if (d >= 0 && d <= UINT32_MAX) {
	limit = (uint32_t)d;
	}
	}
	if (limit == 0) {
	return mkval(T_ARR, vdata(arr));
	}
	if (nargs == 0) goto return_whole;

	jsval_t sep_arg = args[0];
	if (vtype(sep_arg) == T_OBJ) {
	jsoff_t source_off = lkp(js, sep_arg, "source", 6);
	if (source_off == 0) goto return_whole;
	jsval_t source_val = resolveprop(js, mkval(T_PROP, source_off));
	if (vtype(source_val) != T_STR) goto return_whole;

	jsoff_t plen, poff = vstr(js, source_val, &plen);
	const char pattern_ptr = (char ) &js->mem[poff];

	if (plen == 0 \|\| (plen == 4 && memcmp(pattern_ptr, "(?:)", 4) == 0)) {
	jsoff_t idx = 0;
	for (jsoff_t i = 0; i < str_len && idx < limit; i++) {
	jsval_t part = js_mkstr(js, str_ptr + i, 1);
	arr_set(js, arr, idx, part);
	idx++;
	}
	return mkval(T_ARR, vdata(arr));
	}

	char pcre2_pattern[512];
	size_t pcre2_len = js_to_pcre2_pattern(pattern_ptr, plen, pcre2_pattern, sizeof(pcre2_pattern));

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	if (re == NULL) goto return_whole;

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	uint32_t capture_count;
	pcre2_pattern_info(re, PCRE2_INFO_CAPTURECOUNT, &capture_count);

	if (str_len == 0) {
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, 0, 0, 0, match_data, NULL);
	if (rc >= 0) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return mkval(T_ARR, vdata(arr));
	}
	}

	jsoff_t idx = 0;
	PCRE2_SIZE search_pos = 0;
	PCRE2_SIZE segment_start = 0;
	PCRE2_SIZE last_match_end = (PCRE2_SIZE)-1;
	bool had_any_split = false;

	while (idx < limit && search_pos <= str_len) {
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, search_pos, 0, match_data, NULL);
	if (rc < 0) break;

	PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
	PCRE2_SIZE match_start = ovector[0];
	PCRE2_SIZE match_end = ovector[1];

	if (match_start == match_end && match_start == last_match_end) {
	search_pos = match_end + 1;
	continue;
	}

	if (match_start == match_end && capture_count > 0) {
	bool is_pure_empty_capture = true;
	for (uint32_t i = 1; i <= capture_count; i++) {
	PCRE2_SIZE cap_start = ovector[2*i];
	PCRE2_SIZE cap_end = ovector[2*i+1];
	if (cap_start == PCRE2_UNSET \|\| cap_end != cap_start) {
	is_pure_empty_capture = false;
	break;
	}
	}
	if (is_pure_empty_capture) {
	search_pos = match_end + 1;
	continue;
	}
	}

	had_any_split = true;

	jsval_t part = js_mkstr(js, str_ptr + segment_start, match_start - segment_start);
	arr_set(js, arr, idx, part);
	idx++;

	for (uint32_t i = 1; i <= capture_count && idx < limit; i++) {
	PCRE2_SIZE cap_start = ovector[2*i];
	PCRE2_SIZE cap_end = ovector[2*i+1];
	if (cap_start == PCRE2_UNSET) {
	arr_set(js, arr, idx, js_mkundef());
	} else {
	part = js_mkstr(js, str_ptr + cap_start, cap_end - cap_start);
	arr_set(js, arr, idx, part);
	}
	idx++;
	}

	last_match_end = match_end;
	segment_start = match_end;
	if (match_start == match_end) {
	search_pos = match_end + 1;
	} else {
	search_pos = match_end;
	}
	}

	if (!had_any_split) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	arr_set(js, arr, 0, js_mkstr(js, str_ptr, str_len));
	return mkval(T_ARR, vdata(arr));
	}

	if (idx < limit) {
	jsval_t part = js_mkstr(js, str_ptr + segment_start, str_len - segment_start);
	arr_set(js, arr, idx, part);
	idx++;
	}

	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return mkval(T_ARR, vdata(arr));
	}

	if (vtype(sep_arg) != T_STR) goto return_whole;

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

	if (sep_len == 0) {
	for (jsoff_t i = 0; i < str_len && idx < limit; i++) {
	jsval_t part = js_mkstr(js, str_ptr + i, 1);
	arr_set(js, arr, idx, part);
	idx++;
	}
	return mkval(T_ARR, vdata(arr));
	}

	for (jsoff_t i = 0; i + sep_len <= str_len && idx < limit; i++) {
	if (memcmp(str_ptr + i, sep_ptr, sep_len) != 0) continue;
	jsval_t part = js_mkstr(js, str_ptr + start, i - start);
	arr_set(js, arr, idx, part);
	idx++;
	start = i + sep_len;
	i += sep_len - 1;
	}
	if (idx < limit && start <= str_len) {
	jsval_t part = js_mkstr(js, str_ptr + start, str_len - start);
	arr_set(js, arr, idx, part);
	idx++;
	}

	return mkval(T_ARR, vdata(arr));

	return_whole:
	if (limit > 0) {
	arr_set(js, arr, 0, str);
	}
	return mkval(T_ARR, vdata(arr));
	}

	static jsval_t builtin_string_split(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "split called on non-string");

	if (nargs > 0 && is_object_type(args[0])) {
	bool called = false;
	jsval_t call_args[2];
	int call_nargs = 1;
	call_args[0] = str;
	if (nargs >= 2) {
	call_args[1] = args[1];
	call_nargs = 2;
	}
	jsval_t dispatched = maybe_call_symbol_method(
	js, args[0], get_split_sym(), args[0], call_args, call_nargs, &called
	);
	if (is_err(dispatched)) return dispatched;
	if (called) return dispatched;
	}

	return string_split_impl(js, str, args, nargs);
	}

	static jsval_t builtin_string_slice(ant_t js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;

	jsoff_t byte_len, str_off = vstr(js, str, &byte_len);
	const char str_ptr = (char ) &js->mem[str_off];
	size_t utf16_len = utf16_strlen(str_ptr, byte_len);
	jsoff_t start = 0, end = (jsoff_t)utf16_len;
	double dstr_len = D(utf16_len);

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

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

	if (start > end) start = end;
	size_t byte_start, byte_end;
	utf16_range_to_byte_range(str_ptr, byte_len, start, end, &byte_start, &byte_end);
	return js_mkstr(js, str_ptr + byte_start, byte_end - byte_start);
	}

	static jsval_t builtin_string_includes(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "includes called on non-string");
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	if (is_object_type(search)) {
	jsval_t maybe_err = reject_regexp_arg(js, search, "includes");
	if (is_err(maybe_err)) return maybe_err;
	}
	search = js_tostring_val(js, search);
	if (is_err(search)) return search;

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	jsoff_t start = 0;
	if (nargs >= 2) {
	double pos = tod(args[1]);
	if (isnan(pos) \|\| pos < 0) pos = 0;
	if (pos > D(str_len)) return mkval(T_BOOL, 0);
	start = (jsoff_t) pos;
	}

	if (search_len == 0) return mkval(T_BOOL, 1);
	if (start + search_len > str_len) return mkval(T_BOOL, 0);
	for (jsoff_t i = start; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) return mkval(T_BOOL, 1);
	}

	return mkval(T_BOOL, 0);
	}

	static jsval_t builtin_string_startsWith(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "startsWith called on non-string");
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	if (is_object_type(search)) {
	jsval_t maybe_err = reject_regexp_arg(js, search, "startsWith");
	if (is_err(maybe_err)) return maybe_err;
	}
	search = js_tostring_val(js, search);
	if (is_err(search)) return search;

	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(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "endsWith called on non-string");
	if (nargs == 0) return mkval(T_BOOL, 0);
	jsval_t search = args[0];

	if (is_object_type(search)) {
	jsval_t maybe_err = reject_regexp_arg(js, search, "endsWith");
	if (is_err(maybe_err)) return maybe_err;
	}
	search = js_tostring_val(js, search);
	if (is_err(search)) return search;

	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(ant_t js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;
	if (nargs < 1) return str;

	if (is_object_type(args[0])) {
	bool called = false;
	jsval_t replacement_arg = nargs > 1 ? args[1] : js_mkundef();
	jsval_t call_args[2] = { str, replacement_arg };
	jsval_t dispatched = maybe_call_symbol_method(
	js, args[0], get_replace_sym(), args[0], call_args, 2, &called
	);
	if (is_err(dispatched)) return dispatched;
	if (called) return dispatched;
	}
	if (nargs < 2) return str;

	jsval_t search = args[0];
	jsval_t replacement = args[1];

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	bool is_regex = false;
	bool global_flag = false;
	bool is_func_replacement = (vtype(replacement) == T_FUNC);
	char *pattern_buf = NULL;
	jsoff_t pattern_len = 0;

	if (vtype(search) == T_OBJ) {
	jsoff_t pattern_off = lkp(js, search, "source", 6);
	if (pattern_off == 0) goto not_regex;

	jsval_t pattern_val = resolveprop(js, mkval(T_PROP, pattern_off));
	if (vtype(pattern_val) != T_STR) goto not_regex;

	is_regex = true;
	jsoff_t plen, poff = vstr(js, pattern_val, &plen);
	pattern_len = plen;
	pattern_buf = (char *)ant_calloc(plen + 1);
	if (!pattern_buf) return js_mkerr(js, "oom");
	memcpy(pattern_buf, &js->mem[poff], plen);
	pattern_buf[plen] = '\0';

	jsoff_t flags_off = lkp(js, search, "flags", 5);
	if (flags_off == 0) { free(pattern_buf); pattern_buf = NULL; goto not_regex; }

	jsval_t flags_val = resolveprop(js, mkval(T_PROP, flags_off));
	if (vtype(flags_val) != T_STR) { free(pattern_buf); pattern_buf = NULL; goto not_regex; }

	jsoff_t flen, foff = vstr(js, flags_val, &flen);
	const char flags_str = (char ) &js->mem[foff];
	for (jsoff_t i = 0; i < flen; i++) {
	if (flags_str[i] == 'g') global_flag = true;
	}
	}
	not_regex:

	jsoff_t repl_len = 0;
	const char *repl_ptr = NULL;
	if (!is_func_replacement) {
	if (vtype(replacement) != T_STR) { if (pattern_buf) free(pattern_buf); return str; }
	jsoff_t repl_off;
	repl_off = vstr(js, replacement, &repl_len);
	repl_ptr = (char *) &js->mem[repl_off];
	}

	size_t result_cap = str_len + repl_len + 256;
	size_t result_len = 0;
	char result = (char )ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");

	#define ENSURE_RESULT_CAP(need) do { \
	if (result_len + (need) >= result_cap) { \
	result_cap = (result_len + (need) + 1) * 2; \
	char nr = (char )ant_realloc(result, result_cap); \
	if (!nr) return js_mkerr(js, "oom"); \
	result = nr; \
	} \
	} while(0)

	if (is_regex) {
	size_t pcre2_cap = pattern_len * 2 + 16;
	char pcre2_pattern = (char )ant_calloc(pcre2_cap);
	if (!pcre2_pattern) return js_mkerr(js, "oom");
	size_t pcre2_len = js_to_pcre2_pattern(pattern_buf, pattern_len, pcre2_pattern, pcre2_cap);

	uint32_t options = PCRE2_UTF \| PCRE2_UCP \| PCRE2_MATCH_UNSET_BACKREF;
	int errcode;
	PCRE2_SIZE erroffset;
	pcre2_code *re = pcre2_compile((PCRE2_SPTR)pcre2_pattern, pcre2_len, options, &errcode, &erroffset, NULL);
	free(pcre2_pattern);
	if (re == NULL) return js_mkerr(js, "invalid regex pattern");

	pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);
	uint32_t capture_count;
	pcre2_pattern_info(re, PCRE2_INFO_CAPTURECOUNT, &capture_count);

	PCRE2_SIZE pos = 0;
	bool replaced = false;

	while (pos <= str_len) {
	int rc = pcre2_match(re, (PCRE2_SPTR)str_ptr, str_len, pos, 0, match_data, NULL);
	if (rc < 0) break;

	PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
	PCRE2_SIZE match_start = ovector[0];
	PCRE2_SIZE match_end = ovector[1];

	PCRE2_SIZE before_len = match_start - pos;
	ENSURE_RESULT_CAP(before_len);
	memcpy(result + result_len, str_ptr + pos, before_len);
	result_len += before_len;

	if (is_func_replacement) {
	int nargs_cb = 1 + capture_count + 2;
	jsval_t cb_args = (jsval_t )ant_calloc(nargs_cb * sizeof(jsval_t));
	if (!cb_args) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return js_mkerr(js, "oom");
	}
	cb_args[0] = js_mkstr(js, str_ptr + match_start, match_end - match_start);
	for (uint32_t i = 1; i <= capture_count; i++) {
	PCRE2_SIZE cap_start = ovector[2*i];
	PCRE2_SIZE cap_end = ovector[2*i+1];
	if (cap_start == PCRE2_UNSET) {
	cb_args[i] = js_mkundef();
	} else {
	cb_args[i] = js_mkstr(js, str_ptr + cap_start, cap_end - cap_start);
	}
	}
	cb_args[1 + capture_count] = tov((double)match_start);
	cb_args[2 + capture_count] = str;

	jsval_t cb_result = sv_vm_call(js->vm, js, replacement, js_mkundef(), cb_args, nargs_cb, NULL, false);
	free(cb_args);

	if (vtype(cb_result) == T_ERR) {
	pcre2_match_data_free(match_data);
	pcre2_code_free(re);
	return cb_result;
	}

	if (vtype(cb_result) == T_STR) {
	jsoff_t cb_len, cb_off = vstr(js, cb_result, &cb_len);
	ENSURE_RESULT_CAP(cb_len);
	memcpy(result + result_len, &js->mem[cb_off], cb_len);
	result_len += cb_len;
	} else {
	char numbuf[32];
	size_t n = tostr(js, cb_result, numbuf, sizeof(numbuf));
	ENSURE_RESULT_CAP(n);
	memcpy(result + result_len, numbuf, n);
	result_len += n;
	}
	} else {
	repl_capture_t caps_buf[16], caps = (int)capture_count <= 16 ? caps_buf : ant_calloc(sizeof(repl_capture_t) capture_count);
	for (uint32_t ci = 0; ci < capture_count; ci++) {
	PCRE2_SIZE cs = ovector[2(ci+1)], ce = ovector[2(ci+1)+1];
	if (cs != PCRE2_UNSET) caps[ci] = (repl_capture_t){ str_ptr + cs, ce - cs };
	else caps[ci] = (repl_capture_t){ NULL, 0 };
	}
	repl_template(repl_ptr, repl_len, str_ptr + match_start, match_end - match_start,
	str_ptr, str_len, match_start, caps, (int)capture_count, &result, &result_len, &result_cap);
	if (caps != caps_buf) free(caps);
	}

	if (match_start == match_end) {
	if (pos < str_len) {
	ENSURE_RESULT_CAP(1);
	result[result_len++] = str_ptr[pos];
	}
	pos = match_end + 1;
	} else pos = match_end;

	replaced = true;
	if (!global_flag) break;
	}

	if (pos < str_len) {
	size_t remaining = str_len - pos;
	ENSURE_RESULT_CAP(remaining);
	memcpy(result + result_len, str_ptr + pos, remaining);
	result_len += remaining;
	}

	pcre2_match_data_free(match_data); pcre2_code_free(re);
	if (pattern_buf) free(pattern_buf);

	jsval_t ret = replaced ? js_mkstr(js, result, result_len) : str;
	free(result); return ret;
	} else {
	if (vtype(search) != T_STR) { free(result); return str; }
	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	const char search_ptr = (char ) &js->mem[search_off];

	if (search_len > str_len) { free(result); return str; }

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

	if (is_func_replacement) {
	jsval_t match_str = js_mkstr(js, search_ptr, search_len);
	jsval_t cb_args[1] = { match_str };
	jsval_t cb_result = sv_vm_call(js->vm, js, replacement, js_mkundef(), cb_args, 1, NULL, false);

	if (vtype(cb_result) == T_ERR) { free(result); return cb_result; }

	if (vtype(cb_result) == T_STR) {
	jsoff_t cb_len, cb_off = vstr(js, cb_result, &cb_len);
	ENSURE_RESULT_CAP(cb_len);
	memcpy(result + result_len, &js->mem[cb_off], cb_len);
	result_len += cb_len;
	} else {
	char numbuf[32];
	size_t n = tostr(js, cb_result, numbuf, sizeof(numbuf));
	ENSURE_RESULT_CAP(n);
	memcpy(result + result_len, numbuf, n);
	result_len += n;
	}
	} else {
	ENSURE_RESULT_CAP(repl_len);
	memcpy(result + result_len, repl_ptr, repl_len);
	result_len += repl_len;
	}

	jsoff_t after_start = i + search_len;
	jsoff_t after_len = str_len - after_start;
	if (after_len > 0) {
	ENSURE_RESULT_CAP(after_len);
	memcpy(result + result_len, str_ptr + after_start, after_len);
	result_len += after_len;
	}
	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	}
	}
	free(result);
	return str;
	}
	#undef ENSURE_RESULT_CAP
	}

	static jsval_t builtin_string_replaceAll(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "replaceAll called on non-string");
	if (nargs < 2) return str;

	jsval_t search = args[0];
	jsval_t replacement = args[1];

	if (vtype(search) != T_STR) return js_mkerr(js, "replaceAll requires string search pattern");
	if (vtype(replacement) != T_STR) return js_mkerr(js, "replaceAll requires string replacement");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t search_len, search_off = vstr(js, search, &search_len);
	const char search_ptr = (char ) &js->mem[search_off];

	jsoff_t repl_len, repl_off = vstr(js, replacement, &repl_len);
	const char repl_ptr = (char ) &js->mem[repl_off];

	if (search_len == 0) {
	size_t total_len = str_len + (str_len + 1) * repl_len;
	char result = (char )ant_calloc(total_len + 1);
	if (!result) return js_mkerr(js, "oom");

	size_t pos = 0;
	memcpy(result + pos, repl_ptr, repl_len);
	pos += repl_len;
	for (jsoff_t i = 0; i < str_len; i++) {
	result[pos++] = str_ptr[i];
	memcpy(result + pos, repl_ptr, repl_len);
	pos += repl_len;
	}
	jsval_t ret = js_mkstr(js, result, pos);
	free(result);
	return ret;
	}

	jsoff_t count = 0;
	for (jsoff_t i = 0; i <= str_len - search_len; i++) {
	if (memcmp(str_ptr + i, search_ptr, search_len) == 0) {
	count++;
	i += search_len - 1;
	}
	}

	if (count == 0) return str;

	size_t result_total = str_len - (count * search_len) + (count * repl_len);
	char result = (char )ant_calloc(result_total + 1);
	if (!result) return js_mkerr(js, "oom");

	size_t result_pos = 0;
	jsoff_t str_pos = 0;

	while (str_pos <= str_len - search_len) {
	if (memcmp(str_ptr + str_pos, search_ptr, search_len) == 0) {
	memcpy(result + result_pos, repl_ptr, repl_len);
	result_pos += repl_len;
	str_pos += search_len;
	} else {
	result[result_pos++] = str_ptr[str_pos++];
	}
	}

	while (str_pos < str_len) {
	result[result_pos++] = str_ptr[str_pos++];
	}

	jsval_t ret = js_mkstr(js, result, result_pos);
	free(result);
	return ret;
	}


	static jsval_t builtin_string_template(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "template called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_OBJ) return str;

	jsval_t data = args[0];
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	size_t result_cap = str_len + 256;
	size_t result_len = 0;
	char result = (char )ant_calloc(result_cap);
	if (!result) return js_mkerr(js, "oom");
	jsoff_t i = 0;

	#define ENSURE_CAP(need) do { \
	if (result_len + (need) >= result_cap) { \
	result_cap = (result_len + (need) + 1) * 2; \
	char nr = (char )ant_realloc(result, result_cap); \
	if (!nr) return js_mkerr(js, "oom"); \
	result = nr; \
	} \
	} while(0)

	while (i < str_len) {
	if (i < str_len - 3 && str_ptr[i] == '{' && str_ptr[i + 1] == '{') {
	jsoff_t start = i + 2;
	jsoff_t end = start;
	while (end < str_len - 1 && !(str_ptr[end] == '}' && str_ptr[end + 1] == '}')) {
	end++;
	}
	if (end < str_len - 1 && str_ptr[end] == '}' && str_ptr[end + 1] == '}') {
	jsoff_t key_len = end - start;
	jsoff_t prop_off = lkp(js, data, str_ptr + start, key_len);

	if (prop_off != 0) {
	jsval_t value = resolveprop(js, mkval(T_PROP, prop_off));
	if (vtype(value) == T_STR) {
	jsoff_t val_len, val_off = vstr(js, value, &val_len);
	ENSURE_CAP(val_len);
	memcpy(result + result_len, &js->mem[val_off], val_len);
	result_len += val_len;
	} else if (vtype(value) == T_NUM) {
	char numstr[32];
	snprintf(numstr, sizeof(numstr), "%g", tod(value));
	size_t num_len = strlen(numstr);
	ENSURE_CAP(num_len);
	memcpy(result + result_len, numstr, num_len);
	result_len += num_len;
	} else if (vtype(value) == T_BOOL) {
	const char *boolstr = vdata(value) ? "true" : "false";
	size_t bool_len = strlen(boolstr);
	ENSURE_CAP(bool_len);
	memcpy(result + result_len, boolstr, bool_len);
	result_len += bool_len;
	}
	}
	i = end + 2;
	continue;
	}
	}
	ENSURE_CAP(1);
	result[result_len++] = str_ptr[i++];
	}
	jsval_t ret = js_mkstr(js, result, result_len);
	free(result);
	return ret;
	#undef ENSURE_CAP
	}

	static jsval_t builtin_string_charCodeAt(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "charCodeAt called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d)) idx_d = 0.0;
	if (isinf(idx_d) \|\| idx_d > (double)LONG_MAX) return tov(JS_NAN);

	long idx_l = (long) idx_d;
	if (idx_l < 0) return tov(JS_NAN);

	jsoff_t byte_len; jsoff_t str_off = vstr(js, str, &byte_len);
	const char str_data = (const char )&js->mem[str_off];

	uint32_t code_unit = utf16_code_unit_at(str_data, byte_len, idx_l);
	if (code_unit == 0xFFFFFFFF) return tov(JS_NAN);

	return tov((double) code_unit);
	}

	static jsval_t builtin_string_codePointAt(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "codePointAt called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d)) idx_d = 0.0;
	if (isinf(idx_d) \|\| idx_d > (double)LONG_MAX) return js_mkundef();

	long idx_l = (long) idx_d;
	if (idx_l < 0) return js_mkundef();

	jsoff_t byte_len;
	jsoff_t str_off = vstr(js, str, &byte_len);
	const char str_data = (const char )&js->mem[str_off];

	uint32_t cp = utf16_codepoint_at(str_data, byte_len, idx_l);
	if (cp == 0xFFFFFFFF) return js_mkundef();

	return tov((double) cp);
	}

	static jsval_t builtin_string_toLowerCase(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "toLowerCase called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	if (str_len == 0) return js_mkstr(js, "", 0);

	const utf8proc_uint8_t src = (const utf8proc_uint8_t )str_ptr;
	utf8proc_ssize_t src_len = (utf8proc_ssize_t)str_len;

	jsoff_t out_len = 0;
	utf8proc_ssize_t pos = 0;
	while (pos < src_len) {
	utf8proc_int32_t cp;
	utf8proc_ssize_t n = utf8_next(src + pos, src_len - pos, &cp);
	if (cp < 0) { out_len++; pos++; continue; }
	utf8proc_uint8_t tmp[4];
	out_len += (jsoff_t)utf8proc_encode_char(utf8proc_tolower(cp), tmp);
	pos += n;
	}

	jsval_t result = js_mkstr(js, NULL, out_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];

	pos = 0;
	jsoff_t wpos = 0;
	while (pos < src_len) {
	utf8proc_int32_t cp;
	utf8proc_ssize_t n = utf8_next(src + pos, src_len - pos, &cp);
	if (cp < 0) { result_ptr[wpos++] = (char)src[pos]; pos++; continue; }
	wpos += (jsoff_t)utf8proc_encode_char(utf8proc_tolower(cp), (utf8proc_uint8_t *)(result_ptr + wpos));
	pos += n;
	}

	return result;
	}

	static jsval_t builtin_string_toUpperCase(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "toUpperCase called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	if (str_len == 0) return js_mkstr(js, "", 0);

	const utf8proc_uint8_t src = (const utf8proc_uint8_t )str_ptr;
	utf8proc_ssize_t src_len = (utf8proc_ssize_t)str_len;

	jsoff_t out_len = 0;
	utf8proc_ssize_t pos = 0;
	while (pos < src_len) {
	utf8proc_int32_t cp;
	utf8proc_ssize_t n = utf8_next(src + pos, src_len - pos, &cp);
	if (cp < 0) { out_len++; pos++; continue; }
	utf8proc_uint8_t tmp[4];
	out_len += (jsoff_t)utf8proc_encode_char(utf8proc_toupper(cp), tmp);
	pos += n;
	}

	jsval_t result = js_mkstr(js, NULL, out_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];

	pos = 0;
	jsoff_t wpos = 0;
	while (pos < src_len) {
	utf8proc_int32_t cp;
	utf8proc_ssize_t n = utf8_next(src + pos, src_len - pos, &cp);
	if (cp < 0) { result_ptr[wpos++] = (char)src[pos]; pos++; continue; }
	wpos += (jsoff_t)utf8proc_encode_char(utf8proc_toupper(cp), (utf8proc_uint8_t *)(result_ptr + wpos));
	pos += n;
	}

	return result;
	}

	static jsval_t builtin_string_trim(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "trim called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t start = 0, end = str_len;
	while (start < end && is_space(str_ptr[start])) start++;
	while (end > start && is_space(str_ptr[end - 1])) end--;

	return js_mkstr(js, str_ptr + start, end - start);
	}

	static jsval_t builtin_string_trimStart(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "trimStart called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t start = 0;
	while (start < str_len && is_space(str_ptr[start])) start++;

	return js_mkstr(js, str_ptr + start, str_len - start);
	}

	static jsval_t builtin_string_trimEnd(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "trimEnd called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	jsoff_t end = str_len;
	while (end > 0 && is_space(str_ptr[end - 1])) end--;

	return js_mkstr(js, str_ptr, end);
	}

	static jsval_t builtin_string_repeat(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "repeat called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return js_mkerr(js, "repeat count required");

	double count_d = tod(args[0]);
	if (count_d < 0 \|\| count_d != (double)(long)count_d) return js_mkerr(js, "invalid repeat count");
	jsoff_t count = (jsoff_t) count_d;

