[pypy-dev] question

[Christian Tismer]

Samuele Pedroni wrote:
> I admit for now I have just skimmed over the code.
> 
> I can more or less see how something like classic-style classes can be
> implemented.
> 
> Have you already thought on how to implement new-style classes and in
> particular built-in types subclassing like in:
> 
> class myint(int):
>   ...
> 
> e.g. will the implemented multi-dispatching intepreted statically at PyPy
> static translation time ... or should the final low-level runtime support it
> dynamically?

Speaking for myself, I always have wondered how the
multimethod approach should be extended above the
level of builtin types, since I don't understand
how to extend it to derived types, without breaking
compatibility to all the established __xxx__ rules
in Python.
I pointed to this problem on the sprint, but can't remember
that this issue was solved.

One vague idea could be that derived types by default
inherit the multi-method dispatch, but when people override
operators, we have to provide some compatible interpretation
of things like __add__(self, other), or this would not be
Python. Maybe we can find the necessary magic to embed this
into multimethod dispatch dynamically, but I have
really no clue how this should work.

ciao - chris

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