case.py

# -*- coding: utf-8 -*-


class Case(object):
    __slots__ = []

    def __init__(self, *args, **kwargs):
        super_setattr = super(Case, self).__setattr__

        slots = self.__slots__[:]
        for slot, arg in zip(self.__slots__, args):
            slots.remove(slot)
            super_setattr(slot, arg)
        for key, value in kwargs.items():
            if key in self.__slots__:
                super_setattr(key, value)
                slots.remove(key)
        for slot in slots:
            super_setattr(slot, None)

    def __setattr__(self, key, value):
        raise AttributeError("cannot update the attribute of Case instance")

    def __str__(self):
        return self.__class__.__name__ + "(" + \
                ", ".join([s + "=" + str(getattr(self, s)) for s in self.__slots__]) + \
                ")"

    def __repr__(self):
        return self.__str__()

    def __eq__(self, other):
        return isinstance(other, self.__class__) and \
                not bool([True for s in self.__slots__ if getattr(self, s) != getattr(other, s)])

    def __ne__(self, other):
        return not self.__eq__(other)

    def __iter__(self):
        for slot in self.__slots__:
            yield getattr(self, slot)

    def __hash__(self):
        return hash(tuple(getattr(self, s) for s in self.__slots__))

    def copy(self, **kwargs):
        new_case = self.__class__(*[getattr(self, s) for s in self.__slots__])
        super_setattr = super(Case, new_case).__setattr__
        for key, value in kwargs.items():
            super_setattr(key, value)
        return new_case