Add explanation of singletons in unions to PEP484 #240
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| else: # At this point typechecker knows that x can only have type int | ||
| return x * 2 | ||
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| Since the subclasses of ``Enum`` could not be further subclassed, |
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Thanks! Some language nits. I wonder if we should add another example showing an enum with multiple values? |
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I have made corrections and added another example. I think it clarifies that it is not necessary to make many |
| token = 0 | ||
| _empty = Empty.token | ||
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| def func(x: Union[int, None, Empty]=_empty) -> int: |
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Style nit: add spaces around =.
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@JukkaL Done. |
By Ivan Levkivskyi (python/typing#240).
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Pushed to the peps repo and filed python/mypy#1803. Maybe now that the peps repo has moved to GitHub we should switch to doing PRs there? |
Thanks!
Yes, I think we could switch to new peps repo. By the way, what are the plans for PEP484, will it be provisional in 3.6? Or will it "graduate" soon? |
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I would like PEP 484 to drop the provisional status for 3.6, but we have to
discuss this on python-dev.
For asyncio we did two provisional release (3.4 and 3.5) but IMO that was
too long (and yet not long enough -- Yury recently asked me to extend that
to 3.6 as well).
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I tried to keep discussion to a minimum, only including simple examples. I think it is better to add this section right after discussion of Optional, that is actually also a Union with a singleton type (NoneType).