Yet Another Perl Parser compiler. Compiles yacc-like LALR grammars to
generate Perl OO parser modules. It lets you create Perl OO fully
reentrant LALR(1) parser modules (see the Yapp.pm pod pages for more
details) and has been designed to be functionally as close as possible
to yacc, but using the full power of Perl and opened for enhancements.
Package provided by Nathan Ahlstrom <nrahlstr@winternet.com> in PR #12635.