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];

	if (count == 0 \|\| str_len == 0) return js_mkstr(js, "", 0);

	jsval_t result = js_mkstr(js, NULL, str_len * count);
	if (is_err(result)) return result;

	jsoff_t result_len, result_off = vstr(js, result, &result_len);
	char result_ptr = (char ) &js->mem[result_off];

	for (jsoff_t i = 0; i < count; i++) {
	memcpy(result_ptr + i * str_len, str_ptr, str_len);
	}

	return result;
	}

	static jsval_t builtin_string_padStart(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "padStart called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return str;

	jsoff_t target_len = (jsoff_t)tod(args[0]);
	if (target_len <= 0) return str;
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	size_t str_utf16_len = utf16_strlen(str_ptr, (size_t)str_len);

	if ((size_t)target_len <= str_utf16_len) return str;

	jsval_t pad_val = js_mkstr(js, " ", 1);
	if (nargs >= 2 && vtype(args[1]) != T_UNDEF) {
	pad_val = coerce_to_str(js, args[1]);
	if (is_err(pad_val)) return pad_val;
	}
	jsoff_t pad_len, pad_off = vstr(js, pad_val, &pad_len);
	const char pad_str = (char )&js->mem[pad_off];
	size_t pad_utf16_len = utf16_strlen(pad_str, (size_t)pad_len);

	if (pad_utf16_len == 0) return str;

	size_t fill_utf16_len = (size_t)target_len - str_utf16_len;
	size_t full_repeats = fill_utf16_len / pad_utf16_len;
	size_t rem_utf16 = fill_utf16_len % pad_utf16_len;
	size_t rem_bytes = 0;
	if (rem_utf16 > 0) {
	int off = utf16_index_to_byte_offset(pad_str, (size_t)pad_len, rem_utf16, NULL);
	if (off < 0) return str;
	rem_bytes = (size_t)off;
	}
	size_t fill_bytes = full_repeats * (size_t)pad_len + rem_bytes;
	size_t total_bytes = fill_bytes + (size_t)str_len;

	jsval_t result = js_mkstr(js, NULL, (jsoff_t)total_bytes);
	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];

	size_t pos = 0;
	for (size_t i = 0; i < full_repeats; i++) {
	memcpy(result_ptr + pos, pad_str, (size_t)pad_len);
	pos += (size_t)pad_len;
	}
	if (rem_bytes > 0) {
	memcpy(result_ptr + pos, pad_str, rem_bytes);
	pos += rem_bytes;
	}
	memcpy(result_ptr + pos, str_ptr, (size_t)str_len);

	return result;
	}

	static jsval_t builtin_string_padEnd(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "padEnd called on non-string");
	if (nargs < 1 \|\| vtype(args[0]) != T_NUM) return str;

	jsoff_t target_len = (jsoff_t)tod(args[0]);
	if (target_len <= 0) return str;
	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (char ) &js->mem[str_off];
	size_t str_utf16_len = utf16_strlen(str_ptr, (size_t)str_len);

	if ((size_t)target_len <= str_utf16_len) return str;

	jsval_t pad_val = js_mkstr(js, " ", 1);
	if (nargs >= 2 && vtype(args[1]) != T_UNDEF) {
	pad_val = coerce_to_str(js, args[1]);
	if (is_err(pad_val)) return pad_val;
	}
	jsoff_t pad_len, pad_off = vstr(js, pad_val, &pad_len);
	const char pad_str = (char ) &js->mem[pad_off];
	size_t pad_utf16_len = utf16_strlen(pad_str, (size_t)pad_len);

	if (pad_utf16_len == 0) return str;

	size_t fill_utf16_len = (size_t)target_len - str_utf16_len;
	size_t full_repeats = fill_utf16_len / pad_utf16_len;
	size_t rem_utf16 = fill_utf16_len % pad_utf16_len;
	size_t rem_bytes = 0;
	if (rem_utf16 > 0) {
	int off = utf16_index_to_byte_offset(pad_str, (size_t)pad_len, rem_utf16, NULL);
	if (off < 0) return str;
	rem_bytes = (size_t)off;
	}
	size_t fill_bytes = full_repeats * (size_t)pad_len + rem_bytes;
	size_t total_bytes = (size_t)str_len + fill_bytes;

	jsval_t result = js_mkstr(js, NULL, (jsoff_t)total_bytes);
	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, (size_t)str_len);
	size_t pos = (size_t)str_len;
	for (size_t i = 0; i < full_repeats; i++) {
	memcpy(result_ptr + pos, pad_str, (size_t)pad_len);
	pos += (size_t)pad_len;
	}
	if (rem_bytes > 0) {
	memcpy(result_ptr + pos, pad_str, rem_bytes);
	pos += rem_bytes;
	}

	return result;
	}

	static jsval_t builtin_string_charAt(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "charAt called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d)) idx_d = 0;
	else if (idx_d < 0) idx_d = -floor(-idx_d);
	else idx_d = floor(idx_d);
	if (idx_d < 0 \|\| isinf(idx_d)) return js_mkstr(js, "", 0);

	jsoff_t idx = (jsoff_t) idx_d;
	jsoff_t byte_len;
	jsoff_t str_off = vstr(js, str, &byte_len);
	const char str_data = (const char )&js->mem[str_off];

	size_t char_bytes;
	int byte_offset = utf16_index_to_byte_offset(str_data, byte_len, idx, &char_bytes);
	if (byte_offset < 0) return js_mkstr(js, "", 0);

	return js_mkstr(js, str_data + byte_offset, char_bytes);
	}

	static jsval_t builtin_string_at(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "at called on non-string");

	double idx_d = nargs < 1 ? 0.0 : js_to_number(js, args[0]);
	if (isnan(idx_d) \|\| isinf(idx_d)) return js_mkundef();

	jsoff_t byte_len; jsoff_t str_off = vstr(js, str, &byte_len);
	const char str_data = (const char )&js->mem[str_off];
	size_t utf16_len = utf16_strlen(str_data, byte_len);

	long idx = (long) idx_d;
	if (idx < 0) idx += (long) utf16_len;
	if (idx < 0 \|\| idx >= (long) utf16_len) return js_mkundef();

	size_t char_bytes;
	int byte_offset = utf16_index_to_byte_offset(str_data, byte_len, idx, &char_bytes);
	if (byte_offset < 0) return js_mkundef();

	return js_mkstr(js, str_data + byte_offset, char_bytes);
	}

	static jsval_t builtin_string_localeCompare(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "localeCompare called on non-string");
	if (nargs < 1) return tov(0);

	jsval_t that = args[0];
	if (vtype(that) != T_STR) {
	char buf[64];
	size_t n = tostr(js, that, buf, sizeof(buf));
	that = js_mkstr(js, buf, n);
	}

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t that_len, that_off = vstr(js, that, &that_len);
	const char str_ptr = (char )&js->mem[str_off];
	const char that_ptr = (char )&js->mem[that_off];

	int result = strcoll(str_ptr, that_ptr);
	if (result < 0) return tov(-1);
	if (result > 0) return tov(1);
	return tov(0);
	}

	static jsval_t builtin_string_lastIndexOf(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "lastIndexOf called on non-string");
	if (nargs == 0) return tov(-1);

	jsval_t search = args[0];
	if (vtype(search) != T_STR) return tov(-1);

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	jsoff_t search_len, search_off = vstr(js, search, &search_len);

	jsoff_t max_start = str_len;
	double dstr_len = D(str_len);
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	double pos = tod(args[1]);
	if (isnan(pos)) pos = dstr_len;
	if (pos < 0) pos = 0;
	if (pos > dstr_len) pos = dstr_len;
	max_start = (jsoff_t) pos;
	}

	if (search_len == 0) return tov((double) (max_start > str_len ? str_len : max_start));
	if (search_len > str_len) return tov(-1);

	const char str_ptr = (char ) &js->mem[str_off];
	const char search_ptr = (char ) &js->mem[search_off];

	jsoff_t start = (max_start + search_len > str_len) ? str_len - search_len : max_start;
	for (jsoff_t i = start + 1; i > 0; i--) {
	if (memcmp(str_ptr + i - 1, search_ptr, search_len) == 0) return tov((double)(i - 1));
	}
	return tov(-1);
	}

	static jsval_t builtin_string_concat(ant_t js, jsval_t args, int nargs) {
	jsval_t this_unwrapped = unwrap_primitive(js, js->this_val);
	jsval_t str = js_tostring_val(js, this_unwrapped);
	if (is_err(str)) return str;

	jsoff_t total_len;
	jsoff_t base_off = vstr(js, str, &total_len);

	jsval_t *str_args = NULL;
	if (nargs > 0) {
	str_args = (jsval_t )ant_calloc(nargs sizeof(jsval_t));
	if (!str_args) return js_mkerr(js, "oom");
	for (int i = 0; i < nargs; i++) {
	str_args[i] = js_tostring_val(js, args[i]);
	if (is_err(str_args[i])) {
	free(str_args);
	return str_args[i];
	}
	jsoff_t arg_len;
	vstr(js, str_args[i], &arg_len);
	total_len += arg_len;
	}
	}

	char result = (char )ant_calloc(total_len + 1);
	if (!result) {
	if (str_args) free(str_args);
	return js_mkerr(js, "oom");
	}

	jsoff_t base_len;
	base_off = vstr(js, str, &base_len);
	memcpy(result, &js->mem[base_off], base_len);
	jsoff_t pos = base_len;

	for (int i = 0; i < nargs; i++) {
	jsoff_t arg_len, arg_off = vstr(js, str_args[i], &arg_len);
	memcpy(result + pos, &js->mem[arg_off], arg_len);
	pos += arg_len;
	}
	result[pos] = '\0';

	jsval_t ret = js_mkstr(js, result, pos);
	free(result); if (str_args) free(str_args);

	return ret;
	}

	static jsval_t builtin_string_normalize(ant_t js, jsval_t args, int nargs) {
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "normalize called on non-string");

	jsoff_t str_len, str_off = vstr(js, str, &str_len);
	const char str_ptr = (const char )&js->mem[str_off];

	if (str_len == 0) return js_mkstr(js, "", 0);
	utf8proc_option_t opts = UTF8PROC_COMPOSE \| UTF8PROC_STABLE;

	if (nargs >= 1 && vtype(args[0]) != T_UNDEF) {
	jsval_t form_val = js_tostring_val(js, args[0]);
	if (is_err(form_val)) return form_val;
	jsoff_t flen, foff = vstr(js, form_val, &flen);
	const char form = (const char )&js->mem[foff];

	if (flen == 3 && memcmp(form, "NFC", 3) == 0) {
	opts = UTF8PROC_COMPOSE \| UTF8PROC_STABLE;
	} else if (flen == 3 && memcmp(form, "NFD", 3) == 0) {
	opts = UTF8PROC_DECOMPOSE \| UTF8PROC_STABLE;
	} else if (flen == 4 && memcmp(form, "NFKC", 4) == 0) {
	opts = UTF8PROC_COMPOSE \| UTF8PROC_STABLE \| UTF8PROC_COMPAT;
	} else if (flen == 4 && memcmp(form, "NFKD", 4) == 0) {
	opts = UTF8PROC_DECOMPOSE \| UTF8PROC_STABLE \| UTF8PROC_COMPAT;
	} else return js_mkerr_typed(js, JS_ERR_RANGE, "The normalization form should be one of NFC, NFD, NFKC, NFKD");
	}

	utf8proc_uint8_t *result = NULL;
	utf8proc_ssize_t rlen = utf8proc_map(
	(const utf8proc_uint8_t *)str_ptr, (utf8proc_ssize_t)str_len, &result, opts
	);

	if (rlen < 0 \|\| !result) {
	if (result) free(result);
	return js_mkstr(js, str_ptr, str_len);
	}

	jsval_t ret = js_mkstr(js, (const char *)result, (jsoff_t)rlen);
	free(result);

	return ret;
	}

	static jsval_t builtin_string_fromCharCode(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkstr(js, "", 0);

	char buf = (char )ant_calloc(nargs + 1);
	if (!buf) return js_mkerr(js, "oom");

	for (int i = 0; i < nargs; i++) {
	if (vtype(args[i]) != T_NUM) { buf[i] = 0; continue; }
	int code = (int) tod(args[i]);
	buf[i] = (char)(code & 0xFF);
	}
	buf[nargs] = '\0';

	jsval_t ret = js_mkstr(js, buf, nargs);
	free(buf);
	return ret;
	}

	static jsval_t builtin_string_fromCodePoint(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return js_mkstr(js, "", 0);

	char buf = (char )ant_calloc(nargs * 4 + 1);
	if (!buf) return js_mkerr(js, "oom");

	size_t len = 0;
	for (int i = 0; i < nargs; i++) {
	if (vtype(args[i]) != T_NUM) continue;
	double d = tod(args[i]);
	if (d < 0 \|\| d > 0x10FFFF \|\| d != floor(d)) {
	free(buf);
	return js_mkerr_typed(js, JS_ERR_RANGE, "Invalid code point");
	}
	uint32_t cp = (uint32_t)d;
	if (cp < 0x80) {
	buf[len++] = (char)cp;
	} else if (cp < 0x800) {
	buf[len++] = (char)(0xC0 \| (cp >> 6));
	buf[len++] = (char)(0x80 \| (cp & 0x3F));
	} else if (cp < 0x10000) {
	buf[len++] = (char)(0xE0 \| (cp >> 12));
	buf[len++] = (char)(0x80 \| ((cp >> 6) & 0x3F));
	buf[len++] = (char)(0x80 \| (cp & 0x3F));
	} else {
	buf[len++] = (char)(0xF0 \| (cp >> 18));
	buf[len++] = (char)(0x80 \| ((cp >> 12) & 0x3F));
	buf[len++] = (char)(0x80 \| ((cp >> 6) & 0x3F));
	buf[len++] = (char)(0x80 \| (cp & 0x3F));
	}
	}
	buf[len] = '\0';

	jsval_t ret = js_mkstr(js, buf, len);
	free(buf);
	return ret;
	}

	static bool string_builder_append_value(
	ant_t js, char *buf,
	size_t len, size_t cap,
	jsval_t value, jsval_t *err
	) {
	jsval_t s = js_tostring_val(js, value);
	if (is_err(s)) {
	if (err) *err = s;
	return false;
	}

	jsoff_t slen = 0;
	jsoff_t soff = vstr(js, s, &slen);

	size_t need = *len + (size_t)slen + 1;
	if (need > *cap) {
	size_t next = (cap == 0) ? 64 : cap;
	while (next < need) next *= 2;
	char grown = (char )realloc(*buf, next);
	if (!grown) {
	if (err) *err = js_mkerr(js, "oom");
	return false;
	}
	*buf = grown;
	*cap = next;
	}

	if (slen > 0) memcpy(buf + len, &js->mem[soff], (size_t)slen);
	*len += (size_t)slen;
	(buf)[len] = '\0';
	return true;
	}

	static jsval_t builtin_string_raw(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1 \|\| is_null(args[0]) \|\| is_undefined(args[0])) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "String.raw requires a template object");
	}

	jsval_t tmpl = args[0];
	if (!is_object_type(tmpl)) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "String.raw requires a template object");
	}

	jsval_t raw = js_get(js, tmpl, "raw");
	if (is_null(raw) \|\| is_undefined(raw) \|\| !is_object_type(raw)) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "String.raw requires template.raw");
	}

	jsval_t raw_len_val = js_get(js, raw, "length");
	double raw_len_num = js_to_number(js, raw_len_val);
	if (!isfinite(raw_len_num) \|\| raw_len_num <= 0) return js_mkstr(js, "", 0);

	size_t literal_count = (size_t)raw_len_num;
	if (literal_count == 0) return js_mkstr(js, "", 0);

	char *buf = NULL;
	size_t len = 0; size_t cap = 0;
	jsval_t err = js_mkundef();

	for (size_t i = 0; i < literal_count; i++) {
	jsval_t chunk = js_mkundef();
	if (vtype(raw) == T_ARR) chunk = js_arr_get(js, raw, (jsoff_t)i);
	else {
	char key[32];
	snprintf(key, sizeof(key), "%zu", i);
	chunk = js_get(js, raw, key);
	}

	if (!string_builder_append_value(js, &buf, &len, &cap, chunk, &err)) {
	free(buf);
	return is_err(err) ? err : js_mkerr(js, "oom");
	}

	if (i + 1 < literal_count && (int)(i + 1) < nargs) {
	if (!string_builder_append_value(js, &buf, &len, &cap, args[i + 1], &err)) {
	free(buf); return is_err(err) ? err : js_mkerr(js, "oom");
	}
	}
	}

	jsval_t out = js_mkstr(js, buf ? buf : "", len);
	free(buf);

	return out;
	}

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

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

	if (radix == 10) {
	char buf[64];
	size_t len = strnum(num, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	double val = tod(num);

	if (isnan(val)) return js_mkstr(js, "NaN", 3);
	if (isinf(val)) return val > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	char buf[128];
	char *p = buf + sizeof(buf) - 1;
	*p = '\0';

	bool negative = val < 0;
	if (negative) val = -val;

	long long int_part = (long long)val;
	double frac_part = val - (double)int_part;

	if (int_part == 0) {
	*--p = '0';
	} else {
	while (int_part > 0 && p > buf) {
	int digit = int_part % radix;
	*--p = (char)(digit < 10 ? '0' + digit : 'a' + (digit - 10));
	int_part /= radix;
	}
	}

	if (negative && p > buf) {
	*--p = '-';
	}

	size_t int_len = strlen(p);

	if (frac_part > 0.0000001) {
	char frac_buf[64];
	int frac_pos = 0;
	frac_buf[frac_pos++] = '.';

	for (int i = 0; i < 16 && frac_part > 0.0000001 && frac_pos < 63; i++) {
	frac_part *= radix;
	int digit = (int)frac_part;
	frac_buf[frac_pos++] = (char)(digit < 10 ? '0' + digit : 'a' + (digit - 10));
	frac_part -= digit;
	}
	frac_buf[frac_pos] = '\0';

	char result[192];
	snprintf(result, sizeof(result), "%s%s", p, frac_buf);
	return js_mkstr(js, result, strlen(result));
	}

	return js_mkstr(js, p, int_len);
	}

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

	double d = tod(num);
	if (isnan(d)) return js_mkstr(js, "NaN", 3);
	if (isinf(d)) return d > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	int digits = 0;
	if (nargs >= 1 && vtype(args[0]) != T_UNDEF) {
	digits = (int) tod(args[0]);
	if (digits < 0 \|\| digits > 100) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "toFixed() digits argument must be between 0 and 100");
	}
	}

	bool negative = d < 0;
	if (negative) d = -d;

	if (d >= 1e21) {
	char buf[64];
	snprintf(buf, sizeof(buf), "%.0f", negative ? -d : d);
	return js_mkstr(js, buf, strlen(buf));
	}

	double scale = pow(10, digits);
	double scaled = d * scale;
	double rounded = floor(scaled + 0.5);

	char digit_buf[128];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	while (digit_len < digits + 1) {
	memmove(digit_buf + 1, digit_buf, digit_len + 1);
	digit_buf[0] = '0';
	digit_len++;
	}

	char buf[128];
	int pos = 0;

	if (negative && rounded != 0) buf[pos++] = '-';
	int int_digits = digit_len - digits;
	if (int_digits <= 0) int_digits = 1;

	for (int i = 0; i < int_digits; i++) {
	buf[pos++] = digit_buf[i];
	}

	if (digits > 0) {
	buf[pos++] = '.';
	for (int i = int_digits; i < digit_len; i++) {
	buf[pos++] = digit_buf[i];
	}
	}

	buf[pos] = '\0';
	return js_mkstr(js, buf, pos);
	}

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

	double d = tod(num);
	if (isnan(d)) return js_mkstr(js, "NaN", 3);
	if (isinf(d)) return d > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	if (nargs < 1 \|\| vtype(args[0]) == T_UNDEF) {
	char buf[64];
	size_t len = strnum(num, buf, sizeof(buf));
	return js_mkstr(js, buf, len);
	}

	int precision = (int) tod(args[0]);
	if (precision < 1 \|\| precision > 100) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "toPrecision() argument must be between 1 and 100");
	}

	bool negative = d < 0;
	if (negative) d = -d;

	if (d == 0) {
	char buf[128];
	int pos = 0;
	if (negative) buf[pos++] = '-';
	buf[pos++] = '0';
	if (precision > 1) {
	buf[pos++] = '.';
	for (int i = 1; i < precision; i++) buf[pos++] = '0';
	}
	buf[pos] = '\0';
	return js_mkstr(js, buf, pos);
	}

	int exp = (int) floor(log10(d));
	bool use_exp = (exp < -(precision - 1) - 1) \|\| (exp >= precision);

	if (use_exp) {
	double mantissa = d / pow(10, exp);
	double scale = pow(10, precision - 1);
	double rounded = floor(mantissa * scale + 0.5);

	if (rounded >= scale * 10) {
	rounded /= 10;
	exp++;
	}

	char digit_buf[32];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	char buf[128];
	int pos = 0;
	if (negative) buf[pos++] = '-';
	buf[pos++] = digit_buf[0];
	if (precision > 1) {
	buf[pos++] = '.';
	for (int i = 1; i < precision; i++) {
	buf[pos++] = (i < digit_len) ? digit_buf[i] : '0';
	}
	}
	buf[pos++] = 'e';
	buf[pos++] = (exp >= 0) ? '+' : '-';
	if (exp < 0) exp = -exp;
	snprintf(buf + pos, sizeof(buf) - pos, "%d", exp);
	return js_mkstr(js, buf, strlen(buf));
	} else {
	int digits_after_point = precision - exp - 1;
	if (digits_after_point < 0) digits_after_point = 0;

