On Tue, 9 May 2017 at 11:11 Carl Meyer <c...@oddbird.net> wrote: > On 05/09/2017 10:28 AM, Guido van Rossum wrote: > > There's a proposal to change one detail of PEP 484. It currently says: > > > > An optional type is also automatically assumed when the default > value is > > |None|, for example:: > > > > |def handle_employee(e: Employee = None): ... | > > > > This is equivalent to:: > > > > |def handle_employee(e: Optional[Employee] = None) -> None: ... | > > > > > > Now that we've got some experience actually using Optional with mypy > > (originally mypy ignored Optional), we're beginning to think that this > > was a bad idea. There's more discussion at > > https://github.com/python/typing/issues/275 and an implementation of the > > change (using a command-line flag) in > > https://github.com/python/mypy/pull/3248. > > > > Thoughts? Some function declarations will become a bit more verbose, but > > we gain clarity (many users of annotations don't seem to be familiar > > with this feature) and consistency (since this rule doesn't apply to > > variable declarations and class attribute declarations). > > I've been code-reviewing a lot of diffs adding type coverage over the > last few months, and implicit-Optional has been among the most common > points of confusion. So I favor this change. >
I personally like the shorthand, but the type hints I have written are in my own projects so my experience with others is zilch and shouldn't count for much. > > 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. :)
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