BYACC, Programming, Berkeley Yacc parser generator
Berkeley Yacc is an LALR(1) parser generator.  Berkeley Yacc has been made as
compatible as possible with AT&T Yacc.  Berkeley Yacc can accept any input
specification that conforms to the AT&T Yacc documentation.  This version of
Berkeley Yacc has been converted to ISO C, eliminates some nonportable use of
temporary files and provides a few new options.