On 1/21/06, Rob Kinyon <[EMAIL PROTECTED]> wrote: > I'm making a few assumptions here: > 1) Since PGE isn't part of Perl6 (because it's written in PIR), it > can be used as the parser/lexer/etc. for any language, not just Perl6.
Rules, like regexes, are essentially language neutral. So that's true. > 2) Since PGE can be lexically-scoped, one can change the entire > grammar within a given block, including how variables are referenced, > subroutines are called, etc. The grammar only governs the surface syntax. It does not automagically control semantics (e.g. whether .arguments are available, tying, blessing, et cetera). Moreover, writing a Perl 5 parser in PGE alone is... Very difficult. It can be done (eg. PPI), but taking it and emit PIR is a nontrivial task that would not magically happen. > 3) Since everything is, at the heart, just a PMC, so long as the > appropriate PIR is emitted, it doesn't matter how the userside code is > written so long as the right parser/lexer/whatever is used to > translate it to PIR. Again, that'd be handwaving, as Perl5->PIR compiler is currently not championed by anybody. The slightly less ambitious Perl5->PMCs project (Ponie) is also in need of a champion at this moment, and it does not guarantee sane interoperation with other PIR targetting compilers in itself, though we are certainly working on it. > So, if all three assumptions hold, then your monolithic Perl5 script > can easily inline any Parrot-targeted language you want, simply by > doing the following: > 1) Use Ponie. > 2) Within a block, import the appropriate PGE module(s) to > redefine the grammar to P6 and do what you need to do. > > No translator needed. The amount of effort of writing all this is no less heavy than that of a Perl5-to-Perl6 translator. :-) Also it makes sense to have multiple migration paths (runtime-level, bytecode-rewriting-level, source recompilation level), because different people are interested in different subprojects. The P5-to-P6 translator also could work when targetting the JavaScript runtime, or the CLR runtime, or generating native code via LLVM or D; in those places Ponie does not help at all. Audrey