	double scale = pow(10, digits_after_point);
	double rounded = floor(d * scale + 0.5);

	char digit_buf[64];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	while (digit_len < digits_after_point + 1) {
	memmove(digit_buf + 1, digit_buf, digit_len + 1);
	digit_buf[0] = '0';
	digit_len++;
	}

	char buf[128];
	int pos = 0;
	if (negative) buf[pos++] = '-';

	int int_digits = digit_len - digits_after_point;
	for (int i = 0; i < int_digits; i++) {
	buf[pos++] = digit_buf[i];
	}

	if (digits_after_point > 0) {
	buf[pos++] = '.';
	for (int i = int_digits; i < digit_len; i++) {
	buf[pos++] = digit_buf[i];
	}
	}

	buf[pos] = '\0';
	return js_mkstr(js, buf, pos);
	}
	}

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

	double d = tod(num);
	if (isnan(d)) return js_mkstr(js, "NaN", 3);
	if (isinf(d)) return d > 0 ? js_mkstr(js, "Infinity", 8) : js_mkstr(js, "-Infinity", 9);

	int digits = -1;
	if (nargs >= 1 && vtype(args[0]) != T_UNDEF) {
	digits = (int) tod(args[0]);
	if (digits < 0 \|\| digits > 100) {
	return js_mkerr_typed(js, JS_ERR_RANGE, "toExponential() argument must be between 0 and 100");
	}
	}

	bool negative = d < 0;
	if (negative) d = -d;

	int exp = 0;
	if (d != 0) {
	exp = (int) floor(log10(d));
	double test = d / pow(10, exp);
	if (test >= 10) { exp++; test /= 10; }
	if (test < 1) { exp--; test *= 10; }
	}

	if (digits < 0) {
	char temp[32];
	snprintf(temp, sizeof(temp), "%.15g", d);
	int sig = 0;
	for (int i = 0; temp[i] && temp[i] != 'e' && temp[i] != 'E'; i++) {
	if (temp[i] == '.') continue;
	if (temp[i] >= '0' && temp[i] <= '9') if (temp[i] != '0' \|\| sig > 0) sig++;
	}
	digits = sig > 0 ? sig - 1 : 0;
	if (digits > 20) digits = 20;
	}

	double mantissa = d / pow(10, exp);
	double scale = pow(10, digits);
	double scaled = mantissa * scale;
	double rounded = floor(scaled + 0.5);

	if (rounded >= scale * 10) {
	rounded /= 10;
	exp++;
	}

	char buf[64];
	int pos = 0;

	if (negative) buf[pos++] = '-';

	char digit_buf[32];
	snprintf(digit_buf, sizeof(digit_buf), "%.0f", rounded);
	int digit_len = (int)strlen(digit_buf);

	while (digit_len < digits + 1) {
	memmove(digit_buf + 1, digit_buf, digit_len + 1);
	digit_buf[0] = '0';
	digit_len++;
	}

	buf[pos++] = digit_buf[0];

	if (digits > 0) {
	buf[pos++] = '.';
	for (int i = 1; i <= digits; i++) {
	buf[pos++] = (i < digit_len) ? digit_buf[i] : '0';
	}
	}

	buf[pos++] = 'e';
	buf[pos++] = (exp >= 0) ? '+' : '-';
	if (exp < 0) exp = -exp;
	snprintf(buf + pos, sizeof(buf) - pos, "%d", exp);

	return js_mkstr(js, buf, strlen(buf));
	}

	static jsval_t builtin_number_valueOf(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "valueOf called on non-number");
	return num;
	}

	static jsval_t builtin_number_toLocaleString(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t num = unwrap_primitive(js, js->this_val);
	if (vtype(num) != T_NUM) return js_mkerr(js, "toLocaleString called on non-number");
	double d = tod(num);
	char raw[64];
	strnum(num, raw, sizeof(raw));
	if (!isfinite(d) \|\| strchr(raw, 'e') \|\| strchr(raw, 'E'))
	return js_mkstr(js, raw, strlen(raw));
	char *dot = strchr(raw, '.');
	size_t int_len = dot ? (size_t)(dot - raw) : strlen(raw);
	size_t start = (raw[0] == '-') ? 1 : 0;
	size_t frac_len = dot ? strlen(dot) : 0;
	char buf[128];
	size_t pos = 0;
	if (start) buf[pos++] = '-';
	for (size_t i = start; i < int_len; i++) {
	buf[pos++] = raw[i];
	size_t remaining = int_len - 1 - i;
	if (remaining > 0 && remaining % 3 == 0) buf[pos++] = ',';
	}
	if (frac_len) memcpy(buf + pos, dot, frac_len);
	pos += frac_len;
	buf[pos] = '\0';
	return js_mkstr(js, buf, pos);
	}

	static jsval_t builtin_string_valueOf(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t str = to_string_val(js, js->this_val);
	if (vtype(str) != T_STR) return js_mkerr(js, "valueOf called on non-string");
	return str;
	}

	static jsval_t builtin_string_toString(ant_t js, jsval_t args, int nargs) {
	return builtin_string_valueOf(js, args, nargs);
	}

	static jsval_t builtin_boolean_valueOf(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t b = unwrap_primitive(js, js->this_val);
	if (vtype(b) != T_BOOL) return js_mkerr(js, "valueOf called on non-boolean");
	return b;
	}

	static jsval_t builtin_boolean_toString(ant_t js, jsval_t args, int nargs) {
	(void) args; (void) nargs;
	jsval_t b = unwrap_primitive(js, js->this_val);
	if (vtype(b) != T_BOOL) return js_mkerr(js, "toString called on non-boolean");
	return vdata(b) ? js_mkstr(js, "true", 4) : js_mkstr(js, "false", 5);
	}

	static jsval_t builtin_parseInt(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(JS_NAN);

	jsval_t str_val = args[0];
	if (vtype(str_val) != T_STR) {
	const char *str = js_str(js, str_val);
	str_val = js_mkstr(js, str, strlen(str));
	}

	jsoff_t str_len, str_off = vstr(js, str_val, &str_len);
	const char str = (char ) &js->mem[str_off];

	int radix = 0;
	if (nargs >= 2 && vtype(args[1]) == T_NUM) {
	radix = (int) tod(args[1]);
	if (radix != 0 && (radix < 2 \|\| radix > 36)) return tov(JS_NAN);
	}

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

	if (i >= str_len) return tov(JS_NAN);

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

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

	if (radix == 0) radix = 10;

	double result = 0;
	bool found_digit = false;

	while (i < str_len) {
	char ch = str[i];
	int digit = -1;

	if (ch >= '0' && ch <= '9') {
	digit = ch - '0';
	} else if (ch >= 'a' && ch <= 'z') {
	digit = ch - 'a' + 10;
	} else if (ch >= 'A' && ch <= 'Z') {
	digit = ch - 'A' + 10;
	}

	if (digit < 0 \|\| digit >= radix) break;

	result = result * radix + digit;
	found_digit = true;
	i++;
	}

	if (!found_digit) return tov(JS_NAN);

	return tov(sign * result);
	}

	static jsval_t builtin_parseFloat(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return tov(JS_NAN);

	jsval_t str_val = args[0];
	if (vtype(str_val) != T_STR) {
	const char *str = js_str(js, str_val);
	str_val = js_mkstr(js, str, strlen(str));
	}

	jsoff_t str_len, str_off = vstr(js, str_val, &str_len);
	const char str = (char ) &js->mem[str_off];

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

	if (i >= str_len) return tov(JS_NAN);

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

	if (end == &str[i]) return tov(JS_NAN);

	return tov(result);
	}

	static jsval_t builtin_btoa(ant_t 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];

	size_t out_len;
	char out = ant_base64_encode((const uint8_t )str, str_len, &out_len);
	if (!out) return js_mkerr(js, "out of memory");

	jsval_t result = js_mkstr(js, out, out_len);
	free(out);

	return result;
	}

	static jsval_t builtin_atob(ant_t 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);

	size_t out_len;
	uint8_t *out = ant_base64_decode(str, str_len, &out_len);
	if (!out) return js_mkerr(js, "atob: invalid base64 string");

	jsval_t result = js_mkstr(js, (char *)out, out_len);
	free(out);

	return result;
	}

	static jsval_t builtin_resolve_internal(ant_t js, jsval_t args, int nargs);
	static jsval_t builtin_reject_internal(ant_t js, jsval_t args, int nargs);
	static void resolve_promise(ant_t *js, jsval_t p, jsval_t val);
	static void reject_promise(ant_t *js, jsval_t p, jsval_t val);

	static size_t strpromise(ant_t js, jsval_t value, char buf, size_t len) {
	uint32_t pid = get_promise_id(js, value);
	promise_data_entry_t *pd = get_promise_data(pid, false);

	const char *content;
	char *allocated = NULL;

	if (!pd \|\| pd->state == 0) {
	content = "<pending>";
	} else if (pd->state == 2) {
	char *val = tostr_alloc(js, pd->value);
	allocated = ant_calloc(strlen(val) + 12);
	sprintf(allocated, "<rejected> %s", val);
	free(val);
	content = allocated;
	} else { content = allocated = tostr_alloc(js, pd->value); }

	size_t result = (pd && pd->trigger_pid)
	? (size_t)snprintf(buf, len, "Promise {\n %s,\n Symbol(async_id): %u,\n Symbol(trigger_async_id): %u\n}", content, pid, pd->trigger_pid)
	: (size_t)snprintf(buf, len, "Promise {\n %s,\n Symbol(async_id): %u\n}", content, pid);

	if (allocated) free(allocated);
	return result;
	}

	static promise_data_entry_t *get_promise_data(uint32_t promise_id, bool create) {
	promise_data_entry_t *entry = NULL;
	HASH_FIND(hh, promise_registry, &promise_id, sizeof(uint32_t), entry);
	if (entry) return entry;
	if (!create) return NULL;

	entry = (promise_data_entry_t *)malloc(sizeof(promise_data_entry_t));
	entry->promise_id = promise_id;
	entry->trigger_pid = 0;
	entry->obj_offset = 0;
	entry->state = 0;
	entry->value = js_mkundef();
	entry->has_rejection_handler = false;
	utarray_new(entry->handlers, &promise_handler_icd);
	HASH_ADD(hh, promise_registry, promise_id, sizeof(uint32_t), entry);

	return entry;
	}

	static uint32_t get_promise_id(ant_t *js, jsval_t p) {
	jsval_t p_obj = js_as_obj(p);
	jsval_t pid_val = get_slot(js, p_obj, SLOT_PID);
	if (vtype(pid_val) == T_UNDEF) return 0;
	return (uint32_t)tod(pid_val);
	}

	static jsval_t mkpromise(ant_t *js) {
	jsval_t obj = mkobj(js, 0);
	if (is_err(obj)) return obj;

	uint32_t pid = next_promise_id++;
	set_slot(js, obj, SLOT_PID, tov((double)pid));

	jsval_t promise_ctor = js_get(js, js_glob(js), "Promise");
	if (vtype(promise_ctor) == T_FUNC \|\| vtype(promise_ctor) == T_CFUNC) {
	set_slot(js, obj, SLOT_CTOR, promise_ctor);
	}

	jsval_t promise_proto = get_ctor_proto(js, "Promise", 7);
	if (is_object_type(promise_proto)) {
	set_slot(js, obj, SLOT_PROTO, promise_proto);
	}
	promise_data_entry_t *pd = get_promise_data(pid, true);
	if (pd) pd->obj_offset = (jsoff_t)vdata(js_as_obj(obj));

	return mkval(T_PROMISE, vdata(obj));
	}

	static inline void trigger_handlers(ant_t *js, jsval_t p) {
	uint32_t pid = get_promise_id(js, p);
	queue_promise_trigger(pid);
	}

	void js_process_promise_handlers(ant_t *js, uint32_t pid) {
	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (!pd) return;

	int state = pd->state;
	jsval_t val = pd->value;

	unsigned int len = utarray_len(pd->handlers);
	if (len == 0) { return; } pd->processing = true;

	for (unsigned int i = 0; i < len; i++) {
	promise_handler_t h = (promise_handler_t )utarray_eltptr(pd->handlers, i);
	jsval_t handler = (state == 1) ? h->onFulfilled : h->onRejected;

	if (vtype(handler) == T_FUNC \|\| vtype(handler) == T_CFUNC) {
	jsval_t res;
	if (vtype(handler) == T_CFUNC) {
	jsval_t (fn)(ant_t , jsval_t , int) = (jsval_t()(ant_t , jsval_t , int)) vdata(handler);
	res = fn(js, &val, 1);
	} else {
	jsval_t call_args[] = { val };
	res = sv_vm_call(js->vm, js, handler, js_mkundef(), call_args, 1, NULL, false);
	}

	if (is_err(res)) {
	jsval_t reject_val = js->thrown_value;
	if (vtype(reject_val) == T_UNDEF) reject_val = res;
	js->thrown_exists = false;
	js->thrown_value = js_mkundef();
	js->thrown_stack = js_mkundef();
	reject_promise(js, h->nextPromise, reject_val);
	} else resolve_promise(js, h->nextPromise, res);
	} else {
	if (state == 1) resolve_promise(js, h->nextPromise, val);
	else reject_promise(js, h->nextPromise, val);
	}
	}

	pd->processing = false;
	utarray_clear(pd->handlers);
	}

	static void resolve_promise(ant_t *js, jsval_t p, jsval_t val) {
	uint32_t pid = get_promise_id(js, p);
	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (!pd \|\| pd->state != 0) return;

	if (vtype(val) == T_PROMISE) {
	uint32_t val_pid = get_promise_id(js, val);
	if (val_pid == pid) {
	jsval_t err = js_mkerr(js, "TypeError: Chaining cycle");
	return reject_promise(js, p, err);
	}

	jsval_t res_obj = mkobj(js, 0);
	set_slot(js, res_obj, SLOT_DATA, p);
	set_slot(js, res_obj, SLOT_CFUNC, js_mkfun(builtin_resolve_internal));
	jsval_t res_fn = js_obj_to_func(res_obj);

	jsval_t rej_obj = mkobj(js, 0);
	set_slot(js, rej_obj, SLOT_DATA, p);
	set_slot(js, rej_obj, SLOT_CFUNC, js_mkfun(builtin_reject_internal));
	jsval_t rej_fn = js_obj_to_func(rej_obj);

	jsval_t call_args[] = { res_fn, rej_fn };
	jsval_t then_prop = js_get(js, val, "then");

	if (vtype(then_prop) == T_FUNC \|\| vtype(then_prop) == T_CFUNC) {
	(void)sv_vm_call(js->vm, js, then_prop, val, call_args, 2, NULL, false); return;
	}
	}

	pd->state = 1;
	pd->value = val;
	trigger_handlers(js, p);
	}

	static void reject_promise(ant_t *js, jsval_t p, jsval_t val) {
	uint32_t pid = get_promise_id(js, p);
	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (!pd \|\| pd->state != 0) return;

	pd->state = 2;
	pd->value = val;

	if (!pd->has_rejection_handler) {
	promise_data_entry_t *existing = NULL;
	HASH_FIND(hh_unhandled, unhandled_rejections, &pd->promise_id, sizeof(uint32_t), existing);
	if (!existing) {
	HASH_ADD(hh_unhandled, unhandled_rejections, promise_id, sizeof(uint32_t), pd);
	}
	}

	trigger_handlers(js, p);
	}

	static jsval_t builtin_resolve_internal(ant_t js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t p = get_slot(js, me, SLOT_DATA);
	if (vtype(p) != T_PROMISE) return js_mkundef();
	resolve_promise(js, p, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_reject_internal(ant_t js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t p = get_slot(js, me, SLOT_DATA);
	if (vtype(p) != T_PROMISE) return js_mkundef();
	reject_promise(js, p, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_Promise(ant_t js, jsval_t args, int nargs) {
	if (vtype(js->new_target) == T_UNDEF) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Promise constructor cannot be invoked without 'new'");
	}

	if (nargs == 0 \|\| (vtype(args[0]) != T_FUNC && vtype(args[0]) != T_CFUNC)) {
	const char *val_str = nargs == 0 ? "undefined" : js_str(js, args[0]);
	return js_mkerr_typed(js, JS_ERR_TYPE, "Promise resolver %s is not a function", val_str);
	}

	jsval_t p = mkpromise(js);
	jsval_t new_target = js->new_target;
	jsval_t p_obj = js_as_obj(p);

	jsval_t promise_proto = get_ctor_proto(js, "Promise", 7);
	jsval_t instance_proto = js_instance_proto_from_new_target(js, promise_proto);

	if (vtype(new_target) == T_FUNC \|\| vtype(new_target) == T_CFUNC) set_slot(js, p_obj, SLOT_CTOR, new_target);
	if (is_object_type(instance_proto)) set_slot(js, p_obj, SLOT_PROTO, instance_proto);

	jsval_t res_obj = mkobj(js, 0);
	set_slot(js, res_obj, SLOT_DATA, p);
	set_slot(js, res_obj, SLOT_CFUNC, js_mkfun(builtin_resolve_internal));

	jsval_t res_fn = js_obj_to_func(res_obj);
	jsval_t rej_obj = mkobj(js, 0);

	set_slot(js, rej_obj, SLOT_DATA, p);
	set_slot(js, rej_obj, SLOT_CFUNC, js_mkfun(builtin_reject_internal));

	jsval_t rej_fn = js_obj_to_func(rej_obj);
	jsval_t exec_args[] = { res_fn, rej_fn };
	sv_vm_call(js->vm, js, args[0], js_mkundef(), exec_args, 2, NULL, false);

	return p;
	}

	static jsval_t builtin_Promise_resolve(ant_t 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(ant_t 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 promise_species_noop_executor(ant_t js, jsval_t args, int nargs) {
	return js_mkundef();
	}

	static jsval_t builtin_promise_then(ant_t 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 promise_ctor = js_get(js, js_glob(js), "Promise");
	jsval_t species_ctor = promise_ctor;
	jsval_t p_obj = js_as_obj(p);
	jsval_t ctor = js_get(js, p_obj, "constructor");

	if (is_err(ctor)) return ctor;
	if (vtype(ctor) == T_UNDEF) ctor = get_slot(js, p_obj, SLOT_CTOR);

	jsval_t species = get_ctor_species_value(js, ctor);
	if (is_err(species)) return species;

	if (vtype(species) == T_FUNC \|\| vtype(species) == T_CFUNC) {
	species_ctor = species;
	} else if (vtype(species) == T_NULL) {
	species_ctor = promise_ctor;
	} else if (vtype(species) != T_UNDEF) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Promise species is not a constructor");
	}

	jsval_t nextP = mkpromise(js);
	if ((vtype(species_ctor) == T_FUNC \|\| vtype(species_ctor) == T_CFUNC)
	&& !(vtype(species_ctor) == vtype(promise_ctor)
	&& vdata(species_ctor) == vdata(promise_ctor))) {
	jsval_t species_proto = js_get(js, species_ctor, "prototype");
	if (is_object_type(species_proto))
	set_proto(js, js_as_obj(nextP), species_proto);
	set_slot(js, js_as_obj(nextP), SLOT_CTOR, species_ctor);
	} else {
	jsval_t p_proto = get_slot(js, js_as_obj(p), SLOT_PROTO);
	if (vtype(p_proto) == T_OBJ) {
	set_slot(js, js_as_obj(nextP), SLOT_PROTO, p_proto);
	jsval_t p_ctor = get_slot(js, js_as_obj(p), SLOT_CTOR);
	if (vtype(p_ctor) == T_FUNC) set_slot(js, js_as_obj(nextP), SLOT_CTOR, p_ctor);
	}
	}

	jsval_t onFulfilled = nargs > 0 ? args[0] : js_mkundef();
	jsval_t onRejected = nargs > 1 ? args[1] : js_mkundef();

	uint32_t pid = get_promise_id(js, p);
	uint32_t next_pid = get_promise_id(js, nextP);

	promise_data_entry_t *next_pd = get_promise_data(next_pid, false);
	if (next_pd) next_pd->trigger_pid = pid;

	promise_data_entry_t *pd = get_promise_data(pid, false);
	if (pd) {
	promise_handler_t h = { onFulfilled, onRejected, nextP };
	utarray_push_back(pd->handlers, &h);

	if (vtype(onRejected) == T_FUNC \|\| vtype(onRejected) == T_CFUNC) {
	pd->has_rejection_handler = true;
	promise_data_entry_t *in_unhandled = NULL;
	HASH_FIND(hh_unhandled, unhandled_rejections, &pd->promise_id, sizeof(uint32_t), in_unhandled);
	if (in_unhandled) HASH_DELETE(hh_unhandled, unhandled_rejections, pd);
	}
	}

	if (pd && pd->state != 0) trigger_handlers(js, p);
	return nextP;
	}

	static jsval_t builtin_promise_catch(ant_t js, jsval_t args, int nargs) {
	jsval_t args_then[] = { js_mkundef(), nargs > 0 ? args[0] : js_mkundef() };
	return builtin_promise_then(js, args_then, 2);
	}

	static jsval_t finally_value_thunk(ant_t js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	return get_slot(js, me, SLOT_DATA);
	}

	static jsval_t finally_thrower(ant_t js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t reason = get_slot(js, me, SLOT_DATA);
	jsval_t rejected = js_mkpromise(js);
	js_reject_promise(js, rejected, reason);
	return rejected;
	}

	static jsval_t finally_identity_reject(ant_t js, jsval_t args, int nargs) {
	jsval_t reason = nargs > 0 ? args[0] : js_mkundef();
	jsval_t rejected = js_mkpromise(js);
	js_reject_promise(js, rejected, reason);
	return rejected;
	}

	static jsval_t finally_fulfilled_wrapper(ant_t js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t callback = get_slot(js, me, SLOT_DATA);
	jsval_t value = nargs > 0 ? args[0] : js_mkundef();

	jsval_t result = js_mkundef();
	if (vtype(callback) == T_FUNC \|\| vtype(callback) == T_CFUNC) {
	result = sv_vm_call(js->vm, js, callback, js_mkundef(), NULL, 0, NULL, false);
	if (is_err(result)) return result;
	}

	if (vtype(result) == T_PROMISE \|\| (vtype(result) == T_OBJ && vtype(js_get(js, result, "then")) == T_FUNC)) {
	jsval_t thunk_obj = mkobj(js, 0);
	set_slot(js, thunk_obj, SLOT_DATA, value);
	set_slot(js, thunk_obj, SLOT_CFUNC, js_mkfun(finally_value_thunk));
	jsval_t thunk_fn = js_obj_to_func(thunk_obj);

	jsval_t identity_rej_fn = js_mkfun(finally_identity_reject);

	jsval_t then_fn = js_get(js, result, "then");
	jsval_t call_args[] = { thunk_fn, identity_rej_fn };
	return sv_vm_call(js->vm, js, then_fn, result, call_args, 2, NULL, false);
	}

	return value;
	}

	static jsval_t finally_rejected_wrapper(ant_t js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t callback = get_slot(js, me, SLOT_DATA);
	jsval_t reason = nargs > 0 ? args[0] : js_mkundef();

	jsval_t result = js_mkundef();
	if (vtype(callback) == T_FUNC \|\| vtype(callback) == T_CFUNC) {
	result = sv_vm_call(js->vm, js, callback, js_mkundef(), NULL, 0, NULL, false);
	if (is_err(result)) return result;
	}

	if (vtype(result) == T_PROMISE \|\| (vtype(result) == T_OBJ && vtype(js_get(js, result, "then")) == T_FUNC)) {
	jsval_t thrower_obj = mkobj(js, 0);
	set_slot(js, thrower_obj, SLOT_DATA, reason);
	set_slot(js, thrower_obj, SLOT_CFUNC, js_mkfun(finally_thrower));

