// stringstest — exercises lib/strings. Run with
// `out/bin/ww run lib/strings/stringstest.ww`.
// Same signalled-then-fail()-with-+10 shape as bytes / utf8 / hex /
// time tests: non-zero exit pinpoints the failing scenario.
//
// Vectors mirror ref/hare/strings/{dup,concat,trim,contains,index,
// suffix,compare}.ha where ww can express them.

package strings;

import strings;
import encoding.utf8;
import os;

let signalled: i32 = 0;
fn fail() void = { os.exit(signalled + 10); };

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("");
	if (!streq(e, "")) { fail(); };
	if (e.len != 0) { fail(); };

	let h: str = strings.dup("hello");
	if (!streq(h, "hello")) { fail(); };
	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");
	if (m.len != 15) { fail(); };
	if (!streq(m, "こんにちは")) { fail(); };
	if (m.ptr == "こんにちは".ptr) { fail(); };	// fresh alloc
	defer os.free(m.ptr: *void, m.len: u64);
};

// ---- 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. The
// per-row `signalled` bump narrows a failure exit code to the offending
// row.

@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) {
		signalled = 200 + i;
		let argv: []str;
		argv.ptr = &pool[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.concat(argv...);
		if (!streq(got, want[i])) { fail(); };
		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).
// Per-row `signalled` 1620+i narrows the failing row.

@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) {
		signalled = 1620 + i;
		let argv: []str;
		argv.ptr = &pool[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.join(seps[i], argv...);
		if (!streq(got, want[i])) { fail(); };
		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 = {
	if (!strings.hasprefix("hello world", "hello")) { fail(); };
	if (!strings.hasprefix("hello world", 'h')) { fail(); };
	if ( strings.hasprefix("hello world", "world")) { fail(); };
	if ( strings.hasprefix("hello world", 'q')) { fail(); };
	if (!strings.hasprefix("hello", "hello")) { fail(); };	// equal-len
	if (!strings.hasprefix("anything", "")) { fail(); };	// empty prefix
	if ( strings.hasprefix("", "x")) { fail(); };
	// multibyte rune prefix — '\'é\'' literal blocked by single-byte
	// lexrune (lib/ww/lex/lex.ww:659); pass codepoint directly.
	if (!strings.hasprefix("éclat", 0xE9u32: rune))       { fail(); };
	if (!strings.hasprefix("🦀rust", 0x1F980u32: rune)) { fail(); };
};

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

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

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

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

	// Variadic rows. ref/hare/strings/contains.ha:27.
	signalled = 1600;
	if ( strings.contains("hello")) { fail(); };
	signalled = 1601;
	if (!strings.contains("hello world", "world")) { fail(); };
	signalled = 1602;
	if (!strings.contains("hello", 'l')) { fail(); };
	signalled = 1603;
	if (!strings.contains("hello world", "foo", "world", 'x')) { fail(); };
	signalled = 1604;
	if ( strings.contains("hello", "foo", 'z', "bar")) { fail(); };
	signalled = 1605;
	if (!strings.contains("héllo", "x", 0xE9u32: rune)) { fail(); };
};

