59 lines
2.4 KiB
Python
59 lines
2.4 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2009-2020 Joshua Bronson. All Rights Reserved.
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this
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# file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#==============================================================================
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# * Welcome to the bidict source code *
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#==============================================================================
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# Doing a code review? You'll find a "Code review nav" comment like the one
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# below at the top and bottom of the most important source files. This provides
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# a suggested initial path through the source when reviewing.
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#
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# Note: If you aren't reading this on https://github.com/jab/bidict, you may be
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# viewing an outdated version of the code. Please head to GitHub to review the
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# latest version, which contains important improvements over older versions.
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#
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# Thank you for reading and for any feedback you provide.
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# * Code review nav *
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#==============================================================================
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# ← Prev: _base.py Current: _frozenbidict.py Next: _mut.py →
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#==============================================================================
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"""Provide :class:`frozenbidict`, an immutable, hashable bidirectional mapping type."""
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import typing as _t
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from ._delegating import _DelegatingBidict
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from ._typing import KT, VT
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class frozenbidict(_DelegatingBidict[KT, VT]):
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"""Immutable, hashable bidict type."""
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__slots__ = ()
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# Work around lack of support for higher-kinded types in mypy.
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# Ref: https://github.com/python/typing/issues/548#issuecomment-621571821
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# Remove this and similar type stubs from other classes if support is ever added.
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if _t.TYPE_CHECKING:
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@property
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def inverse(self) -> 'frozenbidict[VT, KT]': ...
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def __hash__(self) -> int:
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"""The hash of this bidict as determined by its items."""
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if getattr(self, '_hash', None) is None:
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self._hash = _t.ItemsView(self)._hash() # type: ignore
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return self._hash # type: ignore
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# * Code review nav *
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#==============================================================================
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# ← Prev: _base.py Current: _frozenbidict.py Next: _mut.py →
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#==============================================================================
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