	jsval_t thrower_fn = js_obj_to_func(thrower_obj);
	jsval_t identity_rej_fn = js_mkfun(finally_identity_reject);

	jsval_t then_prop = js_get(js, result, "then");
	jsval_t call_args[] = { thrower_fn, identity_rej_fn };

	return sv_vm_call(js->vm, js, then_prop, result, call_args, 2, NULL, false);
	}

	jsval_t rejected = js_mkpromise(js);
	js_reject_promise(js, rejected, reason);
	return rejected;
	}

	static jsval_t builtin_promise_finally(ant_t js, jsval_t args, int nargs) {
	jsval_t callback = nargs > 0 ? args[0] : js_mkundef();

	jsval_t fulfilled_obj = mkobj(js, 0);
	set_slot(js, fulfilled_obj, SLOT_DATA, callback);
	set_slot(js, fulfilled_obj, SLOT_CFUNC, js_mkfun(finally_fulfilled_wrapper));
	jsval_t fulfilled_fn = js_obj_to_func(fulfilled_obj);

	jsval_t rejected_obj = mkobj(js, 0);
	set_slot(js, rejected_obj, SLOT_DATA, callback);
	set_slot(js, rejected_obj, SLOT_CFUNC, js_mkfun(finally_rejected_wrapper));
	jsval_t rejected_fn = js_obj_to_func(rejected_obj);

	jsval_t args_then[] = { fulfilled_fn, rejected_fn };
	return builtin_promise_then(js, args_then, 2);
	}

	static jsval_t builtin_Promise_try(ant_t js, jsval_t args, int nargs) {
	if (nargs == 0) return builtin_Promise_resolve(js, args, 0);
	jsval_t fn = args[0];
	jsval_t *call_args = nargs > 1 ? &args[1] : NULL;
	int call_nargs = nargs > 1 ? nargs - 1 : 0;
	jsval_t res = sv_vm_call(js->vm, js, fn, js_mkundef(), call_args, call_nargs, NULL, false);
	if (is_err(res)) {
	jsval_t reject_val = js->thrown_value;
	if (vtype(reject_val) == T_UNDEF) reject_val = res;
	js->thrown_exists = false;
	js->thrown_value = js_mkundef();
	js->thrown_stack = js_mkundef();
	jsval_t rej_args[] = { reject_val };
	return builtin_Promise_reject(js, rej_args, 1);
	}
	jsval_t res_args[] = { res };
	return builtin_Promise_resolve(js, res_args, 1);
	}

	static jsval_t builtin_Promise_withResolvers(ant_t js, jsval_t args, int nargs) {
	jsval_t p = mkpromise(js);

	jsval_t res_obj = mkobj(js, 0);
	set_slot(js, res_obj, SLOT_DATA, p);
	set_slot(js, res_obj, SLOT_CFUNC, js_mkfun(builtin_resolve_internal));
	jsval_t res_fn = js_obj_to_func(res_obj);

	jsval_t rej_obj = mkobj(js, 0);
	set_slot(js, rej_obj, SLOT_DATA, p);
	set_slot(js, rej_obj, SLOT_CFUNC, js_mkfun(builtin_reject_internal));
	jsval_t rej_fn = js_obj_to_func(rej_obj);

	jsval_t result = js_newobj(js);
	js_setprop(js, result, js_mkstr(js, "promise", 7), p);
	js_setprop(js, result, js_mkstr(js, "resolve", 7), res_fn);
	js_setprop(js, result, js_mkstr(js, "reject", 6), rej_fn);

	return result;
	}

	static jsval_t mkpromise_with_ctor(ant_t *js, jsval_t ctor) {
	jsval_t p = mkpromise(js);
	if (vtype(ctor) != T_FUNC && vtype(ctor) != T_CFUNC) return p;

	jsval_t proto = js_get(js, ctor, "prototype");
	if (is_err(proto)) return proto;
	if (is_object_type(proto)) {
	jsval_t p_obj = js_as_obj(p);
	set_slot(js, p_obj, SLOT_CTOR, ctor);
	set_slot(js, p_obj, SLOT_PROTO, proto);
	}
	return p;
	}

	static jsval_t builtin_Promise_all_resolve_handler(ant_t 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");
	arr_set(js, results, (jsoff_t)index, value);

	jsval_t remaining_val = js_get(js, tracker, "remaining");
	int remaining = (int)tod(remaining_val) - 1;
	js_setprop(js, tracker, js_mkstr(js, "remaining", 9), tov((double)remaining));

	if (remaining == 0) {
	jsval_t result_promise = get_slot(js, tracker, SLOT_DATA);
	resolve_promise(js, result_promise, mkval(T_ARR, vdata(results)));
	}

	return js_mkundef();
	}

	static jsval_t builtin_Promise_all_reject_handler(ant_t js, jsval_t args, int nargs) {
	jsval_t me = js->current_func;
	jsval_t tracker = js_get(js, me, "tracker");
	jsval_t result_promise = get_slot(js, tracker, SLOT_DATA);

	jsval_t reason = nargs > 0 ? args[0] : js_mkundef();
	reject_promise(js, result_promise, reason);

	return js_mkundef();
	}

	typedef struct {
	jsval_t tracker;
	int index;
	} promise_all_iter_ctx_t;

	static iter_action_t promise_all_iter_cb(ant_t js, jsval_t value, void ctx, jsval_t *out) {
	promise_all_iter_ctx_t pctx = (promise_all_iter_ctx_t )ctx;
	jsval_t item = value;

	if (vtype(item) != T_PROMISE) {
	jsval_t wrap_args[] = { item };
	item = builtin_Promise_resolve(js, wrap_args, 1);
	}

	jsval_t resolve_obj = mkobj(js, 0);
	set_slot(js, resolve_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_all_resolve_handler));
	js_setprop(js, resolve_obj, js_mkstr(js, "index", 5), tov((double)pctx->index));
	js_setprop(js, resolve_obj, js_mkstr(js, "tracker", 7), pctx->tracker);
	jsval_t resolve_fn = js_obj_to_func(resolve_obj);

	jsval_t reject_obj = mkobj(js, 0);
	set_slot(js, reject_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_all_reject_handler));
	js_setprop(js, reject_obj, js_mkstr(js, "tracker", 7), pctx->tracker);
	jsval_t reject_fn = js_obj_to_func(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;

	pctx->index++;
	return ITER_CONTINUE;
	}

	static jsval_t builtin_Promise_all(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Promise.all requires an iterable");

	jsval_t iterable = args[0];
	uint8_t t = vtype(iterable);
	if (t != T_ARR && t != T_OBJ) return js_mkerr(js, "Promise.all requires an iterable");

	jsval_t ctor = js->this_val;
	if (vtype(ctor) != T_FUNC && vtype(ctor) != T_CFUNC) ctor = js_mkundef();

	jsval_t result_promise = mkpromise_with_ctor(js, ctor);
	if (is_err(result_promise)) return result_promise;

	jsval_t tracker = mkobj(js, 0);
	jsval_t results = mkarr(js);

	js_setprop(js, tracker, js_mkstr(js, "remaining", 9), tov(0.0));
	js_setprop(js, tracker, js_mkstr(js, "results", 7), results);
	set_slot(js, tracker, SLOT_DATA, result_promise);

	promise_all_iter_ctx_t ctx = { .tracker = tracker, .index = 0 };
	jsval_t iter_result = iter_foreach(js, iterable, promise_all_iter_cb, &ctx);

	if (is_err(iter_result)) return iter_result;

	int len = ctx.index;
	{
	jsoff_t doff = get_dense_buf(js, results);
	if (doff) {
	if ((jsoff_t)len > dense_capacity(js, doff)) doff = dense_grow(js, results, (jsoff_t)len);
	if (doff) dense_set_length(js, doff, (jsoff_t)len);
	}
	}

	if (len == 0) {
	resolve_promise(js, result_promise, mkval(T_ARR, vdata(results)));
	return result_promise;
	}

	js_setprop(js, tracker, js_mkstr(js, "remaining", 9), tov((double)len));
	return result_promise;
	}

	typedef struct {
	jsval_t result_promise;
	jsval_t resolve_fn;
	jsval_t reject_fn;
	bool settled;
	} promise_race_iter_ctx_t;

	static iter_action_t promise_race_iter_cb(ant_t js, jsval_t value, void ctx, jsval_t *out) {
	promise_race_iter_ctx_t pctx = (promise_race_iter_ctx_t )ctx;
	jsval_t item = value;

	if (vtype(item) != T_PROMISE) {
	resolve_promise(js, pctx->result_promise, item);
	pctx->settled = true;
	return ITER_BREAK;
	}

	uint32_t item_pid = get_promise_id(js, item);
	promise_data_entry_t *pd = get_promise_data(item_pid, false);
	if (pd) {
	if (pd->state == 1) {
	resolve_promise(js, pctx->result_promise, pd->value);
	pctx->settled = true;
	return ITER_BREAK;
	} else if (pd->state == 2) {
	reject_promise(js, pctx->result_promise, pd->value);
	pctx->settled = true;
	return ITER_BREAK;
	}
	}

	jsval_t then_args[] = { pctx->resolve_fn, pctx->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 ITER_CONTINUE;
	}

	static jsval_t builtin_Promise_race(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Promise.race requires an iterable");

	jsval_t iterable = args[0];
	uint8_t t = vtype(iterable);
	if (t != T_ARR && t != T_OBJ) return js_mkerr(js, "Promise.race requires an iterable");

	jsval_t ctor = js->this_val;
	if (vtype(ctor) != T_FUNC && vtype(ctor) != T_CFUNC) ctor = js_mkundef();
	jsval_t result_promise = mkpromise_with_ctor(js, ctor);
	if (is_err(result_promise)) return result_promise;

	jsval_t resolve_obj = mkobj(js, 0);
	set_slot(js, resolve_obj, SLOT_CFUNC, js_mkfun(builtin_resolve_internal));
	set_slot(js, resolve_obj, SLOT_DATA, result_promise);
	jsval_t resolve_fn = js_obj_to_func(resolve_obj);

	jsval_t reject_obj = mkobj(js, 0);
	set_slot(js, reject_obj, SLOT_CFUNC, js_mkfun(builtin_reject_internal));
	set_slot(js, reject_obj, SLOT_DATA, result_promise);
	jsval_t reject_fn = js_obj_to_func(reject_obj);

	promise_race_iter_ctx_t ctx = {
	.result_promise = result_promise,
	.resolve_fn = resolve_fn,
	.reject_fn = reject_fn,
	.settled = false
	};

	jsval_t iter_result = iter_foreach(js, iterable, promise_race_iter_cb, &ctx);
	if (is_err(iter_result)) return iter_result;

	return result_promise;
	}

	static jsval_t mk_aggregate_error(ant_t *js, jsval_t errors) {
	jsval_t args[] = { errors, js_mkstr(js, "All promises were rejected", 26) };
	jsoff_t off = lkp(js, js_glob(js), "AggregateError", 14);
	jsval_t ctor = off ? resolveprop(js, mkval(T_PROP, off)) : js_mkundef();
	return sv_vm_call(js->vm, js, ctor, js_mkundef(), args, 2, NULL, false);
	}

	static bool promise_any_try_resolve(ant_t *js, jsval_t tracker, jsval_t value) {
	if (js_truthy(js, js_get(js, tracker, "resolved"))) return false;
	js_set(js, tracker, "resolved", js_true);
	resolve_promise(js, get_slot(js, tracker, SLOT_DATA), value);
	return true;
	}

	static void promise_any_record_rejection(ant_t *js, jsval_t tracker, int index, jsval_t reason) {
	jsval_t errors = resolveprop(js, js_get(js, tracker, "errors"));
	arr_set(js, errors, (jsoff_t)index, reason);

	int remaining = (int)tod(js_get(js, tracker, "remaining")) - 1;
	js_set(js, tracker, "remaining", tov((double)remaining));

	if (remaining == 0) reject_promise(js, get_slot(js, tracker, SLOT_DATA), mk_aggregate_error(js, errors));
	}

	static jsval_t builtin_Promise_any_resolve_handler(ant_t js, jsval_t args, int nargs) {
	jsval_t tracker = js_get(js, js->this_val, "tracker");
	promise_any_try_resolve(js, tracker, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_Promise_any_reject_handler(ant_t js, jsval_t args, int nargs) {
	jsval_t tracker = js_get(js, js->this_val, "tracker");
	if (js_truthy(js, js_get(js, tracker, "resolved"))) return js_mkundef();

	int index = (int)tod(js_get(js, js->this_val, "index"));
	promise_any_record_rejection(js, tracker, index, nargs > 0 ? args[0] : js_mkundef());
	return js_mkundef();
	}

	static jsval_t builtin_Promise_any(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "Promise.any requires an array");

	jsval_t arr = args[0];
	if (vtype(arr) != T_ARR) return js_mkerr(js, "Promise.any requires an array");

	int len = (int)get_array_length(js, arr);

	if (len == 0) {
	jsval_t reject_args[] = { mk_aggregate_error(js, mkarr(js)) };
	return builtin_Promise_reject(js, reject_args, 1);
	}

	jsval_t result_promise = mkpromise(js);
	jsval_t tracker = mkobj(js, 0);
	jsval_t errors = mkarr(js);

	set_slot(js, tracker, SLOT_DATA, result_promise);

	js_setprop(js, tracker, js_mkstr(js, "remaining", 9), tov((double)len));
	js_setprop(js, tracker, js_mkstr(js, "errors", 6), errors);
	js_setprop(js, tracker, js_mkstr(js, "resolved", 8), js_false);

	{
	jsoff_t doff = get_dense_buf(js, errors);
	if (doff) {
	if ((jsoff_t)len > dense_capacity(js, doff)) doff = dense_grow(js, errors, (jsoff_t)len);
	if (doff) dense_set_length(js, doff, (jsoff_t)len);
	}
	}

	for (int i = 0; i < len; i++) {
	jsval_t item = arr_get(js, arr, (jsoff_t)i);
	item = resolveprop(js, item);

	if (vtype(item) != T_PROMISE) {
	promise_any_try_resolve(js, tracker, item);
	return result_promise;
	}

	uint32_t item_pid = get_promise_id(js, item);
	promise_data_entry_t *pd = get_promise_data(item_pid, false);
	if (pd) {
	pd->has_rejection_handler = true;
	promise_data_entry_t *in_unhandled = NULL;
	HASH_FIND(hh_unhandled, unhandled_rejections, &pd->promise_id, sizeof(uint32_t), in_unhandled);
	if (in_unhandled) HASH_DELETE(hh_unhandled, unhandled_rejections, pd);

	if (pd->state == 1) {
	promise_any_try_resolve(js, tracker, pd->value);
	return result_promise;
	} else if (pd->state == 2) {
	promise_any_record_rejection(js, tracker, i, pd->value);
	continue;
	}
	}

	jsval_t resolve_obj = mkobj(js, 0);
	set_slot(js, resolve_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_any_resolve_handler));
	js_setprop(js, resolve_obj, js_mkstr(js, "tracker", 7), tracker);

	jsval_t reject_obj = mkobj(js, 0);
	set_slot(js, reject_obj, SLOT_CFUNC, js_mkfun(builtin_Promise_any_reject_handler));
	js_setprop(js, reject_obj, js_mkstr(js, "index", 5), tov((double)i));
	js_setprop(js, reject_obj, js_mkstr(js, "tracker", 7), tracker);

	jsval_t then_args[] = { js_obj_to_func(resolve_obj), js_obj_to_func(reject_obj) };
	jsval_t saved_this = js->this_val;
	js->this_val = item;
	builtin_promise_then(js, then_args, 2);
	js->this_val = saved_this;
	}

	return result_promise;
	}

	static jsval_t handle_proxy_instanceof(ant_t *js, jsval_t l, jsval_t r, uint8_t ltype) {
	jsval_t target = proxy_read_target(js, r);
	uint8_t ttype = vtype(target);

	if (ttype != T_FUNC && ttype != T_CFUNC) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Right-hand side of 'instanceof' is not callable");
	}

	{
	jsval_t has_instance = js_get_sym(js, r, get_hasInstance_sym());
	if (is_err(has_instance)) return has_instance;
	uint8_t hit = vtype(has_instance);
	if (hit == T_FUNC \|\| hit == T_CFUNC) {
	jsval_t args[1] = { l };
	jsval_t result = sv_vm_call(js->vm, js, has_instance, r, args, 1, NULL, false);
	if (is_err(result)) return result;
	return js_bool(js_truthy(js, result));
	}
	if (hit != T_UNDEF && hit != T_NULL) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Symbol.hasInstance is not callable");
	}
	}

	jsval_t proto_val = proxy_get(js, r, "prototype", 9);
	uint8_t pt = vtype(proto_val);

	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC) {
	return mkval(T_BOOL, 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);
	for (int depth = 0; vtype(current) != T_NULL && depth < 32; depth++) {
	if (vdata(current) == vdata(proto_val)) {
	return mkval(T_BOOL, 1);
	}
	current = get_proto(js, current);
	}

	return mkval(T_BOOL, 0);
	}

	static jsval_t handle_cfunc_instanceof(jsval_t l, jsval_t r, uint8_t ltype) {
	jsval_t (fn)(ant_t , jsval_t , int) = (jsval_t()(ant_t , jsval_t , int)) vdata(r);

	if (fn == builtin_Object) return mkval(T_BOOL, ltype == T_OBJ ? 1 : 0);
	if (fn == builtin_Function) return mkval(T_BOOL, (ltype == T_FUNC \|\| ltype == T_CFUNC) ? 1 : 0);
	if (fn == builtin_String) return mkval(T_BOOL, ltype == T_STR ? 1 : 0);
	if (fn == builtin_Number) return mkval(T_BOOL, ltype == T_NUM ? 1 : 0);
	if (fn == builtin_Boolean) return mkval(T_BOOL, ltype == T_BOOL ? 1 : 0);
	if (fn == builtin_Array) return mkval(T_BOOL, ltype == T_ARR ? 1 : 0);
	if (fn == builtin_Promise) return mkval(T_BOOL, ltype == T_PROMISE ? 1 : 0);

	return mkval(T_BOOL, 0);
	}

	static jsval_t walk_prototype_chain(ant_t *js, jsval_t l, jsval_t ctor_proto) {
	jsval_t current = get_proto(js, l);
	const int MAX_DEPTH = 32;

	for (int depth = 0; vtype(current) != T_NULL && depth < MAX_DEPTH; depth++) {
	if (vdata(current) == vdata(ctor_proto)) return mkval(T_BOOL, 1);
	current = get_proto(js, current);
	}

	return mkval(T_BOOL, 0);
	}

	jsval_t do_instanceof(ant_t *js, jsval_t l, jsval_t r) {
	uint8_t ltype = vtype(l);
	uint8_t rtype = vtype(r);

	if (rtype != T_FUNC && rtype != T_CFUNC) {
	if (is_proxy(js, r)) return handle_proxy_instanceof(js, l, r, ltype);
	return js_mkerr_typed(js, JS_ERR_TYPE, "Right-hand side of 'instanceof' is not callable");
	}

	if (rtype == T_CFUNC) {
	return handle_cfunc_instanceof(l, r, ltype);
	}

	{
	jsval_t has_instance = js_get_sym(js, r, get_hasInstance_sym());
	if (is_err(has_instance)) return has_instance;
	uint8_t hit = vtype(has_instance);
	if (hit == T_FUNC \|\| hit == T_CFUNC) {
	jsval_t args[1] = { l };
	jsval_t result = sv_vm_call(js->vm, js, has_instance, r, args, 1, NULL, false);
	if (is_err(result)) return result;
	return js_bool(js_truthy(js, result));
	}
	if (hit != T_UNDEF && hit != T_NULL) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Symbol.hasInstance is not callable");
	}
	}

	jsval_t func_obj = js_func_obj(r);
	jsoff_t proto_off = lkp_interned(js, func_obj, INTERN_PROTOTYPE, 9);
	if (proto_off == 0) return mkval(T_BOOL, 0);

	jsval_t ctor_proto = resolveprop(js, mkval(T_PROP, proto_off));
	uint8_t pt = vtype(ctor_proto);
	if (pt != T_OBJ && pt != T_ARR && pt != T_FUNC) return mkval(T_BOOL, 0);

	if (ltype == T_STR \|\| ltype == T_NUM \|\| ltype == T_BOOL) {
	jsval_t type_proto = get_prototype_for_type(js, ltype);
	return mkval(T_BOOL, vdata(ctor_proto) == vdata(type_proto) ? 1 : 0);
	}

	if (ltype != T_OBJ && ltype != T_ARR && ltype != T_FUNC && ltype != T_PROMISE) {
	return mkval(T_BOOL, 0);
	}

	return walk_prototype_chain(js, l, ctor_proto);
	}

	jsval_t do_in(ant_t *js, jsval_t l, jsval_t r) {
	jsoff_t prop_len;
	const char *prop_name;
	char num_buf[32];

	jsval_t key = js_to_primitive(js, l, 1);
	if (is_err(key)) return key;

	bool is_sym = (vtype(key) == T_SYMBOL);

	if (is_sym) {
	const char *d = js_sym_desc(js, key);
	prop_name = d ? d : "symbol";
	prop_len = (jsoff_t)strlen(prop_name);
	} else if (vtype(key) == T_NUM) {
	prop_len = (jsoff_t)strnum(key, num_buf, sizeof(num_buf));
	prop_name = num_buf;
	} else {
	jsval_t key_str = js_tostring_val(js, key);
	if (is_err(key_str)) return key_str;
	jsoff_t prop_off = vstr(js, key_str, &prop_len);
	prop_name = (char *)&js->mem[prop_off];
	}

	if (!is_object_type(r)) {
	if (vtype(r) == T_CFUNC) return mkval(T_BOOL, 0);
	return js_mkerr_typed(js, JS_ERR_TYPE, "Cannot use 'in' operator to search for '%.*s' in non-object", (int)prop_len, prop_name);
	}

	if (is_proxy(js, r)) {
	jsval_t result = is_sym ? proxy_has_val(js, r, key) : proxy_has(js, r, prop_name, prop_len);
	if (is_err(result)) return result;
	return js_bool(js_truthy(js, result));
	}

	if (!is_sym && vtype(r) == T_ARR) {
	unsigned long idx;
	jsoff_t arr_len = get_array_length(js, r);
	if (parse_array_index(prop_name, prop_len, arr_len, &idx)) return mkval(T_BOOL, arr_has(js, r, (jsoff_t)idx) ? 1 : 0);
	if (prop_len == 6 && memcmp(prop_name, "length", 6) == 0) return mkval(T_BOOL, 1);
	}

	jsoff_t found = is_sym ? lkp_sym_proto(js, r, (jsoff_t)vdata(key)) : lkp_proto(js, r, prop_name, prop_len);
	return mkval(T_BOOL, found != 0 ? 1 : 0);
	}

	static jsval_t builtin_import(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "import() requires a string specifier");
	jsval_t ns = js_esm_import_sync(js, args[0]);
	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(ant_t js, jsval_t args, int nargs) {
	if (nargs < 1) return js_mkerr(js, "import.meta.resolve() requires a string specifier");
	if (vtype(js->import_meta) == T_OBJ) {
	jsval_t filename = js_get(js, js->import_meta, "filename");
	if (vtype(filename) == T_STR) {
	jsoff_t n = 0; jsoff_t off = vstr(js, filename, &n);
	return js_esm_resolve_specifier(js, args[0], (const char *)&js->mem[off]);
	}
	} return js_esm_resolve_specifier(js, args[0], NULL);
	}

	void js_setup_import_meta(ant_t js, const char filename) {
	if (!filename) return;

	jsval_t import_meta = mkobj(js, 0);
	if (is_err(import_meta)) return;
	bool is_url = esm_is_url(filename);

	jsval_t url_val = is_url ? js_mkstr(js, filename, strlen(filename)) : js_esm_make_file_url(js, filename);
	if (!is_err(url_val)) js_setprop(js, import_meta, js_mkstr(js, "url", 3), url_val);

	jsval_t filename_val = js_mkstr(js, filename, strlen(filename));
	if (!is_err(filename_val)) js_setprop(js, import_meta, js_mkstr(js, "filename", 8), filename_val);