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

@test fn byteindex_rune_cases() void = {
	// ASCII rune (1-byte encoding).
	match (strings.byteindex("hello world", 'w')) {
	case let i: i32 => { if (i != 6) { fail(); }; };
	case void => { fail(); };
	};
	// 2-byte rune U+00E9 'é' inside "café".
	match (strings.byteindex("café", 0xE9u32: rune)) {
	case let i: i32 => { if (i != 3) { fail(); }; };
	case void => { fail(); };
	};
	// 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 => { if (i != 9) { fail(); }; };
	case void => { fail(); };
	};
	// 4-byte rune U+1F980 '🦀' inside "ab🦀cd".
	match (strings.byteindex("ab🦀cd", 0x1F980u32: rune)) {
	case let i: i32 => { if (i != 2) { fail(); }; };
	case void => { fail(); };
	};
	// absent.
	match (strings.byteindex("こんにちは", 'q')) {
	case let i: i32 => { fail(); };
	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 => { if (i != 3) { fail(); }; };
	case void => { fail(); };
	};
	match (strings.rbyteindex("またあったね", "た")) {
	case let i: i32 => { if (i != 12) { fail(); }; };
	case void => { fail(); };
	};
	// Rune arm, multi-byte 'に' U+306B.
	match (strings.rbyteindex("こんにちは", 0x306Bu32: rune)) {
	case let i: i32 => { if (i != 6) { fail(); }; };
	case void => { fail(); };
	};
	// Absent.
	match (strings.rbyteindex("abc", 'z')) {
	case let i: i32 => { fail(); };
	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.
	signalled = 1400;
	match (strings.index("hello", "ll")) {
	case let i: i32 => { if (i != 2) { fail(); }; };
	case void => { fail(); };
	};
	// str-arm: absent needle.
	signalled = 1401;
	match (strings.index("hello", "world")) {
	case let i: i32 => { fail(); };
	case void => void;
	};
	// Hare vectors at ref/hare/strings/index.ha:113-119.
	signalled = 1402;
	match (strings.index("hello world!", "hello")) {
	case let i: i32 => { if (i != 0) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1403;
	match (strings.index("hello world!", "world")) {
	case let i: i32 => { if (i != 6) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1404;
	match (strings.index("hello world!", "orld!")) {
	case let i: i32 => { if (i != 7) { fail(); }; };
	case void => { fail(); };
	};
	// Multibyte haystack + str needle: "ちは" at rune index 3
	// in "こんにちは" (byteindex returns 9, rune-index is 3).
	signalled = 1405;
	match (strings.index("こんにちは", "ちは")) {
	case let i: i32 => { if (i != 3) { fail(); }; };
	case void => { fail(); };
	};
	// rune-arm.
	signalled = 1406;
	match (strings.index("hello", 'l')) {
	case let i: i32 => { if (i != 2) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1407;
	match (strings.index("hello world", 'w')) {
	case let i: i32 => { if (i != 6) { fail(); }; };
	case void => { fail(); };
	};
	// 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).
	signalled = 1408;
	match (strings.index("héllo", 0xE9u32: rune)) {
	case let i: i32 => { if (i != 1) { fail(); }; };
	case void => { fail(); };
	};
	// Multibyte rune in multibyte haystack: 'ち' U+3061 at rune 3
	// in "こんにちは" (byteindex returns 9, rune-index is 3).
	signalled = 1409;
	match (strings.index("こんにちは", 0x3061u32: rune)) {
	case let i: i32 => { if (i != 3) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1410;
	match (strings.index("こんにちは", 'q')) {
	case let i: i32 => { fail(); };
	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).
	signalled = 1411;
	match (strings.index("またあったね", "あった")) {
	case let i: i32 => { if (i != 2) { fail(); }; };
	case void => { fail(); };
	};
	// str-arm: tail-anchored multibyte needle. "は" is at rune 4
	// (byte 12) in "こんにちは".
	signalled = 1412;
	match (strings.index("こんにちは", "は")) {
	case let i: i32 => { if (i != 4) { fail(); }; };
	case void => { fail(); };
	};
	// 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).
	signalled = 1413;
	match (strings.index("hello", "")) {
	case let i: i32 => { if (i != 0) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1414;
	match (strings.index("", "")) {
	case let i: i32 => { if (i != 0) { fail(); }; };
	case void => { fail(); };
	};
	// Empty haystack, non-empty needle — absent.
	signalled = 1415;
	match (strings.index("", "x")) {
	case let i: i32 => { fail(); };
	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).
	signalled = 1416;
	match (strings.index("こんにちは", "きょうは")) {
	case let i: i32 => { fail(); };
	case void => void;
	};
	// Self-match: haystack == needle, Hare row index.ha:113.
	signalled = 1417;
	match (strings.index("hello", "hello")) {
	case let i: i32 => { if (i != 0) { fail(); }; };
	case void => { fail(); };
	};
};

