Add (?<=...) positive and (?<!...) negative lookbehind support.
The sub-pattern must have a fixed byte length (no quantifiers or
alternation), computed at compile time and stored in the instruction.
At execution time, the engine backs up by that many bytes and runs
the sub-pattern forward. Maximum lookbehind length is 255 bytes.
Co-authored-by: Claude <noreply@anthropic.com>
Internal flags (MULTILINE=2, DOTALL=4, EXTENDED=8) differ from
Ruby constants (EXTENDED=2, MULTILINE=4). Convert in C instead
of returning raw internal flags. Also add Regexp#casefold?.
Co-authored-by: Claude <noreply@anthropic.com>
The x flag ignores unescaped whitespace and #comments in patterns,
making complex regexps more readable. Whitespace inside character
classes [...] remains literal. Implemented as a preprocessing step
that strips whitespace/comments before compilation.
Co-authored-by: Claude <noreply@anthropic.com>
Two regexps are equal when they have the same source and flags.
Hash is computed from source string hash mixed with flags.
Co-authored-by: Claude <noreply@anthropic.com>
Regexp#to_s now returns (?flags:source) format (e.g. "(?i:abc)")
instead of the /source/flags format used by Regexp#inspect.
Co-authored-by: Claude <noreply@anthropic.com>
- $1-$9 global variables set by Regexp#match and Regexp#=~
- $1-$9 cleared to nil on match failure
- add mruby-regexp to stdlib.gembox (auto-included in standard builds)
- remove duplicate gem entry from host-debug.rb
Co-authored-by: Claude <noreply@anthropic.com>
implement positive and negative lookahead in the backtracking engine:
- (?=pattern): succeeds if pattern matches at current position
without consuming characters
- (?!pattern): succeeds if pattern does NOT match at current position
new bytecodes RE_LOOKAHEAD and RE_NEG_LOOKAHEAD implemented in
the backtracking engine via nested bt_match calls.
Co-authored-by: Claude <noreply@anthropic.com>
support named capture groups in patterns:
- compiler parses (?<name>...) syntax and builds name table
- MatchData#[:name] and MatchData#["name"] access by name
- MatchData#named_captures returns {name => value} hash
- Regexp#named_captures returns {name => group_number} hash
- named captures stored in mrb_regexp_pattern for GC safety
Co-authored-by: Claude <noreply@anthropic.com>
non-greedy patterns now correctly match the shortest possible
string. patterns with non-greedy quantifiers are dispatched to
the backtracking engine which naturally handles non-greedy
semantics.
the Pike VM continues to be used for purely greedy patterns
(O(n*m) guarantee).
Co-authored-by: Claude <noreply@anthropic.com>
add a recursive backtracking engine that handles \1-\9
backreferences. the Pike VM (NFA) is used for patterns without
backreferences; patterns with backreferences automatically
fall back to the backtracking engine.
the backtracking engine has a step limit (MRB_REGEXP_STEP_LIMIT,
default 1M) to prevent ReDoS on pathological patterns.
also adds SAVE backtracking (save/restore capture positions on
failed branches) for correct submatch tracking.
Co-authored-by: Claude <noreply@anthropic.com>
add tests for: empty pattern, nested captures, word boundary \b,
non-capturing groups (?:), sub/gsub with block, scan with captures,
split with regexp, case/when with regexp, date reformatting.
known limitation: non-greedy quantifiers (*?, +?) currently behave
as greedy. needs match priority tracking (TODO for Phase 2).
Co-authored-by: Claude <noreply@anthropic.com>
- /regex/ literal syntax now works (compiler generates Regexp.compile)
- Regexp#match and Regexp#=~ set $~ global variable
- Regexp.last_match(n) for accessing capture groups
- Regexp.compile as alias for Regexp.new
- Regexp#options
Co-authored-by: Claude <noreply@anthropic.com>
Yukihiro "Matz" Matsumoto