WareLogging. RecursiveDescentParsing, PerlLanguage.

= tutorials =

* http://www.perlmonks.org/?node_id=108182
* http://www.adp-gmbh.ch/perl/rec_descent.html
* http://www.perl.com/lpt/a/556
* http://www.sidhe.org/~dan/blog/archives/000235.html