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

@test fn rindex_cases() void = {
	// str-arm.
	signalled = 1500;
	match (strings.rindex("hello", "lo")) {
	case let i: i32 => { if (i != 3) { fail(); }; };
	case void => { fail(); };
	};
	// Hare vector at ref/hare/strings/index.ha:122.
	signalled = 1501;
	match (strings.rindex("hello world!", "o")) {
	case let i: i32 => { if (i != 7) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1502;
	match (strings.rindex("hello", "world")) {
	case let i: i32 => { fail(); };
	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).
	signalled = 1503;
	match (strings.rindex("またあったね", "た")) {
	case let i: i32 => { if (i != 4) { fail(); }; };
	case void => { fail(); };
	};
	// rune-arm.
	signalled = 1504;
	match (strings.rindex("hello", 'l')) {
	case let i: i32 => { if (i != 3) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1505;
	match (strings.rindex("aaaaa", 'a')) {
	case let i: i32 => { if (i != 4) { fail(); }; };
	case void => { fail(); };
	};
	// Multibyte rune: 'に' U+306B at rune 2 in "こんにちは".
	signalled = 1506;
	match (strings.rindex("こんにちは", 0x306Bu32: rune)) {
	case let i: i32 => { if (i != 2) { fail(); }; };
	case void => { fail(); };
	};
	signalled = 1507;
	match (strings.rindex("hello", 'z')) {
	case let i: i32 => { fail(); };
	case void => void;
	};
};

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

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

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

// ---- 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) {
		signalled = 1100 + i;
		let argv: []rune;
		argv.ptr = &runes[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.ltrim(inputs[i], argv...);
		if (!streq(got, want[i])) { fail(); };
		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) {
		signalled = 1200 + i;
		let argv: []rune;
		argv.ptr = &runes[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.rtrim(inputs[i], argv...);
		if (!streq(got, want[i])) { fail(); };
		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) {
		signalled = 1300 + i;
		let argv: []rune;
		argv.ptr = &runes[argo[i]];
		argv.len = argn[i];
		argv.cap = argn[i];
		let got: str = strings.trim(inputs[i], argv...);
		if (!streq(got, want[i])) { fail(); };
		i += 1;
	};
};

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

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

// ---- 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). The `is utf8::invalid` row for bytesub is
// deferred to the validating port (#7).

@test fn sub_cases() void = {
	signalled = 1790;
	if (!streq(strings.sub("a string", 0, 8), "a string")) { fail(); };
	signalled = 1791;
	if (!streq(strings.sub("a string", 0, 1), "a")) { fail(); };
	signalled = 1792;
	if (!streq(strings.sub("a string", 0, 3), "a s")) { fail(); };
	signalled = 1793;
	if (!streq(strings.sub("a string", 2, 8), "string")) { fail(); };
	// start == end yields an empty borrowed view.
	signalled = 1794;
	if (!streq(strings.sub("a string", 4, 4), "")) { fail(); };
	if (strings.sub("a string", 4, 4).len != 0) { fail(); };
	// Hare vector — rune indices 1..3 over "こんにちは" select bytes
	// 3..9 ("んに"), not bytes 1..3.
	signalled = 1795;
	if (!streq(strings.sub("こんにちは", 1, 3), "んに")) { fail(); };
	// 2-byte rune at rune index 1 in "héllo" — byte offsets 1..3.
	signalled = 1796;
	if (!streq(strings.sub("héllo", 1, 2), "é")) { fail(); };
	// start == 0, end == rune-len of full string.
	signalled = 1797;
	if (!streq(strings.sub("héllo", 0, 5), "héllo")) { fail(); };
};

