// stringstest — exercises lib/strings. Run with
// `out/bin/ww run lib/strings/stringstest.ww`.
// A failing row aborts via the assert/abort builtin (task #5 @test
// conversion). Per-row exit-code pinpoint is intentionally dropped: an
// abort reports the file, not the row (drew-t2-conversion-spec sec.5;
// Hare-equivalent, which reports file:line not loop index).
//
// Vectors mirror ref/hare/strings/{dup,concat,trim,contains,index,
// suffix,compare}.ha where ww can express them.

// `_test` suffix: Go external-test-package idiom (sanctioned Go-over-Hare
// departure for lib/ tests) — self-import is hard-rejected, so the test
// lives in package strings_test and pulls the real package via import.
// See CLAUDE.md rule-5/9 carve-out; task #16.
package strings_test;

import strings;
import encoding.utf8;
import os;


fn streq(a: str, b: str) bool = {
	if (a.len != b.len) { return false; };
	let i: i32 = 0;
	for (i < a.len) {
		if (a[i] != b[i]) { return false; };
		i += 1;
	};
	return true;
};

// ---- dup --------------------------------------------------------------
// ref/hare/strings/dup.ha:45.

@test fn dup_cases() void = {
	let e: str = strings.dup("");
	assert(!(!streq(e, "")));
	assert(!(e.len != 0));

	let h: str = strings.dup("hello");
	assert(!(!streq(h, "hello")));
	defer os.free(h.ptr: *void, h.len: u64);

	// multi-byte UTF-8: dup must copy raw bytes, not aliased view.
	let m: str = strings.dup("こんにちは");
	assert(!(m.len != 15));
	assert(!(!streq(m, "こんにちは")));
	assert(!(m.ptr == "こんにちは".ptr));	// fresh alloc
	defer os.free(m.ptr: *void, m.len: u64);
};

// ---- dupall -----------------------------------------------------------
// ref/hare/strings/dup.ha:55 (#6). Element reads go through
// `&toks.ptr[i]: *str`
// per the splitn cases (16B element copy gap, cgen.c:6515).

@test fn dupall_cases() void = {
	// Empty input — empty result, mirrors Hare's `payload = []`.
	let empty: []str;
	empty.ptr = nil: *str;
	empty.len = 0;
	empty.cap = 0;
	match (strings.dupall(empty)) {
	case let r: []str => {
		assert(!(r.len != 0));
		strings.freeall(r);
	};
	case nomem => { abort(); };
	};

	// Two-element ASCII — each output element is a fresh allocation
	// independent of the input (ptr differs from the borrowed source).
	let in2: [2]str;
	in2[0] = "hello";
	in2[1] = "world";
	let src2: []str;
	src2.ptr = &in2[0];
	src2.len = 2;
	src2.cap = 2;
	match (strings.dupall(src2)) {
	case let r: []str => {
		assert(!(r.len != 2));
		expect_str(r, 0, "hello");
		expect_str(r, 1, "world");
		let p0: *str = &r.ptr[0];
		assert(!(p0.ptr == in2[0].ptr));
		let p1: *str = &r.ptr[1];
		assert(!(p1.ptr == in2[1].ptr));
		strings.freeall(r);
	};
	case nomem => { abort(); };
	};

	// Singleton — `only` rune-equivalent of Hare's `["only"]`.
	let in1: [1]str;
	in1[0] = "only";
	let src1: []str;
	src1.ptr = &in1[0];
	src1.len = 1;
	src1.cap = 1;
	match (strings.dupall(src1)) {
	case let r: []str => {
		assert(!(r.len != 1));
		expect_str(r, 0, "only");
		strings.freeall(r);
	};
	case nomem => { abort(); };
	};

	// Multibyte — UTF-8 bytes (5-byte and 15-byte) round-trip.
	let inm: [2]str;
	inm[0] = "héllo";
	inm[1] = "こんにちは";
	let srcm: []str;
	srcm.ptr = &inm[0];
	srcm.len = 2;
	srcm.cap = 2;
	match (strings.dupall(srcm)) {
	case let r: []str => {
		assert(!(r.len != 2));
		expect_str(r, 0, "héllo");
		expect_str(r, 1, "こんにちは");
		let p0: *str = &r.ptr[0];
		assert(!(p0.len != 6));	// é is 2 bytes
		assert(!(p0.ptr == inm[0].ptr));
		let p1: *str = &r.ptr[1];
		assert(!(p1.len != 15));	// each kana is 3 bytes
		assert(!(p1.ptr == inm[1].ptr));
		strings.freeall(r);
	};
	case nomem => { abort(); };
	};
};

// ---- concat -----------------------------------------------------------
// ref/hare/strings/concat.ha:18. Rows mirror Hare's vectors (0/1/2/3-arg,
// empty-mid, 2-empty) plus empty-first / empty-last / multibyte.

@test fn concat_cases() void = {
	let pool: [17]str;
	pool[0]  = "hello";
	pool[1]  = "hello ";
	pool[2]  = "world";
	pool[3]  = "hello";
	pool[4]  = " ";
	pool[5]  = "world";
	pool[6]  = "hello";
	pool[7]  = "";
	pool[8]  = "world";
	pool[9]  = "";
	pool[10] = "";
	pool[11] = "";
	pool[12] = "world";
	pool[13] = "hello";
	pool[14] = "";
	pool[15] = "こん";
	pool[16] = "にちは";

	let argo:   [9]i32;
	let argn:   [9]i32;
	let want:   [9]str;
	let labels: [9]str;
	argo[0]=0;  argn[0]=0; want[0]="";              labels[0]="0-arg";
	argo[1]=0;  argn[1]=1; want[1]="hello";         labels[1]="1-arg";
	argo[2]=1;  argn[2]=2; want[2]="hello world";   labels[2]="2-arg";
	argo[3]=3;  argn[3]=3; want[3]="hello world";   labels[3]="3-arg";
	argo[4]=6;  argn[4]=3; want[4]="helloworld";    labels[4]="empty-mid";
	argo[5]=9;  argn[5]=2; want[5]="";              labels[5]="2-empty";
	argo[6]=11; argn[6]=2; want[6]="world";         labels[6]="empty-first";
	argo[7]=13; argn[7]=2; want[7]="hello";         labels[7]="empty-last";
	argo[8]=15; argn[8]=2; want[8]="こんにちは";    labels[8]="multibyte";

	let i: i32 = 0;
	for (i < 9) {
		let argv: []str;
		argv.ptr = &pool[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.concat(argv...);
		assert(!(!streq(got, want[i])));
		if (got.len > 0) { os.free(got.ptr: *void, got.len: u64); };
		i += 1;
	};
};

// ---- join -------------------------------------------------------------
// ref/hare/strings/concat.ha:64. Rows mirror Hare's @test fn join
// (0-arg, 1-arg, empty-sep, 3-arg.) plus 2-arg, all-empties, long sep,
// multibyte, empty-mid (delim still inserted around the empty slot).

@test fn join_cases() void = {
	let pool: [19]str;
	pool[0]  = "hello";
	pool[1]  = "a";
	pool[2]  = "b";
	pool[3]  = "a";
	pool[4]  = "b";
	pool[5]  = "c";
	pool[6]  = "a";
	pool[7]  = "b";
	pool[8]  = "c";
	pool[9]  = "";
	pool[10] = "";
	pool[11] = "a";
	pool[12] = "b";
	pool[13] = "c";
	pool[14] = "こん";
	pool[15] = "にちは";
	pool[16] = "a";
	pool[17] = "";
	pool[18] = "b";

	let argo:   [9]i32;
	let argn:   [9]i32;
	let seps:   [9]str;
	let want:   [9]str;
	argo[0]=0;  argn[0]=0; seps[0]=".";    want[0]="";
	argo[1]=0;  argn[1]=1; seps[1]=".";    want[1]="hello";
	argo[2]=1;  argn[2]=2; seps[2]=", ";   want[2]="a, b";
	argo[3]=3;  argn[3]=3; seps[3]=".";    want[3]="a.b.c";
	argo[4]=6;  argn[4]=3; seps[4]="";     want[4]="abc";
	argo[5]=9;  argn[5]=2; seps[5]=",";    want[5]=",";
	argo[6]=11; argn[6]=3; seps[6]=" :: "; want[6]="a :: b :: c";
	argo[7]=14; argn[7]=2; seps[7]="・";   want[7]="こん・にちは";
	argo[8]=16; argn[8]=3; seps[8]="-";    want[8]="a--b";

	let i: i32 = 0;
	for (i < 9) {
		let argv: []str;
		argv.ptr = &pool[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.join(seps[i], argv...);
		assert(!(!streq(got, want[i])));
		if (got.len > 0) { os.free(got.ptr: *void, got.len: u64); };
		i += 1;
	};
};

// ---- hasprefix --------------------------------------------------------
// ref/hare/strings/suffix.ha:18.

