A regular expression (or regexp) is a pattern that describes a whole class of strings. A full description of regular expressions and their syntax is beyond the scope of this manual; an introduction can be found in the Emacs manual (see Syntax of Regular Expressions), or in many general Unix reference books.
If your system does not include a POSIX regular expression library,
and you have not linked Guile with a third-party regexp library such
as Rx, these functions will not be available. You can tell whether
your Guile installation includes regular expression support by
(provided? 'regex) returns true.
The following regexp and string matching features are provided by the
(ice-9 regex) module. Before using the described functions,
you should load this module by executing