@test fn bytesub_cases() void = {
	signalled = 1800;
	if (!streq(strings.bytesub("a string", 0, 8), "a string")) { fail(); };
	signalled = 1801;
	if (!streq(strings.bytesub("a string", 0, 1), "a")) { fail(); };
	signalled = 1802;
	if (!streq(strings.bytesub("a string", 0, 3), "a s")) { fail(); };
	signalled = 1803;
	if (!streq(strings.bytesub("a string", 2, 8), "string")) { fail(); };
	signalled = 1804;
	if (!streq(strings.bytesub("a string", 4, 4), "")) { fail(); };
	// Hare vector — byte indices 3..9 over "こんにちは" select "んに".
	signalled = 1805;
	if (!streq(strings.bytesub("こんにちは", 3, 9), "んに")) { fail(); };
	// 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.
	signalled = 1806;
	if (!streq(strings.sub("こんにちは", 0, 3), "こんに")) { fail(); };
	if (!streq(strings.bytesub("こんにちは", 0, 3), "こ")) { fail(); };
	// Borrowed view: ptr aliases input.
	signalled = 1807;
	let s: str = "hello";
	let r: str = strings.bytesub(s, 1, 4);
	if (r.ptr != s.ptr + 1u64) { fail(); };
	if (r.len != 3) { fail(); };
};

// ---- toutf8 / fromutf8_unsafe roundtrip -------------------------------
// ref/hare/strings/utf8.ha:31.

@test fn utf8_roundtrip_cases() void = {
	let s: str = "hello";
	let b: []u8 = strings.toutf8(s);
	if (b.len != 5) { fail(); };
	if (b[0] != 104u8) { fail(); };	// 'h'
	let r: str = strings.fromutf8_unsafe(b);
	if (!streq(r, "hello")) { fail(); };
	if (r.ptr != s.ptr) { fail(); };	// 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       => { fail(); };
	case utf8.done         => void;
	};
	// Repeated next after done stays done.
	match (strings.next(&it)) {
	case let r: rune       => { fail(); };
	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       => { if (r != 'h') { fail(); }; };
	case utf8.done         => { fail(); };
	};
	match (strings.next(&it)) {
	case let r: rune       => { if (r != 'i') { fail(); }; };
	case utf8.done         => { fail(); };
	};
	match (strings.next(&it)) {
	case let r: rune       => { if (r != '!') { fail(); }; };
	case utf8.done         => { fail(); };
	};
	match (strings.next(&it)) {
	case let r: rune       => { fail(); };
	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   => { if (r != expect[i]) { fail(); }; };
		case utf8.done     => { fail(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { fail(); };
	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   => { if (r != expect[i]) { fail(); }; };
		case utf8.done     => { fail(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { fail(); };
	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   => { if (r != expect[i]) { fail(); }; };
		case utf8.done     => { fail(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { fail(); };
	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   => { if (r != expect[i]) { fail(); }; };
		case utf8.done     => { fail(); };
		};
		i += 1;
	};
	match (strings.next(&it)) {
	case let r: rune       => { fail(); };
	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     => { fail(); };
	};
};

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

// 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       => { fail(); };
	};
	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   => { if (r != expect1[i]) { fail(); }; };
		case utf8.done     => { fail(); };
		};
		i += 1;
	};
	if (!streq(strings.iterstr(&s), "にちは")) { fail(); };
	match (strings.prev(&s)) {
	case let r: rune       => { if (r != 0x3093u32: rune) { fail(); }; };	// 'ん'
	case utf8.done         => { fail(); };
	};
	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   => { if (r != expect2[i]) { fail(); }; };
		case utf8.done     => { fail(); };
		};
		i += 1;
	};
	match (strings.next(&s)) {
	case utf8.done         => void;
	case let r: rune       => { fail(); };
	};
	// Repeated next-after-done stays done.
	match (strings.next(&s)) {
	case utf8.done         => void;
	case let r: rune       => { fail(); };
	};
	match (strings.prev(&s)) {
	case let r: rune       => { if (r != 0x306Fu32: rune) { fail(); }; };	// 'は'
	case utf8.done         => { fail(); };
	};

