[Python-Dev] readonly __doc__
Guido van Rossum
guido at python.org
Thu Oct 22 19:58:08 CEST 2009
Well __doc__ isn't a normal attribute -- it doesn't follow inheritance rules.
On Thu, Oct 22, 2009 at 10:25 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> Guido van Rossum <guido <at> python.org> writes:
>>>> On Thu, Oct 22, 2009 at 9:45 AM, Antoine Pitrou <solipsis <at> pitrou.net>
> wrote:
>> >
>> > Speaking of the __doc__ property, I just noticed the following thing
> on py3k:
>> >
>> >>>> class C: pass
>> > ...
>> >>>> C.__doc__ = "hop"
>> > Traceback (most recent call last):
>> > File "<stdin>", line 1, in <module>
>> > AttributeError: attribute '__doc__' of 'type' objects is not writable
>> >
>> > Is this deliberate?
>>>> Yes.
>> I might add why I was asking this question. I was trying to demonstrate the use
> of class decorators and the simplest example I found was to add a docstring to
> the class. And I was surprised when I saw the following fail with the
> aforementioned exception:
>> def classdeco(cls):
> cls.__doc__ = "decorated!"
> return cls
>> @classdeco
> class C:
> pass
>>> Regards
>> Antoine.
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--
--Guido van Rossum (home page: http://www.python.org/~guido/)
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