@test fn hasprefix_cases() void = {
	assert(!(!strings.hasprefix("hello world", "hello")));
	assert(!(!strings.hasprefix("hello world", 'h')));
	assert(!( strings.hasprefix("hello world", "world")));
	assert(!( strings.hasprefix("hello world", 'q')));
	assert(!(!strings.hasprefix("hello", "hello")));	// equal-len
	assert(!(!strings.hasprefix("anything", "")));	// empty prefix
	assert(!( strings.hasprefix("", "x")));
	// multibyte rune prefix — '\'é\'' literal blocked by single-byte
	// lexrune (lib/ww/lex/lex.ww:659); pass codepoint directly.
	assert(!(!strings.hasprefix("éclat", 0xE9u32: rune)));
	assert(!(!strings.hasprefix("🦀rust", 0x1F980u32: rune)));
};

// ---- hassuffix --------------------------------------------------------
// ref/hare/strings/suffix.ha:36.

@test fn hassuffix_cases() void = {
	assert(!(!strings.hassuffix("hello world", "world")));
	assert(!(!strings.hassuffix("hello world", 'd')));
	assert(!( strings.hassuffix("hello world", "hello")));
	assert(!( strings.hassuffix("hello world", 'h')));
	assert(!(!strings.hassuffix("café", 0xE9u32: rune)));	// multibyte
};

// ---- contains ---------------------------------------------------------
// ref/hare/strings/contains.ha:27.

@test fn contains_cases() void = {
	assert(!(!strings.contains("hello world", "hello")));
	assert(!(!strings.contains("hello world", 'h')));
	assert(!( strings.contains("hello world", 'x')));
	assert(!(!strings.contains("hello world", "world")));
	assert(!(!strings.contains("hello world", "")));	// empty hits at 0
	assert(!( strings.contains("hello world", "foobar")));
	assert(!(!strings.contains("こんにちは", 0x306Bu32: rune)));	// 'に'
	assert(!(!strings.contains("こんにちは", "ちは")));

	// Variadic rows. ref/hare/strings/contains.ha:27.
	assert(!( strings.contains("hello")));
	assert(!(!strings.contains("hello world", "world")));
	assert(!(!strings.contains("hello", 'l')));
	assert(!(!strings.contains("hello world", "foo", "world", 'x')));
	assert(!( strings.contains("hello", "foo", 'z', "bar")));
	assert(!(!strings.contains("héllo", "x", 0xE9u32: rune)));
};

// ---- byteindex --------------------------------------------------------
// ref/hare/strings/index.ha:147 (byteindex tests, both arms).

@test fn byteindex_str_cases() void = {
	match (strings.byteindex("hello", "hello")) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => { abort(); };
	};
	match (strings.byteindex("hello world!", "world")) {
	case let i: i32 => { assert(!(i != 6)); };
	case void => { abort(); };
	};
	match (strings.byteindex("hello world!", "orld!")) {
	case let i: i32 => { assert(!(i != 7)); };
	case void => { abort(); };
	};
	match (strings.byteindex("hello world!", "word")) {
	case let i: i32 => { abort(); };
	case void => void;
	};
	// empty needle hits at 0 (ref/hare/bytes/index.ha:63).
	match (strings.byteindex("hello", "")) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => { abort(); };
	};
	// empty haystack, non-empty needle — absent.
	match (strings.byteindex("", "x")) {
	case let i: i32 => { abort(); };
	case void => void;
	};
	// multibyte substring in multibyte haystack.
	match (strings.byteindex("こんにちは", "ちは")) {
	case let i: i32 => { assert(!(i != 9)); };
	case void => { abort(); };
	};
};

@test fn byteindex_rune_cases() void = {
	// ASCII rune (1-byte encoding).
	match (strings.byteindex("hello world", 'w')) {
	case let i: i32 => { assert(!(i != 6)); };
	case void => { abort(); };
	};
	// 2-byte rune U+00E9 'é' inside "café".
	match (strings.byteindex("café", 0xE9u32: rune)) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => { abort(); };
	};
	// 3-byte rune U+3061 'ち' inside "こんにちは".
	match (strings.byteindex("こんにちは", 0x3061u32: rune)) {
	case let i: i32 => { assert(!(i != 9)); };
	case void => { abort(); };
	};
	// 4-byte rune U+1F980 '🦀' inside "ab🦀cd".
	match (strings.byteindex("ab🦀cd", 0x1F980u32: rune)) {
	case let i: i32 => { assert(!(i != 2)); };
	case void => { abort(); };
	};
	// absent.
	match (strings.byteindex("こんにちは", 'q')) {
	case let i: i32 => { abort(); };
	case void => void;
	};
};

// ---- rbyteindex -------------------------------------------------------

@test fn rbyteindex_cases() void = {
	// Two 'た' in "またあったね" — ref/hare/strings/index.ha:160-161.
	match (strings.byteindex("またあったね", "た")) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => { abort(); };
	};
	match (strings.rbyteindex("またあったね", "た")) {
	case let i: i32 => { assert(!(i != 12)); };
	case void => { abort(); };
	};
	// Rune arm, multi-byte 'に' U+306B.
	match (strings.rbyteindex("こんにちは", 0x306Bu32: rune)) {
	case let i: i32 => { assert(!(i != 6)); };
	case void => { abort(); };
	};
	// Absent.
	match (strings.rbyteindex("abc", 'z')) {
	case let i: i32 => { abort(); };
	case void => void;
	};
};

// ---- index ------------------------------------------------------------
// ref/hare/strings/index.ha:108. Rune-wise offset, NOT byte-wise — the
// multibyte rows pin that distinction (Hare doc at index.ha:7).

@test fn index_cases() void = {
	// str-arm: ASCII haystack/needle, mid-string match.
	match (strings.index("hello", "ll")) {
	case let i: i32 => { assert(!(i != 2)); };
	case void => { abort(); };
	};
	// str-arm: absent needle.
	match (strings.index("hello", "world")) {
	case let i: i32 => { abort(); };
	case void => void;
	};
	// Hare vectors at ref/hare/strings/index.ha:113-119.
	match (strings.index("hello world!", "hello")) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => { abort(); };
	};
	match (strings.index("hello world!", "world")) {
	case let i: i32 => { assert(!(i != 6)); };
	case void => { abort(); };
	};
	match (strings.index("hello world!", "orld!")) {
	case let i: i32 => { assert(!(i != 7)); };
	case void => { abort(); };
	};
	// Multibyte haystack + str needle: "ちは" at rune index 3
	// in "こんにちは" (byteindex returns 9, rune-index is 3).
	match (strings.index("こんにちは", "ちは")) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => { abort(); };
	};
	// rune-arm.
	match (strings.index("hello", 'l')) {
	case let i: i32 => { assert(!(i != 2)); };
	case void => { abort(); };
	};
	match (strings.index("hello world", 'w')) {
	case let i: i32 => { assert(!(i != 6)); };
	case void => { abort(); };
	};
	// Multibyte rune: 'é' U+00E9 at rune 1 in "héllo" — pins
	// rune-index vs byte-index (byteindex returns 1; rune-index is
	// 1 also — but the str-arm's 1405 row covers the distinction).
	match (strings.index("héllo", 0xE9u32: rune)) {
	case let i: i32 => { assert(!(i != 1)); };
	case void => { abort(); };
	};
	// Multibyte rune in multibyte haystack: 'ち' U+3061 at rune 3
	// in "こんにちは" (byteindex returns 9, rune-index is 3).
	match (strings.index("こんにちは", 0x3061u32: rune)) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => { abort(); };
	};
	match (strings.index("こんにちは", 'q')) {
	case let i: i32 => { abort(); };
	case void => void;
	};
	// str-arm: rune-index ≠ byte-index again, mid-string match.
	// "あった" starts at rune 2 (byte 6) in "またあったね"
	// (each kana is 3 bytes; ref/hare/strings/index.ha:60). Pins
	// the dual-iterator walk against the discarded byteindex-and-walk
	// shape (#10).
	match (strings.index("またあったね", "あった")) {
	case let i: i32 => { assert(!(i != 2)); };
	case void => { abort(); };
	};
	// str-arm: tail-anchored multibyte needle. "は" is at rune 4
	// (byte 12) in "こんにちは".
	match (strings.index("こんにちは", "は")) {
	case let i: i32 => { assert(!(i != 4)); };
	case void => { abort(); };
	};
	// Empty needle hits at rune 0 — Hare's `index_string` falls into
	// the `needle_rune is done` branch on the very first inner step
	// (ref/hare/strings/index.ha:70).
	match (strings.index("hello", "")) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => { abort(); };
	};
	match (strings.index("", "")) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => { abort(); };
	};
	// Empty haystack, non-empty needle — absent.
	match (strings.index("", "x")) {
	case let i: i32 => { abort(); };
	case void => void;
	};
	// Multibyte haystack, multibyte absent needle — exercises the
	// inner-loop mismatch-break across runes (#10, Hare row
	// ref/hare/strings/index.ha:119).
	match (strings.index("こんにちは", "きょうは")) {
	case let i: i32 => { abort(); };
	case void => void;
	};
	// Self-match: haystack == needle, Hare row index.ha:113.
	match (strings.index("hello", "hello")) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => { abort(); };
	};
};

