Regex
Regex is a full-featured regular expression compiler and matching engine written by Michael Parker. If you're one of those who believe that Lisp is slow, note that this regex engine is roughly 5x-20x times faster than the GNU regex matcher (which is obviously written in C).

Homepage: http://www.foldr.org/~michaelw/lisp/clawk/#regex

License: ???

libregex clisp REGEXP module michael parker's regex
gcc -O3 clisp-2.33.2(#) clisp-2.33.2(#) sbcl-0.8.14 regexp
3236/SEC 47893/SEC 10289/SEC 148810/SEC A*BD
1412/SEC 1685/SEC 10233/SEC 136986/SEC (A|A)*BD
1848/SEC 2061/SEC 9012/SEC 140449/SEC (A|B)*BD
1821/SEC 1993/SEC 7159/SEC 128041/SEC (B|A)*BD
3921/SEC 4049/SEC 10100/SEC 131234/SEC ((A*B)|(AC))D
3322/SEC 3545/SEC 10122/SEC 130890/SEC ((A*B)|(A*C))D
3831/SEC 47870/SEC 9106/SEC 145773/SEC [Aa]*[Bb][Dd]
1000000/SEC 840336/SEC 826446/SEC 253807/SEC STRING=
83333/SEC 151745/SEC 143678/SEC 150150/SEC STRING-EQUAL(*)
(*) not using a library stricmp.
(#) bytecode compiled.
All tests on Athlon 1200MHz, 1GB DDR2700.

The second column is retest adapted to use the REGEXP module of clisp instead of Parker's REGEX package. This module is a FFI to the libc regex, so it should give a better comparison of a C implementation of regex with a Common-Lisp one. The faster results in the second column vs. the first are even stranger.

It would be nice to see this regular expression library benchmarked against cl-ppcre -AK

RegEx seems to be slower by a factor of 4 than cl-ppcre on patterns like "[0-9]+ [0-9]+ [a-z]+ [0-9]+" tested on "23424 3242324 ab 234432432 22334242 23 232 23", for example.

ASDF-install package (obsolete) http://www.foldr.org/~michaelw/lisp/clawk/regex.tar.gz