Parse::Yapp provides a set of modules and a frontend to generate Perl OO LALR(1) parsers. It can input clean yacc or bison grammars. The generated parsers are fast, being based, like yacc, on building Deterministic Finite Automata (DFA) and moving through a set of states using Deterministic Push Down Automata (DPDA) derived from the DFA to match the input stream tokens.
Yap is a high-performance Prolog compiler developed at LIACC, Universidade do Porto. Its Prolog engine is based on the WAM (Warren Abstract Machine), with several optimizations for better performance, and achieves performance comparable or exceeding that of commercial Prolog systems. Yap is largely compatible with the major Edinburgh Prolog systems, and has been ported to most 32-bit and 64-bit Unix based platforms. A Windows port is also available.
Perthon converts Python source code to human- readable Perl 5.x source code. It makes use of Damian Conway's Parse::RecDescent for parsing, and aims to reimplement the Python language as specified in the Python Reference Manual and BNF grammar. Perthon is similar to Jython (www.jython.org), which reimplements Python on the JVM, except that Perthon works at the source code (not byte code) level. Perthon does the reverse of Bridgekeeper (http://www.crazy-compilers.com/bridgekeeper/), which attempts to solve the (much harder) problem of Perl-to-Python source code machine translation.