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40 lines
1.2 KiB
40 lines
1.2 KiB
3 years ago
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"""Utilities for defining models
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"""
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import operator
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from typing import Any, Callable, Type
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class KeyBasedCompareMixin:
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"""Provides comparison capabilities that is based on a key"""
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__slots__ = ["_compare_key", "_defining_class"]
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def __init__(self, key: Any, defining_class: Type["KeyBasedCompareMixin"]) -> None:
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self._compare_key = key
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self._defining_class = defining_class
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def __hash__(self) -> int:
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return hash(self._compare_key)
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def __lt__(self, other: Any) -> bool:
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return self._compare(other, operator.__lt__)
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def __le__(self, other: Any) -> bool:
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return self._compare(other, operator.__le__)
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def __gt__(self, other: Any) -> bool:
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return self._compare(other, operator.__gt__)
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def __ge__(self, other: Any) -> bool:
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return self._compare(other, operator.__ge__)
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def __eq__(self, other: Any) -> bool:
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return self._compare(other, operator.__eq__)
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def _compare(self, other: Any, method: Callable[[Any, Any], bool]) -> bool:
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if not isinstance(other, self._defining_class):
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return NotImplemented
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return method(self._compare_key, other._compare_key)
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