// ---- rindex -----------------------------------------------------------
// ref/hare/strings/index.ha:22. Symmetric: last-occurrence rune index.

@test fn rindex_cases() void = {
	// str-arm.
	match (strings.rindex("hello", "lo")) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => { abort(); };
	};
	// Hare vector at ref/hare/strings/index.ha:122.
	match (strings.rindex("hello world!", "o")) {
	case let i: i32 => { assert(!(i != 7)); };
	case void => { abort(); };
	};
	match (strings.rindex("hello", "world")) {
	case let i: i32 => { abort(); };
	case void => void;
	};
	// Multibyte: last "た" in "またあったね" — rbyteindex returns
	// 12, rune-index is 4 (ま=0 た=1 あ=2 っ=3 た=4 ね=5).
	match (strings.rindex("またあったね", "た")) {
	case let i: i32 => { assert(!(i != 4)); };
	case void => { abort(); };
	};
	// rune-arm.
	match (strings.rindex("hello", 'l')) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => { abort(); };
	};
	match (strings.rindex("aaaaa", 'a')) {
	case let i: i32 => { assert(!(i != 4)); };
	case void => { abort(); };
	};
	// Multibyte rune: 'に' U+306B at rune 2 in "こんにちは".
	match (strings.rindex("こんにちは", 0x306Bu32: rune)) {
	case let i: i32 => { assert(!(i != 2)); };
	case void => { abort(); };
	};
	match (strings.rindex("hello", 'z')) {
	case let i: i32 => { abort(); };
	case void => void;
	};
};

// ---- trimprefix / trimsuffix ------------------------------------------
// ref/hare/strings/trim.ha:99-107.

@test fn trimprefix_cases() void = {
	assert(!(!streq(strings.trimprefix("", ""), "")));
	assert(!(!streq(strings.trimprefix("", "blablabla"), "")));
	assert(!(!streq(strings.trimprefix("hello, world", "hello"), ", world")));
	assert(!(!streq(strings.trimprefix("blablabla", "bla"), "blabla")));
	// equal-length match strips to empty.
	assert(!(!streq(strings.trimprefix("hello", "hello"), "")));
};

@test fn trimsuffix_cases() void = {
	assert(!(!streq(strings.trimsuffix("", ""), "")));
	assert(!(!streq(strings.trimsuffix("", "blablabla"), "")));
	assert(!(!streq(strings.trimsuffix("hello, world", "world"), "hello, ")));
	assert(!(!streq(strings.trimsuffix("blablabla", "bla"), "blabla")));
	assert(!(!streq(strings.trimsuffix("hello", "hello"), "")));
};

// ---- ltrim / rtrim / trim ---------------------------------------------
// ref/hare/strings/trim.ha:75-97. 0-arg rows (#9) pin the ASCII
// whitespace set (' ', '\t', '\n', '\r' — ref/hare/strings/trim.ha:6).

@test fn ltrim_cases() void = {
	let runes: [9]rune;
	runes[0] = 'x';
	runes[1] = 'a';
	runes[2] = 0x1D68Au32: rune;
	runes[3] = '(';
	runes[4] = ')';
	runes[5] = 'a';
	runes[6] = 'b';
	runes[7] = 'c';
	runes[8] = 'd';

	// 0-arg rows (8..10) strip ASCII whitespace per Hare (#9):
	// only the leading side is stripped for ltrim.
	let inputs: [11]str;
	let argo:   [11]i32;
	let argn:   [11]i32;
	let want:   [11]str;
	inputs[0]="";              argo[0]=0; argn[0]=1; want[0]="";
	inputs[1]="aaabc";         argo[1]=1; argn[1]=1; want[1]="bc";
	inputs[2]="xyz";           argo[2]=1; argn[2]=1; want[2]="xyz";
	inputs[3]="aaaa";          argo[3]=1; argn[3]=1; want[3]="";
	inputs[4]="𝚊𝚊hi";       argo[4]=2; argn[4]=1; want[4]="hi";
	inputs[5]="((()(())))())"; argo[5]=3; argn[5]=2; want[5]="";
	inputs[6]="abacadabra";    argo[6]=5; argn[6]=4; want[6]="ra";
	inputs[7]="hello";         argo[7]=0; argn[7]=0; want[7]="hello";
	inputs[8]=" hello ";       argo[8]=0; argn[8]=0; want[8]="hello ";
	inputs[9]="\t\r\n  hello"; argo[9]=0; argn[9]=0; want[9]="hello";
	inputs[10]="  ";           argo[10]=0; argn[10]=0; want[10]="";

	let i: i32 = 0;
	for (i < 11) {
		let argv: []rune;
		argv.ptr = &runes[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.ltrim(inputs[i], argv...);
		assert(!(!streq(got, want[i])));
		i += 1;
	};
};

@test fn rtrim_cases() void = {
	let runes: [19]rune;
	runes[0]  = 'x';
	runes[1]  = 'a';
	runes[2]  = 0x1D68Au32: rune;
	runes[3]  = 'w';
	runes[4]  = 'd';
	runes[5]  = 'o';
	runes[6]  = 'r';
	runes[7]  = ' ';
	runes[8]  = 's';
	runes[9]  = 'i';
	runes[10] = 'l';
	runes[11] = 'z';
	runes[12] = 't';
	runes[13] = 'm';
	runes[14] = 'n';
	runes[15] = 'o';
	runes[16] = 'e';
	runes[17] = 'a';
	runes[18] = 'd';

	// 0-arg rows (8..10) strip ASCII whitespace per Hare (#9):
	// only the trailing side is stripped for rtrim.
	let inputs: [11]str;
	let argo:   [11]i32;
	let argn:   [11]i32;
	let want:   [11]str;
	inputs[0]="";        argo[0]=0; argn[0]=1; want[0]="";
	inputs[1]="bcaaa";   argo[1]=1; argn[1]=1; want[1]="bc";
	inputs[2]="xyz";     argo[2]=1; argn[2]=1; want[2]="xyz";
	inputs[3]="aaaa";    argo[3]=1; argn[3]=1; want[3]="";
	inputs[4]="hi𝚊𝚊"; argo[4]=2; argn[4]=1; want[4]="hi";
	inputs[5]="yellowwooddoor";
	                     argo[5]=3; argn[5]=4; want[5]="yell";
	inputs[6]="Sentimentalized sensationalism sensationalized sentimentalisms";
	                     argo[6]=7; argn[6]=12; want[6]="S";
	inputs[7]="hello";   argo[7]=0; argn[7]=0; want[7]="hello";
	inputs[8]=" hello "; argo[8]=0; argn[8]=0; want[8]=" hello";
	inputs[9]="hello, world\r\n\r\n";
	                     argo[9]=0; argn[9]=0; want[9]="hello, world";
	inputs[10]="  ";     argo[10]=0; argn[10]=0; want[10]="";

	let i: i32 = 0;
	for (i < 11) {
		let argv: []rune;
		argv.ptr = &runes[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.rtrim(inputs[i], argv...);
		assert(!(!streq(got, want[i])));
		i += 1;
	};
};