	// 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   => { if (r != expect3[i]) { fail(); }; };
		case utf8.done     => { fail(); };
		};
		i += 1;
	};
	match (strings.next(&s)) {
	case utf8.done         => void;
	case let r: rune       => { fail(); };
	};
	match (strings.prev(&s)) {
	case let r: rune       => { if (r != 0x306Bu32: rune) { fail(); }; };	// 'に'
	case utf8.done         => { fail(); };
	};
};

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

// 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");
	if (strings.slice(&s, &t).len != 0) { fail(); };
	if (strings.slice(&t, &s).len != 0) { fail(); };
	let i: i32 = 0;
	for (i < 2) {
		match (strings.next(&s)) {
		case let r: rune     => void;
		case utf8.done       => { fail(); };
		};
		match (strings.next(&t)) {
		case let r: rune     => void;
		case utf8.done       => { fail(); };
		};
		i += 1;
	};
	if (strings.slice(&s, &t).len != 0) { fail(); };
	if (strings.slice(&t, &s).len != 0) { fail(); };
	i = 0;
	for (i < 3) {
		match (strings.next(&t)) {
		case let r: rune     => void;
		case utf8.done       => { fail(); };
		};
		i += 1;
	};
	if (!streq(strings.slice(&s, &t), "にちは")) { fail(); };
	i = 0;
	for (i < 3) {
		match (strings.next(&s)) {
		case let r: rune     => void;
		case utf8.done       => { fail(); };
		};
		i += 1;
	};
	if (strings.slice(&s, &t).len != 0) { fail(); };
	if (strings.slice(&t, &s).len != 0) { fail(); };
};

@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");
	if (!streq(strings.iterstr(&rit), "hello")) { fail(); };
	match (strings.next(&rit)) { case let r: rune => void; case utf8.done => { fail(); }; };
	if (!streq(strings.iterstr(&rit), "hell")) { fail(); };
	match (strings.next(&rit)) { case let r: rune => void; case utf8.done => { fail(); }; };
	match (strings.next(&rit)) { case let r: rune => void; case utf8.done => { fail(); }; };
	if (!streq(strings.iterstr(&rit), "he")) { fail(); };
};

// ---- 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    => { if (!streq(p, want)) { fail(); }; };
	case bytes.done    => { fail(); };
	};
	match (strings.next_token(t)) {
	case let n: str    => { if (!streq(n, want)) { fail(); }; };
	case bytes.done    => { fail(); };
	};
};

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

@test fn tokenize_cases() void = {
	// Hare vector — single-space delim. ref/hare/strings/tokenize.ha:112.
	signalled = 1700;
	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.
	signalled = 1701;
	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.
	signalled = 1702;
	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.
	signalled = 1703;
	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.
	signalled = 1704;
	let t5: strings.tokenizer = strings.tokenize("abc", " ");
	expect_str_token(&t5, "abc");
	expect_str_done(&t5);

	// Empty input — done immediately.
	signalled = 1705;
	let t6: strings.tokenizer = strings.tokenize("", " ");
	expect_str_done(&t6);
};

@test fn rtokenize_cases() void = {
	// Reverse direction — first next_token is the last token.
	signalled = 1710;
	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.
	signalled = 1711;
	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.
	signalled = 1712;
	let t3: strings.tokenizer = strings.rtokenize("", " ");
	expect_str_done(&t3);
};

