After thinking about this a bit, it became glaringly obvious that the right way to instantiate an object for class "Foo" is to do:
new P5, .Foo
Or whatever the constant value assigned to the Foo class upon its creation
is. When a class is created, it should be assigned a number, and for most
things PMC-only classes or full-on HLL classes should behave identically.
Duh.
That makes sense. What I keep wondering is what about things with the semantics of Perl5, in which new objects aren't instantiated directly--already-allocated things later become associated with a class. This doesn't seem quite like a case of morphing, since for instance a Perl array can be blessed into a class, but it's still a Perl array.
JEff