@test fn trim_cases() void = {
	let runes: [8]rune;
	runes[0] = 'x';
	runes[1] = 'a';
	runes[2] = 'm';
	runes[3] = 'i';
	runes[4] = 'p';
	runes[5] = 's';
	runes[6] = '[';
	runes[7] = ']';

	// 0-arg rows (7..9) strip ASCII whitespace per Hare (#9) from
	// both ends.
	let inputs: [10]str;
	let argo:   [10]i32;
	let argn:   [10]i32;
	let want:   [10]str;
	inputs[0]="";            argo[0]=0; argn[0]=1; want[0]="";
	inputs[1]="aaabcaaa";    argo[1]=1; argn[1]=1; want[1]="bc";
	inputs[2]="xyz";         argo[2]=1; argn[2]=1; want[2]="xyz";
	inputs[3]="aaaa";        argo[3]=1; argn[3]=1; want[3]="";
	inputs[4]="mississippi"; argo[4]=2; argn[4]=4; want[4]="";
	inputs[5]="[[][[[]]][][].[[]][]]][]]]";
	                         argo[5]=6; argn[5]=2; want[5]=".";
	inputs[6]="hello";       argo[6]=0; argn[6]=0; want[6]="hello";
	inputs[7]=" hello ";     argo[7]=0; argn[7]=0; want[7]="hello";
	inputs[8]="\r\thello\n\r"; argo[8]=0; argn[8]=0; want[8]="hello";
	inputs[9]="  ";          argo[9]=0; argn[9]=0; want[9]="";

	let i: i32 = 0;
	for (i < 10) {
		let argv: []rune;
		argv.ptr = &runes[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.trim(inputs[i], argv...);
		assert(!(!streq(got, want[i])));
		i += 1;
	};
};

// ---- compare ----------------------------------------------------------
// ref/hare/strings/compare.ha:16.

@test fn compare_cases() void = {
	assert(!(strings.compare("ABC", "ABC") != 0));
	assert(!(strings.compare("ABC", "AB")  <= 0));
	assert(!(strings.compare("AB", "ABC")  >= 0));
	assert(!(strings.compare("BCD", "ABC") <= 0));
	assert(!(strings.compare("ABC", "abc") >= 0));
	assert(!(strings.compare("ABC", "こんにちは") >= 0));
};

// ---- sub / bytesub ----------------------------------------------------
// ref/hare/strings/sub.ha:44 (@test fn sub), :79 (@test fn bytesub). Hare's
// 2-arg `sub(s, start)` rows are omitted: ww has no default-parameter
// syntax (filed as #37). bytesub now validates rune boundaries (#7).

@test fn sub_cases() void = {
	assert(!(!streq(strings.sub("a string", 0, 8), "a string")));
	assert(!(!streq(strings.sub("a string", 0, 1), "a")));
	assert(!(!streq(strings.sub("a string", 0, 3), "a s")));
	assert(!(!streq(strings.sub("a string", 2, 8), "string")));
	// start == end yields an empty borrowed view.
	assert(!(!streq(strings.sub("a string", 4, 4), "")));
	assert(!(strings.sub("a string", 4, 4).len != 0));
	// Hare vector — rune indices 1..3 over "こんにちは" select bytes
	// 3..9 ("んに"), not bytes 1..3.
	assert(!(!streq(strings.sub("こんにちは", 1, 3), "んに")));
	// 2-byte rune at rune index 1 in "héllo" — byte offsets 1..3.
	assert(!(!streq(strings.sub("héllo", 1, 2), "é")));
	// start == 0, end == rune-len of full string.
	assert(!(!streq(strings.sub("héllo", 0, 5), "héllo")));
};

// Match-shape mirrors Hare's `bytesub(...)!` at ref/hare/strings/sub.ha:
// 80-86. Inlined at each call site (rather than a helper that takes
// `(str | utf8.invalid)` by value) because the union-by-value path
// crashes — same lift-on-pass-by-value family as #48.
@test fn bytesub_cases() void = {
	match (strings.bytesub("a string", 0, 8)) {
	case let s: str          => { assert(!(!streq(s, "a string"))); };
	case let e: utf8.invalid => { abort(); };
	};
	match (strings.bytesub("a string", 0, 1)) {
	case let s: str          => { assert(!(!streq(s, "a"))); };
	case let e: utf8.invalid => { abort(); };
	};
	match (strings.bytesub("a string", 0, 3)) {
	case let s: str          => { assert(!(!streq(s, "a s"))); };
	case let e: utf8.invalid => { abort(); };
	};
	match (strings.bytesub("a string", 2, 8)) {
	case let s: str          => { assert(!(!streq(s, "string"))); };
	case let e: utf8.invalid => { abort(); };
	};
	match (strings.bytesub("a string", 4, 4)) {
	case let s: str          => { assert(!(!streq(s, ""))); };
	case let e: utf8.invalid => { abort(); };
	};
	// Hare vector — byte indices 3..9 over "こんにちは" select "んに".
	match (strings.bytesub("こんにちは", 3, 9)) {
	case let s: str          => { assert(!(!streq(s, "んに"))); };
	case let e: utf8.invalid => { abort(); };
	};
	// Rune/byte axis disagree on identical args (#3): sub(s,0,3) walks 3
	// runes and yields 9 bytes; bytesub(s,0,3) yields the first 3 bytes
	// — one 3-byte codepoint.
	assert(!(!streq(strings.sub("こんにちは", 0, 3), "こんに")));
	match (strings.bytesub("こんにちは", 0, 3)) {
	case let s: str          => { assert(!(!streq(s, "こ"))); };
	case let e: utf8.invalid => { abort(); };
	};
	// Borrowed view: ptr aliases input.
	let s: str = "hello";
	match (strings.bytesub(s, 1, 4)) {
	case let r: str => {
		assert(!(r.ptr != s.ptr + 1u64));
		assert(!(r.len != 3));
	};
	case let e: utf8.invalid => { abort(); };
	};
	// Hare's invalid row (ref/hare/strings/sub.ha:87) — start lands on
	// a continuation byte (2nd byte of "こ"), bytesub must reject (#7).
	match (strings.bytesub("こんにちは", 1, 3)) {
	case let r: str          => { abort(); };
	case let e: utf8.invalid => void;
	};
	// Symmetric: end lands on a continuation byte (2nd byte of "ん").
	match (strings.bytesub("こんにちは", 0, 4)) {
	case let r: str          => { abort(); };
	case let e: utf8.invalid => void;
	};
	// end == s.len bypasses the continuation check (s[end] is OOB).
	match (strings.bytesub("こんにちは", 0, 15)) {
	case let s: str          => { assert(!(!streq(s, "こんにちは"))); };
	case let e: utf8.invalid => { abort(); };
	};
};

// ---- toutf8 / frombytes roundtrip -------------------------------
// ref/hare/strings/utf8.ha:31. Validation-half coverage lives in
// lib/encoding/utf8 (utf8test) per CLAUDE.md rule 9 carve-out.

@test fn utf8_roundtrip_cases() void = {
	let s: str = "hello";
	let b: []u8 = strings.toutf8(s);
	assert(!(b.len != 5));
	assert(!(b[0] != 104u8));	// 'h'
	let r: str = strings.frombytes(b);
	assert(!(!streq(r, "hello")));
	assert(!(r.ptr != s.ptr));	// borrowed, not copied
};

// ---- iter / next ------------------------------------------------------
// ref/hare/strings/iter.ha:84-108. Hare's @test fn iter() uses prev +
// riter heavily; both are deferred (no `utf8.prev`). Rebuild forward-
// only here: empty / ASCII / 2-byte / 3-byte / 4-byte / done@EOI /
// mixed-width.

