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48 lines
1.3 KiB
Python
48 lines
1.3 KiB
Python
2 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, defining_class):
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# type: (Any, 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):
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# type: () -> int
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return hash(self._compare_key)
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def __lt__(self, other):
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# type: (Any) -> bool
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return self._compare(other, operator.__lt__)
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def __le__(self, other):
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# type: (Any) -> bool
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return self._compare(other, operator.__le__)
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def __gt__(self, other):
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# type: (Any) -> bool
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return self._compare(other, operator.__gt__)
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def __ge__(self, other):
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# type: (Any) -> bool
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return self._compare(other, operator.__ge__)
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def __eq__(self, other):
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# type: (Any) -> bool
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return self._compare(other, operator.__eq__)
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def _compare(self, other, method):
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# type: (Any, 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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