(...) | Group a regular expression to override default operator precedence. |
(?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. OptionsOption | Description |
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i | Case insensitive. | -i | Case sensitive. | s | Alters the meaning of '.' to match any character whatsoever. | -s | Alters the meaning of '.' to match any character except '\n'. | 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. |