@test fn peek_token_cases() void = {
	// Two peeks without advancing return the same token.
	signalled = 1720;
	let t: strings.tokenizer = strings.tokenize("a b c", " ");
	match (strings.peek_token(&t)) {
	case let p: str    => { if (!streq(p, "a")) { fail(); }; };
	case bytes.done    => { fail(); };
	};
	match (strings.peek_token(&t)) {
	case let p: str    => { if (!streq(p, "a")) { fail(); }; };
	case bytes.done    => { fail(); };
	};
	// Advance once — peek then returns "b".
	signalled = 1721;
	match (strings.next_token(&t)) {
	case let n: str    => { if (!streq(n, "a")) { fail(); }; };
	case bytes.done    => { fail(); };
	};
	match (strings.peek_token(&t)) {
	case let p: str    => { if (!streq(p, "b")) { fail(); }; };
	case bytes.done    => { fail(); };
	};

	// Empty input — peek is done.
	signalled = 1722;
	let t2: strings.tokenizer = strings.tokenize("", " ");
	match (strings.peek_token(&t2)) {
	case let p: str    => { fail(); };
	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.".
	signalled = 1730;
	let t: strings.tokenizer = strings.tokenize(
		"Hello world! My name is Harriet.", " ");
	match (strings.next_token(&t)) {
	case let n: str    => { if (!streq(n, "Hello")) { fail(); }; };
	case bytes.done    => { fail(); };
	};
	match (strings.next_token(&t)) {
	case let n: str    => { if (!streq(n, "world!")) { fail(); }; };
	case bytes.done    => { fail(); };
	};
	if (!streq(strings.remaining_tokens(&t), "My name is Harriet.")) {
		fail();
	};

	// Fresh tokenizer — remaining_tokens is the whole input.
	signalled = 1731;
	let t2: strings.tokenizer = strings.tokenize("a b c", " ");
	if (!streq(strings.remaining_tokens(&t2), "a b c")) { fail(); };
};

// ---- 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 = {
	if (i >= toks.len) { fail(); };
	let p: *str = &toks.ptr[i];
	if (p.len != want.len) { fail(); };
	let j: i32 = 0;
	for (j < want.len) {
		if (p.ptr[j] != want[j]) { fail(); };
		j += 1;
	};
};

@test fn splitn_cases() void = {
	// ref/hare/strings/tokenize.ha:247 — n=4 buckets the trailing
	// "is Drew" as the remainder slot.
	signalled = 1740;
	let t1: []str = strings.splitn("Hello, my name is Drew", " ", 4);
	if (t1.len != 4) { fail(); };
	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) * 16u64);

	// ref/hare/strings/tokenize.ha:263 — n > tokens leaves a single
	// slot holding the unchanged input (delim not found).
	signalled = 1741;
	let t2: []str = strings.splitn("one", "=", 2);
	if (t2.len != 1) { fail(); };
	expect_str(t2, 0, "one");
	os.free(t2.ptr: *void, (t2.cap: u64) * 16u64);

	// n == 1 — single slot holding the whole input as remainder.
	signalled = 1742;
	let t3: []str = strings.splitn("a b c", " ", 1);
	if (t3.len != 1) { fail(); };
	expect_str(t3, 0, "a b c");
	os.free(t3.ptr: *void, (t3.cap: u64) * 16u64);

	// Empty input — empty result.
	signalled = 1743;
	let t4: []str = strings.splitn("", " ", 5);
	if (t4.len != 0) { fail(); };
	if (t4.cap > 0) {
		os.free(t4.ptr: *void, (t4.cap: u64) * 16u64);
	};

	// Multi-byte delim set (byte-set semantics per
	// ref/hare/strings/tokenize.ha:35) — split on ',' OR ':' OR ';'.
	signalled = 1744;
	let t5: []str = strings.splitn("hello;world,foo:bar", ",:;", 10);
	if (t5.len != 4) { fail(); };
	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) * 16u64);
};

@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.
	signalled = 1750;
	let t1: []str = strings.rsplitn("Hello, my name is Drew", " ", 4);
	if (t1.len != 4) { fail(); };
	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) * 16u64);

