Data type for wrapping an indexed value.

indexed.py

from typing import Generic, TypeVar, Union, Dict, Any, Type, cast

T = TypeVar("T")


class Indexed(Generic[T]):
    __slots__ = ("_index", "_value")

    def __init__(self, index: int, value: T) -> None:
        self._index = index
        self._value = value

    @property
    def index(self) -> int:
        return self._index

    @property
    def value(self) -> T:
        return self._value

    def __str__(self) -> str:
      return f"({self.index}, {self.value})"

    def __eq__(self, other) -> bool:
      return isinstance(other, Indexed) and other.index == self.index and other.value == self.value

    def __hash__(self) -> int:
      return hash(self.index) + 31 * hash(self.value)


def serialize_index(i: Indexed[T]) -> Dict[str, Union[int, T]]:
    return {"index": i.index, "value": i.value}


def deserialize_index(value_type: Type[T], d: Dict[str, Any]) -> Indexed[T]:
    return Indexed(index=d["index"], value=cast(value_type, d["value"]))