Backtracking parser generator based on byacc

 btyacc is a hacked version of the original Berkeley "byacc". The main
 change to byacc is the addition of backtracking code, allowing you to
 try both alternatives in case of shift-reduce or reduce-reduce conflicts.
 As long as no backtracking takes place, the speed is comparable to bison's
 one.
 .
 Additional features:
  - Enhanced support for storing of text position information for tokens.
  - Closes the potential *yacc/bison memory leak during error recovery.
  - Preprocessor directives like %ifdef, %include.
  - C++ friendly.
 .
 Related packages: bison, byacc, antlr