Re: Meta decorator with parameters, defined in explicit functions

From	Ian Kelly <ian.g.kelly@gmail.com>
Newsgroups	comp.lang.python
Subject	Re: Meta decorator with parameters, defined in explicit functions
Date	2016-07-03 05:52 -0600
Message-ID	<mailman.38.1467546815.2295.python-list@python.org> (permalink)
References	(5 earlier) <facf7142-25f5-4a8b-ab37-771884ab8d64@googlegroups.com> <CALwzid=GfLU8nbc5m4M9FxEO1ObWDTcvLJ3-wJXS0=w88-v8sw@mail.gmail.com> <mailman.33.1467521333.2295.python-list@python.org> <46690e10-1534-4f99-a40f-a148b4a21a27@googlegroups.com> <CALwzidmn-0TyxfKxcZoNoV5CgiFuOqRS_X=W34gSn5a-NVOy_w@mail.gmail.com>

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On Sat, Jul 2, 2016 at 11:37 PM, Lawrence D’Oliveiro
<lawrencedo99@gmail.com> wrote:
> On Sunday, July 3, 2016 at 4:49:15 PM UTC+12, Ian wrote:
>>
>> On Sat, Jul 2, 2016 at 12:40 AM, Lawrence D’Oliveiro wrote:
>>>
>>> On Saturday, July 2, 2016 at 5:10:06 PM UTC+12, Ian wrote:
>>>>
>>>> You should use functools.wraps instead of clobbering the decorated
>>>> function's name and docstring:
>>>
>>> Where am I doing that?
>>
>> Using the implementation you posted:
>>
>>>>> @decorator_with_args
>> ... def my_decorator(func, *args, **kwargs):
>> ...     """Returns func unmodified."""
>> ...     return func
>> ...
>>>>> my_decorator.__doc__
>> 'generates a decorator which applies my_decorator to the given arguments'
>
> That is a function that I am generating, so naturally I want to give it a useful docstring. Am I “clobbering” any objects passed in by the caller, or returned by the caller? No, I am not.

It isn't useful, though. If somebody writes a docstring for a
function, it's because they want that to be the docstring for the
function, not some arbitrary and vague docstring assigned by a
decorator. If I type "help(my_decorator)" in the interactive
interpreter, I should see what my_decorator actually does, not
"generates a decorator which applies my_decorator", which just
confuses with its recursiveness. The only way to find out what
my_decorator actually does from the interactive interpreter would be
to realize that it's been opaquely decorated and type out something
like this:

>>> my_decorator.__closure__[0].cell_contents.__doc__
'Returns func unmodified.'

That's far too obscure. Alternatively, one could go read the source.
But if you have to go read the source to understand what a function
does, then you've lost the purpose of having a docstring in the first
place.

Thread

Meta decorator with parameters, defined in explicit functions Ben Finney <ben+python@benfinney.id.au> - 2016-06-28 15:02 +1000
  Re: Meta decorator with parameters, defined in explicit functions Paul Rubin <no.email@nospam.invalid> - 2016-06-27 23:08 -0700
  Re: Meta decorator with parameters, defined in explicit functions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-28 18:39 +1000
  Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-29 19:43 -0700
    Re: Meta decorator with parameters, defined in explicit functions Steven D'Aprano <steve@pearwood.info> - 2016-06-30 13:49 +1000
    Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions Peter Otten <__peter__@web.de> - 2016-06-30 09:25 +0200
      Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-30 00:43 -0700
        Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-30 18:00 +1000
        Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions Peter Otten <__peter__@web.de> - 2016-06-30 10:41 +0200
    Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions dieter <dieter@handshake.de> - 2016-07-01 09:04 +0200
      Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-07-01 21:25 +0100
        Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions Ben Finney <ben+python@benfinney.id.au> - 2016-07-02 11:52 +1000
        Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions dieter <dieter@handshake.de> - 2016-07-02 08:57 +0200
        Re: Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions Ben Finney <ben+python@benfinney.id.au> - 2016-07-02 18:00 +1000
  Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-29 19:50 -0700
  Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-01 15:08 -0700
    Re: Meta decorator with parameters, defined in explicit functions Ian Kelly <ian.g.kelly@gmail.com> - 2016-07-01 23:09 -0600
      Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-01 23:40 -0700
        Re: Meta decorator with parameters, defined in explicit functions Ian Kelly <ian.g.kelly@gmail.com> - 2016-07-02 22:48 -0600
          Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-02 22:37 -0700
            Re: Meta decorator with parameters, defined in explicit functions Ian Kelly <ian.g.kelly@gmail.com> - 2016-07-03 05:52 -0600
              Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-03 14:17 -0700
                Re: Meta decorator with parameters, defined in explicit functions Ian Kelly <ian.g.kelly@gmail.com> - 2016-07-03 16:38 -0600
                Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-03 16:25 -0700
                Re: Meta decorator with parameters, defined in explicit functions Chris Angelico <rosuav@gmail.com> - 2016-07-04 09:39 +1000
                Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-03 16:59 -0700
                Re: Meta decorator with parameters, defined in explicit functions Chris Angelico <rosuav@gmail.com> - 2016-07-04 10:06 +1000
                Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-03 17:23 -0700
                Re: Meta decorator with parameters, defined in explicit functions Ian Kelly <ian.g.kelly@gmail.com> - 2016-07-03 18:01 -0600
                Re: Meta decorator with parameters, defined in explicit functions Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-03 17:06 -0700
                Re: Meta decorator with parameters, defined in explicit functions Ian Kelly <ian.g.kelly@gmail.com> - 2016-07-03 18:20 -0600
    Re: Meta decorator with parameters, defined in explicit functions Ben Finney <ben+python@benfinney.id.au> - 2016-07-02 15:32 +1000
    Re: Meta decorator with parameters, defined in explicit functions Ian Kelly <ian.g.kelly@gmail.com> - 2016-07-01 23:53 -0600

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