[Python-Dev] PEP: Adding data-type objects to Python

["Martin v. Löwis"]

Travis Oliphant schrieb:
> I think it actually is.  Perhaps I'm wrong, but a type-object is still a 
> special kind of an instance of a meta-type.  I once tried to add 
> function pointers to a type object by inheriting from it.  But, I was 
> told that Python is not set up to handle that.  Maybe I misunderstood.

I'm not quite sure what the problems are: one "obvious" problem is
that the next Python version may also extend the size of type objects.
But, AFAICT, even that should "work", in the sense that this new version
should check for the presence of a flag to determine whether the
additional fields are there. The only tricky question is how you can
find out whether your own extension is there.

If that is a common problem, I think a framework could be added to
support extensible type objects (with some kind of registry for
additional fields, and a per-type-object indicator whether a certain
extension field is present).

> Let me be very clear.  The whole reason I make any statements about 
> ctypes is because somebody else brought it up.  I'm not trying to 
> replace ctypes and the way it uses type objects to represent data 
> internally.

Ok. I understood you differently earlier.

Regards,
Martin