pure virtual functions in python

[holger krekel]

polux wrote:
> how to emulate them ?
> I mean, how to force a user to redifine some functions in a derivated 
> class ?

    class a:
        def method(self):
            raise NotImplementedError(
                  "class %s misses 'method'" % repr(self.__class__))
    class b(a):
        pass

    b().method()

you can also use 'inspect.getabsfile(self.__class__)' to point to
the source file.  This doesn't work if you define your class
on the command line.

HTH,

    holger