Override a method but inherit the docstring

[Peter Otten]

Ben Finney wrote:

> Howdy all,
> 
> The following is a common idiom::
> 
>     class FooGonk(object):
>         def frobnicate(self):
>             """ Frobnicate this gonk. """
>             basic_implementation(self.wobble)
> 
>     class BarGonk(FooGonk):
>         def frobnicate(self):
>             special_implementation(self.warble)
> 
> The docstring for ‘FooGonk.frobnicate’ is, intentionally, perfectly
> applicable to the ‘BarGonk.frobnicate’ method also. Yet in overriding
> the method, the original docstring is not associated with it.
> 
> Ideally there would be a way to specify that the docstring should be
> inherited. The best I can come up with is::
> 
>     class BarGonk(FooGonk):
>         def frobnicate(self):
>             special_implementation(self.warble)
>         frobnicate.__doc__ = FooGonk.frobnicate.__doc__
> 
> but that violates DRY (the association between BarGonk and FooGonk is
> being repeated), puts the docstring assignment awkwardly after the end
> of the method instead of at the beginning where docstrings normally go,
> and reads poorly besides.
> 
> What is the most Pythonic, DRY-adherent, and preferably least-ugly
> approach to override a method, but have the same docstring on both
> methods?

Just thinking aloud: Write a patch for pydoc that looks up the base-class 
documentation.

B.f.__doc__ will continue to return None, but

help(B.f) will show something like

    No documentation available for B.f. 

    Help for A.f:
    yadda yadda


Of course that might be misleading when A.f and B.f are up to something 
completely different...

Peter