372bd22475
* raise error when passing a str(var) * make it faster * fix typo * fix tests * mocker consistency Co-authored-by: Thomas Brandého <thomas.brandeho@gmail.com> * ditto Co-authored-by: Thomas Brandého <thomas.brandeho@gmail.com> --------- Co-authored-by: Thomas Brandého <thomas.brandeho@gmail.com>
26 lines
568 B
Python
26 lines
568 B
Python
"""Decorator utilities."""
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from typing import Callable, TypeVar
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T = TypeVar("T")
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def once(f: Callable[[], T]) -> Callable[[], T]:
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"""A decorator that calls the function once and caches the result.
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Args:
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f: The function to call.
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Returns:
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A function that calls the function once and caches the result.
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"""
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unset = object()
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value: object | T = unset
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def wrapper() -> T:
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nonlocal value
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value = f() if value is unset else value
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return value # pyright: ignore[reportReturnType]
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return wrapper
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