• Pattern matching
  • Grouping

  • Grouping
  • Grouping


    Sequence Description
    (…) Group a regular expression to override default operator
    (?r-s:pattern) Apply option r and omit option s while interpreting pattern.
    Options may be zero or more of the characters i, s, or x.

    Option Description
    i Case insensitive.
    -i Case sensitive.
    s Alters the meaning of ‘.’ to match any character
    -s “lters the meaning of ‘.’ to match any character except
    x Ignores comments and whitespace in patterns. Whitespace is
    ignored unless it is backslash-escaped, contained within “”s, or
    appears inside a character range.

    These options can be applied globally at the rules level by passing
    a combination of the bit flags to the lexer.

    (?# comment ) Omit everything within (). The first ) character encountered
    ends the pattern. It is not possible for the comment to contain a )
    character. The comment may span lines.