Regular Expressions

Regular expressions (regex, regexes) are at the heart of dialplan, and used in many other parts of FreeSWITCH configuration.

They are an uber-clever way to analyze, slice, dice, and massage text strings. We in FreeSWITCH we use the best and brightest, the greatest regular expressions of them all: Perl Compatible Regular Expressions (PCRE). Isn't that beautiful? It is.

A regular expression checks if a string matches a pattern (the pattern being the regex). A regular expression can also substitute parts of the strings with something else. Also, regular expressions can "select" a part of a string, and reuse it in returning the result.

In dialplan regexes are used to define the "expression" criterion of the "condition" tag. ...

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