oic, yes ur right. Meanwhile I also came across Damian's Perl6::Rules, version dated April 12th 2007, don't know if there was one before that on CPAN, which provides a limited subset for use under Perl5 already - it has an example of using it to define a language grammar for HTML prior to parsing. And I was already considering a "special-needs" XML parser as an example to demonstrate when you can and can't use Parse::RecDescent - hmmm the plot thickens!