[Python-Dev] PEP 484 proposal: don't default to Optional if argument default is None (original) (raw)

Guido van Rossum guido at python.org
Tue May 9 23:31:52 EDT 2017

On Tue, May 9, 2017 at 7:37 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:

On 10 May 2017 at 08:51, Brett Cannon <brett at python.org> wrote: > On Tue, 9 May 2017 at 11:11 Carl Meyer <carl at oddbird.net> wrote: >> It might be nice to have a less verbose syntax for Optional, but that >> can be a separate discussion. > > You should be able to do that today with from typing import Optional as_ _Eh > or whatever your preferred optional/maybe name is. :)

While "from typing import Optional as Opt" can indeed help, perhaps PEP 505 should be updated to discuss this point in addition to the current proposals for None-aware binary operators? If it included a ? prefix operator as a shorthand for "typing.Optional[]", that would shorten affected declarations back to: def handleemployee(e: ?Employee = None) -> None: ...

I really don't want to go there. And this idea should definitely not be a condition for removing the existing PEP 484 feature. Whatever gets done syntax-wise won't affect anyone who needs any kind of backward compatibility anyways, and that's very important for practical adoption of PEP 484.

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