The Free On-line Dictionary of Computing (30 December 2018):

Faster LEX

    (FLEX) A reimplementation of the Lex scanner
   generator, by Vern Paxson .

   Flex++ produces C++ and aflex produces Ada.

   FTP flex-2.3.8.tar.Z from a GNU archive site or
   (ftp://ftp.ee.lbl.gov/pub/flex-2.4.3.tar.Z).

   ["The FLEX Scanner Generator", Vern Paxson ,
   Systems Engineering, LBL, CA].

   [Home?  Current version?]

   (2003-12-16)