Class SON

bson/son.py:51–227

SON data. A subclass of dict that maintains ordering of keys and provides a few extra niceties for dealing with SON. SON provides an API similar to collections.OrderedDict.

class SON(Dict[_Key, _Value]):
    """SON data.

    A subclass of dict that maintains ordering of keys and provides a
    few extra niceties for dealing with SON. SON provides an API
    similar to collections.OrderedDict.
    """

    __keys: list[Any]

    def __init__(
        self,
        data: Optional[Union[Mapping[_Key, _Value], Iterable[Tuple[_Key, _Value]]]] = None,
        **kwargs: Any,
    ) -> None:
        self.__keys = []
        dict.__init__(self)
        self.update(data)
        self.update(kwargs)

    def __new__(cls: Type[SON[_Key, _Value]], *args: Any, **kwargs: Any) -> SON[_Key, _Value]:
        instance = super().__new__(cls, *args, **kwargs)
        instance.__keys = []
        return instance

    def __repr__(self) -> str:
        result = []
        for key in self.__keys:
            result.append(f"({key!r}, {self[key]!r})")
        return "SON([%s])" % ", ".join(result)

    def __setitem__(self, key: _Key, value: _Value) -> None:
        if key not in self.__keys:
            self.__keys.append(key)
        dict.__setitem__(self, key, value)

    def __delitem__(self, key: _Key) -> None:
        self.__keys.remove(key)
        dict.__delitem__(self, key)

    def copy(self) -> SON[_Key, _Value]:
        other: SON[_Key, _Value] = SON()
        other.update(self)
        return other

    # TODO this is all from UserDict.DictMixin. it could probably be made more
    # efficient.
    # second level definitions support higher levels
    def __iter__(self) -> Iterator[_Key]:
        yield from self.__keys

    def has_key(self, key: _Key) -> bool:
        warnings.warn(
            "SON.has_key() is deprecated, use the in operator instead",
            DeprecationWarning,
            stacklevel=2,
        )
        return key in self.__keys