[Python-Dev] PEP 362 Third Revision

[Alexandre Zani]

On Thu, Jun 14, 2012 at 1:45 PM, Yury Selivanov <yselivanov.ml at gmail.com> wrote:
> On 2012-06-14, at 4:24 PM, Benjamin Peterson wrote:
>
>> 2012/6/14 Alexandre Zani <alexandre.zani at gmail.com>:
>>> On Thu, Jun 14, 2012 at 12:57 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
>>>> On Thu, 14 Jun 2012 12:46:38 -0700
>>>> Ethan Furman <ethan at stoneleaf.us> wrote:
>>>>>
>>>>> This is no different from what we have with strings now:
>>>>>
>>>>> --> 'aA'.islower()
>>>>> False
>>>>> --> 'aA'.isupper()
>>>>> False
>>>>> --> 'a'.islower()
>>>>> True
>>>>> --> 'A'.isupper()
>>>>> True
>>>>>
>>>>> We know that a string cannot be both all-upper and all-lower at the same
>>>>> time;
>>>>
>>>> We know that because it's common wisdom for everyone (although who knows
>>>> what oddities the unicode consortium may come up with in the future).
>>>> Whether a given function argument may be of several kinds at the same
>>>> time is much less obvious to most people.
>>>
>>> Is it obvious to most people? No. Is it obvious to most users of this
>>> functionality? I would expect so. This isn't some implementation
>>> detail, this is a characteristic of python parameters. If you don't
>>> understand it, you are probably not the audience for signature.
>>
>> Consequently, the "kind" model should match up very well with their
>> understanding that a parameter can only be one "kind" at a time.
>
> I myself now like the 'kind' attribute more than 'is_*' family.
> Brett and Larry also voted for it, as well the majority here.
>
> I'll amend the PEP this evening to replace 'is_args', 'is_kwargs',
> and 'is_keyword_only' with a 'kind' attribute, with possible
> values: 'positional', 'vararg', 'varkw', 'kwonly'.
>
> Parameter class will have four constants, respectively:
>
>     class Parameter:
>         KIND_POSITIONAL = 'positional'
>         KIND_VARARG = 'vararg'
>         KIND_VARKW = 'varkw'
>         KIND_KWONLY = 'kwonly'
>
> 'Parameter.is_implemented' will be renamed to 'Parameter.implemented'
>
> Is everybody OK with this?  Thoughts?
>
> I, for instance, like 'varkwarg' more than 'varkw' (+ it is more
> consistent with **kwargs)
>
> -
> Yury

How about keyword instead of kwonly? I find kwonly clear when
side-by-side with varkw, but ambiguous standalone.

I like the idea of using args and kwargs just because those are the
defacto standard way we refer to that type of argument.