	if (is_url) {
	char *filename_copy = strdup(filename);
	if (filename_copy) {
	char *last_slash = strrchr(filename_copy, '/');
	char *scheme_end = strstr(filename_copy, "://");
	if (last_slash && scheme_end && last_slash > scheme_end + 2) {
	*last_slash = '\0';
	jsval_t dirname_val = js_mkstr(js, filename_copy, strlen(filename_copy));
	if (!is_err(dirname_val)) js_setprop(js, import_meta, js_mkstr(js, "dirname", 7), dirname_val);
	}
	free(filename_copy);
	}
	} else {
	char *filename_copy = strdup(filename);
	if (filename_copy) {
	char *dir = dirname(filename_copy);
	if (dir) {
	jsval_t dirname_val = js_mkstr(js, dir, strlen(dir));
	if (!is_err(dirname_val)) js_setprop(js, import_meta, js_mkstr(js, "dirname", 7), dirname_val);
	}
	free(filename_copy);
	}
	}

	js_setprop(js, import_meta, js_mkstr(js, "main", 4), js_true);
	jsval_t resolve_fn = js_mkfun(builtin_import_meta_resolve);
	js_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 = js_func_obj(import_fn);
	js_setprop(js, import_obj, js_mkstr(js, "meta", 4), import_meta);
	}
	}
	}

	static proxy_data_t *get_proxy_data(jsval_t obj) {
	if (vtype(obj) != T_OBJ) return NULL;
	jsoff_t off = (jsoff_t)vdata(obj);
	proxy_data_t *data = NULL;
	HASH_FIND(hh, proxy_registry, &off, sizeof(jsoff_t), data);
	return data;
	}

	bool is_proxy(ant_t *js, jsval_t obj) {
	(void)js;
	return get_proxy_data(obj) != NULL;
	}

	static jsval_t proxy_read_target(ant_t *js, jsval_t obj) {
	proxy_data_t *data = get_proxy_data(obj);
	return data ? data->target : obj;
	}

	static jsoff_t proxy_aware_length(ant_t *js, jsval_t obj) {
	jsval_t src = is_proxy(js, obj) ? proxy_read_target(js, obj) : obj;
	if (vtype(src) == T_ARR) {
	jsoff_t doff = get_dense_buf(js, src);
	if (doff) return dense_length(js, doff);
	}
	jsoff_t off = lkp_interned(js, src, INTERN_LENGTH, 6);
	if (off == 0) return 0;
	jsval_t len_val = resolveprop(js, mkval(T_PROP, off));
	return vtype(len_val) == T_NUM ? (jsoff_t)tod(len_val) : 0;
	}

	static jsval_t proxy_aware_get_elem(ant_t js, jsval_t obj, const char key, size_t key_len) {
	jsval_t src = is_proxy(js, obj) ? proxy_read_target(js, obj) : obj;
	jsoff_t off = lkp(js, src, key, key_len);
	return off ? resolveprop(js, mkval(T_PROP, off)) : js_mkundef();
	}

	static jsval_t throw_proxy_error(ant_t js, const char message) {
	jsval_t err_obj = mkobj(js, 0);
	js_setprop(js, err_obj, js_mkstr(js, "message", 7), js_mkstr(js, message, strlen(message)));
	js_setprop(js, err_obj, js_mkstr(js, "name", 4), js_mkstr(js, "TypeError", 9));
	return js_throw(js, err_obj);
	}

	static bool proxy_target_is_extensible(ant_t *js, jsval_t obj) {
	uint8_t t = vtype(obj);
	if (t != T_OBJ && t != T_ARR && t != T_FUNC) return false;

	jsval_t as_obj = js_as_obj(obj);
	if (js_truthy(js, get_slot(js, as_obj, SLOT_FROZEN))) return false;
	if (js_truthy(js, get_slot(js, as_obj, SLOT_SEALED))) return false;

	jsval_t ext_slot = get_slot(js, as_obj, SLOT_EXTENSIBLE);
	if (vtype(ext_slot) != T_UNDEF) return js_truthy(js, ext_slot);
	return true;
	}

	static jsoff_t proxy_target_prop_flags(ant_t *js, jsval_t target, jsoff_t prop_off) {
	if (prop_off == 0) return 0;
	jsoff_t obj_off = (jsoff_t)vdata(js_as_obj(target));
	jsoff_t head = loadoff(js, obj_off);
	if ((head & ~(3U \| FLAGMASK)) == prop_off) return head;
	return loadoff(js, prop_off);
	}

	static bool proxy_target_prop_is_nonconfig(ant_t *js, jsval_t target, jsoff_t prop_off) {
	return (proxy_target_prop_flags(js, target, prop_off) & NONCONFIGMASK) != 0;
	}

	static bool proxy_target_prop_is_const(ant_t *js, jsval_t target, jsoff_t prop_off) {
	return (proxy_target_prop_flags(js, target, prop_off) & CONSTMASK) != 0;
	}

	static jsval_t proxy_get(ant_t js, jsval_t proxy, const char key, size_t key_len) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkundef();
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'get' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t get_trap_off = vtype(handler) == T_OBJ
	? lkp_interned(js, handler, INTERN_GET, 3)
	: 0;

	if (get_trap_off != 0) {
	jsval_t get_trap = resolveprop(js, mkval(T_PROP, get_trap_off));
	if (vtype(get_trap) == T_FUNC \|\| vtype(get_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);

	jsval_t args[3] = { target, key_val, proxy };
	jsval_t result = sv_vm_call(js->vm, js, get_trap, js_mkundef(), args, 3, NULL, false);
	if (is_err(result)) return result;

	jsoff_t prop_off = lkp(js, target, key, key_len);
	if (prop_off != 0 && proxy_target_prop_is_nonconfig(js, target, prop_off) &&
	proxy_target_prop_is_const(js, target, prop_off)) {
	jsval_t target_value = resolveprop(js, mkval(T_PROP, prop_off));
	if (!strict_eq_values(js, result, target_value))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'get' on proxy: trap returned invalid value for non-configurable, non-writable property");
	}

	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(js_as_obj(target)), key, key_len);
	if (desc && !desc->configurable) {
	if (!desc->has_getter && !desc->has_setter && !desc->writable && prop_off != 0) {
	jsval_t target_value = resolveprop(js, mkval(T_PROP, prop_off));
	if (!strict_eq_values(js, result, target_value))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'get' on proxy: trap returned invalid value for non-configurable, non-writable property");
	}
	if ((desc->has_getter \|\| desc->has_setter) && !desc->has_getter && vtype(result) != T_UNDEF)
	return js_mkerr_typed(js, JS_ERR_TYPE, "'get' on proxy: trap returned non-undefined for property with undefined getter");
	}

	return result;
	}
	}

	char key_buf[256];
	size_t len = key_len < sizeof(key_buf) - 1 ? key_len : sizeof(key_buf) - 1;
	memcpy(key_buf, key, len);
	key_buf[len] = '\0';

	jsoff_t off = lkp(js, target, key_buf, len);
	if (off != 0) return resolveprop(js, mkval(T_PROP, off));

	jsoff_t proto_off = lkp_proto(js, target, key_buf, len);
	if (proto_off != 0) return resolveprop(js, mkval(T_PROP, proto_off));

	return js_mkundef();
	}

	static jsval_t proxy_set(ant_t js, jsval_t proxy, const char key, size_t key_len, jsval_t value) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkundef();
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'set' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t set_trap_off = vtype(handler) == T_OBJ ? lkp_interned(js, handler, INTERN_SET, 3) : 0;
	if (set_trap_off != 0) {
	jsval_t set_trap = resolveprop(js, mkval(T_PROP, set_trap_off));
	if (vtype(set_trap) == T_FUNC \|\| vtype(set_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);
	jsval_t args[4] = { target, key_val, value, proxy };
	jsval_t result = sv_vm_call(js->vm, js, set_trap, js_mkundef(), args, 4, NULL, false);
	if (is_err(result)) return result;
	if (js_truthy(js, result)) {
	jsoff_t prop_off = lkp(js, target, key, key_len);
	if (prop_off != 0 && proxy_target_prop_is_nonconfig(js, target, prop_off) &&
	proxy_target_prop_is_const(js, target, prop_off)) {
	jsval_t target_value = resolveprop(js, mkval(T_PROP, prop_off));
	if (!strict_eq_values(js, value, target_value))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'set' on proxy: trap returned truthy for non-configurable, non-writable property with different value");
	}

	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(js_as_obj(target)), key, key_len);
	if (desc && !desc->configurable) {
	if (!desc->has_getter && !desc->has_setter && !desc->writable && prop_off != 0) {
	jsval_t target_value = resolveprop(js, mkval(T_PROP, prop_off));
	if (!strict_eq_values(js, value, target_value))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'set' on proxy: trap returned truthy for non-configurable, non-writable property with different value");
	}
	if ((desc->has_getter \|\| desc->has_setter) && !desc->has_setter)
	return js_mkerr_typed(js, JS_ERR_TYPE, "'set' on proxy: trap returned truthy for property with undefined setter");
	}
	}
	return js_true;
	}
	}

	jsval_t key_str = js_mkstr(js, key, key_len);
	js_setprop(js, target, key_str, value);
	return js_true;
	}

	static jsval_t proxy_has(ant_t js, jsval_t proxy, const char key, size_t key_len) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_false;
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'has' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t has_trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "has", 3) : 0;
	if (has_trap_off != 0) {
	jsval_t has_trap = resolveprop(js, mkval(T_PROP, has_trap_off));
	if (vtype(has_trap) == T_FUNC \|\| vtype(has_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);
	jsval_t args[2] = { target, key_val };
	jsval_t result = sv_vm_call(js->vm, js, has_trap, js_mkundef(), args, 2, NULL, false);
	if (is_err(result)) return result;

	if (!js_truthy(js, result)) {
	jsoff_t prop_off = lkp(js, target, key, key_len);
	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(js_as_obj(target)), key, key_len);
	bool has_own = (prop_off != 0) \|\| (desc != NULL);

	if ((prop_off != 0 && proxy_target_prop_is_nonconfig(js, target, prop_off)) \|\| (desc && !desc->configurable))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'has' on proxy: trap returned falsy for non-configurable property");

	if (has_own && !proxy_target_is_extensible(js, target))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'has' on proxy: trap returned falsy for existing property on non-extensible target");
	}

	return result;
	}
	}

	char key_buf[256];
	size_t len = key_len < sizeof(key_buf) - 1 ? key_len : sizeof(key_buf) - 1;
	memcpy(key_buf, key, len);
	key_buf[len] = '\0';

	jsoff_t off = lkp_proto(js, target, key_buf, len);
	return js_bool(off != 0);
	}

	static jsval_t proxy_delete(ant_t js, jsval_t proxy, const char key, size_t key_len) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_true;
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'deleteProperty' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t delete_trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "deleteProperty", 14) : 0;
	if (delete_trap_off != 0) {
	jsval_t delete_trap = resolveprop(js, mkval(T_PROP, delete_trap_off));
	if (vtype(delete_trap) == T_FUNC \|\| vtype(delete_trap) == T_CFUNC) {
	jsval_t key_val = js_mkstr(js, key, key_len);
	jsval_t args[2] = { target, key_val };
	jsval_t result = sv_vm_call(js->vm, js, delete_trap, js_mkundef(), args, 2, NULL, false);
	if (is_err(result)) return result;
	if (js_truthy(js, result)) {
	jsoff_t prop_off = lkp(js, target, key, key_len);
	if (prop_off != 0 && is_nonconfig_prop(js, prop_off))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'deleteProperty' on proxy: trap returned truthy for non-configurable property");
	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(js_as_obj(target)), key, key_len);
	if (desc && !desc->configurable)
	return js_mkerr_typed(js, JS_ERR_TYPE, "'deleteProperty' on proxy: trap returned truthy for non-configurable property");
	}
	return result;
	}
	}

	jsval_t key_str = js_mkstr(js, key, key_len);
	js_setprop(js, target, key_str, js_mkundef());
	return js_true;
	}

	static jsval_t proxy_get_val(ant_t *js, jsval_t proxy, jsval_t key_val) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkundef();
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'get' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t get_trap_off = vtype(handler) == T_OBJ
	? lkp_interned(js, handler, INTERN_GET, 3) : 0;
	if (get_trap_off != 0) {
	jsval_t get_trap = resolveprop(js, mkval(T_PROP, get_trap_off));
	if (vtype(get_trap) == T_FUNC \|\| vtype(get_trap) == T_CFUNC) {
	jsval_t args[3] = { target, key_val, proxy };
	return sv_vm_call(js->vm, js, get_trap, js_mkundef(), args, 3, NULL, false);
	}
	}

	if (vtype(key_val) == T_SYMBOL) {
	jsoff_t off = lkp_sym_proto(js, target, (jsoff_t)vdata(key_val));
	return off != 0 ? resolveprop(js, mkval(T_PROP, off)) : js_mkundef();
	}

	return proxy_get(js, proxy, "", 0);
	}

	static jsval_t proxy_has_val(ant_t *js, jsval_t proxy, jsval_t key_val) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_false;
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'has' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t has_trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "has", 3) : 0;
	if (has_trap_off != 0) {
	jsval_t has_trap = resolveprop(js, mkval(T_PROP, has_trap_off));
	if (vtype(has_trap) == T_FUNC \|\| vtype(has_trap) == T_CFUNC) {
	jsval_t args[2] = { target, key_val };
	return sv_vm_call(js->vm, js, has_trap, js_mkundef(), args, 2, NULL, false);
	}
	}

	if (vtype(key_val) == T_SYMBOL) {
	jsoff_t off = lkp_sym_proto(js, target, (jsoff_t)vdata(key_val));
	return js_bool(off != 0);
	}
	return js_false;
	}

	static jsval_t proxy_delete_val(ant_t *js, jsval_t proxy, jsval_t key_val) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_true;
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'deleteProperty' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	jsoff_t delete_trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "deleteProperty", 14) : 0;
	if (delete_trap_off != 0) {
	jsval_t delete_trap = resolveprop(js, mkval(T_PROP, delete_trap_off));
	if (vtype(delete_trap) == T_FUNC \|\| vtype(delete_trap) == T_CFUNC) {
	jsval_t args[2] = { target, key_val };
	jsval_t result = sv_vm_call(js->vm, js, delete_trap, js_mkundef(), args, 2, NULL, false);
	if (is_err(result)) return result;
	if (js_truthy(js, result) && vtype(key_val) == T_SYMBOL) {
	jsoff_t prop_off = lkp_sym(js, target, (jsoff_t)vdata(key_val));
	if (prop_off != 0 && is_nonconfig_prop(js, prop_off))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'deleteProperty' on proxy: trap returned truthy for non-configurable property");
	}
	return result;
	}
	}

	if (vtype(key_val) == T_SYMBOL) {
	jsoff_t sym_off = (jsoff_t)vdata(key_val);
	jsoff_t prop_off = lkp_sym(js, target, sym_off);
	if (prop_off != 0) {
	jsoff_t obj_off = (jsoff_t)vdata(js_as_obj(target));
	jsoff_t first_prop = loadoff(js, obj_off) & ~(3U \| FLAGMASK);
	if (first_prop == prop_off) {
	unlink_prop(js, obj_off, prop_off, 0);
	} else {
	for (jsoff_t prev = first_prop; prev != 0; ) {
	jsoff_t np = loadoff(js, prev) & ~(3U \| FLAGMASK);
	if (np == prop_off) { unlink_prop(js, obj_off, prop_off, prev); break; }
	prev = np;
	}
	}
	}
	}
	return js_true;
	}

	jsval_t js_proxy_apply(ant_t js, jsval_t proxy, jsval_t this_arg, jsval_t args, int argc) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkerr_typed(js, JS_ERR_TYPE, "object is not a function");
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'apply' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;
	uint8_t target_type = vtype(target);

	if (target_type != T_FUNC && target_type != T_CFUNC && !(target_type == T_OBJ && is_proxy(js, target)))
	return js_mkerr_typed(js, JS_ERR_TYPE, "%s is not a function", typestr(target_type));

	jsoff_t trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "apply", 5) : 0;
	if (trap_off != 0) {
	jsval_t trap = resolveprop(js, mkval(T_PROP, trap_off));
	if (vtype(trap) == T_FUNC \|\| vtype(trap) == T_CFUNC) {
	jsval_t args_arr = mkarr(js);
	for (int i = 0; i < argc; i++)
	js_arr_push(js, args_arr, args[i]);
	jsval_t trap_args[3] = { target, this_arg, args_arr };
	return sv_vm_call(js->vm, js, trap, handler, trap_args, 3, NULL, false);
	}
	}

	return sv_vm_call(js->vm, js, target, this_arg, args, argc, NULL, false);
	}

	jsval_t js_proxy_construct(ant_t js, jsval_t proxy, jsval_t args, int argc, jsval_t new_target) {
	proxy_data_t *data = get_proxy_data(proxy);
	if (!data) return js_mkerr_typed(js, JS_ERR_TYPE, "not a constructor");
	if (data->revoked) return throw_proxy_error(js, "Cannot perform 'construct' on a proxy that has been revoked");

	jsval_t target = data->target;
	jsval_t handler = data->handler;

	if (vtype(target) != T_FUNC)
	return js_mkerr_typed(js, JS_ERR_TYPE, "not a constructor");

	jsoff_t trap_off = vtype(handler) == T_OBJ ? lkp(js, handler, "construct", 9) : 0;
	if (trap_off != 0) {
	jsval_t trap = resolveprop(js, mkval(T_PROP, trap_off));
	if (vtype(trap) == T_FUNC \|\| vtype(trap) == T_CFUNC) {
	jsval_t args_arr = mkarr(js);
	for (int i = 0; i < argc; i++)
	js_arr_push(js, args_arr, args[i]);
	jsval_t trap_args[3] = { target, args_arr, new_target };
	jsval_t result = sv_vm_call(js->vm, js, trap, js_mkundef(), trap_args, 3, NULL, false);
	if (is_err(result)) return result;
	if (!is_object_type(result))
	return js_mkerr_typed(js, JS_ERR_TYPE, "'construct' on proxy: trap returned non-Object");
	return result;
	}
	}

	jsval_t obj = mkobj(js, 0);
	jsval_t proto = js_getprop_fallback(js, target, "prototype");
	if (is_object_type(proto)) js_set_proto(js, obj, proto);
	jsval_t saved = js->new_target;
	js->new_target = new_target;
	jsval_t ctor_this = obj;
	jsval_t result = sv_vm_call(js->vm, js, target, obj, args, argc, &ctor_this, true);
	js->new_target = saved;
	if (is_err(result)) return result;
	return is_object_type(result) ? result : (is_object_type(ctor_this) ? ctor_this : obj);
	}

	static jsval_t mkproxy(ant_t *js, jsval_t target, jsval_t handler) {
	jsval_t proxy_obj = mkobj(js, 0);
	jsoff_t off = (jsoff_t)vdata(proxy_obj);

	proxy_data_t data = (proxy_data_t )ant_calloc(sizeof(proxy_data_t));
	if (!data) return js_mkerr(js, "out of memory");

	data->obj_offset = off;
	data->target = target;
	data->handler = handler;
	data->revoked = false;

	HASH_ADD(hh, proxy_registry, obj_offset, sizeof(jsoff_t), data);
	return proxy_obj;
	}

	static jsval_t create_proxy_checked(ant_t js, jsval_t args, int nargs, bool require_new) {
	if (require_new && vtype(js->new_target) == T_UNDEF) {
	return js_mkerr_typed(js, JS_ERR_TYPE, "Proxy constructor requires 'new'");
	}
	if (nargs < 2) return js_mkerr(js, "Proxy requires two arguments: target and handler");

	jsval_t target = args[0];
	jsval_t handler = args[1];

	uint8_t target_type = vtype(target);
	if (target_type != T_OBJ && target_type != T_FUNC && target_type != T_ARR) {
	return js_mkerr(js, "Proxy target must be an object");
	}

	uint8_t handler_type = vtype(handler);
	if (handler_type != T_OBJ && handler_type != T_FUNC) {
	return js_mkerr(js, "Proxy handler must be an object");
	}

	return mkproxy(js, target, handler);
	}

	static jsval_t builtin_Proxy(ant_t js, jsval_t args, int nargs) {
	return create_proxy_checked(js, args, nargs, true);
	}

	static jsval_t proxy_revoke_fn(ant_t js, jsval_t args, int nargs) {
	(void)args; (void)nargs;
	jsval_t func = js->current_func;
	jsval_t ref_slot = get_slot(js, func, SLOT_PROXY_REF);

	if (vtype(ref_slot) != T_UNDEF && vdata(ref_slot) != 0) {
	jsval_t proxy = resolveprop(js, mkval(T_PROP, (jsoff_t)vdata(ref_slot)));
	proxy_data_t *data = get_proxy_data(proxy);
	if (data) data->revoked = true;
	}

	return js_mkundef();
	}

	static jsval_t builtin_Proxy_revocable(ant_t js, jsval_t args, int nargs) {
	jsval_t proxy = create_proxy_checked(js, args, nargs, false);
	if (is_err(proxy)) return proxy;

	jsval_t revoke_obj = mkobj(js, 0);
	set_slot(js, revoke_obj, SLOT_CFUNC, js_mkfun(proxy_revoke_fn));
	set_slot(js, revoke_obj, SLOT_PROXY_REF, proxy);

	jsval_t revoke_func = js_obj_to_func(revoke_obj);

	jsval_t result = mkobj(js, 0);
	js_setprop(js, result, js_mkstr(js, "proxy", 5), proxy);
	js_setprop(js, result, js_mkstr(js, "revoke", 6), revoke_func);

	return result;
	}

	ant_t js_create(void buf, size_t len) {
	assert(
	(uintptr_t)buf <= ((1ULL << 53) - 1) &&
	"ANT_PTR: pointer exceeds 53-bit double-precision integer limit"
	);

	intern_init();
	ant_t *js = NULL;

	if (len < sizeof(*js) + esize(T_OBJ)) return js;
	memset(buf, 0, len);

	js = (ant_t *) buf;
	js->mem = (uint8_t *) (js + 1);
	js->size = (jsoff_t) (len - sizeof(*js));
	js->brk = NANBOX_HEAP_OFFSET;
	js->global = mkobj(js, 0);
	js->size = js->size / 8U * 8U;
	js->this_val = js->global;
	js->new_target = js_mkundef();
	js->length_str = ANT_STRING("length");

	jsval_t glob = js->global;
	jsval_t object_proto = js_mkobj(js);
	set_proto(js, object_proto, js_mknull());

	js_setprop(js, object_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_object_toString));
	js_set_descriptor(js, object_proto, "toString", 8, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, object_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_object_valueOf));
	js_set_descriptor(js, object_proto, "valueOf", 7, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, object_proto, js_mkstr(js, "toLocaleString", 14), js_mkfun(builtin_object_toLocaleString));
	js_set_descriptor(js, object_proto, "toLocaleString", 14, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, object_proto, js_mkstr(js, "hasOwnProperty", 14), js_mkfun(builtin_object_hasOwnProperty));
	js_set_descriptor(js, object_proto, "hasOwnProperty", 14, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, object_proto, js_mkstr(js, "isPrototypeOf", 13), js_mkfun(builtin_object_isPrototypeOf));
	js_set_descriptor(js, object_proto, "isPrototypeOf", 13, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, object_proto, js_mkstr(js, "propertyIsEnumerable", 20), js_mkfun(builtin_object_propertyIsEnumerable));
	js_set_descriptor(js, object_proto, "propertyIsEnumerable", 20, JS_DESC_W \| JS_DESC_C);

	jsval_t proto_getter = js_mkfun(builtin_proto_getter);
	jsval_t proto_setter = js_mkfun(builtin_proto_setter);
	js_set_accessor_desc(js, object_proto, STR_PROTO, STR_PROTO_LEN, proto_getter, proto_setter, JS_DESC_C);

