%YAML 1.2
---
# http://php.net/manual/en/reference.pcre.pattern.syntax.php
name: Regular Expressions (PHP)
comment: Matches PHP's regular expression syntax.
scope: source.regexp.php
hidden: true
contexts:
  main:
    # comment
    # ref: http://php.net/manual/en/regexp.reference.comments.php
    - match: \(\?\#
      scope: punctuation.definition.comment.begin.regexp
      push:
        - meta_scope: comment.block.regexp
        - match: \)
          scope: punctuation.definition.comment.end.regexp
          pop: true

    # backreference
    # ref: http://php.net/manual/en/regexp.reference.back-references.php
    - match: \\{1,2}[1-9]
      scope: keyword.other.back-reference.regexp
    - match: \\{1,2}g([1-9]|\{-?[0-9]+\})
      scope: keyword.other.back-reference.regexp

    # named group backreference
    # ref: http://php.net/manual/en/regexp.reference.back-references.php
    - match: \\{1,2}(?:[gk]\{([^\}]+)\}|k(?:<([^>]+)>|'([^']+)'))
      scope: keyword.other.back-reference.named.regexp
      captures:
        1: entity.name.other.group.regexp
        2: entity.name.other.group.regexp
        3: entity.name.other.group.regexp
    - match: (\()(\?P=)([a-zA-Z_][a-zA-Z_0-9]*\w*)(\))
      captures:
        1: punctuation.definition.group.begin.regexp
        2: keyword.other.back-reference.named.regexp
        3: entity.name.other.group.regexp
        4: punctuation.definition.group.begin.regexp

    # anchor
    # ref: http://php.net/manual/en/regexp.reference.anchors.php
    - match: \\{1,2}[bBAZzG]|\^|\$
      scope: keyword.control.anchor.regexp

    # repetition
    # ref: http://php.net/manual/en/regexp.reference.repetition.php
    - match: '[?+*][?+]?|\{([0-9]+(,([0-9]+)?)?|,[0-9]+)\}\??'
      scope: keyword.operator.quantifier.regexp

    # alternation
    # ref: http://php.net/manual/en/regexp.reference.alternation.php
    - match: \|
      scope: keyword.operator.or.regexp

    # recursive pattern
    # ref: http://php.net/manual/en/regexp.reference.recursive.php
    - match: \(\?R\)
      scope: keyword.other.recursive-pattern.regexp

    # option setting
    # ref: http://php.net/manual/en/regexp.reference.internal-options.php
    - match: \(\?[imsxJUX]+\)
      scope: keyword.other.option-toggle.regexp

    # group assertion
    - match: (\()((\?=)|(\?!)|(\?<=)|(\?<!)|(\?>)|(\?:)|(\?\|)|(\?[imsxJUX]+:))
      captures:
        1: punctuation.definition.group.begin.regexp
        2: constant.other.assertion.regexp
        3: meta.assertion.look-ahead.regexp
        4: meta.assertion.negative-look-ahead.regexp
        5: meta.assertion.look-behind.regexp
        6: meta.assertion.negative-look-behind.regexp
        7: meta.assertion.atomic-group.regexp
        8: meta.assertion.no-capture-group.regexp
        9: meta.assertion.branch-reset-group.regexp
        10: keyword.other.option-toggle.regexp
      push:
        - meta_scope: meta.group.assertion.regexp
        - match: \)
          scope: punctuation.definition.group.end.regexp
          pop: true
        - include: main

    # named group
    # ref: http://php.net/manual/en/regexp.reference.subpatterns.php
    - match: (\()(\?)(?:(P)?(<)([^>]+)(>)|(')([^']+)('))
      captures:
        1: punctuation.definition.group.begin.regexp
        2: constant.other.assertion.regexp
        3: constant.other.assertion.regexp
        4: punctuation.definition.group.capture.begin.regexp
        5: entity.name.other.group.regexp
        6: punctuation.definition.group.capture.end.regexp
        7: punctuation.definition.group.capture.begin.regexp
        8: entity.name.other.group.regexp
        9: punctuation.definition.group.capture.end.regexp
      push:
        - meta_scope: meta.group.regexp
        - match: \)
          scope: punctuation.definition.group.end.regexp
          pop: true
        - include: main

    # capture group
    - match: (\()
      scope: punctuation.definition.group.begin.regexp
      push:
        - meta_scope: meta.group.regexp
        - match: \)
          scope: punctuation.definition.group.end.regexp
          pop: true
        - include: main

    - include: character-class

  character-class:
    # 3~4 backslashes = matches actualy 1 backslash
    # 1~2 backslashes = esacpe the next character
    # ref: http://php.net/manual/en/regexp.reference.escape.php
    - match: \\{1,2}(\\{2}|[^wWsSdDhH\\])
      scope: constant.character.escape.backslash.regexp
    - match: \\{1,2}[wWsSdDhH]|\.
      scope: constant.character.character-class.regexp
    - match: (\[)(\^)?
      captures:
        1: punctuation.definition.character-class.begin.regexp
        2: keyword.operator.negation.regexp
      push:
        - meta_scope: constant.other.character-class.set.regexp
        - match: \]
          scope: punctuation.definition.character-class.end.regexp
          pop: true
        - include: character-class
        - match: ((\\{1,2}.)|.)\-((\\{1,2}.)|[^\]])
          scope: constant.other.character-class.range.regexp
          captures:
            2: constant.character.escape.backslash.regexp
            4: constant.character.escape.backslash.regexp