@test fn iter_empty_cases() void = {
	let it: strings.iterator = strings.iter("");
	match (strings.next(&it)) {
	case let r: rune       => { abort(); };
	case utf8.done         => void;
	};
	// Repeated next after done stays done.
	match (strings.next(&it)) {
	case let r: rune       => { abort(); };
	case utf8.done         => void;
	};
};

@test fn iter_ascii_cases() void = {
	let it: strings.iterator = strings.iter("hi!");
	match (strings.next(&it)) {
	case let r: rune       => { assert(!(r != 'h')); };
	case utf8.done         => { abort(); };
	};
	match (strings.next(&it)) {
	case let r: rune       => { assert(!(r != 'i')); };
	case utf8.done         => { abort(); };
	};
	match (strings.next(&it)) {
	case let r: rune       => { assert(!(r != '!')); };
	case utf8.done         => { abort(); };
	};
	match (strings.next(&it)) {
	case let r: rune       => { abort(); };
	case utf8.done         => void;
	};
};

@test fn iter_twobyte_cases() void = {
	let it: strings.iterator = strings.iter("café");
	let i: i32 = 0;
	let expect: [4]rune;
	expect[0] = 'c'; expect[1] = 'a'; expect[2] = 'f';
	expect[3] = 0xE9u32: rune;	// 'é' U+00E9
	for (i < 4) {
		match (strings.next(&it)) {
		case let r: rune   => { assert(!(r != expect[i])); };
		case utf8.done     => { abort(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { abort(); };
	case utf8.done         => void;
	};
};

@test fn iter_threebyte_cases() void = {
	let it: strings.iterator = strings.iter("こんにちは");
	let i: i32 = 0;
	let expect: [5]rune;
	expect[0] = 0x3053u32: rune;	// 'こ'
	expect[1] = 0x3093u32: rune;	// 'ん'
	expect[2] = 0x306Bu32: rune;	// 'に'
	expect[3] = 0x3061u32: rune;	// 'ち'
	expect[4] = 0x306Fu32: rune;	// 'は'
	for (i < 5) {
		match (strings.next(&it)) {
		case let r: rune   => { assert(!(r != expect[i])); };
		case utf8.done     => { abort(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { abort(); };
	case utf8.done         => void;
	};
};

@test fn iter_fourbyte_cases() void = {
	let it: strings.iterator = strings.iter("🦀rust");
	let i: i32 = 0;
	let expect: [5]rune;
	expect[0] = 0x1F980u32: rune;	// '🦀'
	expect[1] = 'r'; expect[2] = 'u'; expect[3] = 's'; expect[4] = 't';
	for (i < 5) {
		match (strings.next(&it)) {
		case let r: rune   => { assert(!(r != expect[i])); };
		case utf8.done     => { abort(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { abort(); };
	case utf8.done         => void;
	};
};

@test fn iter_mixed_cases() void = {
	// "Hello, 世界! 🌍" — 1+1+1+1+1+1+1+3+3+1+1+4 = 12 runes,
	// widths 1/3/4 mixed.
	let it: strings.iterator = strings.iter("Hello, 世界! 🌍");
	let i: i32 = 0;
	let expect: [12]rune;
	expect[0] = 'H';  expect[1] = 'e'; expect[2] = 'l'; expect[3] = 'l';
	expect[4] = 'o';  expect[5] = ','; expect[6] = ' ';
	expect[7] = 0x4E16u32: rune;	// '世'
	expect[8] = 0x754Cu32: rune;	// '界'
	expect[9] = '!';  expect[10] = ' ';
	expect[11] = 0x1F30Du32: rune;	// '🌍'
	for (i < 12) {
		match (strings.next(&it)) {
		case let r: rune   => { assert(!(r != expect[i])); };
		case utf8.done     => { abort(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { abort(); };
	case utf8.done         => void;
	};
};

// ---- prev / riter / iterstr / slice / position -----------------------
// ref/hare/strings/iter.ha:84-127. The Hare @test fn iter body uses
// `s = riter(...)` mid-test to swap the iterator's direction; ww's
// sret-into-existing-slot path handles that fine (probed pre-port).

@test fn iter_prev_at_start_cases() void = {
	let it: strings.iterator = strings.iter("hi");
	match (strings.prev(&it)) {
	case utf8.done       => void;
	case let r: rune     => { abort(); };
	};
};

@test fn iter_prev_ascii_cases() void = {
	let it: strings.iterator = strings.iter("abc");
	match (strings.next(&it)) {
	case let r: rune       => { assert(!(r != 'a')); };
	case utf8.done         => { abort(); };
	};
	match (strings.prev(&it)) {
	case let r: rune       => { assert(!(r != 'a')); };
	case utf8.done         => { abort(); };
	};
	match (strings.prev(&it)) {
	case utf8.done         => void;
	case let r: rune       => { abort(); };
	};
};

// Mirror of ref/hare/strings/iter.ha:84-108 — `iter("こんにちは")`,
// step+back+iterstr+riter-reassign sequence.
@test fn iter_full_cases() void = {
	let s: strings.iterator = strings.iter("こんにちは");
	match (strings.prev(&s)) {
	case utf8.done         => void;
	case let r: rune       => { abort(); };
	};
	let expect1: [2]rune;
	expect1[0] = 0x3053u32: rune;	// 'こ'
	expect1[1] = 0x3093u32: rune;	// 'ん'
	let i: i32 = 0;
	for (i < 2) {
		match (strings.next(&s)) {
		case let r: rune   => { assert(!(r != expect1[i])); };
		case utf8.done     => { abort(); };
		};
		i += 1;
	};
	assert(!(!streq(strings.iterstr(&s), "にちは")));
	match (strings.prev(&s)) {
	case let r: rune       => { assert(!(r != 0x3093u32: rune)); };	// 'ん'
	case utf8.done         => { abort(); };
	};
	let expect2: [4]rune;
	expect2[0] = 0x3093u32: rune;	// 'ん'
	expect2[1] = 0x306Bu32: rune;	// 'に'
	expect2[2] = 0x3061u32: rune;	// 'ち'
	expect2[3] = 0x306Fu32: rune;	// 'は'
	i = 0;
	for (i < 4) {
		match (strings.next(&s)) {
		case let r: rune   => { assert(!(r != expect2[i])); };
		case utf8.done     => { abort(); };
		};
		i += 1;
	};
	match (strings.next(&s)) {
	case utf8.done         => void;
	case let r: rune       => { abort(); };
	};
	// Repeated next-after-done stays done.
	match (strings.next(&s)) {
	case utf8.done         => void;
	case let r: rune       => { abort(); };
	};
	match (strings.prev(&s)) {
	case let r: rune       => { assert(!(r != 0x306Fu32: rune)); };	// 'は'
	case utf8.done         => { abort(); };
	};

	// Swap to a reverse iterator. sret-into-existing-slot.
	s = strings.riter("にちは");
	let expect3: [3]rune;
	expect3[0] = 0x306Fu32: rune;	// 'は'
	expect3[1] = 0x3061u32: rune;	// 'ち'
	expect3[2] = 0x306Bu32: rune;	// 'に'
	i = 0;
	for (i < 3) {
		match (strings.next(&s)) {
		case let r: rune   => { assert(!(r != expect3[i])); };
		case utf8.done     => { abort(); };
		};
		i += 1;
	};
	match (strings.next(&s)) {
	case utf8.done         => void;
	case let r: rune       => { abort(); };
	};
	match (strings.prev(&s)) {
	case let r: rune       => { assert(!(r != 0x306Bu32: rune)); };	// 'に'
	case utf8.done         => { abort(); };
	};
};

@test fn iter_position_cases() void = {
	let it: strings.iterator = strings.iter("café");	// 5 bytes: c-a-f-é(2)
	assert(!(strings.position(&it) != 0));
	match (strings.next(&it)) { case let r: rune => void; case utf8.done => { abort(); }; };
	assert(!(strings.position(&it) != 1));
	match (strings.next(&it)) { case let r: rune => void; case utf8.done => { abort(); }; };
	match (strings.next(&it)) { case let r: rune => void; case utf8.done => { abort(); }; };
	assert(!(strings.position(&it) != 3));
	match (strings.next(&it)) { case let r: rune => void; case utf8.done => { abort(); }; };
	assert(!(strings.position(&it) != 5));
};