	jsval_t function_proto_obj = js_mkobj(js);
	set_proto(js, function_proto_obj, object_proto);
	set_slot(js, function_proto_obj, SLOT_CFUNC, js_mkfun(builtin_function_empty));
	js_setprop(js, function_proto_obj, ANT_STRING("call"), js_mkfun(builtin_function_call));
	js_setprop(js, function_proto_obj, ANT_STRING("apply"), js_mkfun(builtin_function_apply));
	js_setprop(js, function_proto_obj, ANT_STRING("bind"), js_mkfun(builtin_function_bind));
	js_setprop(js, function_proto_obj, ANT_STRING("toString"), js_mkfun(builtin_function_toString));
	jsval_t function_proto = js_obj_to_func(function_proto_obj);
	set_slot(js, glob, SLOT_FUNC_PROTO, function_proto);

	jsval_t array_proto = js_mkobj(js);
	set_proto(js, array_proto, object_proto);
	js_setprop(js, array_proto, js_mkstr(js, "push", 4), js_mkfun(builtin_array_push));
	js_setprop(js, array_proto, js_mkstr(js, "pop", 3), js_mkfun(builtin_array_pop));
	js_setprop(js, array_proto, js_mkstr(js, "slice", 5), js_mkfun(builtin_array_slice));
	js_setprop(js, array_proto, js_mkstr(js, "join", 4), js_mkfun(builtin_array_join));
	js_setprop(js, array_proto, js_mkstr(js, "includes", 8), js_mkfun(builtin_array_includes));
	js_setprop(js, array_proto, js_mkstr(js, "every", 5), js_mkfun(builtin_array_every));
	js_setprop(js, array_proto, js_mkstr(js, "reverse", 7), js_mkfun(builtin_array_reverse));
	js_setprop(js, array_proto, js_mkstr(js, "map", 3), js_mkfun(builtin_array_map));
	js_setprop(js, array_proto, js_mkstr(js, "filter", 6), js_mkfun(builtin_array_filter));
	js_setprop(js, array_proto, js_mkstr(js, "reduce", 6), js_mkfun(builtin_array_reduce));
	js_setprop(js, array_proto, js_mkstr(js, "flat", 4), js_mkfun(builtin_array_flat));
	js_setprop(js, array_proto, js_mkstr(js, "concat", 6), js_mkfun(builtin_array_concat));
	js_setprop(js, array_proto, js_mkstr(js, "at", 2), js_mkfun(builtin_array_at));
	js_setprop(js, array_proto, js_mkstr(js, "fill", 4), js_mkfun(builtin_array_fill));
	js_setprop(js, array_proto, js_mkstr(js, "find", 4), js_mkfun(builtin_array_find));
	js_setprop(js, array_proto, js_mkstr(js, "findIndex", 9), js_mkfun(builtin_array_findIndex));
	js_setprop(js, array_proto, js_mkstr(js, "findLast", 8), js_mkfun(builtin_array_findLast));
	js_setprop(js, array_proto, js_mkstr(js, "findLastIndex", 13), js_mkfun(builtin_array_findLastIndex));
	js_setprop(js, array_proto, js_mkstr(js, "flatMap", 7), js_mkfun(builtin_array_flatMap));
	js_setprop(js, array_proto, js_mkstr(js, "forEach", 7), js_mkfun(builtin_array_forEach));
	js_setprop(js, array_proto, js_mkstr(js, "indexOf", 7), js_mkfun(builtin_array_indexOf));
	js_setprop(js, array_proto, js_mkstr(js, "lastIndexOf", 11), js_mkfun(builtin_array_lastIndexOf));
	js_setprop(js, array_proto, js_mkstr(js, "reduceRight", 11), js_mkfun(builtin_array_reduceRight));
	js_setprop(js, array_proto, js_mkstr(js, "shift", 5), js_mkfun(builtin_array_shift));
	js_setprop(js, array_proto, js_mkstr(js, "unshift", 7), js_mkfun(builtin_array_unshift));
	js_setprop(js, array_proto, js_mkstr(js, "some", 4), js_mkfun(builtin_array_some));
	js_setprop(js, array_proto, js_mkstr(js, "sort", 4), js_mkfun(builtin_array_sort));
	js_setprop(js, array_proto, js_mkstr(js, "splice", 6), js_mkfun(builtin_array_splice));
	js_setprop(js, array_proto, js_mkstr(js, "copyWithin", 10), js_mkfun(builtin_array_copyWithin));
	js_setprop(js, array_proto, js_mkstr(js, "toReversed", 10), js_mkfun(builtin_array_toReversed));
	js_setprop(js, array_proto, js_mkstr(js, "toSorted", 8), js_mkfun(builtin_array_toSorted));
	js_setprop(js, array_proto, js_mkstr(js, "toSpliced", 9), js_mkfun(builtin_array_toSpliced));
	js_setprop(js, array_proto, js_mkstr(js, "with", 4), js_mkfun(builtin_array_with));
	js_setprop(js, array_proto, js_mkstr(js, "keys", 4), js_mkfun(builtin_array_keys));
	js_setprop(js, array_proto, js_mkstr(js, "values", 6), js_mkfun(builtin_array_values));
	js_setprop(js, array_proto, js_mkstr(js, "entries", 7), js_mkfun(builtin_array_entries));
	js_setprop(js, array_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_array_toString));
	js_setprop(js, array_proto, js_mkstr(js, "toLocaleString", 14), js_mkfun(builtin_array_toLocaleString));

	jsval_t string_proto = js_mkobj(js);
	set_proto(js, string_proto, object_proto);
	js_setprop(js, string_proto, js_mkstr(js, "indexOf", 7), js_mkfun(builtin_string_indexOf));
	js_setprop(js, string_proto, js_mkstr(js, "substring", 9), js_mkfun(builtin_string_substring));
	js_setprop(js, string_proto, js_mkstr(js, "substr", 6), js_mkfun(builtin_string_substr));
	js_setprop(js, string_proto, js_mkstr(js, "split", 5), js_mkfun(builtin_string_split));
	js_setprop(js, string_proto, js_mkstr(js, "slice", 5), js_mkfun(builtin_string_slice));
	js_setprop(js, string_proto, js_mkstr(js, "includes", 8), js_mkfun(builtin_string_includes));
	js_setprop(js, string_proto, js_mkstr(js, "startsWith", 10), js_mkfun(builtin_string_startsWith));
	js_setprop(js, string_proto, js_mkstr(js, "endsWith", 8), js_mkfun(builtin_string_endsWith));
	js_setprop(js, string_proto, js_mkstr(js, "replace", 7), js_mkfun(builtin_string_replace));
	js_setprop(js, string_proto, js_mkstr(js, "replaceAll", 10), js_mkfun(builtin_string_replaceAll));
	js_setprop(js, string_proto, js_mkstr(js, "template", 8), js_mkfun(builtin_string_template));
	js_setprop(js, string_proto, js_mkstr(js, "charCodeAt", 10), js_mkfun(builtin_string_charCodeAt));
	js_setprop(js, string_proto, js_mkstr(js, "codePointAt", 11), js_mkfun(builtin_string_codePointAt));
	js_setprop(js, string_proto, js_mkstr(js, "toLowerCase", 11), js_mkfun(builtin_string_toLowerCase));
	js_setprop(js, string_proto, js_mkstr(js, "toUpperCase", 11), js_mkfun(builtin_string_toUpperCase));
	js_setprop(js, string_proto, js_mkstr(js, "toLocaleLowerCase", 17), js_mkfun(builtin_string_toLowerCase));
	js_setprop(js, string_proto, js_mkstr(js, "toLocaleUpperCase", 17), js_mkfun(builtin_string_toUpperCase));
	js_setprop(js, string_proto, js_mkstr(js, "trim", 4), js_mkfun(builtin_string_trim));
	js_setprop(js, string_proto, js_mkstr(js, "trimStart", 9), js_mkfun(builtin_string_trimStart));
	js_setprop(js, string_proto, js_mkstr(js, "trimEnd", 7), js_mkfun(builtin_string_trimEnd));
	js_setprop(js, string_proto, js_mkstr(js, "repeat", 6), js_mkfun(builtin_string_repeat));
	js_setprop(js, string_proto, js_mkstr(js, "padStart", 8), js_mkfun(builtin_string_padStart));
	js_setprop(js, string_proto, js_mkstr(js, "padEnd", 6), js_mkfun(builtin_string_padEnd));
	js_setprop(js, string_proto, js_mkstr(js, "charAt", 6), js_mkfun(builtin_string_charAt));
	js_setprop(js, string_proto, js_mkstr(js, "at", 2), js_mkfun(builtin_string_at));
	js_setprop(js, string_proto, js_mkstr(js, "lastIndexOf", 11), js_mkfun(builtin_string_lastIndexOf));
	js_setprop(js, string_proto, js_mkstr(js, "concat", 6), js_mkfun(builtin_string_concat));
	js_setprop(js, string_proto, js_mkstr(js, "localeCompare", 13), js_mkfun(builtin_string_localeCompare));
	js_setprop(js, string_proto, js_mkstr(js, "normalize", 9), js_mkfun(builtin_string_normalize));
	js_setprop(js, string_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_string_valueOf));
	js_setprop(js, string_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_string_toString));

	jsval_t number_proto = js_mkobj(js);
	set_proto(js, number_proto, object_proto);
	js_setprop(js, number_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_number_toString));
	js_setprop(js, number_proto, js_mkstr(js, "toFixed", 7), js_mkfun(builtin_number_toFixed));
	js_setprop(js, number_proto, js_mkstr(js, "toPrecision", 11), js_mkfun(builtin_number_toPrecision));
	js_setprop(js, number_proto, js_mkstr(js, "toExponential", 13), js_mkfun(builtin_number_toExponential));
	js_setprop(js, number_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_number_valueOf));
	js_setprop(js, number_proto, js_mkstr(js, "toLocaleString", 14), js_mkfun(builtin_number_toLocaleString));

	jsval_t boolean_proto = js_mkobj(js);
	set_proto(js, boolean_proto, object_proto);
	js_setprop(js, boolean_proto, js_mkstr(js, "valueOf", 7), js_mkfun(builtin_boolean_valueOf));
	js_setprop(js, boolean_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_boolean_toString));

	jsval_t bigint_proto = js_mkobj(js);
	set_proto(js, bigint_proto, object_proto);
	js_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);
	js_setprop(js, error_proto, ANT_STRING("name"), ANT_STRING("Error"));
	js_setprop(js, error_proto, ANT_STRING("message"), js_mkstr(js, "", 0));
	js_setprop(js, error_proto, js_mkstr(js, "toString", 8), js_mkfun(builtin_Error_toString));

	jsval_t err_ctor_obj = mkobj(js, 0);
	set_proto(js, err_ctor_obj, function_proto);
	set_slot(js, err_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Error));
	js_setprop_nonconfigurable(js, err_ctor_obj, "prototype", 9, error_proto);
	js_setprop(js, err_ctor_obj, ANT_STRING("name"), ANT_STRING("Error"));
	jsval_t err_ctor_func = js_obj_to_func(err_ctor_obj);
	js_setprop(js, glob, ANT_STRING("Error"), err_ctor_func);
	js_setprop(js, error_proto, js_mkstr(js, "constructor", 11), err_ctor_func);
	js_set_descriptor(js, error_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	#define REGISTER_ERROR_SUBTYPE(name_str) do { \
	jsval_t proto = js_mkobj(js); \
	set_proto(js, proto, error_proto); \
	js_setprop(js, proto, ANT_STRING("name"), ANT_STRING(name_str)); \
	jsval_t ctor = mkobj(js, 0); \
	set_proto(js, ctor, function_proto); \
	set_slot(js, ctor, SLOT_CFUNC, js_mkfun(builtin_Error)); \
	js_setprop_nonconfigurable(js, ctor, "prototype", 9, proto); \
	js_setprop(js, ctor, ANT_STRING("name"), ANT_STRING(name_str)); \
	jsval_t ctor_func = js_obj_to_func(ctor); \
	js_setprop(js, proto, ANT_STRING("constructor"), ctor_func); \
	js_set_descriptor(js, proto, "constructor", 11, JS_DESC_W \| JS_DESC_C); \
	js_setprop(js, glob, ANT_STRING(name_str), ctor_func); \
	} while(0)

	REGISTER_ERROR_SUBTYPE("EvalError");
	REGISTER_ERROR_SUBTYPE("RangeError");
	REGISTER_ERROR_SUBTYPE("ReferenceError");
	REGISTER_ERROR_SUBTYPE("SyntaxError");
	REGISTER_ERROR_SUBTYPE("TypeError");
	REGISTER_ERROR_SUBTYPE("URIError");
	REGISTER_ERROR_SUBTYPE("InternalError");

	#undef REGISTER_ERROR_SUBTYPE

	jsval_t proto = js_mkobj(js);
	set_proto(js, proto, error_proto);
	js_setprop(js, proto, ANT_STRING("name"), ANT_STRING("AggregateError"));
	jsval_t ctor = mkobj(js, 0);
	set_proto(js, ctor, function_proto);
	set_slot(js, ctor, SLOT_CFUNC, js_mkfun(builtin_AggregateError));
	js_setprop_nonconfigurable(js, ctor, "prototype", 9, proto);
	js_setprop(js, ctor, ANT_STRING("name"), ANT_STRING("AggregateError"));
	js_setprop(js, proto, ANT_STRING("constructor"), js_obj_to_func(ctor));
	js_set_descriptor(js, proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);
	js_setprop(js, glob, ANT_STRING("AggregateError"), js_obj_to_func(ctor));

	jsval_t promise_proto = js_mkobj(js);
	set_proto(js, promise_proto, object_proto);
	js_setprop(js, promise_proto, js_mkstr(js, "then", 4), js_mkfun(builtin_promise_then));
	js_setprop(js, promise_proto, js_mkstr(js, "catch", 5), js_mkfun(builtin_promise_catch));
	js_setprop(js, promise_proto, js_mkstr(js, "finally", 7), js_mkfun(builtin_promise_finally));
	// Symbol.toStringTag is set in init_symbol_module after symbols are initialized

	jsval_t obj_func_obj = mkobj(js, 0);
	set_proto(js, obj_func_obj, function_proto);
	set_slot(js, obj_func_obj, SLOT_BUILTIN, tov(BUILTIN_OBJECT));
	js_setprop(js, obj_func_obj, js_mkstr(js, "keys", 4), js_mkfun(builtin_object_keys));
	js_setprop(js, obj_func_obj, js_mkstr(js, "values", 6), js_mkfun(builtin_object_values));
	js_setprop(js, obj_func_obj, js_mkstr(js, "entries", 7), js_mkfun(builtin_object_entries));
	js_setprop(js, obj_func_obj, js_mkstr(js, "is", 2), js_mkfun(builtin_object_is));
	js_setprop(js, obj_func_obj, js_mkstr(js, "getPrototypeOf", 14), js_mkfun(builtin_object_getPrototypeOf));
	js_setprop(js, obj_func_obj, js_mkstr(js, "setPrototypeOf", 14), js_mkfun(builtin_object_setPrototypeOf));
	js_setprop(js, obj_func_obj, js_mkstr(js, "create", 6), js_mkfun(builtin_object_create));
	js_setprop(js, obj_func_obj, js_mkstr(js, "hasOwn", 6), js_mkfun(builtin_object_hasOwn));
	js_setprop(js, obj_func_obj, js_mkstr(js, "groupBy", 7), js_mkfun(builtin_object_groupBy));
	js_setprop(js, obj_func_obj, js_mkstr(js, "defineProperty", 14), js_mkfun(builtin_object_defineProperty));
	js_setprop(js, obj_func_obj, js_mkstr(js, "defineProperties", 16), js_mkfun(builtin_object_defineProperties));
	js_setprop(js, obj_func_obj, js_mkstr(js, "assign", 6), js_mkfun(builtin_object_assign));
	js_setprop(js, obj_func_obj, js_mkstr(js, "freeze", 6), js_mkfun(builtin_object_freeze));
	js_setprop(js, obj_func_obj, js_mkstr(js, "isFrozen", 8), js_mkfun(builtin_object_isFrozen));
	js_setprop(js, obj_func_obj, js_mkstr(js, "seal", 4), js_mkfun(builtin_object_seal));
	js_setprop(js, obj_func_obj, js_mkstr(js, "isSealed", 8), js_mkfun(builtin_object_isSealed));
	js_setprop(js, obj_func_obj, js_mkstr(js, "fromEntries", 11), js_mkfun(builtin_object_fromEntries));
	js_setprop(js, obj_func_obj, js_mkstr(js, "getOwnPropertyDescriptor", 24), js_mkfun(builtin_object_getOwnPropertyDescriptor));
	js_setprop(js, obj_func_obj, js_mkstr(js, "getOwnPropertyNames", 19), js_mkfun(builtin_object_getOwnPropertyNames));
	js_setprop(js, obj_func_obj, js_mkstr(js, "getOwnPropertySymbols", 21), js_mkfun(builtin_object_getOwnPropertySymbols));
	js_setprop(js, obj_func_obj, js_mkstr(js, "isExtensible", 12), js_mkfun(builtin_object_isExtensible));
	js_setprop(js, obj_func_obj, js_mkstr(js, "preventExtensions", 17), js_mkfun(builtin_object_preventExtensions));
	js_setprop(js, obj_func_obj, ANT_STRING("name"), ANT_STRING("Object"));
	js_setprop_nonconfigurable(js, obj_func_obj, "prototype", 9, object_proto);
	jsval_t obj_func = js_obj_to_func(obj_func_obj);
	js_setprop(js, glob, js_mkstr(js, "Object", 6), obj_func);

	jsval_t func_ctor_obj = mkobj(js, 0);
	set_proto(js, func_ctor_obj, function_proto);
	set_slot(js, func_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Function));
	js_setprop_nonconfigurable(js, func_ctor_obj, "prototype", 9, function_proto);
	js_setprop(js, func_ctor_obj, js->length_str, tov(1.0));
	js_set_descriptor(js, func_ctor_obj, "length", 6, JS_DESC_C);
	js_setprop(js, func_ctor_obj, ANT_STRING("name"), ANT_STRING("Function"));
	jsval_t func_ctor_func = js_obj_to_func(func_ctor_obj);
	js_setprop(js, glob, js_mkstr(js, "Function", 8), func_ctor_func);

	jsval_t async_func_proto_obj = js_mkobj(js);
	set_proto(js, async_func_proto_obj, function_proto);
	set_slot(js, async_func_proto_obj, SLOT_ASYNC, js_true);
	jsval_t async_func_proto = js_obj_to_func(async_func_proto_obj);
	set_slot(js, glob, SLOT_ASYNC_PROTO, async_func_proto);

	jsval_t async_func_ctor_obj = mkobj(js, 0);
	set_proto(js, async_func_ctor_obj, function_proto);
	set_slot(js, async_func_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_AsyncFunction));
	js_setprop_nonconfigurable(js, async_func_ctor_obj, "prototype", 9, async_func_proto);
	js_setprop(js, async_func_ctor_obj, js->length_str, tov(1.0));
	js_set_descriptor(js, async_func_ctor_obj, "length", 6, JS_DESC_C);
	js_setprop(js, async_func_ctor_obj, ANT_STRING("name"), ANT_STRING("AsyncFunction"));
	jsval_t async_func_ctor = js_obj_to_func(async_func_ctor_obj);

	js_setprop(js, async_func_proto_obj, js_mkstr(js, "constructor", 11), async_func_ctor);
	js_set_descriptor(js, async_func_proto_obj, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	jsval_t str_ctor_obj = mkobj(js, 0);
	set_proto(js, str_ctor_obj, function_proto);
	set_slot(js, str_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_String));
	js_setprop_nonconfigurable(js, str_ctor_obj, "prototype", 9, string_proto);
	js_setprop(js, str_ctor_obj, js_mkstr(js, "fromCharCode", 12), js_mkfun(builtin_string_fromCharCode));
	js_setprop(js, str_ctor_obj, js_mkstr(js, "fromCodePoint", 13), js_mkfun(builtin_string_fromCodePoint));
	js_setprop(js, str_ctor_obj, js_mkstr(js, "raw", 3), js_mkfun(builtin_string_raw));
	js_setprop(js, str_ctor_obj, ANT_STRING("name"), ANT_STRING("String"));
	jsval_t str_ctor_func = js_obj_to_func(str_ctor_obj);
	js_setprop(js, glob, js_mkstr(js, "String", 6), str_ctor_func);

	jsval_t number_ctor_obj = mkobj(js, 0);
	set_proto(js, number_ctor_obj, function_proto);

	set_slot(js, number_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Number));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "isNaN", 5), js_mkfun(builtin_Number_isNaN));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "isFinite", 8), js_mkfun(builtin_Number_isFinite));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "isInteger", 9), js_mkfun(builtin_Number_isInteger));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "isSafeInteger", 13), js_mkfun(builtin_Number_isSafeInteger));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "parseInt", 8), js_mkfun(builtin_parseInt));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "parseFloat", 10), js_mkfun(builtin_parseFloat));

	js_setprop(js, number_ctor_obj, js_mkstr(js, "MAX_VALUE", 9), tov(1.7976931348623157e+308));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "MIN_VALUE", 9), tov(5e-324));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "MAX_SAFE_INTEGER", 16), tov(9007199254740991.0));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "MIN_SAFE_INTEGER", 16), tov(-9007199254740991.0));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "POSITIVE_INFINITY", 17), tov(JS_INF));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "NEGATIVE_INFINITY", 17), tov(JS_NEG_INF));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "NaN", 3), tov(JS_NAN));
	js_setprop(js, number_ctor_obj, js_mkstr(js, "EPSILON", 7), tov(2.220446049250313e-16));

	js_setprop_nonconfigurable(js, number_ctor_obj, "prototype", 9, number_proto);
	js_setprop(js, number_ctor_obj, ANT_STRING("name"), ANT_STRING("Number"));
	jsval_t number_ctor_func = js_obj_to_func(number_ctor_obj);
	js_setprop(js, glob, js_mkstr(js, "Number", 6), number_ctor_func);

	jsval_t bool_ctor_obj = mkobj(js, 0);
	set_proto(js, bool_ctor_obj, function_proto);
	set_slot(js, bool_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Boolean));
	js_setprop_nonconfigurable(js, bool_ctor_obj, "prototype", 9, boolean_proto);
	js_setprop(js, bool_ctor_obj, ANT_STRING("name"), ANT_STRING("Boolean"));
	jsval_t bool_ctor_func = js_obj_to_func(bool_ctor_obj);
	js_setprop(js, glob, js_mkstr(js, "Boolean", 7), bool_ctor_func);

	jsval_t arr_ctor_obj = mkobj(js, 0);
	set_proto(js, arr_ctor_obj, function_proto);
	set_slot(js, arr_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Array));
	js_setprop_nonconfigurable(js, arr_ctor_obj, "prototype", 9, array_proto);
	js_setprop(js, arr_ctor_obj, js_mkstr(js, "isArray", 7), js_mkfun(builtin_Array_isArray));
	js_setprop(js, arr_ctor_obj, js_mkstr(js, "from", 4), js_mkfun(builtin_Array_from));
	js_setprop(js, arr_ctor_obj, js_mkstr(js, "of", 2), js_mkfun(builtin_Array_of));
	js_setprop(js, arr_ctor_obj, js->length_str, tov(1.0));
	js_set_descriptor(js, arr_ctor_obj, "length", 6, JS_DESC_C);
	js_setprop(js, arr_ctor_obj, ANT_STRING("name"), ANT_STRING("Array"));
	jsval_t arr_ctor_func = js_obj_to_func(arr_ctor_obj);
	js_setprop(js, glob, js_mkstr(js, "Array", 5), arr_ctor_func);

	jsval_t proxy_ctor_obj = mkobj(js, 0);
	set_proto(js, proxy_ctor_obj, function_proto);
	set_slot(js, proxy_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Proxy));
	js_setprop(js, proxy_ctor_obj, js_mkstr(js, "revocable", 9), js_mkfun(builtin_Proxy_revocable));
	js_setprop(js, proxy_ctor_obj, ANT_STRING("name"), ANT_STRING("Proxy"));
	js_setprop(js, glob, js_mkstr(js, "Proxy", 5), js_obj_to_func(proxy_ctor_obj));

