# pyright: reportIncompatibleMethodOverride=false
import abc
import collections
import typing
from . import types
if typing.TYPE_CHECKING:
import _typeshed # noqa: F401
#: A type alias for a type that can be used as a key in a dictionary.
KT = types.TypeVar('KT')
#: A type alias for a type that can be used as a value in a dictionary.
VT = types.TypeVar('VT')
#: A type alias for a dictionary with keys of type KT and values of type VT.
DT = types.Dict[KT, VT]
#: A type alias for the casted type of a dictionary key.
KT_cast = types.Optional[types.Callable[..., KT]]
#: A type alias for the casted type of a dictionary value.
VT_cast = types.Optional[types.Callable[..., VT]]
#: A type alias for the hashable values of the `UniqueList`
HT = types.TypeVar('HT', bound=types.Hashable)
#: A type alias for a regular generic type
T = types.TypeVar('T')
# Using types.Union instead of | since Python 3.7 doesn't fully support it
DictUpdateArgs = types.Union[
types.Mapping[KT, VT],
types.Iterable[types.Tuple[KT, VT]],
types.Iterable[types.Mapping[KT, VT]],
'_typeshed.SupportsKeysAndGetItem[KT, VT]',
]
OnDuplicate = types.Literal['ignore', 'raise']
class CastedDictBase(types.Dict[KT, VT], abc.ABC):
_key_cast: KT_cast[KT]
_value_cast: VT_cast[VT]
def __init__(
self,
key_cast: KT_cast[KT] = None,
value_cast: VT_cast[VT] = None,
*args: DictUpdateArgs[KT, VT],
**kwargs: VT,
) -> None:
self._value_cast = value_cast
self._key_cast = key_cast
self.update(*args, **kwargs)
def update(
self, *args: DictUpdateArgs[types.Any, types.Any], **kwargs: types.Any
) -> None:
if args:
kwargs.update(*args)
if kwargs:
for key, value in kwargs.items():
self[key] = value
def __setitem__(self, key: types.Any, value: types.Any) -> None:
if self._key_cast is not None:
key = self._key_cast(key)
return super().__setitem__(key, value)
[docs]
class CastedDict(CastedDictBase[KT, VT]):
'''
Custom dictionary that casts keys and values to the specified typing.
Note that you can specify the types for mypy and type hinting with:
CastedDict[int, int](int, int)
>>> d: CastedDict[int, int] = CastedDict(int, int)
>>> d[1] = 2
>>> d['3'] = '4'
>>> d.update({'5': '6'})
>>> d.update([('7', '8')])
>>> d
{1: 2, 3: 4, 5: 6, 7: 8}
>>> list(d.keys())
[1, 3, 5, 7]
>>> list(d)
[1, 3, 5, 7]
>>> list(d.values())
[2, 4, 6, 8]
>>> list(d.items())
[(1, 2), (3, 4), (5, 6), (7, 8)]
>>> d[3]
4
# Casts are optional and can be disabled by passing None as the cast
>>> d = CastedDict()
>>> d[1] = 2
>>> d['3'] = '4'
>>> d.update({'5': '6'})
>>> d.update([('7', '8')])
>>> d
{1: 2, '3': '4', '5': '6', '7': '8'}
'''
def __setitem__(self, key: typing.Any, value: typing.Any) -> None:
if self._value_cast is not None:
value = self._value_cast(value)
super().__setitem__(key, value)
[docs]
class LazyCastedDict(CastedDictBase[KT, VT]):
'''
Custom dictionary that casts keys and lazily casts values to the specified
typing. Note that the values are cast only when they are accessed and
are not cached between executions.
Note that you can specify the types for mypy and type hinting with:
LazyCastedDict[int, int](int, int)
>>> d: LazyCastedDict[int, int] = LazyCastedDict(int, int)
>>> d[1] = 2
>>> d['3'] = '4'
>>> d.update({'5': '6'})
>>> d.update([('7', '8')])
>>> d
{1: 2, 3: '4', 5: '6', 7: '8'}
>>> list(d.keys())
[1, 3, 5, 7]
>>> list(d)
[1, 3, 5, 7]
>>> list(d.values())
[2, 4, 6, 8]
>>> list(d.items())
[(1, 2), (3, 4), (5, 6), (7, 8)]
>>> d[3]
4
# Casts are optional and can be disabled by passing None as the cast
>>> d = LazyCastedDict()
>>> d[1] = 2
>>> d['3'] = '4'
>>> d.update({'5': '6'})
>>> d.update([('7', '8')])
>>> d
{1: 2, '3': '4', '5': '6', '7': '8'}
>>> list(d.keys())
[1, '3', '5', '7']
>>> list(d.values())
[2, '4', '6', '8']
>>> list(d.items())
[(1, 2), ('3', '4'), ('5', '6'), ('7', '8')]
>>> d['3']
'4'
'''
def __setitem__(self, key: types.Any, value: types.Any):
if self._key_cast is not None:
key = self._key_cast(key)
super().__setitem__(key, value)
def __getitem__(self, key: types.Any) -> VT:
if self._key_cast is not None:
key = self._key_cast(key)
value = super().__getitem__(key)
if self._value_cast is not None:
value = self._value_cast(value)
return value
[docs]
def items( # type: ignore
self,
) -> types.Generator[types.Tuple[KT, VT], None, None]:
if self._value_cast is None:
yield from super().items()
else:
for key, value in super().items():
yield key, self._value_cast(value)
[docs]
def values(self) -> types.Generator[VT, None, None]: # type: ignore
if self._value_cast is None:
yield from super().values()
else:
for value in super().values():
yield self._value_cast(value)
[docs]
class UniqueList(types.List[HT]):
'''
A list that only allows unique values. Duplicate values are ignored by
default, but can be configured to raise an exception instead.