// ref/hare/strings/iter.ha:110 @test fn slice. Hare uses `let t = s;`
// to copy the iterator; ww re-initialises t from the same source to
// stay in scope of #32 (local struct ident rhs already fixed) without
// reaching for #35's sibling latents.
@test fn iter_slice_cases() void = {
	let s: strings.iterator = strings.iter("こんにちは");
	let t: strings.iterator = strings.iter("こんにちは");
	assert(!(strings.slice(&s, &t).len != 0));
	assert(!(strings.slice(&t, &s).len != 0));
	let i: i32 = 0;
	for (i < 2) {
		match (strings.next(&s)) {
		case let r: rune     => void;
		case utf8.done       => { abort(); };
		};
		match (strings.next(&t)) {
		case let r: rune     => void;
		case utf8.done       => { abort(); };
		};
		i += 1;
	};
	assert(!(strings.slice(&s, &t).len != 0));
	assert(!(strings.slice(&t, &s).len != 0));
	i = 0;
	for (i < 3) {
		match (strings.next(&t)) {
		case let r: rune     => void;
		case utf8.done       => { abort(); };
		};
		i += 1;
	};
	assert(!(!streq(strings.slice(&s, &t), "にちは")));
	i = 0;
	for (i < 3) {
		match (strings.next(&s)) {
		case let r: rune     => void;
		case utf8.done       => { abort(); };
		};
		i += 1;
	};
	assert(!(strings.slice(&s, &t).len != 0));
	assert(!(strings.slice(&t, &s).len != 0));
};

@test fn iter_iterstr_reverse_cases() void = {
	// Reverse iter: iterstr is `src[0:offs]` — bytes BEFORE the cursor
	// (the still-to-be-walked region in reverse direction).
	let rit: strings.iterator = strings.riter("hello");
	assert(!(!streq(strings.iterstr(&rit), "hello")));
	match (strings.next(&rit)) { case let r: rune => void; case utf8.done => { abort(); }; };
	assert(!(!streq(strings.iterstr(&rit), "hell")));
	match (strings.next(&rit)) { case let r: rune => void; case utf8.done => { abort(); }; };
	match (strings.next(&rit)) { case let r: rune => void; case utf8.done => { abort(); }; };
	assert(!(!streq(strings.iterstr(&rit), "he")));
};

// ---- tokenize / rtokenize / peek_token / remaining_tokens -----------
// ref/hare/strings/tokenize.ha:110 @test fn tokenize. Row drivers
// mirror lib/bytes/bytestest expect_token / expect_done but compare
// str via streq.

fn expect_str_token(t: *strings.tokenizer, want: str) void = {
	match (strings.peek_token(t)) {
	case let p: str    => { assert(!(!streq(p, want))); };
	case bytes.done    => { abort(); };
	};
	match (strings.next_token(t)) {
	case let n: str    => { assert(!(!streq(n, want))); };
	case bytes.done    => { abort(); };
	};
};

fn expect_str_done(t: *strings.tokenizer) void = {
	match (strings.peek_token(t)) {
	case let p: str    => { abort(); };
	case bytes.done    => void;
	};
	match (strings.next_token(t)) {
	case let n: str    => { abort(); };
	case bytes.done    => void;
	};
};

@test fn tokenize_cases() void = {
	// Hare vector — single-space delim. ref/hare/strings/tokenize.ha:112.
	let t: strings.tokenizer = strings.tokenize(
		"Hello world! My name is Harriet.", " ");
	expect_str_token(&t, "Hello");
	expect_str_token(&t, "world!");
	expect_str_token(&t, "My");
	expect_str_token(&t, "name");
	expect_str_token(&t, "is");
	expect_str_token(&t, "Harriet.");
	expect_str_done(&t);

	// Multi-byte delim set — space + tab.
	// ref/hare/strings/tokenize.ha:124.
	let t2: strings.tokenizer = strings.tokenize(
		"/dev/sda1\t/ ext4 rw,relatime\t0 0", " \t");
	expect_str_token(&t2, "/dev/sda1");
	expect_str_token(&t2, "/");
	expect_str_token(&t2, "ext4");
	expect_str_token(&t2, "rw,relatime");
	expect_str_token(&t2, "0");
	expect_str_token(&t2, "0");
	expect_str_done(&t2);

	// Consecutive delimiters — empty interior tokens.
	// ref/hare/strings/tokenize.ha:136.
	let t3: strings.tokenizer = strings.tokenize("hello    world", " ");
	expect_str_token(&t3, "hello");
	expect_str_token(&t3, "");
	expect_str_token(&t3, "");
	expect_str_token(&t3, "");
	expect_str_token(&t3, "world");
	expect_str_done(&t3);

	// Leading + trailing delimiters yield empty tokens.
	// ref/hare/strings/tokenize.ha:147.
	let t4: strings.tokenizer = strings.tokenize(" hello world ", " ");
	expect_str_token(&t4, "");
	expect_str_token(&t4, "hello");
	expect_str_token(&t4, "world");
	expect_str_token(&t4, "");
	expect_str_done(&t4);

	// No delim hit — single full token.
	let t5: strings.tokenizer = strings.tokenize("abc", " ");
	expect_str_token(&t5, "abc");
	expect_str_done(&t5);

	// Empty input — done immediately.
	let t6: strings.tokenizer = strings.tokenize("", " ");
	expect_str_done(&t6);
};

@test fn rtokenize_cases() void = {
	// Reverse direction — first next_token is the last token.
	let t: strings.tokenizer = strings.rtokenize(
		"Hello world! My name is Harriet.", " ");
	expect_str_token(&t, "Harriet.");
	expect_str_token(&t, "is");
	expect_str_token(&t, "name");
	expect_str_token(&t, "My");
	expect_str_token(&t, "world!");
	expect_str_token(&t, "Hello");
	expect_str_done(&t);

	// Multi-byte delim set, reverse direction.
	let t2: strings.tokenizer = strings.rtokenize("a b\tc", " \t");
	expect_str_token(&t2, "c");
	expect_str_token(&t2, "b");
	expect_str_token(&t2, "a");
	expect_str_done(&t2);

	// Empty input — done immediately.
	let t3: strings.tokenizer = strings.rtokenize("", " ");
	expect_str_done(&t3);
};

@test fn peek_token_cases() void = {
	// Two peeks without advancing return the same token.
	let t: strings.tokenizer = strings.tokenize("a b c", " ");
	match (strings.peek_token(&t)) {
	case let p: str    => { assert(!(!streq(p, "a"))); };
	case bytes.done    => { abort(); };
	};
	match (strings.peek_token(&t)) {
	case let p: str    => { assert(!(!streq(p, "a"))); };
	case bytes.done    => { abort(); };
	};
	// Advance once — peek then returns "b".
	match (strings.next_token(&t)) {
	case let n: str    => { assert(!(!streq(n, "a"))); };
	case bytes.done    => { abort(); };
	};
	match (strings.peek_token(&t)) {
	case let p: str    => { assert(!(!streq(p, "b"))); };
	case bytes.done    => { abort(); };
	};

	// Empty input — peek is done.
	let t2: strings.tokenizer = strings.tokenize("", " ");
	match (strings.peek_token(&t2)) {
	case let p: str    => { abort(); };
	case bytes.done    => void;
	};
};

@test fn remaining_tokens_cases() void = {
	// ref/hare/strings/tokenize.ha:157. After 2 next_tokens, remaining
	// is "My name is Harriet.".
	let t: strings.tokenizer = strings.tokenize(
		"Hello world! My name is Harriet.", " ");
	match (strings.next_token(&t)) {
	case let n: str    => { assert(!(!streq(n, "Hello"))); };
	case bytes.done    => { abort(); };
	};
	match (strings.next_token(&t)) {
	case let n: str    => { assert(!(!streq(n, "world!"))); };
	case bytes.done    => { abort(); };
	};
	if (!streq(strings.remaining_tokens(&t), "My name is Harriet.")) {
		abort();
	};

	// Fresh tokenizer — remaining_tokens is the whole input.
	let t2: strings.tokenizer = strings.tokenize("a b c", " ");
	assert(!(!streq(strings.remaining_tokens(&t2), "a b c")));
};

// ---- splitn / rsplitn / split ----------------------------------------
// ref/hare/strings/tokenize.ha:245 @test fn split. Hare's vectors
// mirrored here directly; element reads go through `&toks.ptr[i]: *str`
// rather than `toks[i]` so the 16B str element copy stays out of the
// multi-word-store gap noted at cmd/w6c/cgen.c:6515.

fn expect_str(toks: []str, i: i32, want: str) void = {
	assert(!(i >= toks.len));
	let p: *str = &toks.ptr[i];
	assert(!(p.len != want.len));
	let j: i32 = 0;
	for (j < want.len) {
		assert(!(p.ptr[j] != want[j]));
		j += 1;
	};
};

