[ I think this still needs some clarification ] Leopold Toetsch <[EMAIL PROTECTED]> wrote: > Dan Sugalski <[EMAIL PROTECTED]> wrote: >> At 10:42 PM +0100 12/17/03, Leopold Toetsch wrote: >>>While playing with calling threaded subs, I came along a thing which >>>I think might be suboptimal: >>>pdd03 states that the method PMC should go into P2. This doesn't >>>really play with Perl5 <-> Perl6 interoperbility IMHO. Perl5 methods >>>are plain subs, where the first param is the object.
>> PDD 03 states that the *object* goes in P2. > Yep, typo - sorry. >> This works out just fine >> with perl 5 style method calls, where the argument list doesn't >> distinguish the object other than by position. What happens is that >> when a perl 5 sub is called, @_ is a combination of P2 if it's >> non-NULL, and the remaining PMC registers. It's slightly more work >> for the perl 5 code generator to handle the check, but other than >> that it shouldn't be a problem. > That seems to indicate, that we have to expose the whole parameter > passing to HLLs and that Perl5 (and probably other languages) can't use > the builtin PIR shortcuts (or we have to provide both schemes depending > on some pragma directive). > Additionally to the test: > isnull P2, no_object # must be set to NULL on non-method calls > we would need 2 code paths: For leaf subs[1], one can use registers as > is, one would need rearanging the param regs. > And as outlined by Juergen it doesn't fit very well for calling NCI PMC > class methods: We would need another signature letter to denote the > object. > That's of course all doable but is adding assymmetry to method calls, > which I don't like much. > [1] these just use P5..Pn as passed in. > leo leo
