Processor to convert the function parameters. A `callable` argument will be used to convert the corresponding function argument. For example, here `x` will be converted to float, before entering the function body:: >>> conv = Processor(float) >>> conv <clas
| 123 | |
| 124 | |
| 125 | class Processor(object): |
| 126 | """Processor to convert the function parameters. |
| 127 | |
| 128 | A `callable` argument will be used to convert the corresponding |
| 129 | function argument. |
| 130 | |
| 131 | For example, here `x` will be converted to float, before entering |
| 132 | the function body:: |
| 133 | |
| 134 | >>> conv = Processor(float) |
| 135 | >>> conv |
| 136 | <class 'float'> |
| 137 | >>> conv('10') |
| 138 | 10.0 |
| 139 | |
| 140 | The processor supports multiple argument conversion in a tuple:: |
| 141 | |
| 142 | >>> conv = Processor((float, str)) |
| 143 | >>> type(conv) |
| 144 | <class 'lantz.processors.Processor'> |
| 145 | >>> conv(('10', 10)) |
| 146 | (10.0, '10') |
| 147 | |
| 148 | """ |
| 149 | |
| 150 | def __new__(cls, processors): |
| 151 | |
| 152 | if isinstance(processors, (tuple, list)): |
| 153 | if len(processors) > 1: |
| 154 | inst = super().__new__(cls) |
| 155 | inst.processors = tuple(cls._to_callable(processor) |
| 156 | for processor in processors) |
| 157 | return inst |
| 158 | else: |
| 159 | return cls._to_callable(processors[0]) |
| 160 | else: |
| 161 | return cls._to_callable(processors) |
| 162 | |
| 163 | def __call__(self, values): |
| 164 | return tuple(processor(value) |
| 165 | for processor, value in zip(self.processors, values)) |
| 166 | |
| 167 | @classmethod |
| 168 | def _to_callable(cls, obj): |
| 169 | if callable(obj): |
| 170 | return obj |
| 171 | if obj is None: |
| 172 | return _do_nothing |
| 173 | return cls.to_callable(obj) |
| 174 | |
| 175 | @classmethod |
| 176 | def to_callable(cls, obj): |
| 177 | raise TypeError('Preprocessor argument must callable, not {}'.format(obj)) |
| 178 | |
| 179 | def __len__(self): |
| 180 | if isinstance(self.processors, tuple): |
| 181 | return len(self.processors) |
| 182 | return 1 |