|
| 1 | +from __future__ import annotations |
| 2 | + |
| 3 | +import abc |
| 4 | +from typing import Any |
| 5 | +from typing import Generator |
| 6 | + |
| 7 | +from . import types |
| 8 | + |
| 9 | +KT = types.TypeVar('KT') |
| 10 | +VT = types.TypeVar('VT') |
| 11 | +DT = types.Dict[KT, VT] |
| 12 | +KT_cast = types.Optional[types.Callable[[Any], KT]] |
| 13 | +VT_cast = types.Optional[types.Callable[[Any], VT]] |
| 14 | + |
| 15 | +# Using types.Union instead of | since Python 3.7 doesn't fully support it |
| 16 | +DictUpdateArgs = types.Union[ |
| 17 | + types.Mapping, |
| 18 | + types.Iterable[types.Union[types.Tuple[Any, Any], types.Mapping]], |
| 19 | +] |
| 20 | + |
| 21 | + |
| 22 | +class CastedDictBase(types.Dict[KT, VT], abc.ABC): |
| 23 | + _key_cast: KT_cast |
| 24 | + _value_cast: VT_cast |
| 25 | + |
| 26 | + def __init__( |
| 27 | + self, |
| 28 | + key_cast: KT_cast = None, |
| 29 | + value_cast: VT_cast = None, |
| 30 | + *args, |
| 31 | + **kwargs |
| 32 | + ) -> None: |
| 33 | + self._value_cast = value_cast |
| 34 | + self._key_cast = key_cast |
| 35 | + self.update(*args, **kwargs) |
| 36 | + |
| 37 | + def update( |
| 38 | + self, |
| 39 | + *args: DictUpdateArgs, |
| 40 | + **kwargs |
| 41 | + ) -> None: |
| 42 | + if args: |
| 43 | + kwargs.update(*args) |
| 44 | + |
| 45 | + if kwargs: |
| 46 | + for key, value in kwargs.items(): |
| 47 | + self[key] = value |
| 48 | + |
| 49 | + def __setitem__(self, key: Any, value: Any) -> None: |
| 50 | + if self._key_cast is not None: |
| 51 | + key = self._key_cast(key) |
| 52 | + |
| 53 | + return super().__setitem__(key, value) |
| 54 | + |
| 55 | + |
| 56 | +class CastedDict(CastedDictBase): |
| 57 | + ''' |
| 58 | + Custom dictionary that casts keys and values to the specified typing. |
| 59 | +
|
| 60 | + Note that you can specify the types for mypy and type hinting with: |
| 61 | + CastedDict[int, int](int, int) |
| 62 | +
|
| 63 | + >>> d = CastedDict(int, int) |
| 64 | + >>> d[1] = 2 |
| 65 | + >>> d['3'] = '4' |
| 66 | + >>> d.update({'5': '6'}) |
| 67 | + >>> d.update([('7', '8')]) |
| 68 | + >>> d |
| 69 | + {1: 2, 3: 4, 5: 6, 7: 8} |
| 70 | + >>> list(d.keys()) |
| 71 | + [1, 3, 5, 7] |
| 72 | + >>> list(d) |
| 73 | + [1, 3, 5, 7] |
| 74 | + >>> list(d.values()) |
| 75 | + [2, 4, 6, 8] |
| 76 | + >>> list(d.items()) |
| 77 | + [(1, 2), (3, 4), (5, 6), (7, 8)] |
| 78 | + >>> d[3] |
| 79 | + 4 |
| 80 | +
|
| 81 | + # Casts are optional and can be disabled by passing None as the cast |
| 82 | + >>> d = CastedDict() |
| 83 | + >>> d[1] = 2 |
| 84 | + >>> d['3'] = '4' |
| 85 | + >>> d.update({'5': '6'}) |
| 86 | + >>> d.update([('7', '8')]) |
| 87 | + >>> d |
| 88 | + {1: 2, '3': '4', '5': '6', '7': '8'} |
| 89 | + ''' |
| 90 | + |
| 91 | + def __setitem__(self, key, value): |
| 92 | + if self._value_cast is not None: |
| 93 | + value = self._value_cast(value) |
