Regular expression

Regular expressions, also referred to as regex or regexp, provide a concise and flexible means for matching strings of text, such as particular characters, words, or patterns of characters. In the UNL^arium framework, regular expressions follow the PCRE library and must be provided between / /. They are used mainly to enhance the power of Ph-rules. The main features are the following:

Characters
a	match the character a
3	match the number 3
\n	newline (NL, LF)
\r	return (CR)
\f	form feed (FF)
\t	tab (TAB)
\x3C	character with the hex code 3C
\u561A	character with the hex code 561A
\e	escape character (alias \u001B)
\c…	control character
Wildcards
.	match any character
\…	quote single metacharacter: \. matches a dot instead of any character and \\ matches a single backslash
\w	alphanumeric + underscore (shortcut for [0-9a-zA-Z_])
\W	any character not covered by \w
\d	numeric (shortcut for [0-9])
\D	any character not covered by \d
\s	whitespace (shortcut for [ \t\n\r\f])
\S	any character not covered by \s
[…]	any character listed: [a5!d-g] means a, 5, ! and d, e, f, g
[^…]	any character not listed: [^a5!d-g] means anything but a, 5, ! and d, e, f, g
Boundaries
\b	matches at a word boundary (spot between \w and \W)
\B	matches anything but a word boundary
^	matches at the beginning of a line (m) or entire string (s)
\A	matches at the beginning of the entire string		$	matches at the end of a line (m) or entire string (s)
\Z	matches at the end of the entire string ignoring a tailing \n
\z	matches at the end of the entire string
Quantifiers
?	match 1 or 0 times
*	0 or more times
1 or more times
{n}	exactly n times
{n,}	at least n times
{n,m}	at least n but not more than m times, as often as possible