Partial classes

[Kay Schluehr]

brianmce at gmail.com wrote:
> Sanjay wrote:
> > Hi All,
> >
> > Not being able to figure out how are partial classes coded in Python.
> >
> > Example: Suppose I have a code generator which generates part of a
> > business class, where as the custome part is to be written by me. In
> > ruby (or C#), I divide the code into two source files. Like this:
>
> I would do this by inheritance if really needed - what isn't working?
> That said, you can get this behaviour fairly easy with a metaclass:
>
> class PartialMeta(type):
>     registry = {}
>     def __new__(cls,name,bases,dct):
>         if name in PartialMeta.registry:
>             cls2=PartialMeta.registry[name]
>             for k,v in dct.items():
>                 setattr(cls2, k, v)
>         else:
>             cls2 = type.__new__(cls,name,bases,dct)
>             PartialMeta.registry[name] = cls2
>         return cls2
>
> class PartialClass(object):
>     __metaclass__=PartialMeta

This definition lacks a check for disjointness of the parts. No two
partial classes shall contain a method with the same name.