Regarding the "perl5 not in parrot" citation, i found some pretty good hints at this problem: From the Perl Wikipedia page: It is often said that "Only perl c

Regarding the "perl5 not in parrot" citation, i found some pretty good hints at this problem: From the Perl Wikipedia page: It is often said that "Only perl can parse Perl",[49] meaning that only the Perl interpreter (perl) can parse the Perl language (Perl), but even this is not, in general, true. Because the Perl interpreter can simulate a Turing machine during its compile phase, it would need to decide the Halting Problem in order to complete parsing in every case. It's a long-standing result that the Halting Problem is undecidable, and therefore not even perl can always parse Perl. Perl makes the unusual choice of giving the user access to its full programming power in its own compile phase. The cost in terms of theoretical purity is high, but practical inconvenience seems to be rare. Other programs that undertake to parse Perl, such as source-code analyzers and auto-indenters, have to contend not only with ambiguous syntactic constructs but also with the undecidability of Perl parsing in the general case. Adam Kennedy's PPI project focused on parsing Perl code as a document (retaining its integrity as a document), instead of parsing Perl as executable code (which not even Perl itself can always do). It was Kennedy who first conjectured that "parsing Perl suffers from the 'Halting Problem'",[50] which was later proved.[51] Also interesting is the proof that Perl cannot be parsed: http://www.jeffreykegler.com/Home/perl-and-undecidability http://www.jeffreykegler.com/Home/perl-and-undecidability In general the saying "only perl can parse perl" has to have some root... http://www.google.de/search?q=%E2%80%9COnly+Perl+can+parse+Perl http://www.google.de/search?q=%E2%80%9COnly+Perl+can+parse+P...