	jsval_t p_ctor_obj = mkobj(js, 0);
	set_proto(js, p_ctor_obj, function_proto);
	set_slot(js, p_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_Promise));
	js_setprop(js, p_ctor_obj, js_mkstr(js, "resolve", 7), js_mkfun(builtin_Promise_resolve));
	js_setprop(js, p_ctor_obj, js_mkstr(js, "reject", 6), js_mkfun(builtin_Promise_reject));
	js_setprop(js, p_ctor_obj, js_mkstr(js, "try", 3), js_mkfun(builtin_Promise_try));
	js_setprop(js, p_ctor_obj, js_mkstr(js, "withResolvers", 13), js_mkfun(builtin_Promise_withResolvers));
	js_setprop(js, p_ctor_obj, js_mkstr(js, "all", 3), js_mkfun(builtin_Promise_all));
	js_setprop(js, p_ctor_obj, js_mkstr(js, "race", 4), js_mkfun(builtin_Promise_race));
	js_setprop(js, p_ctor_obj, js_mkstr(js, "any", 3), js_mkfun(builtin_Promise_any));
	js_setprop_nonconfigurable(js, p_ctor_obj, "prototype", 9, promise_proto);
	js_setprop(js, p_ctor_obj, ANT_STRING("name"), ANT_STRING("Promise"));
	js_setprop(js, glob, js_mkstr(js, "Promise", 7), js_obj_to_func(p_ctor_obj));

	jsval_t bigint_ctor_obj = mkobj(js, 0);
	set_proto(js, bigint_ctor_obj, function_proto);
	set_slot(js, bigint_ctor_obj, SLOT_CFUNC, js_mkfun(builtin_BigInt));
	js_setprop(js, bigint_ctor_obj, js_mkstr(js, "asIntN", 6), js_mkfun(builtin_BigInt_asIntN));
	js_setprop(js, bigint_ctor_obj, js_mkstr(js, "asUintN", 7), js_mkfun(builtin_BigInt_asUintN));
	js_setprop_nonconfigurable(js, bigint_ctor_obj, "prototype", 9, bigint_proto);
	js_setprop(js, bigint_ctor_obj, ANT_STRING("name"), ANT_STRING("BigInt"));
	js_setprop(js, glob, js_mkstr(js, "BigInt", 6), js_obj_to_func(bigint_ctor_obj));

	js_setprop(js, glob, js_mkstr(js, "parseInt", 8), js_mkfun(builtin_parseInt));
	js_setprop(js, glob, js_mkstr(js, "parseFloat", 10), js_mkfun(builtin_parseFloat));
	js_setprop(js, glob, js_mkstr(js, "eval", 4), js_mkfun(builtin_eval));
	js_setprop(js, glob, js_mkstr(js, "isNaN", 5), js_mkfun(builtin_global_isNaN));
	js_setprop(js, glob, js_mkstr(js, "isFinite", 8), js_mkfun(builtin_global_isFinite));
	js_setprop(js, glob, js_mkstr(js, "btoa", 4), js_mkfun(builtin_btoa));
	js_setprop(js, glob, js_mkstr(js, "atob", 4), js_mkfun(builtin_atob));
	js_setprop(js, glob, js_mkstr(js, "NaN", 3), tov(JS_NAN));
	js_set_descriptor(js, glob, "NaN", 3, 0);
	js_setprop(js, glob, js_mkstr(js, "Infinity", 8), tov(JS_INF));
	js_set_descriptor(js, glob, "Infinity", 8, 0);
	js_setprop(js, glob, js_mkstr(js, "undefined", 9), js_mkundef());
	js_set_descriptor(js, glob, "undefined", 9, 0);

	jsval_t math_obj = mkobj(js, 0);
	set_proto(js, math_obj, object_proto);
	js_setprop(js, math_obj, js_mkstr(js, "E", 1), tov(M_E));
	js_setprop(js, math_obj, js_mkstr(js, "LN10", 4), tov(M_LN10));
	js_setprop(js, math_obj, js_mkstr(js, "LN2", 3), tov(M_LN2));
	js_setprop(js, math_obj, js_mkstr(js, "LOG10E", 6), tov(M_LOG10E));
	js_setprop(js, math_obj, js_mkstr(js, "LOG2E", 5), tov(M_LOG2E));
	js_setprop(js, math_obj, js_mkstr(js, "PI", 2), tov(M_PI));
	js_setprop(js, math_obj, js_mkstr(js, "SQRT1_2", 7), tov(M_SQRT1_2));
	js_setprop(js, math_obj, js_mkstr(js, "SQRT2", 5), tov(M_SQRT2));
	js_setprop(js, math_obj, js_mkstr(js, "abs", 3), js_mkfun(builtin_Math_abs));
	js_setprop(js, math_obj, js_mkstr(js, "acos", 4), js_mkfun(builtin_Math_acos));
	js_setprop(js, math_obj, js_mkstr(js, "acosh", 5), js_mkfun(builtin_Math_acosh));
	js_setprop(js, math_obj, js_mkstr(js, "asin", 4), js_mkfun(builtin_Math_asin));
	js_setprop(js, math_obj, js_mkstr(js, "asinh", 5), js_mkfun(builtin_Math_asinh));
	js_setprop(js, math_obj, js_mkstr(js, "atan", 4), js_mkfun(builtin_Math_atan));
	js_setprop(js, math_obj, js_mkstr(js, "atanh", 5), js_mkfun(builtin_Math_atanh));
	js_setprop(js, math_obj, js_mkstr(js, "atan2", 5), js_mkfun(builtin_Math_atan2));
	js_setprop(js, math_obj, js_mkstr(js, "cbrt", 4), js_mkfun(builtin_Math_cbrt));
	js_setprop(js, math_obj, js_mkstr(js, "ceil", 4), js_mkfun(builtin_Math_ceil));
	js_setprop(js, math_obj, js_mkstr(js, "clz32", 5), js_mkfun(builtin_Math_clz32));
	js_setprop(js, math_obj, js_mkstr(js, "cos", 3), js_mkfun(builtin_Math_cos));
	js_setprop(js, math_obj, js_mkstr(js, "cosh", 4), js_mkfun(builtin_Math_cosh));
	js_setprop(js, math_obj, js_mkstr(js, "exp", 3), js_mkfun(builtin_Math_exp));
	js_setprop(js, math_obj, js_mkstr(js, "expm1", 5), js_mkfun(builtin_Math_expm1));
	js_setprop(js, math_obj, js_mkstr(js, "floor", 5), js_mkfun(builtin_Math_floor));
	js_setprop(js, math_obj, js_mkstr(js, "fround", 6), js_mkfun(builtin_Math_fround));
	js_setprop(js, math_obj, js_mkstr(js, "hypot", 5), js_mkfun(builtin_Math_hypot));
	js_setprop(js, math_obj, js_mkstr(js, "imul", 4), js_mkfun(builtin_Math_imul));
	js_setprop(js, math_obj, js_mkstr(js, "log", 3), js_mkfun(builtin_Math_log));
	js_setprop(js, math_obj, js_mkstr(js, "log1p", 5), js_mkfun(builtin_Math_log1p));
	js_setprop(js, math_obj, js_mkstr(js, "log10", 5), js_mkfun(builtin_Math_log10));
	js_setprop(js, math_obj, js_mkstr(js, "log2", 4), js_mkfun(builtin_Math_log2));
	js_setprop(js, math_obj, js_mkstr(js, "max", 3), js_mkfun(builtin_Math_max));
	js_setprop(js, math_obj, js_mkstr(js, "min", 3), js_mkfun(builtin_Math_min));
	js_setprop(js, math_obj, js_mkstr(js, "pow", 3), js_mkfun(builtin_Math_pow));
	js_setprop(js, math_obj, js_mkstr(js, "random", 6), js_mkfun(builtin_Math_random));
	js_setprop(js, math_obj, js_mkstr(js, "round", 5), js_mkfun(builtin_Math_round));
	js_setprop(js, math_obj, js_mkstr(js, "sign", 4), js_mkfun(builtin_Math_sign));
	js_setprop(js, math_obj, js_mkstr(js, "sin", 3), js_mkfun(builtin_Math_sin));
	js_setprop(js, math_obj, js_mkstr(js, "sinh", 4), js_mkfun(builtin_Math_sinh));
	js_setprop(js, math_obj, js_mkstr(js, "sqrt", 4), js_mkfun(builtin_Math_sqrt));
	js_setprop(js, math_obj, js_mkstr(js, "tan", 3), js_mkfun(builtin_Math_tan));
	js_setprop(js, math_obj, js_mkstr(js, "tanh", 4), js_mkfun(builtin_Math_tanh));
	js_setprop(js, math_obj, js_mkstr(js, "trunc", 5), js_mkfun(builtin_Math_trunc));
	js_setprop(js, glob, js_mkstr(js, "Math", 4), math_obj);

	jsval_t import_obj = mkobj(js, 0);
	set_proto(js, import_obj, function_proto);

	set_slot(js, import_obj, SLOT_CFUNC, js_mkfun(builtin_import));
	js_setprop(js, glob, js_mkstr(js, "import", 6), js_obj_to_func(import_obj));

	js->module_ns = js_mkundef();
	js->import_meta = js_mkundef();

	js_setprop(js, object_proto, js_mkstr(js, "constructor", 11), obj_func);
	js_set_descriptor(js, object_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, function_proto, js_mkstr(js, "constructor", 11), func_ctor_func);
	js_set_descriptor(js, function_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, array_proto, js_mkstr(js, "constructor", 11), arr_ctor_func);
	js_set_descriptor(js, array_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, string_proto, js_mkstr(js, "constructor", 11), str_ctor_func);
	js_set_descriptor(js, string_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, number_proto, js_mkstr(js, "constructor", 11), number_ctor_func);
	js_set_descriptor(js, number_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	js_setprop(js, boolean_proto, js_mkstr(js, "constructor", 11), bool_ctor_func);
	js_set_descriptor(js, boolean_proto, "constructor", 11, JS_DESC_W \| JS_DESC_C);

	set_proto(js, glob, object_proto);

	js->object = object_proto;
	js->owns_mem = false;
	js->max_size = 0;

	return js;
	}

	ant_t *js_create_dynamic() {
	void *init_buf = ant_calloc(ANT_ARENA_MIN);
	if (init_buf == NULL) return NULL;

	ant_t *js = js_create(init_buf, ANT_ARENA_MIN);
	if (js == NULL) { free(init_buf); return NULL; }

	uint8_t arena = (uint8_t )ant_arena_reserve(ANT_ARENA_MAX);
	if (arena == NULL) { free(init_buf); return NULL; }

	if (ant_arena_commit(arena, 0, js->size) != 0) {
	ant_arena_free(arena, ANT_ARENA_MAX);
	free(init_buf); return NULL;
	}

	memcpy(arena, js->mem, js->brk);
	js->mem = arena;

	js->owns_mem = true;
	js->max_size = (jsoff_t) ANT_ARENA_MAX;

	ant_t new_js = (ant_t )malloc(sizeof(ant_t));
	if (new_js == NULL) {
	ant_arena_free(arena, ANT_ARENA_MAX);
	free(init_buf);
	return NULL;
	}

	memcpy(new_js, js, sizeof(ant_t));
	free(init_buf);

	new_js->vm = sv_vm_create(new_js, SV_VM_MAIN);

	return new_js;
	}

	void js_destroy(ant_t *js) {
	if (js == NULL) return;

	if (js->vm) {
	sv_vm_destroy(js->vm);
	js->vm = NULL;
	}

	js_esm_cleanup_module_cache();
	code_arena_reset();
	cleanup_buffer_module();
	cleanup_collections_module();
	cleanup_lmdb_module();

	if (js->owns_mem) {
	ant_arena_free(js->mem, js->max_size);
	free(js);
	}

	destroy_runtime(js);
	}

	inline double js_getnum(jsval_t value) { return tod(value); }
	inline void js_setstackbase(ant_t js, void base) { js->cstk.base = base; js->cstk.main_base = base; }
	inline void js_setstacklimit(ant_t *js, size_t max) { js->cstk.limit = max; }
	inline void js_set_filename(ant_t js, const char filename) { js->filename = filename; }

	inline jsval_t js_mkundef(void) { return mkval(T_UNDEF, 0); }
	inline jsval_t js_mknull(void) { return mkval(T_NULL, 0); }
	inline jsval_t js_mknum(double value) { return tov(value); }
	inline jsval_t js_mkobj(ant_t *js) { return mkobj(js, 0); }
	inline jsval_t js_glob(ant_t *js) { return js->global; }
	inline jsval_t js_mkfun(jsval_t (fn)(ant_t , jsval_t , int)) { return mkval(T_CFUNC, (size_t) (void ) fn); }

	inline jsval_t js_getthis(ant_t *js) { return js->this_val; }
	inline void js_setthis(ant_t *js, jsval_t val) { js->this_val = val; }
	inline jsval_t js_getcurrentfunc(ant_t *js) { return js->current_func; }

	jsval_t js_heavy_mkfun(ant_t js, jsval_t (fn)(ant_t , jsval_t , int), jsval_t data) {
	jsval_t cfunc = js_mkfun(fn);
	jsval_t fn_obj = mkobj(js, 0);

	set_slot(js, fn_obj, SLOT_CFUNC, cfunc);
	set_slot(js, fn_obj, SLOT_DATA, data);

	return js_obj_to_func(fn_obj);
	}

	void js_set(ant_t 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, 0);
	}
	} else if (vtype(obj) == T_FUNC) {
	jsval_t func_obj = js_func_obj(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, 0);
	}
	}
	}

	void js_set_sym(ant_t *js, jsval_t obj, jsval_t sym, jsval_t val) {
	if (vtype(sym) != T_SYMBOL) return;
	jsoff_t sym_off = (jsoff_t)vdata(sym);

	if (vtype(obj) == T_FUNC) obj = js_func_obj(obj);
	if (vtype(obj) != T_OBJ && vtype(obj) != T_ARR) return;

	jsoff_t existing = lkp_sym(js, obj, sym_off);
	if (existing > 0) {
	if (is_const_prop(js, existing)) return;
	saveval(js, existing + sizeof(jsoff_t) * 2, val);
	} else mkprop(js, obj, sym, val, 0);
	}

	jsval_t js_get_sym(ant_t *js, jsval_t obj, jsval_t sym) {
	if (vtype(sym) != T_SYMBOL) return js_mkundef();
	jsoff_t sym_off = (jsoff_t)vdata(sym);

	jsval_t receiver = obj;
	if (vtype(obj) == T_FUNC) obj = js_func_obj(obj);
	uint8_t ot = vtype(obj);
	if (!is_object_type(obj)) {
	if (ot == T_STR \|\| ot == T_NUM \|\| ot == T_BOOL \|\| ot == T_BIGINT \|\| ot == T_SYMBOL) {
	jsval_t proto = get_prototype_for_type(js, ot);
	if (!is_object_type(proto)) return js_mkundef();
	obj = js_as_obj(proto);
	} else {
	return js_mkundef();
	}
	} else {
	obj = js_as_obj(obj);
	}

	if (is_proxy(js, obj)) return proxy_get_val(js, obj, sym);

	jsval_t cur = obj;
	for (int i = 0; i < MAX_PROTO_CHAIN_DEPTH; i++) {
	jsoff_t cur_off = (jsoff_t)vdata(cur);
	descriptor_entry_t *sd = lookup_sym_descriptor(cur_off, sym_off);
	if (sd && sd->has_getter) {
	jsval_t g = sd->getter;
	if (vtype(g) == T_FUNC \|\| vtype(g) == T_CFUNC)
	return sv_vm_call(js->vm, js, g, receiver, NULL, 0, NULL, false);
	return js_mkundef();
	}
	jsval_t proto = get_proto(js, cur);
	if (!is_object_type(proto)) break;
	cur = js_as_obj(proto);
	}

	jsoff_t off = lkp_sym_proto(js, obj, sym_off);
	if (off == 0) return js_mkundef();
	return resolveprop(js, mkval(T_PROP, off));
	}

	bool js_del(ant_t js, jsval_t obj, const char key) {
	size_t len = strlen(key);
	jsoff_t obj_off;

	if (vtype(obj) == T_OBJ) {
	obj_off = (jsoff_t)vdata(obj);
	} else if (vtype(obj) == T_ARR \|\| vtype(obj) == T_FUNC) {
	obj_off = (jsoff_t)vdata(js_as_obj(obj));
	if (vtype(obj) == T_ARR) {
	unsigned long del_idx;
	jsoff_t arr_len = get_array_length(js, obj);
	if (parse_array_index(key, len, arr_len, &del_idx)) {
	arr_del(js, obj, (jsoff_t)del_idx);
	return true;
	}
	}
	obj = mkval(T_OBJ, obj_off);
	} else {
	return false;
	}

	jsoff_t prop_off = lkp(js, obj, key, len);
	if (prop_off == 0) return true;
	if (is_nonconfig_prop(js, prop_off)) return false;

	descriptor_entry_t *desc = lookup_descriptor(js, obj_off, key, len);
	if (desc && !desc->configurable) return false;

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

	if (first_prop == prop_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~FLAGMASK;
	jsoff_t current = loadoff(js, obj_off);

	saveoff(js, obj_off, (deleted_next & ~3ULL) \| (current & (FLAGMASK \| 3ULL)));
	if (tail == prop_off) saveoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t), 0);

	invalidate_prop_cache(js, obj_off, prop_off);
	js->needs_gc = true;

	return true;
	}

	jsoff_t prev = first_prop;
	while (prev != 0 && prev < js->brk) {
	jsoff_t next = loadoff(js, prev) & ~(3U \| FLAGMASK);
	if (next == prop_off) {
	jsoff_t deleted_next = loadoff(js, prop_off) & ~(3U \| FLAGMASK);
	jsoff_t prev_flags = loadoff(js, prev) & FLAGMASK;

	saveoff(js, prev, deleted_next \| prev_flags);
	if (tail == prop_off) saveoff(js, obj_off + sizeof(jsoff_t) + sizeof(jsoff_t), prev);

	invalidate_prop_cache(js, obj_off, prop_off);
	js->needs_gc = true;

	return true;
	}
	prev = next;
	}

	return false;
	}

	static bool js_try_get(ant_t js, jsval_t obj, const char key, jsval_t *out) {
	size_t key_len = strlen(key);

	if (vtype(obj) == T_FUNC) {
	if (sv_vm_is_strict(js->vm) &&
	((key_len == 6 && memcmp(key, "caller", 6) == 0) \|\|
	(key_len == 9 && memcmp(key, "arguments", 9) == 0))) {
	*out = js_mkerr_typed(js, JS_ERR_TYPE,
	"'%.*s' not allowed on functions in strict mode",
	(int)key_len, key);
	return true;
	}

	jsval_t func_obj = js_func_obj(obj);
	if (key_len == 4 && memcmp(key, "meta", 4) == 0 && vtype(js->import_meta) != T_UNDEF) {
	jsval_t cfunc = js_get_slot(js, func_obj, SLOT_CFUNC);
	if (vtype(cfunc) == T_CFUNC && js_as_cfunc(cfunc) == builtin_import) {
	*out = js->import_meta;
	return true;
	}
	}
	jsoff_t off = lkp(js, func_obj, key, key_len);
	if (off == 0) {
	jsval_t accessor_result;
	if (try_accessor_getter(js, obj, key, key_len, &accessor_result)) {
	*out = accessor_result;
	return true;
	}
	return false;
	}

	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(func_obj), key, key_len);
	if (desc && desc->has_getter) {
	jsval_t accessor_result;
	if (try_accessor_getter(js, obj, key, key_len, &accessor_result)) {
	*out = accessor_result;
	return true;
	}
	}

	*out = resolveprop(js, mkval(T_PROP, off));
	return true;
	}

	if (vtype(obj) == T_ARR) {
	if (((key_len == 6 && memcmp(key, "callee", 6) == 0) \|\|
	(key_len == 6 && memcmp(key, "caller", 6) == 0)) &&
	vtype(get_slot(js, obj, SLOT_STRICT_ARGS)) != T_UNDEF) {
	*out = js_mkerr_typed(js, JS_ERR_TYPE,
	"'%.*s' not allowed on strict arguments",
	(int)key_len, key);
	return true;
	}

	if (key_len == 6 && memcmp(key, "length", 6) == 0) {
	*out = tov((double)get_array_length(js, obj));
	return true;
	}
	unsigned long idx;
	jsoff_t arr_len = get_array_length(js, obj);
	if (parse_array_index(key, key_len, arr_len, &idx)) {
	if (arr_has(js, obj, (jsoff_t)idx)) {
	*out = arr_get(js, obj, (jsoff_t)idx);
	return true;
	} return false;
	}

	jsval_t arr_obj = js_as_obj(obj);
	jsoff_t off = lkp(js, arr_obj, key, key_len);
	if (off == 0) {
	jsval_t accessor_result;
	if (try_accessor_getter(js, arr_obj, key, key_len, &accessor_result)) {
	*out = accessor_result; return true;
	} return false;
	}

	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(arr_obj), key, key_len);
	if (desc && desc->has_getter) {
	jsval_t accessor_result;
	if (try_accessor_getter(js, arr_obj, key, key_len, &accessor_result)) {
	*out = accessor_result; return true;
	}
	}

	*out = resolveprop(js, mkval(T_PROP, off));
	return true;
	}

	uint8_t t = vtype(obj);
	bool is_promise = (t == T_PROMISE);
	if (t == T_OBJ && is_proxy(js, obj)) {
	*out = proxy_get(js, obj, key, key_len);
	return true;
	}
	if (is_promise) obj = js_as_obj(obj);
	else if (t != T_OBJ) return false;
	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) { *out = result; return true; }
	}

	if (off == 0 && is_promise) {
	jsval_t promise_proto = get_ctor_proto(js, "Promise", 7);
	if (vtype(promise_proto) != T_UNDEF && vtype(promise_proto) != T_NULL) {
	off = lkp(js, promise_proto, key, key_len);
	if (off != 0) { *out = resolveprop(js, mkval(T_PROP, off)); return true; }
	}
	}

	if (off == 0) {
	jsval_t accessor_result;
	if (try_accessor_getter(js, obj, key, key_len, &accessor_result)) {
	*out = accessor_result; return true;
	}
	return false;
	}

	descriptor_entry_t *desc = lookup_descriptor(js, (jsoff_t)vdata(js_as_obj(obj)), key, key_len);
	if (desc && desc->has_getter) {
	jsval_t accessor_result;
	if (try_accessor_getter(js, obj, key, key_len, &accessor_result)) {
	*out = accessor_result; return true;
	}
	}

