[New-bugs-announce] [issue32227] singledispatch support for type annotations
report at bugs.python.org
Tue Dec 5 16:24:12 EST 2017
New submission from Łukasz Langa <lukasz at langa.pl>:
With the patch attached to this issue, @singledispatch gains support for passing the type in @register via annotations.
This looks more natural and enables more thorough type checking without repeating yourself:
def generic(arg): ...
def _(arg: str): ...
def _(arg: int): ...
The previous API is still available for backwards compatibility, as well as stacking, and use with classes (sic, I was surprised to learn it's used that way, too).
The patch should be uncontroversial, maybe except for the fact that it's importing the `typing` module if annotations are used. This is necessary because of forward references, usage of None as a type, and so on. More importantly, with PEP 563 it's mandatory.
components: Library (Lib)
nosy: lukasz.langa, rhettinger, yselivanov
title: singledispatch support for type annotations
versions: Python 3.7
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