lallous <elias.bachaal...@gmail.com> writes:
> Hello
>
> How can I do something similar to pure virtual functions in C++ ?
>
> Let us consider this:
>
> class C1:
>
> # Pure virtual
> def cb(self, param1, param2):
> """
> This is a callback
>
> @param param1: ...
> @param param2: ...
> """
> raise NotImplementedError, "Implement me"
Why define it if it is virtual?
> # Implementation w/o a 'cb', thus 'cb' should not be used
> class C2(C1):
> def __init__(self):
> pass
>
> # Implementation w/ 'cb', thus 'cb' can be used
> class C3(C1):
> def __init__(self):
> pass
>
> def cb(self, param1, param2):
> print "i am c3 cb"
>
> # Dispatcher function that calls 'cb' only if 'cb' is implemented in
> child classes
> def dispatcher(c):
> if hasattr(c, 'cb'):
> c.cb("Hello", "World")
>
> dispatcher(C2())
> dispatcher(C3())
>
> What I want is the ability to have the dispatcher() not to call 'cb'
> if it was not implemented in one of the child classes.
If you don't define cb in the parent class, it'll work.
--
Arnaud
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