	// 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).
	signalled = 1751;
	let t2: []str = strings.rsplitn("a b c", " ", 10);
	if (t2.len != 3) { fail(); };
	expect_str(t2, 0, "c");
	expect_str(t2, 1, "b");
	expect_str(t2, 2, "a");
	os.free(t2.ptr: *void, (t2.cap: u64) * 16u64);

	// n == 1 — single slot holding the whole input as remainder.
	signalled = 1752;
	let t3: []str = strings.rsplitn("a b c", " ", 1);
	if (t3.len != 1) { fail(); };
	expect_str(t3, 0, "a b c");
	os.free(t3.ptr: *void, (t3.cap: u64) * 16u64);

	// 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).
	signalled = 1753;
	let t4: []str = strings.rsplitn("abc", "=", 5);
	if (t4.len != 1) { fail(); };
	expect_str(t4, 0, "abc");
	os.free(t4.ptr: *void, (t4.cap: u64) * 16u64);
};

@test fn split_cases() void = {
	// ref/hare/strings/tokenize.ha:255 — full split, every delim hit
	// is a boundary.
	signalled = 1760;
	let t1: []str = strings.split("Hello, my name is Drew", " ");
	if (t1.len != 5) { fail(); };
	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) * 16u64);

	// Leading + trailing delim — empty tokens at ends.
	signalled = 1761;
	let t2: []str = strings.split(" a b ", " ");
	if (t2.len != 4) { fail(); };
	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) * 16u64);

	// Multi-byte delim set, byte-set semantics matching Hare's
	// strings::split example at ref/hare/strings/tokenize.ha:235.
	signalled = 1762;
	let t3: []str = strings.split("hello;world,foo:bar", ",:;");
	if (t3.len != 4) { fail(); };
	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) * 16u64);
};

// ---- 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.
	signalled = 1770;
	let r1: str = strings.lpad("2", '0', 5);
	if (!streq(r1, "00002")) { fail(); };
	if (r1.len != 5) { fail(); };
	os.free(r1.ptr: *void, r1.len: u64);

	// Hare row 2: s.len == maxlen — early dup path.
	signalled = 1771;
	let r2: str = strings.lpad("12345", '0', 5);
	if (!streq(r2, "12345")) { fail(); };
	if (r2.len != 5) { fail(); };
	os.free(r2.ptr: *void, r2.len: u64);

	// Hare row 3: empty s, full-width pad.
	signalled = 1772;
	let r3: str = strings.lpad("", '0', 5);
	if (!streq(r3, "00000")) { fail(); };
	if (r3.len != 5) { fail(); };
	os.free(r3.ptr: *void, r3.len: u64);

	// ww row 1: s.len > maxlen — early dup path returns input copy.
	signalled = 1773;
	let r4: str = strings.lpad("abcdef", '_', 3);
	if (!streq(r4, "abcdef")) { fail(); };
	if (r4.len != 6) { fail(); };
	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.
	signalled = 1774;
	let r5: str = strings.lpad("café", '_', 7);
	if (!streq(r5, "__café")) { fail(); };
	if (r5.len != 7) { fail(); };
	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.
	signalled = 1775;
	let r6: str = strings.lpad("x", 0x03B1u32: rune, 5);
	if (r6.len != 5) { fail(); };
	if (r6.ptr[0] != 0xCEu8) { fail(); };	// α byte 0
	if (r6.ptr[1] != 0xB1u8) { fail(); };	// α byte 1
	if (r6.ptr[2] != 0xCEu8) { fail(); };	// α byte 0
	if (r6.ptr[3] != 0xB1u8) { fail(); };	// α byte 1
	if (r6.ptr[4] != 0xCEu8) { fail(); };	// truncated α byte 0
	os.free(r6.ptr: *void, r6.len: u64);
};