| 94 | + |
| 95 | + super().__setitem__(key, value) |
| 96 | + |
| 97 | + |
| 98 | +class LazyCastedDict(CastedDictBase): |
| 99 | + ''' |
| 100 | + Custom dictionary that casts keys and lazily casts values to the specified |
| 101 | + typing. Note that the values are cast only when they are accessed and |
| 102 | + are not cached between executions. |
| 103 | +
|
| 104 | + Note that you can specify the types for mypy and type hinting with: |
| 105 | + LazyCastedDict[int, int](int, int) |
| 106 | +
|
| 107 | + >>> d = LazyCastedDict(int, int) |
| 108 | + >>> d[1] = 2 |
| 109 | + >>> d['3'] = '4' |
| 110 | + >>> d.update({'5': '6'}) |
| 111 | + >>> d.update([('7', '8')]) |
| 112 | + >>> d |
| 113 | + {1: 2, 3: '4', 5: '6', 7: '8'} |
| 114 | + >>> list(d.keys()) |
| 115 | + [1, 3, 5, 7] |
| 116 | + >>> list(d) |
| 117 | + [1, 3, 5, 7] |
| 118 | + >>> list(d.values()) |
| 119 | + [2, 4, 6, 8] |
| 120 | + >>> list(d.items()) |
| 121 | + [(1, 2), (3, 4), (5, 6), (7, 8)] |
| 122 | + >>> d[3] |
| 123 | + 4 |
| 124 | +
|
| 125 | + # Casts are optional and can be disabled by passing None as the cast |
| 126 | + >>> d = LazyCastedDict() |
| 127 | + >>> d[1] = 2 |
| 128 | + >>> d['3'] = '4' |
| 129 | + >>> d.update({'5': '6'}) |
| 130 | + >>> d.update([('7', '8')]) |
| 131 | + >>> d |
| 132 | + {1: 2, '3': '4', '5': '6', '7': '8'} |
| 133 | + >>> list(d.keys()) |
| 134 | + [1, '3', '5', '7'] |
| 135 | + >>> list(d.values()) |
| 136 | + [2, '4', '6', '8'] |
| 137 | +
|
| 138 | + >>> list(d.items()) |
| 139 | + [(1, 2), ('3', '4'), ('5', '6'), ('7', '8')] |
| 140 | + >>> d['3'] |
| 141 | + '4' |
| 142 | + ''' |
| 143 | + |
| 144 | + def __setitem__(self, key, value): |
| 145 | + if self._key_cast is not None: |
| 146 | + key = self._key_cast(key) |
| 147 | + |
| 148 | + super().__setitem__(key, value) |
| 149 | + |
| 150 | + def __getitem__(self, key) -> VT: |
| 151 | + if self._key_cast is not None: |
| 152 | + key = self._key_cast(key) |
| 153 | + |
| 154 | + value = super().__getitem__(key) |
| 155 | + |
| 156 | + if self._value_cast is not None: |
| 157 | + value = self._value_cast(value) |
| 158 | + |
| 159 | + return value |
| 160 | + |
| 161 | + def items(self) -> Generator[tuple[KT, VT], None, None]: # type: ignore |
| 162 | + if self._value_cast is None: |
| 163 | + yield from super().items() |
| 164 | + else: |
| 165 | + for key, value in super().items(): |
| 166 | + yield key, self._value_cast(value) |
| 167 | + |
| 168 | + def values(self) -> Generator[VT, None, None]: # type: ignore |
| 169 | + if self._value_cast is None: |
| 170 | + yield from super().values() |
| 171 | + else: |
| 172 | + for value in super().values(): |
| 173 | + yield self._value_cast(value) |
| 174 | + |
| 175 | + |
| 176 | +if __name__ == '__main__': |
| 177 | + import doctest |
| 178 | + |
| 179 | + doctest.testmod() |
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