(you must include this at the top of your source: "import standard.lib.preg" (no quotes)
Regular Expression Functions (Perl-Compatible). Check http://www.pcre.org/pcre.txt for more information on PCRE.
The syntax for patterns used in these functions closely resembles Perl. The expression should be enclosed in the delimiters, a forward slash (/), for example. Any character can be used for delimiter as long as it's not alphanumeric or backslash (\). If the delimiter character has to be used in the expression itself, it needs to be escaped by backslash.