RegexParser

Java-regex-style parser producing a normalized Regex.

Supported subset (see Regex doc): literals, escapes (\d \D \s \S \w \W \t \n \r \f \a \e \v \cX \0[n[n]] \xhh \x{h...h} \uhhhh \Q...\E \R and meta-escapes . * + ? ( ) [ ] { } | ^ $ -), Unicode property escapes \p{...} \P{...} (general categories like L/Lu/Nd, and the ASCII-only POSIX classes like Alpha/Digit - see UnicodeCategories; script/block properties are unsupported), ., char classes [...] [^...] with ranges, nested shorthand escapes ([\da-f]), nested subclasses, and && intersection ([a-z&&[^aeiou]]) (\b inside a class means backspace, matching Java), alternation |, capturing groups (...), named groups (?...), non-capturing groups (?:...), lookahead (?=...) (?!...), the i inline flag (?i) (?-i) (?i:...) (?-i:...) (ASCII-only case folding, matching Java's CASE_INSENSITIVE without UNICODE_CASE), quantifiers * + ? {n} {n,} {n,m} (bounds capped at Regex.maxRepeatBound), anchors ^ $ \A \Z \z.

Capturing/named groups are recognized structurally (numbered/named correctly - see Regex.Group) but their captured spans aren't extractable yet - that's tracked separately, same as Regex's own doc comment notes.

Unsupported: word-boundary anchors \b \B, \G, lookbehind, backreferences \1..\9 \k \g{...}, Unicode script/block properties (\p{IsGreek}, \p{InGreek}, etc.), grapheme clusters \X, other inline flags ((?m), (?s), (?d), (?u), (?x), (?U)). Any other undefined letter escape (e.g. \m, \y, \q) is rejected as invalid syntax, matching java.util.regex.Pattern's own behavior.