Creating Subclassable Objects??

[Greg Ewing]

Pete Shinners wrote:

> At this point you are able to subclass the objects, the problem is they 
> just don't work. If my new class has an __init__ method, it seems i 
> cannot properly instance the objects (since it needs some args).


I'm just guessing here (I haven't played with this stuff
much myself) but if your subclass's __init__ takes different
arguments from the base class, you may need to override
the __new__ method as well as the __init__ method, e.g.

   class MySubclass(SomeExtensionType):

     def __new__(self, my_args):
       return SomeExtensionType.__new__(...base class args...)

     def __init__(self, my_args):
       SomeExtensionType.__init__(...base class args...)
       ...more init...

 > If I

> don't have an __init__ method, i can instance the new class, but none of 
> the new methods i add to it work (AttributeError).


I don't know what might be causing that. Are you sure you've
done all the necessary things to make your extension type
subclassable? Have you put PyObject_Generic{Get,Set}Attribute
in the appropriate type slots?

-- 
Greg Ewing, Computer Science Dept,
University of Canterbury,	
Christchurch, New Zealand
http://www.cosc.canterbury.ac.nz/~greg