%YAML 1.2
---
name: Regular Expressions (Python)
comment: Matches Python's regular expression syntax.
scope: source.regexp.python
hidden: true
contexts:
  main:
    - match: (#)[^]\[(){}^$+*?\\|"']*$
      comment:
        We are restrictive in what we allow to go after the comment character to avoid
        false positives, since the availability of comments depend on regexp flags.
      scope: comment.line.number-sign.regexp
      captures:
        1: punctuation.definition.comment.regexp
    - match: '\\[bBAZzG]|\^|\$'
      scope: keyword.control.anchor.regexp
    - match: '\\[1-9][0-9]?'
      scope: keyword.other.back-reference.regexp
    - match: '[?+*][?+]?|\{(\d+,\d+|\d+,|,\d+|\d+)\}\??'
      scope: keyword.operator.quantifier.regexp
    - match: \|
      scope: keyword.operator.or.regexp
    - match: '\(\?\#'
      scope: punctuation.definition.comment.begin.regexp
      push:
        - meta_scope: comment.block.regexp
        - match: \)
          scope: punctuation.definition.comment.end.regexp
          pop: true
    - match: '\(\?[iLmsux]+\)'
      scope: keyword.other.option-toggle.regexp
    - match: '(\()(\?P=([a-zA-Z_][a-zA-Z_0-9]*\w*))(\))'
      scope: keyword.other.back-reference.named.regexp
    - match: (\()((\?=)|(\?!)|(\?<=)|(\?<!))
      captures:
        1: punctuation.definition.group.begin.regexp
        2: constant.other.assertion.regexp
        3: meta.assertion.look-ahead.regexp
        4: meta.assertion.negative-look-ahead.regexp
        5: meta.assertion.look-behind.regexp
        6: meta.assertion.negative-look-behind.regexp
      push:
        - meta_scope: meta.group.assertion.regexp
        - match: \)
          scope: punctuation.definition.group.end.regexp
          pop: true
        - include: main
    - match: '(\()(\?\(([1-9][0-9]?|[a-zA-Z_][a-zA-Z_0-9]*)\))'
      comment:
        We can make this more sophisticated to match the | character that separates
        yes-pattern from no-pattern, but it's not really necessary.
      captures:
        1: punctuation.definition.group.begin.regexp
        2: punctuation.definition.group.assertion.conditional.regexp
        3: entity.name.section.back-reference.regexp
      push:
        - meta_scope: meta.group.assertion.conditional.regexp
        - match: \)
          scope: punctuation.definition.group.end.regexp
          pop: true
        - include: main
    - match: '(\()((\?P<)([a-z]\w*)(>)|(\?:))?'
      captures:
        1: punctuation.definition.group.begin.regexp
        3: punctuation.definition.group.capture.regexp
        4: entity.name.section.group.regexp
        5: punctuation.definition.group.capture.regexp
        6: punctuation.definition.group.no-capture.regexp
      push:
        - meta_scope: meta.group.regexp
        - match: \)
          scope: punctuation.definition.group.end.regexp
          pop: true
        - include: main
    - include: character-class
  character-class:
    - match: '\\[wWsSdDhH]|\.'
      scope: constant.character.character-class.regexp
    - match: \\.
      scope: constant.character.escape.backslash.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: '((\\.)|.)\-((\\.)|[^\]])'
          scope: constant.other.character-class.range.regexp
          captures:
            2: constant.character.escape.backslash.regexp
            4: constant.character.escape.backslash.regexp