Delaney, Timothy (Tim) wrote:
> Peter Hansen wrote:
>
>> Change those to "raise NotImplementedError('blah')" instead and you'll
>> be taking the more idiomatic approach.
>
> One thing I've noticed, which I may raise on python-dev ...
> NotImplementedError does *not* play well with super() ...
>
> class A (object):
> def test (self):
> raise NotImplementedError
>
> class B (object):
> def test (self):
> print 'B'
> super(B, self).test()
>
> class C (B, A):
> def test (self):
> print 'C'
> super(C, self).test()
>
> It's actually worse than AttributeError, because the method actually
> exists. In both cases though you need to know when you create the base
> class how it's going to be used to work out whether a super() call is
> needed.
>
> One option is to do a try: except (AttributeError, NotImplementedError).
> Yuk - talk about hiding errors :(
Hm... one could return NotImplemented from the abstract method. It won't raise
an error immediately, but will certainly be discovered at some point.
Not optimal though.
Reinhold
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