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import typing |
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from ._adt_constructor import ADTConstructor |
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from ._match_failure import MatchFailure |
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from ._not_in import not_in |
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from ._patterns.basic_patterns import Pattern |
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from ._patterns.compound_match import CompoundMatch |
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from ._unpack import unpack |
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_TYPE = type |
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class Destructurer: |
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def __init_subclass__(cls, type, **kwargs): |
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super().__init_subclass__(**kwargs) |
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cls.type: _TYPE = type |
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def __init__(self, target): |
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self.target = target |
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def __call__(self, value): |
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return self.destructure(value) |
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def destructure(self, value): |
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raise NotImplementedError |
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class ADTDestructurer(Destructurer, type=ADTConstructor): |
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def destructure(self, value): |
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if value.__class__ is not self.target.__class__: |
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raise MatchFailure |
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return reversed(unpack(value)) |
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class TupleDestructurer(Destructurer, type=tuple): |
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def destructure(self, value): |
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if isinstance(value, self.target.__class__) and len(self.target) == len(value): |
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return reversed(value) |
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raise MatchFailure |
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T = typing.TypeVar("T", bound="DestructurerList") |
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class DestructurerList(tuple): |
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__slots__ = () |
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def __new__(cls, *destructurers): |
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return super().__new__(cls, destructurers) |
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def get_destructurer( |
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self, item |
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) -> typing.Optional[typing.Callable[[typing.Any], typing.Sequence[typing.Any]]]: |
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if isinstance(item, CompoundMatch): |
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return item.destructure |
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for destructurer in self: |
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if isinstance(item, destructurer.type): |
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return destructurer(item) |
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return None |
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@classmethod |
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def custom(cls: typing.Type[T], *destructurers) -> T: |
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return cls(*destructurers, ADTDestructurer, TupleDestructurer) |
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def destructure(self, item): |
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destructurer = self.get_destructurer(item) |
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if destructurer: |
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yield from destructurer(item) |
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def stack_iter(self, target): |
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to_process = [target] |
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while to_process: |
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item = to_process.pop() |
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if isinstance(item, Pattern): |
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yield item |
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else: |
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to_process.extend(self.destructure(item)) |
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def names(self, target) -> typing.List[str]: |
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name_list: typing.List[str] = [] |
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for item in self.stack_iter(target): |
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not_in(name_list, item.name) |
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name_list.append(item.name) |
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return name_list |
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DESTRUCTURERS = DestructurerList.custom() |
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mwchase /
python-structured-data
