Class StableSet

python/pathway/internals/helpers.py:89–134

class StableSet(MutableSet[T]):
    _inner: dict[T, None]

    def __init__(self, /, iterable: Iterable[T] = ()):
        self._inner = dict.fromkeys(iterable)

    def __contains__(self, element: object) -> bool:
        return element in self._inner

    def __iter__(self) -> Iterator[T]:
        return iter(self._inner.keys())

    def __len__(self) -> int:
        return len(self._inner)

    def __repr__(self) -> str:
        type_name = type(self).__name__
        if self._inner:
            values = repr(list(self._inner.keys()))
        else:
            values = ""
        return f"{type_name}({values})"

    def add(self, element: T) -> None:
        self._inner[element] = None

    def discard(self, element: T) -> None:
        self._inner.pop(element, None)

    def copy(self) -> StableSet[T]:
        return StableSet(self)

    def __or__(self, other: Iterable[T2]) -> StableSet[T | T2]:
        return super().__or__(other)  # type: ignore

    def __ior__(self, other: Iterable[T2]) -> StableSet[T | T2]:
        return super().__ior__(other)  # type: ignore

    def update(self, *sets: Iterable[T]) -> None:
        for s in sets:
            self |= s

    def union(*sets: Iterable[T]) -> StableSet[T]:
        res: StableSet[T] = StableSet()
        res.update(*sets)
        return res