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Nestable Iterable
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| class NestableIterable(Iterable[T]): | |
| index_stack: list | |
| iterable: Iterable[T] | |
| def __init__(self, iterable: Iterable[T]) -> None: | |
| self.iterable = iterable | |
| self.index_stack = [0] | |
| def __iter__(self): | |
| index = self.index_stack[-1] | |
| self.index_stack.append(self.index_stack[-1]) | |
| start_offset = index + int(bool(index)) | |
| try: | |
| for self.index_stack[-1], content in enumerate( | |
| itertools.islice(self.iterable, start_offset, None, None), | |
| start=start_offset, | |
| ): | |
| yield content | |
| finally: | |
| self.index_stack.pop() | |
| def with_new(self, target): | |
| self.iterable = target | |
| return self |
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| T = TypeVar("T") | |
| I = TypeVar("I") | |
| class NestableIterable(Generic[I, T]): | |
| iterable: Iterable[T] | |
| indexes: List[I] | |
| generator_with_index_factory: Callable[ | |
| [Iterable[T], I], Generator[None, None, Tuple[I, T]] | |
| ] | |
| index_increase_func: Callable[[I, Iterable[T]], I] | |
| is_index_origin: Callable[[I], bool] | |
| @staticmethod | |
| def default_generator_factory(iterable: Iterable[T], start: I): | |
| return enumerate(iterable[start:], start=start) | |
| def __init__( | |
| self, | |
| iterable: Iterable[T], | |
| generator_with_index_factory: Callable[ | |
| [Iterable[T], I], Generator[None, None, Tuple[I, T]] | |
| ] = None, | |
| index_increase_func: Callable[[I, Iterable[T]], I] = lambda x, _: x + 1, | |
| initial_index_value_factory: Callable[[], I] = lambda: 0, | |
| is_index_origin: Callable[[I], bool] = lambda x: x == 0, | |
| ) -> None: | |
| self.iterable = iterable | |
| self.indexes = [initial_index_value_factory()] | |
| self.generator_with_index_factory = ( | |
| generator_with_index_factory or self.default_generator_factory | |
| ) | |
| self.index_increase_func = index_increase_func | |
| self.is_index_origin = is_index_origin | |
| def __iter__(self): | |
| current_index = self.indexes[-1] | |
| self.indexes.append(current_index) | |
| if self.is_index_origin(current_index): | |
| start_offset = current_index | |
| else: | |
| start_offset = self.index_increase_func(current_index, self.iterable) | |
| for self.indexes[-1], content in self.generator_with_index_factory( | |
| self.iterable, | |
| start=start_offset, | |
| ): | |
| yield content | |
| self.indexes.pop() |
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