>>> l = UniqueList(1, 2, 3)
>>> l.append(4)
>>> l.append(4)
>>> l.insert(0, 4)
>>> l.insert(0, 5)
>>> l[1] = 10
>>> l
[5, 10, 2, 3, 4]
>>> l = UniqueList(1, 2, 3, on_duplicate='raise')
>>> l.append(4)
>>> l.append(4)
Traceback (most recent call last):
...
ValueError: Duplicate value: 4
>>> l.insert(0, 4)
Traceback (most recent call last):
...
ValueError: Duplicate value: 4
>>> 4 in l
True
>>> l[0]
1
>>> l[1] = 4
Traceback (most recent call last):
...
ValueError: Duplicate value: 4
'''
_set: types.Set[HT]
def __init__(
self,
*args: HT,
on_duplicate: OnDuplicate = 'ignore',
):
self.on_duplicate = on_duplicate
self._set = set()
super().__init__()
for arg in args:
self.append(arg)
[docs]
def insert(self, index: types.SupportsIndex, value: HT) -> None:
if value in self._set:
if self.on_duplicate == 'raise':
raise ValueError(f'Duplicate value: {value}')
else:
return
self._set.add(value)
super().insert(index, value)
[docs]
def append(self, value: HT) -> None:
if value in self._set:
if self.on_duplicate == 'raise':
raise ValueError(f'Duplicate value: {value}')
else:
return
self._set.add(value)
super().append(value)
def __contains__(self, item: HT) -> bool: # type: ignore
return item in self._set
@typing.overload
def __setitem__(self, indices: types.SupportsIndex, values: HT) -> None:
...
@typing.overload
def __setitem__(self, indices: slice, values: types.Iterable[HT]) -> None:
...
def __setitem__(
self,
indices: types.Union[slice, types.SupportsIndex],
values: types.Union[types.Iterable[HT], HT],
) -> None:
if isinstance(indices, slice):
values = types.cast(types.Iterable[HT], values)
if self.on_duplicate == 'ignore':
raise RuntimeError(
'ignore mode while setting slices introduces ambiguous '
'behaviour and is therefore not supported'
)
duplicates: types.Set[HT] = set(values) & self._set
if duplicates and values != list(self[indices]):
raise ValueError(f'Duplicate values: {duplicates}')
self._set.update(values)
else:
values = types.cast(HT, values)
if values in self._set and values != self[indices]:
if self.on_duplicate == 'raise':
raise ValueError(f'Duplicate value: {values}')
else:
return
self._set.add(values)
super().__setitem__(
types.cast(slice, indices), types.cast(types.List[HT], values)
)
def __delitem__(
self, index: types.Union[types.SupportsIndex, slice]
) -> None:
if isinstance(index, slice):
for value in self[index]:
self._set.remove(value)
else:
self._set.remove(self[index])
super().__delitem__(index)
# Type hinting `collections.deque` does not work consistently between Python
# runtime, mypy and pyright currently so we have to ignore the errors
class SliceableDeque(types.Generic[T], collections.deque): # type: ignore
@typing.overload
def __getitem__(self, index: types.SupportsIndex) -> T:
...
@typing.overload
def __getitem__(self, index: slice) -> 'SliceableDeque[T]':
...
def __getitem__(
self, index: types.Union[types.SupportsIndex, slice]
) -> types.Union[T, 'SliceableDeque[T]']:
'''
Return the item or slice at the given index.
>>> d = SliceableDeque[int]([1, 2, 3, 4, 5])
>>> d[1:4]
SliceableDeque([2, 3, 4])
>>> d = SliceableDeque[str](['a', 'b', 'c'])
>>> d[-2:]
SliceableDeque(['b', 'c'])
'''
if isinstance(index, slice):
start, stop, step = index.indices(len(self))
return self.__class__(self[i] for i in range(start, stop, step))
else:
return types.cast(T, super().__getitem__(index))
def __eq__(self, other: types.Any) -> bool:
# Allow for comparison with a list or tuple
if isinstance(other, list):
return list(self) == other
elif isinstance(other, tuple):
return tuple(self) == other
elif isinstance(other, set):
return set(self) == other
else:
return super().__eq__(other)
def pop(self, index: int = -1) -> T:
# We need to allow for an index but a deque only allows the removal of
# the first or last item.
if index == 0:
return typing.cast(T, super().popleft())
elif index in {-1, len(self) - 1}:
return typing.cast(T, super().pop())
else:
raise IndexError(
'Only index 0 and the last index (`N-1` or `-1`) '
'are supported'
)
if __name__ == '__main__':
import doctest
doctest.testmod()