pure virtual functions in python

[Chad Netzer]

> 	class AbstractSomething:
> 	    def __init__(self, ...):
> 	        if self.__class__ is AbstractSomething:
> 	            raise NotImplementedError
> 	        ...
>
> 	class ConcreteSomething(AbstractSomething):
> 	    def __init__(self, ...):
> 	        AbstractSomething.__init__(self, ...)
>
> This will prevent people from creating AbstractSomethings directly,
> but they'll have no problem calling the AbstractSomething.__init__
> method from a subclass.

Awesome.  I was doing this by using a separate initializing method, but 
your version has some real advantages.  Thanks for the great idea 
(simple and elegant; no wonder I missed it. :).

-- 
Bay Area Python Interest Group - http://www.baypiggies.net/

Chad Netzer
cnetzer at mail.arc.nasa.gov