PyBison is a sophisticated yet easy-to-use parser creation toolkit for Python that interfaces directly to Bison (yacc)-based parsers. It provides full LALR(1) grammar support, allowing for simple parsing tasks through to writing compilers for high-level languages. Parser code is automatically generated from rules within user-created Parser classes (written in Python), and then, compiled, yacc'ed and linked into a shared library, which is loaded into the running process. All this happens automatically. When the parser runs, it connects directly with the yyparse() routine, and takes event callbacks upon parse targets being reached.
