New primitives in sx_primitives.ml:
char-at, char-code, parse-number — string inspection + conversion
regex-match, regex-match?, regex-find-all — PCRE pattern matching
regex-replace, regex-replace-first — PCRE substitution
regex-split — split by PCRE pattern
Uses Re.Pcre (OCaml re library) so regex patterns use the same syntax
as JS RegExp — patterns in .sx files work identically on browser and
server. Replaces the old test-only regex-find-all stub.
Also: split now handles multi-char separators via Re.
176 new tests (10 suites). 2912/2912 total, zero failures.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
5d88b363e4