@test fn splitn_cases() void = {
	// ref/hare/strings/tokenize.ha:247 — n=4 buckets the trailing
	// "is Drew" as the remainder slot.
	let t1: []str = strings.splitn("Hello, my name is Drew", " ", 4);
	assert(!(t1.len != 4));
	expect_str(t1, 0, "Hello,");
	expect_str(t1, 1, "my");
	expect_str(t1, 2, "name");
	expect_str(t1, 3, "is Drew");
	os.free(t1.ptr: *void, (t1.cap: u64) * size(str): u64);

	// ref/hare/strings/tokenize.ha:263 — n > tokens leaves a single
	// slot holding the unchanged input (delim not found).
	let t2: []str = strings.splitn("one", "=", 2);
	assert(!(t2.len != 1));
	expect_str(t2, 0, "one");
	os.free(t2.ptr: *void, (t2.cap: u64) * size(str): u64);

	// n == 1 — single slot holding the whole input as remainder.
	let t3: []str = strings.splitn("a b c", " ", 1);
	assert(!(t3.len != 1));
	expect_str(t3, 0, "a b c");
	os.free(t3.ptr: *void, (t3.cap: u64) * size(str): u64);

	// Empty input — empty result.
	let t4: []str = strings.splitn("", " ", 5);
	assert(!(t4.len != 0));
	if (t4.cap > 0) {
		os.free(t4.ptr: *void, (t4.cap: u64) * size(str): u64);
	};

	// Multi-byte delim set (byte-set semantics per
	// ref/hare/strings/tokenize.ha:35) — split on ',' OR ':' OR ';'.
	let t5: []str = strings.splitn("hello;world,foo:bar", ",:;", 10);
	assert(!(t5.len != 4));
	expect_str(t5, 0, "hello");
	expect_str(t5, 1, "world");
	expect_str(t5, 2, "foo");
	expect_str(t5, 3, "bar");
	os.free(t5.ptr: *void, (t5.cap: u64) * size(str): u64);
};

@test fn rsplitn_cases() void = {
	// ref/hare/strings/tokenize.ha:271 — reverse n=4 with the
	// "Hello, my" prefix as the remainder slot at index 0.
	let t1: []str = strings.rsplitn("Hello, my name is Drew", " ", 4);
	assert(!(t1.len != 4));
	expect_str(t1, 0, "Hello, my");
	expect_str(t1, 1, "name");
	expect_str(t1, 2, "is");
	expect_str(t1, 3, "Drew");
	os.free(t1.ptr: *void, (t1.cap: u64) * size(str): u64);

	// n > token count — done short-circuit returns toks UN-reversed
	// (last-token-first order). Mirrors bytes.rsplitn (Hare's
	// ref/hare/strings/tokenize.ha:219-224 reverse step is gated
	// behind the n-1 loop completion).
	let t2: []str = strings.rsplitn("a b c", " ", 10);
	assert(!(t2.len != 3));
	expect_str(t2, 0, "c");
	expect_str(t2, 1, "b");
	expect_str(t2, 2, "a");
	os.free(t2.ptr: *void, (t2.cap: u64) * size(str): u64);

	// n == 1 — single slot holding the whole input as remainder.
	let t3: []str = strings.rsplitn("a b c", " ", 1);
	assert(!(t3.len != 1));
	expect_str(t3, 0, "a b c");
	os.free(t3.ptr: *void, (t3.cap: u64) * size(str): u64);

	// delim absent — first next_token yields the entire input as the
	// sole token; second iter sees done and short-circuits with the
	// 1-elem toks un-reversed (single element, reverse is a no-op).
	let t4: []str = strings.rsplitn("abc", "=", 5);
	assert(!(t4.len != 1));
	expect_str(t4, 0, "abc");
	os.free(t4.ptr: *void, (t4.cap: u64) * size(str): u64);
};

@test fn split_cases() void = {
	// ref/hare/strings/tokenize.ha:255 — full split, every delim hit
	// is a boundary.
	let t1: []str = strings.split("Hello, my name is Drew", " ");
	assert(!(t1.len != 5));
	expect_str(t1, 0, "Hello,");
	expect_str(t1, 1, "my");
	expect_str(t1, 2, "name");
	expect_str(t1, 3, "is");
	expect_str(t1, 4, "Drew");
	os.free(t1.ptr: *void, (t1.cap: u64) * size(str): u64);

	// Leading + trailing delim — empty tokens at ends.
	let t2: []str = strings.split(" a b ", " ");
	assert(!(t2.len != 4));
	expect_str(t2, 0, "");
	expect_str(t2, 1, "a");
	expect_str(t2, 2, "b");
	expect_str(t2, 3, "");
	os.free(t2.ptr: *void, (t2.cap: u64) * size(str): u64);

	// Multi-byte delim set, byte-set semantics matching Hare's
	// strings::split example at ref/hare/strings/tokenize.ha:235.
	let t3: []str = strings.split("hello;world,foo:bar", ",:;");
	assert(!(t3.len != 4));
	expect_str(t3, 0, "hello");
	expect_str(t3, 1, "world");
	expect_str(t3, 2, "foo");
	expect_str(t3, 3, "bar");
	os.free(t3.ptr: *void, (t3.cap: u64) * size(str): u64);
};

// ---- lpad / rpad -----------------------------------------------------
// ref/hare/strings/pad.ha:23 (@test fn lpad), :54 (@test fn rpad). Hare's
// row triple (s<maxlen, s==maxlen, s=="" empty) is mirrored; ww extras
// pin s>maxlen (early return path), multibyte s with byte-length
// counting, and multibyte pad rune (encoded width >1 byte). The
// multibyte-pad rows pin Hare's `[..maxlen]` slice contract — a
// multibyte trailing pad may be truncated mid-codepoint, exactly as
// Hare does.

@test fn lpad_cases() void = {
	// Hare row 1: shorter s, ASCII pad.
	let r1: str = strings.lpad("2", '0', 5);
	assert(!(!streq(r1, "00002")));
	assert(!(r1.len != 5));
	os.free(r1.ptr: *void, r1.len: u64);

	// Hare row 2: s.len == maxlen — early dup path.
	let r2: str = strings.lpad("12345", '0', 5);
	assert(!(!streq(r2, "12345")));
	assert(!(r2.len != 5));
	os.free(r2.ptr: *void, r2.len: u64);

	// Hare row 3: empty s, full-width pad.
	let r3: str = strings.lpad("", '0', 5);
	assert(!(!streq(r3, "00000")));
	assert(!(r3.len != 5));
	os.free(r3.ptr: *void, r3.len: u64);

	// ww row 1: s.len > maxlen — early dup path returns input copy.
	let r4: str = strings.lpad("abcdef", '_', 3);
	assert(!(!streq(r4, "abcdef")));
	assert(!(r4.len != 6));
	os.free(r4.ptr: *void, r4.len: u64);

	// ww row 2: multibyte s — byte-length contract (Hare `len(s)`).
	// "café" is 5 bytes; maxlen 7 → 2 pad bytes prepended.
	let r5: str = strings.lpad("café", '_', 7);
	assert(!(!streq(r5, "__café")));
	assert(!(r5.len != 7));
	os.free(r5.ptr: *void, r5.len: u64);

	// ww row 3: multibyte pad rune. 'α' U+03B1 is 2 bytes (0xCE 0xB1).
	// s="x" (1 byte), maxlen=5 → npads = 5 - 1 = 4, pad_bytes=2,
	// total writes = 4*2 + 1 = 9 bytes; result `[..5]` = "αα" (4 bytes)
	// + 0xCE (truncated leading byte of next α) — exactly Hare's slice.
	let r6: str = strings.lpad("x", 0x03B1u32: rune, 5);
	assert(!(r6.len != 5));
	assert(!(r6.ptr[0] != 0xCEu8));	// α byte 0
	assert(!(r6.ptr[1] != 0xB1u8));	// α byte 1
	assert(!(r6.ptr[2] != 0xCEu8));	// α byte 0
	assert(!(r6.ptr[3] != 0xB1u8));	// α byte 1
	assert(!(r6.ptr[4] != 0xCEu8));	// truncated α byte 0
	os.free(r6.ptr: *void, r6.len: u64);
};

