The Common Lisp Cookbook – Pattern Matching & Regular Expressions

The ANSI Common Lisp standard does not include facilities for pattern matching and regular expressions, but a couple of libraries exist for those tasks: see Optima or Trivia for pattern matching and cl-ppcre for regular expressions.

See also the respective Cliki: pattern matching and Cliki: regexp pages for more links.

Note that some CL implementations include regexp facilities, notably CLISP and ALLEGRO CL. If in doubt, check your manual or ask your vendor.