| (...) |
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.
i means case-insensitive.
-i means 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. |