selfhost: port forrange — N_FORRANGE parser + cgen + tuple destructure

test/wcc/990_selfhost.c

@@ -345,6 +345,32 @@ probe_ww_compile(const char *bin)
 		  "  dec(&c); dec(&c); dec(&c);\n"
 		  "  return c.x;\n"
 		  "};", 2 },
+		/* Hare-style for-range over a slice: `for (let b .. s)`.
+		 * Allocates `.rgi`/`.rgl` scratch slots, walks i=0..s.len
+		 * loading s.ptr[i] into the binding. esz=1 here so the
+		 * load is MOVZBQ. Sum 10+20+30+40 = 100. */
+		{ "use os;\n"
+		  "fn main() i32 = {\n"
+		  "  let s: []u8;\n"
+		  "  s.ptr = nil; s.len = 0; s.cap = 0;\n"
+		  "  append(s, 10u8, 20u8, 30u8, 40u8);\n"
+		  "  let total: i32 = 0;\n"
+		  "  for (let b .. s) { total += b: i32; };\n"
+		  "  return total;\n"
+		  "};", 100 },
+		/* for-range with tuple destructure on `(i64, i64)`. Element
+		 * size is 16 (sum of raw param sizes); each binding loads
+		 * via BX+foff. Buf has (1,10) (2,20); sum = 33. */
+		{ "fn main() i32 = {\n"
+		  "  let buf: [4]i64;\n"
+		  "  buf[0] = 1i64; buf[1] = 10i64; buf[2] = 2i64; buf[3] = 20i64;\n"
+		  "  let s: [](i64, i64);\n"
+		  "  s.ptr = buf.ptr: *(i64, i64);\n"
+		  "  s.len = 2; s.cap = 2;\n"
+		  "  let total: i64 = 0i64;\n"
+		  "  for (let (k, v) .. s) { total += k + v; };\n"
+		  "  return total: i32;\n"
+		  "};", 33 },
 		/* append(s, v, ...) builtin — Hare's rt::ensure model.
 		 * Each value: PUSHQ AX, ADDQ $1 to s.len, LEAQ s/MOVQ esz
 		 * args for rt_ensure, then write into the freshly-grown

test/wcc/994_w6c_ww.c

@@ -178,6 +178,27 @@ main(void)
 		  "  append(dst, src...);\n"
 		  "  return dst.len: i32;\n"
 		  "};" },
+		{ "forrange",
+		  "use os;\n"
+		  "fn main() i32 = {\n"
+		  "  let s: []u8;\n"
+		  "  s.ptr = nil; s.len = 0; s.cap = 0;\n"
+		  "  append(s, 10u8, 20u8, 30u8);\n"
+		  "  let total: i32 = 0;\n"
+		  "  for (let b .. s) { total += b: i32; };\n"
+		  "  return total;\n"
+		  "};" },
+		{ "forrange_tuple",
+		  "fn main() i32 = {\n"
+		  "  let buf: [4]i64;\n"
+		  "  buf[0] = 1i64; buf[1] = 10i64; buf[2] = 2i64; buf[3] = 20i64;\n"
+		  "  let s: [](i64, i64);\n"
+		  "  s.ptr = buf.ptr: *(i64, i64);\n"
+		  "  s.len = 2; s.cap = 2;\n"
+		  "  let total: i64 = 0i64;\n"
+		  "  for (let (k, v) .. s) { total += k + v; };\n"
+		  "  return total: i32;\n"
+		  "};" },
 		{ NULL, NULL },
 	};