[Python-ideas] Passing positional arguments as keyword arguments (to provide function arguments out of order)

[Jonathan Goble]

On Wed, May 15, 2019 at 3:45 AM Anders Hovmöller <boxed at killingar.net> wrote:
>
> > On 15 May 2019, at 07:51, Jonathan Goble <jcgoble3 at gmail.com> wrote:
> >
> > That's not a realistic goal; there are some use cases, including in
> > CPython builtins, that cannot be accomplished without positional-only
> > arguments. For example, the current behavior of the `dict` constructor
> > is to accept both certain iterables as a positional-only argument
> > and/or keyword arguments from which a dict can be created. If the
> > iterable argument was not positional-only, then it would be forced to
> > consume a keyword (even if the caller passes it as a positional
> > argument), meaning that that keyword could never be included in
> > **kwargs and could not become a dict key via keyword arguments.
>
> You lost me. How is this not handled by *args and **kwargs? I think it is. "Positional only" isn't needed in this case.

Because `def func(*args, **kwargs):` obfuscates the true signature,
making `help()` and the `inspect` module less useful and forcing one
to analyze the implementation code or study the docs to understand
what and how many arguments are actually expected.