frozenjson.py

class FrozenJSON:
    """A read-only facade for nevigating a JSON-like object"""

    def __init__(self, mapping):
        self.__data = dict(mapping)

    def __getattr__(self, name):
        if hasattr(self.__data, name):
            return getattr(self.__data, name)
        else:
            return FrozenJSON(self.__data[name])

    def __new__(cls, arg):
        if isinstance(arg, abc.Mapping):
            return cls(arg)
        elif isinstance(arg, abc.MutableSequence):
            return [cls.build(item) for item in arg]
        else:
            return arg