Replies: 1 comment 14 replies
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You can use a from typing import Callable
class Collection:
def make[**P, T](
self, type_: Callable[P, T], *args: P.args, **kwargs: P.kwargs
) -> T: ...Here's the same thing using older (pre-3.12) syntax: from typing import Callable, ParamSpec, TypeVar
P = ParamSpec("P")
T = TypeVar("T")
class Collection:
def make(self, type_: Callable[P, T], *args: P.args, **kwargs: P.kwargs) -> T: ... |
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Sorry, not following this, could you provide a code example of what you mean?
This sounds pretty sub-optimal :-/ What's pytype? That's not a phrase I've heard before... |
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The spec for def allowed[**P](self, *args: P.args, **kwargs: P.kwargs): ...
def positional_only_prepend_allowed[**P](self, arg: int, /, *args: P.args, **kwargs: P.kwargs): ...
def no_kwargs_disallowed[**P](self, *args: P.args): ...
def no_args_disallowed[**P](self, **kwargs: P.kwargs): ...
def middle_extra_kwarg_disallowed[**P](self, *args: P.args, my_new_kwarg: int = 0, **kwargs: P.kwargs): ...With upper bounds on
It's a Python type checker made by Google. It performs very deep type inference and allows a lot of things other type checkers would disallow because their inference is too shallow to ensure type safety without an explicit type annotation. So it can be useful in code that doesn't make heavy use of type annotations, since it will still be able to detect a lot of problems anyways. |
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The irony's not lost on me that some of the things that have made Python so powerful over the last two or three decades end up being the things that are hardest to express in static typing... Thanks for the pytype pointer; is this one, right? https://github.com/google/pytype |
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Correct |
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Hmm, unfortunately, pytype seems to trip up on much simpler stuff that mypy is happy with :-/ |
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So, for this code:
How can I annotate
**attrssuch that a type checker, mypy in particular, will correctly ensure that any keywords passed are a valid subset of those that could be passed toT's constructor?Beta Was this translation helpful? Give feedback.
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