@test fn rpad_cases() void = {
	// Hare row 1: shorter s, ASCII pad.
	let r1: str = strings.rpad("2", '0', 5);
	assert(!(!streq(r1, "20000")));
	assert(!(r1.len != 5));
	os.free(r1.ptr: *void, r1.len: u64);

	// Hare row 2: s.len == maxlen — early dup path.
	let r2: str = strings.rpad("12345", '0', 5);
	assert(!(!streq(r2, "12345")));
	assert(!(r2.len != 5));
	os.free(r2.ptr: *void, r2.len: u64);

	// Hare row 3: empty s.
	let r3: str = strings.rpad("", '0', 5);
	assert(!(!streq(r3, "00000")));
	assert(!(r3.len != 5));
	os.free(r3.ptr: *void, r3.len: u64);

	// ww row 1: s.len > maxlen — early dup path.
	let r4: str = strings.rpad("abcdef", '_', 3);
	assert(!(!streq(r4, "abcdef")));
	assert(!(r4.len != 6));
	os.free(r4.ptr: *void, r4.len: u64);

	// ww row 2: multibyte s — byte-length contract.
	let r5: str = strings.rpad("café", '_', 7);
	assert(!(!streq(r5, "café__")));
	assert(!(r5.len != 7));
	os.free(r5.ptr: *void, r5.len: u64);

	// ww row 3: multibyte pad rune (2-byte 'α'). s="x" (1 byte),
	// maxlen=5 → "xαα" appended is 1 + 4 = 5 bytes (no truncation).
	let r6: str = strings.rpad("x", 0x03B1u32: rune, 5);
	assert(!(r6.len != 5));
	assert(!(r6.ptr[0] != 'x'));
	assert(!(r6.ptr[1] != 0xCEu8));	// α byte 0
	assert(!(r6.ptr[2] != 0xB1u8));	// α byte 1
	assert(!(r6.ptr[3] != 0xCEu8));	// α byte 0
	assert(!(r6.ptr[4] != 0xB1u8));	// α byte 1
	os.free(r6.ptr: *void, r6.len: u64);
};

// ---- replace ----------------------------------------------------------
// ref/hare/strings/replace.ha:46 (#4). Hare rows 1-5 (target found
// once / multiple times / shorter / longer / multibyte) plus ww rows
// (no-match returns fresh copy, empty-replacement, result-shrinks-to-
// empty).

@test fn replace_cases() void = {
	// Hare row 1: target found once.
	match (strings.replace("Hello world!", "world", "there")) {
	case let s: str => {
		assert(!(!streq(s, "Hello there!")));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// Hare row 2: needle found four times (replacement same length).
	match (strings.replace("I like dogs, dogs, birds, dogs", "dogs", "cats")) {
	case let s: str => {
		assert(!(!streq(s, "I like cats, cats, birds, cats")));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// Hare row 3: replacement shorter than needle, non-overlapping
	// matches (Hare advances by needle.len, not 1).
	match (strings.replace("aaaaaa", "aa", "a")) {
	case let s: str => {
		assert(!(!streq(s, "aaa")));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// Hare row 4: replacement longer than needle.
	match (strings.replace("aaa", "a", "aa")) {
	case let s: str => {
		assert(!(!streq(s, "aaaaaa")));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// Hare row 5: multibyte UTF-8 (3-byte runes).
	match (strings.replace("こんにちは", "にち", "ばん")) {
	case let s: str => {
		assert(!(!streq(s, "こんばんは")));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// ww row 1: needle not found — fresh copy (distinct from
	// borrowed input ptr).
	let src: str = "hello world";
	match (strings.replace(src, "xyz", "abc")) {
	case let s: str => {
		assert(!(!streq(s, "hello world")));
		assert(!(s.ptr == src.ptr));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// ww row 2: empty replacement — needle is removed.
	match (strings.replace("foo-bar-baz", "-", "")) {
	case let s: str => {
		assert(!(!streq(s, "foobarbaz")));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// ww row 3: result shrinks to empty — total==0 nil-alloc path.
	match (strings.replace("aaaa", "aa", "")) {
	case let s: str => {
		assert(!(!streq(s, "")));
		assert(!(s.len != 0));
	};
	case nomem => { abort(); };
	};

	// ww row 4: multibyte single-rune replace — every "に" → "X".
	match (strings.replace("こんにちは", "に", "X")) {
	case let s: str => {
		assert(!(!streq(s, "こんXちは")));
		os.free(s.ptr: *void, s.len: u64);
	};
	case nomem => { abort(); };
	};

	// ww row 5: empty input — returns empty.
	match (strings.replace("", "x", "y")) {
	case let s: str => {
		assert(!(s.len != 0));
	};
	case nomem => { abort(); };
	};
};

// ---- cut / rcut -------------------------------------------------------
// ref/hare/strings/tokenize.ha:316 (@test fn cut). str wrappers over
// bytes.cut/rcut. The `let (a, b) = cut(...)` destructure drives the
// over-cap tuple-return (sret) path end-to-end (a 2nd #10 witness).

@test fn cut_cases() void = {
	// both halves present.
	let (a0, b0) = strings.cut("hello=world", "=");
	assert(!(!streq(a0, "hello")));
	assert(!(!streq(b0, "world")));

	// only first instance is cut; rest stays in the second half.
	let (a1, b1) = strings.cut("hello=world=foobar", "=");
	assert(!(!streq(a1, "hello")));
	assert(!(!streq(b1, "world=foobar")));

	// delim absent -> (whole input, "").
	let (a2, b2) = strings.cut("hello world", "=");
	assert(!(!streq(a2, "hello world")));
	assert(!(!streq(b2, "")));

	// delim at start -> empty before.
	let (a3, b3) = strings.cut("=world", "=");
	assert(!(!streq(a3, "")));
	assert(!(!streq(b3, "world")));

	// delim at end -> empty after.
	let (a4, b4) = strings.cut("hello=", "=");
	assert(!(!streq(a4, "hello")));
	assert(!(!streq(b4, "")));

	// empty input -> ("", "").
	let (a5, b5) = strings.cut("", "=");
	assert(!(!streq(a5, "")));
	assert(!(!streq(b5, "")));

	// multi-byte delim present.
	let (a6, b6) = strings.cut("aXYbXYc", "XY");
	assert(!(!streq(a6, "a")));
	assert(!(!streq(b6, "bXYc")));

	// multi-byte delim absent.
	let (a7, b7) = strings.cut("abc", "XY");
	assert(!(!streq(a7, "abc")));
	assert(!(!streq(b7, "")));

	// borrowed, not copied: first half aliases the input bytes.
	let in: str = "hello=world";
	let (a8, b8) = strings.cut(in, "=");
	assert(!(a8.ptr != in.ptr));
};

@test fn rcut_cases() void = {
	// rcut splits along the LAST instance.
	let (a0, b0) = strings.rcut("hello=world=foobar", "=");
	assert(!(!streq(a0, "hello=world")));
	assert(!(!streq(b0, "foobar")));

	// single instance == cut.
	let (a1, b1) = strings.rcut("hello=world", "=");
	assert(!(!streq(a1, "hello")));
	assert(!(!streq(b1, "world")));

	// delim absent -> (whole input, "").
	let (a2, b2) = strings.rcut("hello world", "=");
	assert(!(!streq(a2, "hello world")));
	assert(!(!streq(b2, "")));

	// delim at end -> empty after.
	let (a3, b3) = strings.rcut("hello=", "=");
	assert(!(!streq(a3, "hello")));
	assert(!(!streq(b3, "")));

	// delim at start -> empty before.
	let (a4, b4) = strings.rcut("=world", "=");
	assert(!(!streq(a4, "")));
	assert(!(!streq(b4, "world")));

	// empty input -> ("", "").
	let (a5, b5) = strings.rcut("", "=");
	assert(!(!streq(a5, "")));
	assert(!(!streq(b5, "")));

	// multi-byte delim, two instances -> cut at LAST.
	let (a6, b6) = strings.rcut("XYaXYb", "XY");
	assert(!(!streq(a6, "XYa")));
	assert(!(!streq(b6, "b")));

	// multi-byte delim absent.
	let (a7, b7) = strings.rcut("abc", "XY");
	assert(!(!streq(a7, "abc")));
	assert(!(!streq(b7, "")));
};