This is a variant of the Flex fast lexical scanner. Flex was written
in the early 1990s by Verne Paxson. This version has been modified
by Thomas Dickey, so that it conforms to ANSI C. It includes other
improvements, but remains compatible with Paxson's 2.5.4 release
(as well as POSIX lex). See the NEWS file for details.

WWW: http://invisible-island.net/reflex/reflex.html