[Python-ideas] PEP-3150

[Nick Coghlan]

On Thu, Apr 14, 2011 at 9:47 PM, Carl M. Johnson
<cmjohnson.mailinglist at gmail.com> wrote:
> sorted_list = sorted(original_list, key=keyfunc) given:
>   "A list of widgets sorted by removing whitespace and lowercasing..."
>   def keyfunc(item):
>       ...
>
>>>> help(sorted_list)
> "A list of widgets sorted by removing whitespace and lowercasing..."

Alas, it isn't going to be quite that simple:

>>> x = []
>>> x.__doc__ = "This is a list"
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'list' object attribute '__doc__' is read-only
>>> x = 1
>>> x.__doc__ = "This is an integer"
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'int' object attribute '__doc__' is read-only

I don't see adding an extra pointer slot that will rarely be used to
the mutable builtins flying, and obviously the immutable types can't
reasonably accept a docstring that may vary by instance without
completely destroying their caching strategies.

Making the docstring available as a __doc__ variable in the given
namespace could potentially work, but I'm not sure the idea offers
much over an ordinary triple-quoted string variable at that point.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia