A cell object that doesn’t require knowledge of any names

magic_cell.py

_NOTHING = object()
DELETE = object()


class Cell:
    def __init__(self, value=_NOTHING):
        if value is not _NOTHING:
            self.value = value

    def __call__(self, value=_NOTHING):
        if value is DELETE:
            del self.value
        else:
            if value is not _NOTHING:
                self.value = value
            return self.value

    def __getattr__(self, _key):
        if "value" not in self.__dict__:
            raise ValueError("Cell is empty.")
        else:
            return self.value

    def __setattr__(self, key, value):
        if key == "value":
            self.__dict__[key] = value
        else:
            self.value = value

    def __delattr__(self, key):
        if key == "value":
            del self.__dict__[key]
        else:
            del self.value

    def __getitem__(self, _key):
        return self.value

    def __setitem__(self, _key, value):
        self.value = value

    def __delitem__(self, key):
        del self.value


if __name__ == "__main__":
    cell = Cell()
    cell("x")
    # cell(DELETE)
    print(cell["z"])