Question about subclassing - version 2

[Maric Michaud]

Le vendredi 08 septembre 2006 09:51, bearophileHUGS at lycos.com a écrit :
> Frank Millman, just a short note, more expert people can give you
> better answers. There aren't abstract classes in Python. They are all
> concrete.
Really ? This is like saying there is no singleton in Python...

class AbstractClass(object) :

	def __init__(self) : raise RuntimeError('Ths class is an abstract one !')

The abstract class can then define APIs (methods which raise 
NotImplementedError) and/or logic (fully implemented methods).
With this scheme you are not stuck to the "API only" usage of abstract classes 
like in Java nad its interfaces.

> You may have classes with undefined methods (they may raise 
> NotImplementedError).

C++ "pure virtual methods" is only the C++ way of doing something which is a 
more general concept in OOP.


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Maric Michaud
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