[Python-Dev] PEP 443 - Single-dispatch generic functions

[Ethan Furman]

On 05/23/2013 07:58 AM, Łukasz Langa wrote:
> On 23 maj 2013, at 16:49, Guido van Rossum <guido at python.org> wrote:
>
>> Łukasz, are there any open issues? Otherwise I'm ready to accept the PEP.
>
> There's one. Quoting the PEP:
>
> "The dispatch type is currently specified as a decorator argument. The
> implementation could allow a form using argument annotations. This usage
> pattern is out of scope for the standard library (per PEP 8). However,
> whether this registration form would be acceptable for general usage, is
> up to debate."
>
> I feel that the PEP should explicitly allow or disallow for the
> implementation to accept dispatch on annotations, e.g.:
>
> @func.register
> def _(arg: int):
>    ...
>
> versus
>
> @func.register(int)
> def _(arg):
>    ...

If the stdlib is still staying out of the annotation business, then it should not be allowed.

--
~Ethan~