perl-Parse-Yapp -- Perl extension for generating and using LALR parsers.
http://www.cpan.org
Parse::Yapp (Yet Another Perl Parser compiler) is a collection of modules
that let you generate and use yacc like thread safe (reentrant) parsers
with perl object oriented interface. The script yapp is a front-end to
the Parse::Yapp module and let you easily create a Perl OO parser from
an input grammar file.