Source code for maps.fixedkeymap
try:
import collections.abc as collections_abc
except ImportError:
import collections as collections_abc
import maps.utils as utils
[docs]class FixedKeyMap(collections_abc.MutableMapping):
'''A key-value mapping with a fixed set of keys whose items are accessible
via bracket-notation (i.e. ``__getitem__`` and ``__setitem__``). Though the
set of keys is immutable, the corresponding values can be edited.
:param args: Position arguments in the same form as the :py:class:`dict` constructor.
:param kwargs: Keyword arguments in the same form as the :py:class:`dict` constructor.
Usage::
>>> import maps
>>> fkm = maps.FixedKeyMap({'a': 1, 'b': 2})
>>> fkm['a']
1
>>> fkm['b'] += 10
>>> fkm['b']
12
>>> list(fkm.items())
[('a', 1), ('b', 12)]
>>> len(fkm)
2
'''
@classmethod
[docs] def recurse(cls, obj, list_fn=None, object_fn=None):
'''Recursively create :class:`FixedKeyMap` s when :py:class:`collections.Mapping`
are encountered.
:param obj: Object to be recursively converted.
:param func list_fn: Conversion function applied to any :py:class:`collections.Sequence` s and :py:class:`collections.Set` s encountered. Defaults to the identity function.
:param func object_fn: Conversion function applied to all other objects encountered. Defaults to the identity function.
Usage::
>>> import maps
>>> fkm = maps.FixedKeyMap.recurse({'a': 1, 'b': [2, {'c': 3}]})
>>> fkm.b[1]
FixedKeyMap(c=3)
'''
return utils._recurse(obj, map_fn=cls, list_fn=list_fn, object_fn=object_fn)
def __init__(self, *args, **kwargs):
self._data = dict(*args, **kwargs)
def __getitem__(self, name):
return self._data[name]
def __iter__(self):
return iter(self._data)
def __len__(self):
return len(self._data)
def __delitem__(self, name):
raise TypeError(
"'{}' object does not support item deletion".format(type(self).__name__))
def __setitem__(self, name, value):
if name not in self._data:
raise TypeError(
"'{}' object does not support new item assignment".format(type(self).__name__))
self._data[name] = value
def __repr__(self): # pragma: no cover
return '{}({!r})'.format(type(self).__name__, self._data)