Port of ref/hare/regex/regex.ha:135-225 (handle_bracket, whole),
265-275 (in_bracket dispatch), 313-314 (the `[` flip), 249-252 (the
bracket state quad) and 704-737 (the consuming charset arm). `[`
graduates from the fold-2a loud set; `(` `)` `{` are the last
three loud metachars. The POSIX-class arm keeps its DETECTION
verbatim but loud-aborts its BODY (charclass_map stays #25-blocked;
falling through to the literal arm would silently compile
[[:alpha:]] as a 9-literal charset). is_consuming_inst already
covered inst_charset.
Spelling divergences, all site-documented: the dispatch propagates
via the explicit D13 match, not `?` (compile's 64B sret return is
the #38b loud-stop; the fold-3 find_last_groupstart precedent);
charset's declaration moves BELOW its member types (cstage sizes a
tagged alias with forward-declared members at a degenerate 8B —
ww-core #69, wwstage is correct); run_thread binds the charset
structurally, not via the alias (alias-typed slice locals mis-scale
their index reads in wwstage — ww-core #68).
Tests: Hare's own bracket block (+test.ha:278-345, the group and
POSIX rows excluded with their loud arms) as the 72-row find/test
table incl. multibyte literal+range brackets and an unanchored
[ab]+ composition row; charsets-table content pins (lit/range
discrimination, first-char ]/[ literals, literal dashes, multibyte
codepoints); program-shape pins ([abc] / ^[abc]$ / [^ab] /
[ab][cd] / [abc]*); exact-text error rows (Unmatched '[' ×3 incl
the escape interaction, descending [z-a]); findall composition.
The [[:alpha:]] abort text is unpinnable in-process (it kills the
runner) — source-audited until the POSIX fold.
Hojun-Cho
95fea97868