# Copyright 2009-2023 Joshua Bronson. All rights reserved.
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
"""Provide :class:`OnDup` and related functionality."""
from __future__ import annotations
from enum import Enum
import typing as t
class OD(Enum):
"""An action to take to prevent duplication from occurring."""
#: Raise a :class:`~bidict.DuplicationError`.
RAISE = 'RAISE'
#: Overwrite existing items with new items.
DROP_OLD = 'DROP_OLD'
#: Keep existing items and drop new items.
DROP_NEW = 'DROP_NEW'
def __repr__(self) -> str:
return f'{self.__class__.__name__}.{self.name}'
RAISE: t.Final[OD] = OD.RAISE
DROP_OLD: t.Final[OD] = OD.DROP_OLD
DROP_NEW: t.Final[OD] = OD.DROP_NEW
class OnDup(t.NamedTuple('_OnDup', [('key', OD), ('val', OD), ('kv', OD)])):
r"""A 3-tuple of :class:`OD`\s specifying how to handle the 3 kinds of duplication.
*See also* :ref:`basic-usage:Values Must Be Unique`
(https://bidict.rtfd.io/basic-usage.html#values-must-be-unique)
If *kv* is not specified, *val* will be used for *kv*.
"""
__slots__ = ()
[docs] def __new__(cls, key: OD = DROP_OLD, val: OD = RAISE, kv: OD | None = None) -> OnDup:
"""Override to provide user-friendly default values."""
return super().__new__(cls, key, val, kv or val)
#: Default :class:`OnDup` used for the
#: :meth:`~bidict.bidict.__init__`,
#: :meth:`~bidict.bidict.__setitem__`, and
#: :meth:`~bidict.bidict.update` methods.
ON_DUP_DEFAULT: t.Final[OnDup] = OnDup(key=DROP_OLD, val=RAISE, kv=RAISE)
#: An :class:`OnDup` whose members are all :obj:`RAISE`.
ON_DUP_RAISE: t.Final[OnDup] = OnDup(key=RAISE, val=RAISE, kv=RAISE)
#: An :class:`OnDup` whose members are all :obj:`DROP_OLD`.
ON_DUP_DROP_OLD: t.Final[OnDup] = OnDup(key=DROP_OLD, val=DROP_OLD, kv=DROP_OLD)