# -*- coding: utf-8 -*-
# Copyright 2009-2019 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/.
#==============================================================================
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# ← Prev: _frozenbidict.py Current: _mut.py Next: _bidict.py →
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"""Provides :class:`bidict`."""
from ._base import BidictBase
from ._dup import OVERWRITE, RAISE, _OnDup
from ._miss import _MISS
from .compat import MutableMapping
# Extend MutableMapping explicitly because it doesn't implement __subclasshook__, as well as to
# inherit method implementations it provides that we can reuse (namely `setdefault`).
[docs]class MutableBidict(BidictBase, MutableMapping):
"""Base class for mutable bidirectional mappings."""
__slots__ = ()
__hash__ = None # since this class is mutable; explicit > implicit.
_ON_DUP_OVERWRITE = _OnDup(key=OVERWRITE, val=OVERWRITE, kv=OVERWRITE)
[docs] def __delitem__(self, key):
u"""*x.__delitem__(y) ⟺ del x[y]*"""
self._pop(key)
[docs] def __setitem__(self, key, val):
"""
Set the value for *key* to *val*.
If *key* is already associated with *val*, this is a no-op.
If *key* is already associated with a different value,
the old value will be replaced with *val*,
as with dict's :meth:`__setitem__`.
If *val* is already associated with a different key,
an exception is raised
to protect against accidental removal of the key
that's currently associated with *val*.
Use :meth:`put` instead if you want to specify different policy in
the case that the provided key or value duplicates an existing one.
Or use :meth:`forceput` to unconditionally associate *key* with *val*,
replacing any existing items as necessary to preserve uniqueness.
:raises bidict.ValueDuplicationError: if *val* duplicates that of an
existing item.
:raises bidict.KeyAndValueDuplicationError: if *key* duplicates the key of an
existing item and *val* duplicates the value of a different
existing item.
"""
on_dup = self._get_on_dup()
self._put(key, val, on_dup)
[docs] def put(self, key, val, on_dup_key=RAISE, on_dup_val=RAISE, on_dup_kv=None):
"""
Associate *key* with *val* with the specified duplication policies.
If *on_dup_kv* is ``None``, the *on_dup_val* policy will be used for it.
For example, if all given duplication policies are :attr:`~bidict.RAISE`,
then *key* will be associated with *val* if and only if
*key* is not already associated with an existing value and
*val* is not already associated with an existing key,
otherwise an exception will be raised.
If *key* is already associated with *val*, this is a no-op.
:raises bidict.KeyDuplicationError: if attempting to insert an item
whose key only duplicates an existing item's, and *on_dup_key* is
:attr:`~bidict.RAISE`.
:raises bidict.ValueDuplicationError: if attempting to insert an item
whose value only duplicates an existing item's, and *on_dup_val* is
:attr:`~bidict.RAISE`.
:raises bidict.KeyAndValueDuplicationError: if attempting to insert an
item whose key duplicates one existing item's, and whose value
duplicates another existing item's, and *on_dup_kv* is
:attr:`~bidict.RAISE`.
"""
on_dup = self._get_on_dup((on_dup_key, on_dup_val, on_dup_kv))
self._put(key, val, on_dup)
[docs] def forceput(self, key, val):
"""
Associate *key* with *val* unconditionally.
Replace any existing mappings containing key *key* or value *val*
as necessary to preserve uniqueness.
"""
self._put(key, val, self._ON_DUP_OVERWRITE)
[docs] def clear(self):
"""Remove all items."""
self._fwdm.clear()
self._invm.clear()
[docs] def pop(self, key, default=_MISS):
u"""*x.pop(k[, d]) → v*
Remove specified key and return the corresponding value.
:raises KeyError: if *key* is not found and no *default* is provided.
"""
try:
return self._pop(key)
except KeyError:
if default is _MISS:
raise
return default
[docs] def popitem(self):
u"""*x.popitem() → (k, v)*
Remove and return some item as a (key, value) pair.
:raises KeyError: if *x* is empty.
"""
if not self:
raise KeyError('mapping is empty')
key, val = self._fwdm.popitem()
del self._invm[val]
return key, val
[docs] def update(self, *args, **kw):
"""Like :meth:`putall` with default duplication policies."""
if args or kw:
self._update(False, None, *args, **kw)
[docs] def forceupdate(self, *args, **kw):
"""Like a bulk :meth:`forceput`."""
self._update(False, self._ON_DUP_OVERWRITE, *args, **kw)
[docs] def putall(self, items, on_dup_key=RAISE, on_dup_val=RAISE, on_dup_kv=None):
"""
Like a bulk :meth:`put`.
If one of the given items causes an exception to be raised,
none of the items is inserted.
"""
if items:
on_dup = self._get_on_dup((on_dup_key, on_dup_val, on_dup_kv))
self._update(False, on_dup, items)
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