A regex (a regular expression, regexp) is a sequence of characters that specifies a match pattern in text. Use this tag for questions about regex as it pertains to developing/implementing a programming language. General regex questions are off-topic.

A regex (a regular expression, regexp) is a textual form for specifying sets of strings in a regular language, often used for matching against. Use this tag for questions about regex as it pertains to developing/implementing a programming language, including for constructs that are not strictly regular such as backreferences. General regex questions are off-topic.

A regex (a regular expression, regexp) is a sequence of characters that specifies a match pattern in text. Use this tag for questions about regex as it pertains to developing/implementing a programming language. General regex questions are off-topic.