StÃphane Payrard writes: > That would allow to implement typechecking in imcc. > > .sym Scalar a > a = new .PerlInt # ok. Perlint is derived from Scalar
Ugh, yeah, but what does that buy you? In dynamic languages pure derivational typechecking is very close to useless. The reason C++[1] has pure derivational semantics is because of implementation. The vtable functions have the same relative address, so you can use a derived object interchangably. In a language where methods are looked up by name, such strictures are more often over-restrictive than helpful. Anyway, that's just my rant. If such a thing is to be in imcc, it _must_ be optional without loss of feature. I have quibble with the automatic typechecking of .param variables for the same reason. Luke [1] And the reason Java has it is because C++ did. Great design work, guys.
