Perl 6 is about being a metalanguage in which you can express many languages, and doing so in a sufficiently controlled fashion that we always know what language any given lexical scope is expressed in. ... Anyway, IDEs, syntax highlighters, and refactoring engines are all going to want to access Perl 6 annotated parse trees (ASTs), and we intend to make it possible for them to do that. That is at the very heart of Perl 6, and the main reason it's so important for Perl 6 to be parsed in Perl 6.