	*out = resolveprop(js, mkval(T_PROP, off));
	return true;
	}

	jsval_t js_get(ant_t js, jsval_t obj, const char key) {
	jsval_t val;
	if (js_try_get(js, obj, key, &val)) return val;
	return js_mkundef();
	}

	jsval_t js_getprop_proto(ant_t js, jsval_t obj, const char key) {
	size_t key_len = strlen(key);
	jsoff_t off = lkp_proto(js, obj, key, key_len);
	return off == 0 ? js_mkundef() : resolveprop(js, mkval(T_PROP, off));
	}

	jsval_t js_getprop_fallback(ant_t js, jsval_t obj, const char name) {
	jsval_t val;
	if (js_try_get(js, obj, name, &val)) return val;
	return js_getprop_proto(js, obj, name);
	}

	jsval_t js_getprop_super(ant_t js, jsval_t super_obj, jsval_t receiver, const char name) {
	if (!name) return js_mkundef();

	if (vtype(super_obj) == T_FUNC) super_obj = js_func_obj(super_obj);
	if (!is_object_type(super_obj)) return js_mkundef();

	size_t key_len = strlen(name);
	if (is_proxy(js, super_obj)) return proxy_get(js, super_obj, name, key_len);

	const char *key_intern = intern_string(name, key_len);
	if (!key_intern) return js_mkundef();

	jsval_t cur = js_as_obj(super_obj);
	for (int i = 0; i < MAX_PROTO_CHAIN_DEPTH; i++) {
	jsoff_t cur_off = (jsoff_t)vdata(cur);
	descriptor_entry_t *desc = lookup_descriptor(js, cur_off, name, key_len);
	if (desc) {
	if (desc->has_getter) {
	jsval_t getter = desc->getter;
	if (vtype(getter) == T_FUNC \|\| vtype(getter) == T_CFUNC)
	return sv_vm_call(js->vm, js, getter, receiver, NULL, 0, NULL, false);
	return js_mkundef();
	}
	if (desc->has_setter) return js_mkundef();
	}

	jsoff_t prop_off = lkp_interned(js, cur, key_intern, key_len);
	if (prop_off != 0) return resolveprop(js, mkval(T_PROP, prop_off));

	jsval_t proto = get_proto(js, cur);
	if (!is_object_type(proto)) break;
	cur = js_as_obj(proto);
	}

	return js_mkundef();
	}

	typedef struct {
	bool (callback)(ant_t js, jsval_t value, void *udata);
	void *udata;
	} js_iter_ctx_t;

	static iter_action_t js_iter_cb(ant_t js, jsval_t value, void ctx, jsval_t *out) {
	js_iter_ctx_t ictx = (js_iter_ctx_t )ctx;
	return ictx->callback(js, value, ictx->udata) ? ITER_CONTINUE : ITER_BREAK;
	}

	bool js_iter(ant_t js, jsval_t iterable, bool (callback)(ant_t js, jsval_t value, void udata), void *udata) {
	js_iter_ctx_t ctx = { .callback = callback, .udata = udata };
	jsval_t result = iter_foreach(js, iterable, js_iter_cb, &ctx);
	return !is_err(result);
	}

	char js_getstr(ant_t 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(ant_t *js, jsval_t dst, jsval_t src) {
	if (vtype(dst) != T_OBJ \|\| vtype(src) != T_OBJ) return;
	jsoff_t next = loadoff(js, (jsoff_t) vdata(src)) & ~(3U \| FLAGMASK);
	while (next < js->brk && next != 0) {
	jsoff_t header = loadoff(js, next);
	if (is_slot_prop(header)) { next = next_prop(header); continue; }

	jsoff_t koff = loadoff(js, next + (jsoff_t) sizeof(next));
	jsval_t val = loadval(js, next + (jsoff_t) (sizeof(next) + sizeof(koff)));

	js_setprop(js, dst, mkval(T_STR, koff), val);
	next = next_prop(header);
	}
	}

	#define UTARRAY_EACH(arr, type, var) \
	if (arr) for (type var = (type )utarray_front(arr), *_end = var + utarray_len(arr); var < _end; var++)

	#define REHASH_REGISTRY(registry, entry, tmp, new_reg, key_field, key_size, body) \
	for (typeof(registry) new_reg = NULL, _once = NULL; !_once; _once = (void)1, registry = new_reg) \
	HASH_ITER(hh, registry, entry, tmp) { \
	HASH_DEL(registry, entry); \
	body; \
	HASH_ADD(hh, new_reg, key_field, key_size, entry); \
	}

	typedef jsoff_t (gc_fwd_off_fn)(void ctx, jsoff_t old);
	typedef jsval_t (gc_fwd_val_fn)(void ctx, jsval_t old);
	typedef void (gc_off_op_t)(void cb_ctx, jsoff_t *off);
	typedef void (gc_val_op_t)(void cb_ctx, jsval_t *val);

	typedef struct {
	gc_fwd_off_fn fwd_off;
	gc_fwd_val_fn fwd_val;
	gc_fwd_off_fn weak_off;
	void *ctx;
	ant_t *js;
	} gc_cb_ctx_t;

	static inline void gc_reserve_off_cb(void cb_ctx, jsoff_t off) {
	gc_cb_ctx_t *c = cb_ctx;
	if (off) (void)c->fwd_off(c->ctx, off);
	}

	static inline void gc_reserve_val_cb(void cb_ctx, jsval_t val) {
	gc_cb_ctx_t *c = cb_ctx;
	(void)c->fwd_val(c->ctx, *val);
	}

	static inline void gc_update_off_cb(void cb_ctx, jsoff_t off) {
	gc_cb_ctx_t *c = cb_ctx;
	if (off) off = c->fwd_off(c->ctx, *off);
	}

	static inline void gc_update_val_cb(void cb_ctx, jsval_t val) {
	gc_cb_ctx_t *c = cb_ctx;
	val = c->fwd_val(c->ctx, val);
	}

	static inline jsoff_t gc_weak_off_cb(void *cb_ctx, jsoff_t old) {
	gc_cb_ctx_t *c = cb_ctx;
	return c->weak_off(c->ctx, old);
	}

	void js_gc_visit_frame_funcs(ant_t js, void (visitor)(void , sv_func_t ), void *ctx) {
	sv_vm_visit_frame_funcs(js->vm, visitor, ctx);
	for (coroutine_t *coro = pending_coroutines.head; coro; coro = coro->next) {
	if (coro->sv_vm) sv_vm_visit_frame_funcs(coro->sv_vm, visitor, ctx);
	}
	}

	static void gc_roots_common(gc_off_op_t op_off, gc_val_op_t op_val, gc_cb_ctx_t *c) {
	if (rt && rt->js == c->js)
	op_val(c, &rt->ant_obj);

	for (coroutine_t *coro = pending_coroutines.head; coro; coro = coro->next) {
	op_val(c, &coro->this_val);
	op_val(c, &coro->super_val);
	op_val(c, &coro->new_target);
	op_val(c, &coro->awaited_promise);
	op_val(c, &coro->result);
	op_val(c, &coro->async_func);
	op_val(c, &coro->yield_value);
	op_val(c, &coro->async_promise);
	}

	js_esm_gc_roots(op_val, c);
	op_val(c, &c->js->import_meta);
	timer_gc_update_roots(op_val, c);
	ffi_gc_update_roots(op_val, c);
	fetch_gc_update_roots(op_val, c);
	fs_gc_update_roots(op_val, c);
	child_process_gc_update_roots(op_val, c);
	readline_gc_update_roots(op_val, c);
	process_gc_update_roots(op_val, c);
	navigator_gc_update_roots(op_val, c);
	server_gc_update_roots(op_val, c);
	events_gc_update_roots(op_val, c);
	lmdb_gc_update_roots(op_val, c);
	symbol_gc_update_roots(op_val, c);

	op_val(c, &c->js->global);
	op_val(c, &c->js->object);
	op_val(c, &c->js->this_val);
	op_val(c, &c->js->new_target);
	op_val(c, &c->js->module_ns);
	op_val(c, &c->js->current_func);
	op_val(c, &c->js->thrown_value);
	op_val(c, &c->js->length_str);

	sv_vm_gc_roots(c->js->vm, op_val, c);
	sv_vm_gc_roots_pending(op_val, c);

	for (jshdl_t i = 0; i < c->js->gc_roots_len; i++) op_val(c, &c->js->gc_roots[i]);
	}

	void js_gc_reserve_roots(GC_RESERVE_ARGS) {
	#define RSV_OFF(x) ((x) ? (void)fwd_off(ctx, x) : (void)0)
	#define RSV_VAL(x) (void)fwd_val(ctx, x)

	gc_cb_ctx_t cb_ctx = { fwd_off, fwd_val, NULL, ctx, js };
	gc_roots_common(gc_reserve_off_cb, gc_reserve_val_cb, &cb_ctx);
	collections_gc_reserve_roots(gc_reserve_val_cb, &cb_ctx);

	promise_data_entry_t pd, pd_tmp;
	HASH_ITER(hh, promise_registry, pd, pd_tmp) {
	bool can_collect = (pd->state != 0)
	&& (utarray_len(pd->handlers) == 0)
	&& !pd->processing;

	if (can_collect) continue;
	RSV_OFF(pd->obj_offset);
	RSV_VAL(pd->value);

	UTARRAY_EACH(pd->handlers, promise_handler_t, h) {
	RSV_VAL(h->onFulfilled);
	RSV_VAL(h->onRejected);
	RSV_VAL(h->nextPromise);
	}
	}

	proxy_data_t proxy, proxy_tmp;
	HASH_ITER(hh, proxy_registry, proxy, proxy_tmp) {
	RSV_VAL(proxy->target);
	RSV_VAL(proxy->handler);
	}

	descriptor_entry_t desc, desc_tmp;
	HASH_ITER(hh, desc_registry, desc, desc_tmp) {
	if (desc->has_getter) RSV_VAL(desc->getter);
	if (desc->has_setter) RSV_VAL(desc->setter);
	}

	// accessor registry is a weak reference
	// objects only survive if reachable from other roots
	(void)accessor_registry;

	#undef RSV_OFF
	#undef RSV_VAL
	}

	void js_gc_update_roots(GC_UPDATE_ARGS) {
	#define FWD_OFF(x) ((x) ? ((x) = fwd_off(ctx, x)) : 0)
	#define FWD_VAL(x) ((x) = fwd_val(ctx, x))
	#define IS_UNREACHABLE(old, new) ((new) == (old) && (old) != 0 && (old) < js->brk)

	gc_cb_ctx_t cb_ctx = { fwd_off, fwd_val, weak_off, ctx, js };
	gc_roots_common(gc_update_off_cb, gc_update_val_cb, &cb_ctx);

	promise_data_entry_t pd, pd_tmp;
	promise_data_entry_t *new_unhandled = NULL;

	for (
	promise_data_entry_t new_promise_registry = NULL, _once = NULL; !_once; _once = (void*)1,
	promise_registry = new_promise_registry, unhandled_rejections = new_unhandled
	)
	HASH_ITER(hh, promise_registry, pd, pd_tmp) {
	HASH_DEL(promise_registry, pd);
	promise_data_entry_t *in_unhandled = NULL;

	HASH_FIND(
	hh_unhandled, unhandled_rejections,
	&pd->promise_id, sizeof(uint32_t), in_unhandled
	);

	if (in_unhandled) HASH_DELETE(hh_unhandled, unhandled_rejections, pd);
	jsoff_t new_off = weak_off(ctx, pd->obj_offset);

	if (new_off == (jsoff_t)~0 && !pd->processing) {
	utarray_free(pd->handlers);
	free(pd); continue;
	}

	bool can_collect = (pd->state != 0)
	&& (utarray_len(pd->handlers) == 0)
	&& !pd->processing;

	if (can_collect) {
	utarray_free(pd->handlers);
	free(pd); continue;
	}

	pd->obj_offset = new_off;
	FWD_VAL(pd->value);

	UTARRAY_EACH(pd->handlers, promise_handler_t, h) {
	FWD_VAL(h->onFulfilled);
	FWD_VAL(h->onRejected);
	FWD_VAL(h->nextPromise);
	}

	HASH_ADD(hh, new_promise_registry, promise_id, sizeof(uint32_t), pd);
	if (in_unhandled) HASH_ADD(hh_unhandled, new_unhandled, promise_id, sizeof(uint32_t), pd);
	}


	proxy_data_t proxy, proxy_tmp;
	for (proxy_data_t new_proxy_registry = NULL, _once = NULL; !_once; _once = (void*)1, proxy_registry = new_proxy_registry)
	HASH_ITER(hh, proxy_registry, proxy, proxy_tmp) {
	HASH_DEL(proxy_registry, proxy);
	jsoff_t new_off = weak_off(ctx, proxy->obj_offset);
	if (new_off == (jsoff_t)~0) { free(proxy); continue; }
	proxy->obj_offset = new_off;
	FWD_VAL(proxy->target); FWD_VAL(proxy->handler);
	HASH_ADD(hh, new_proxy_registry, obj_offset, sizeof(jsoff_t), proxy);
	}

	dynamic_accessors_t acc, acc_tmp;
	for (dynamic_accessors_t new_acc_registry = NULL, _once = NULL; !_once; _once = (void*)1, accessor_registry = new_acc_registry)
	HASH_ITER(hh, accessor_registry, acc, acc_tmp) {
	HASH_DEL(accessor_registry, acc);
	jsoff_t new_off = weak_off(ctx, acc->obj_offset);
	if (new_off == (jsoff_t)~0) { free(acc); continue; }
	acc->obj_offset = new_off;
	HASH_ADD(hh, new_acc_registry, obj_offset, sizeof(jsoff_t), acc);
	}

	descriptor_entry_t desc, desc_tmp;
	for (descriptor_entry_t new_desc_registry = NULL, _once = NULL; !_once; _once = (void*)1, desc_registry = new_desc_registry)
	HASH_ITER(hh, desc_registry, desc, desc_tmp) {
	HASH_DEL(desc_registry, desc);
	jsoff_t new_off = weak_off(ctx, (jsoff_t)(desc->key >> 32));
	if (new_off == (jsoff_t)~0) { free(desc); continue; }
	if (desc->has_getter) FWD_VAL(desc->getter);
	if (desc->has_setter) FWD_VAL(desc->setter);
	if (desc->prop_name) {
	desc->key = ((uint64_t)new_off << 32) \| (uint32_t)(desc->key & 0xFFFFFFFF);
	} else {
	jsoff_t new_sym = fwd_off(ctx, desc->sym_off);
	desc->sym_off = new_sym;
	desc->key = make_sym_desc_key(new_off, new_sym);
	}
	desc->obj_off = new_off;
	HASH_ADD(hh, new_desc_registry, key, sizeof(uint64_t), desc);
	}

	intern_prop_cache_gen++;
	collections_gc_update_roots(gc_weak_off_cb, gc_update_val_cb, &cb_ctx);
	regex_gc_update_roots(gc_weak_off_cb, gc_update_val_cb, &cb_ctx);

	#undef FWD_OFF
	#undef FWD_VAL
	}

	#undef UTARRAY_EACH
	#undef REHASH_REGISTRY

	bool js_chkargs(jsval_t args, int nargs, const char spec) {
	int i = 0, ok = 1;
	for (; ok && i < nargs && spec[i]; i++) {
	uint8_t t = vtype(args[i]), c = (uint8_t) spec[i];
	ok = (c == 'b' && t == T_BOOL) \|\| (c == 'd' && t == T_NUM) \|\|
	(c == 's' && t == T_STR) \|\| (c == 'j');
	}
	if (spec[i] != '\0' \|\| i != nargs) ok = 0;
	return ok;
	}

	static jsval_t js_eval_bytecode_mode(ant_t js, const char buf, size_t len, sv_compile_mode_t mode, bool parse_strict) {
	if (len == (size_t)~0U) len = strlen(buf);
	sv_ast_t *program = sv_parse(js, buf, (jsoff_t)len, parse_strict);

	if (!program) {
	if (js->thrown_exists) return mkval(T_ERR, 0);
	return js_mkerr_typed(js, JS_ERR_INTERNAL \| JS_ERR_NO_STACK, "Unexpected parse error");
	}

	sv_func_t *func = sv_compile(js, program, mode, buf, (jsoff_t)len);
	if (!func) {
	if (js->thrown_exists) return mkval(T_ERR, 0);
	return js_mkerr_typed(js, JS_ERR_INTERNAL \| JS_ERR_NO_STACK, "Unexpected compile error");
	}

	js_clear_error_site(js);
	jsval_t result;

	if (sv_dump_bytecode_unlikely) sv_disasm(js, func, js->filename);
	if (func->is_tla) result = sv_execute_entry_tla(js, func, js->this_val);
	else result = sv_execute_entry(js->vm, func, js->this_val, NULL, 0);

	return result;
	}

	jsval_t js_eval_bytecode(ant_t js, const char buf, size_t len) {
	return js_eval_bytecode_mode(js, buf, len, SV_COMPILE_SCRIPT, false);
	}

	jsval_t js_eval_bytecode_module(ant_t js, const char buf, size_t len) {
	return js_eval_bytecode_mode(js, buf, len, SV_COMPILE_MODULE, false);
	}

	jsval_t js_eval_bytecode_eval(ant_t js, const char buf, size_t len) {
	return js_eval_bytecode_mode(js, buf, len, SV_COMPILE_EVAL, false);
	}

	jsval_t js_eval_bytecode_eval_with_strict(ant_t js, const char buf, size_t len, bool inherit_strict) {
	return js_eval_bytecode_mode(js, buf, len, SV_COMPILE_EVAL, inherit_strict);
	}

	jsval_t js_eval_bytecode_repl(ant_t js, const char buf, size_t len) {
	return js_eval_bytecode_mode(js, buf, len, SV_COMPILE_REPL, false);
	}

	jsval_t sv_call_native(
	ant_t *js, jsval_t func, jsval_t this_val,
	jsval_t *args, int nargs
	) {
	if (vtype(func) == T_FFI)
	return ffi_call_by_index(js, (unsigned int)vdata(func), args, nargs);

	if (vtype(func) == T_CFUNC) {
	jsval_t saved_this = js->this_val;
	js->this_val = this_val;
	jsval_t (fn)(ant_t , jsval_t , int) = (jsval_t()(ant_t , jsval_t , int))vdata(func);
	jsval_t res = fn(js, args, nargs);
	js->this_val = saved_this;
	return res;
	}

	if (vtype(func) == T_FUNC) {
	jsval_t func_obj = js_func_obj(func);

	jsval_t cfunc_slot = get_slot(js, func_obj, SLOT_CFUNC);
	if (vtype(cfunc_slot) == T_CFUNC) {
	jsval_t slot_bound_this = get_slot(js, func_obj, SLOT_BOUND_THIS);
	int final_nargs;
	jsval_t *combined = resolve_bound_args(js, func_obj, args, nargs, &final_nargs);
	jsval_t *final_args = combined ? combined : args;
	jsval_t saved_func = js->current_func;
	jsval_t saved_this = js->this_val;
	js->current_func = func;
	js->this_val = (vtype(slot_bound_this) != T_UNDEF) ? slot_bound_this : this_val;
	jsval_t (fn)(ant_t , jsval_t , int) = (jsval_t()(ant_t , jsval_t , int))vdata(cfunc_slot);
	jsval_t res = fn(js, final_args, final_nargs);
	js->current_func = saved_func;
	js->this_val = saved_this;
	if (combined) free(combined);
	return res;
	}

	jsval_t builtin_slot = get_slot(js, func_obj, SLOT_BUILTIN);
	if (vtype(builtin_slot) == T_NUM && (int)tod(builtin_slot) == BUILTIN_OBJECT) {
	jsval_t saved_this = js->this_val;
	js->this_val = this_val;
	jsval_t res = builtin_Object(js, args, nargs);
	js->this_val = saved_this;
	return res;
	}
	}

	return js_mkerr_typed(js, JS_ERR_TYPE, "%s is not a function", typestr(vtype(func)));
	}

	ant_iter_t js_prop_iter_begin(ant_t *js, jsval_t obj) {
	ant_iter_t iter = {.ctx = js, .off = 0};

	uint8_t t = vtype(obj);
	if (t == T_OBJ \|\| t == T_ARR \|\| t == T_FUNC) {
	iter.off = (jsoff_t)vdata(js_as_obj(obj));
	}

	return iter;
	}

	bool js_prop_iter_next(ant_iter_t iter, const char key, size_t key_len, jsval_t *value) {
	if (!iter \|\| !iter->ctx) return false;

	ant_t js = (ant_t )iter->ctx;
	jsoff_t next = loadoff(js, iter->off) & ~(3U \| FLAGMASK);

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

	if (next >= js->brk \|\| next == 0) return false;
	iter->off = next;

	jsoff_t koff = loadoff(js, next + (jsoff_t)sizeof(jsoff_t));
	jsval_t val = loadval(js, next + (jsoff_t)(sizeof(jsoff_t) * 2));

	if (key) {
	jsoff_t klen = offtolen(loadoff(js, koff));
	key = (const char )&js->mem[koff + sizeof(jsoff_t)];
	if (key_len) *key_len = klen;
	}
	if (value) *value = val;

	return true;
	}

	void js_prop_iter_end(ant_iter_t *iter) {
	if (iter) { iter->off = 0; iter->ctx = NULL; }
	}

	jsval_t js_mkpromise(ant_t *js) { return mkpromise(js); }
	void js_resolve_promise(ant_t *js, jsval_t promise, jsval_t value) { resolve_promise(js, promise, value); }
	void js_reject_promise(ant_t *js, jsval_t promise, jsval_t value) { reject_promise(js, promise, value); }

	void js_check_unhandled_rejections(ant_t *js) {
	promise_data_entry_t pd, tmp;

	HASH_ITER(hh_unhandled, unhandled_rejections, pd, tmp) {
	if (pd->has_rejection_handler) {
	HASH_DELETE(hh_unhandled, unhandled_rejections, pd); continue;
	}

	if (pd->trigger_pid != 0) {
	promise_data_entry_t *parent;
	HASH_FIND(hh, promise_registry, &pd->trigger_pid, sizeof(uint32_t), parent);
	if (parent && parent->has_rejection_handler) {
	HASH_DELETE(hh_unhandled, unhandled_rejections, pd); continue;
	}
	}

	if (js->fatal_error) {
	js->thrown_exists = true;
	js->thrown_value = pd->value;
	print_uncaught_throw(js);
	js_destroy(js); exit(1);
	}

	print_unhandled_promise_rejection(js, pd->value);
	pd->has_rejection_handler = true;
	HASH_DELETE(hh_unhandled, unhandled_rejections, pd);
	}
	}

	bool js_is_slot_prop(jsoff_t header) { return is_slot_prop(header); }
	jsoff_t js_next_prop(jsoff_t header) { return next_prop(header); }
	jsoff_t js_loadoff(ant_t *js, jsoff_t off) { return loadoff(js, off); }

	void js_set_getter(ant_t *js, jsval_t obj, js_getter_fn getter) {
	if (!is_object_type(obj)) return;
	if (vtype(obj) != T_OBJ) obj = js_as_obj(obj);
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry) {
	entry = (dynamic_accessors_t *)malloc(sizeof(dynamic_accessors_t));
	if (!entry) return;
	entry->obj_offset = obj_off;
	entry->getter = NULL; entry->setter = NULL;
	entry->deleter = NULL; entry->keys = NULL;
	HASH_ADD(hh, accessor_registry, obj_offset, sizeof(jsoff_t), entry);
	}
	entry->getter = getter;
	}

	void js_set_setter(ant_t *js, jsval_t obj, js_setter_fn setter) {
	if (!is_object_type(obj)) return;
	if (vtype(obj) != T_OBJ) obj = js_as_obj(obj);
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry) {
	entry = (dynamic_accessors_t *)malloc(sizeof(dynamic_accessors_t));
	if (!entry) return;
	entry->obj_offset = obj_off;
	entry->getter = NULL; entry->setter = NULL;
	entry->deleter = NULL; entry->keys = NULL;
	HASH_ADD(hh, accessor_registry, obj_offset, sizeof(jsoff_t), entry);
	}
	entry->setter = setter;
	}

	void js_set_deleter(ant_t *js, jsval_t obj, js_deleter_fn deleter) {
	if (!is_object_type(obj)) return;
	if (vtype(obj) != T_OBJ) obj = js_as_obj(obj);
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry) {
	entry = (dynamic_accessors_t *)malloc(sizeof(dynamic_accessors_t));
	if (!entry) return;
	entry->obj_offset = obj_off;
	entry->getter = NULL; entry->setter = NULL;
	entry->deleter = NULL; entry->keys = NULL;
	HASH_ADD(hh, accessor_registry, obj_offset, sizeof(jsoff_t), entry);
	}
	entry->deleter = deleter;
	}

	void js_set_keys(ant_t *js, jsval_t obj, js_keys_fn keys) {
	if (!is_object_type(obj)) return;
	if (vtype(obj) != T_OBJ) obj = js_as_obj(obj);
	jsoff_t obj_off = (jsoff_t)vdata(obj);
	dynamic_accessors_t *entry = NULL;
	HASH_FIND(hh, accessor_registry, &obj_off, sizeof(jsoff_t), entry);
	if (!entry) {
	entry = (dynamic_accessors_t *)malloc(sizeof(dynamic_accessors_t));
	if (!entry) return;
	entry->obj_offset = obj_off;
	entry->getter = NULL; entry->setter = NULL;
	entry->deleter = NULL; entry->keys = NULL;
	HASH_ADD(hh, accessor_registry, obj_offset, sizeof(jsoff_t), entry);
	}
	entry->keys = keys;
	}

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