Filter::Simple - Simplified source filtering

Source filtering is an immensely powerful feature of recent versions of Perl.
It allows one to extend the language itself (e.g. the Switch module), to
simplify the language (e.g. Language::Pythonesque), or to completely recast the
language (e.g. Lingua::Romana::Perligata). Effec- tively, it allows one to use
the full power of Perl as its own, recur- sively applied, macro language.