Hojun-Cho
77e62e5ed2
index(haystack: str, needle: (str|rune)) (i32|void) per
ref/hare/strings/index.ha:10. rindex symmetric per :22.
Returns RUNE-index (not byte-index) per Hare contract. str-arm reuses
byteindex/rbyteindex for the anchor byte offset, then walks iter
forward counting runes until position(&it) >= bo. rune-arm forward-
iterates with next(), counts rune positions.
rindex_rune divergence from ref/hare/strings/index.ha:45: Hare's
rindex_rune walks i = len(s) - 1 by 1 per step (byte-len-1 minus
decrement count) — neither pure-byte nor pure-rune for multibyte
input, contradicts its own docstring's rune-wise claim. ww honors
the docstring contract: forward iter + last-match-index. Cited
inline at strings.ww.
Unblocked by #13 (d2c64bc) — pre-#13 the test rows
"strings.index" + "bytes.index" would collide on
*.index_match_next_1 labels in combined.s.
index_cases + rindex_cases per-row inline-match (sister convention of
byteindex_str/rune_cases at stringstest.ww:147-231; sum-type-needle
single-struct table awkward). Bisect via signalled = 1400+i / 1500+i.
Rune-vs-byte pin rows: "こんにちは"+"ちは" → 3 (byte 9),
"またあったね"+"た" rindex → 4 (byte 12). Void miss + 4-byte rune
multibyte coverage.
make test 125/125; ww2==ww3==ww4 byte-id holds via 995_self_rebuild.