byacc

from The Free On-line Dictionary of Computing (8 July 2008)

Berkeley Yacc
byacc
Zeus
Zoo

   <tool> (byacc, previously Zeus, then Zoo) Probably the best
   variant of the {Yacc} {parser generator}.  Written by Robert
   Corbett <[email protected]>.

   Latest version: 1.9, as of 2000-06-09.

   (ftp://ftp.cs.berkeley.edu/pub/4bsd/byacc.1.9.tar.Z).

   (2000-07-16)