@test fn rpad_cases() void = {
	// Hare row 1: shorter s, ASCII pad.
	signalled = 1780;
	let r1: str = strings.rpad("2", '0', 5);
	if (!streq(r1, "20000")) { fail(); };
	if (r1.len != 5) { fail(); };
	os.free(r1.ptr: *void, r1.len: u64);

	// Hare row 2: s.len == maxlen — early dup path.
	signalled = 1781;
	let r2: str = strings.rpad("12345", '0', 5);
	if (!streq(r2, "12345")) { fail(); };
	if (r2.len != 5) { fail(); };
	os.free(r2.ptr: *void, r2.len: u64);

	// Hare row 3: empty s.
	signalled = 1782;
	let r3: str = strings.rpad("", '0', 5);
	if (!streq(r3, "00000")) { fail(); };
	if (r3.len != 5) { fail(); };
	os.free(r3.ptr: *void, r3.len: u64);

	// ww row 1: s.len > maxlen — early dup path.
	signalled = 1783;
	let r4: str = strings.rpad("abcdef", '_', 3);
	if (!streq(r4, "abcdef")) { fail(); };
	if (r4.len != 6) { fail(); };
	os.free(r4.ptr: *void, r4.len: u64);

	// ww row 2: multibyte s — byte-length contract.
	signalled = 1784;
	let r5: str = strings.rpad("café", '_', 7);
	if (!streq(r5, "café__")) { fail(); };
	if (r5.len != 7) { fail(); };
	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).
	signalled = 1785;
	let r6: str = strings.rpad("x", 0x03B1u32: rune, 5);
	if (r6.len != 5) { fail(); };
	if (r6.ptr[0] != 'x') { fail(); };
	if (r6.ptr[1] != 0xCEu8) { fail(); };	// α byte 0
	if (r6.ptr[2] != 0xB1u8) { fail(); };	// α byte 1
	if (r6.ptr[3] != 0xCEu8) { fail(); };	// α byte 0
	if (r6.ptr[4] != 0xB1u8) { fail(); };	// α byte 1
	os.free(r6.ptr: *void, r6.len: u64);
};

export fn main() i32 = {
	signalled = 1;  dup_cases();
	signalled = 2;  concat_cases();
	signalled = 30; join_cases();
	signalled = 3;  hasprefix_cases();
	signalled = 4;  hassuffix_cases();
	signalled = 5;  contains_cases();
	signalled = 6;  byteindex_str_cases();
	signalled = 7;  byteindex_rune_cases();
	signalled = 8;  rbyteindex_cases();
	signalled = 28; index_cases();
	signalled = 29; rindex_cases();
	signalled = 9;  trimprefix_cases();
	signalled = 10; trimsuffix_cases();
	signalled = 11; ltrim_cases();
	signalled = 12; rtrim_cases();
	signalled = 13; trim_cases();
	signalled = 14; compare_cases();
	signalled = 40; sub_cases();
	signalled = 41; bytesub_cases();
	signalled = 15; utf8_roundtrip_cases();
	signalled = 16; iter_empty_cases();
	signalled = 17; iter_ascii_cases();
	signalled = 18; iter_twobyte_cases();
	signalled = 19; iter_threebyte_cases();
	signalled = 20; iter_fourbyte_cases();
	signalled = 21; iter_mixed_cases();
	signalled = 22; iter_prev_at_start_cases();
	signalled = 23; iter_prev_ascii_cases();
	signalled = 24; iter_full_cases();
	signalled = 25; iter_position_cases();
	signalled = 26; iter_iterstr_reverse_cases();
	signalled = 27; iter_slice_cases();
	signalled = 31; tokenize_cases();
	signalled = 32; rtokenize_cases();
	signalled = 33; peek_token_cases();
	signalled = 34; remaining_tokens_cases();
	signalled = 35; splitn_cases();
	signalled = 36; rsplitn_cases();
	signalled = 37; split_cases();
	signalled = 38; lpad_cases();
	signalled = 39; rpad_cases();
	return 0;
};