# There are a dozen ways to implement the Prototype or Properties Pattern in Python.
#
# You could use copy.copy(), or program with classes and classmethods only for example.
#
# But if you want to use an existing library in this style, and don't want to loose
# Python's flexibility (multiple inheritance, etc) I believe this solution works best.
#
# Prototypes, in Pythonic terms, are objects that behave like instances and classes/types,
# unifying instantiation and inheritance. So the most obvious solution, even if wasteful,
# is to have a thin layer over a type and it's single instance.

import attr

class BaseObject:
    """ Could be any class that you want to adapt to the prototyped style
    """
    def __init__(self, **kw):
        self.__dict__.update(kw)


@attr.s
class PObject:
    ptype = attr.ib(default=None)
    pinstance = attr.ib(default=object)
    def clone(self, name):
        new_ptype = type(name, (self.ptype or BaseObject,), {})
        new_pinstance = new_ptype(**self.pinstance.__dict__)
        return PObject(new_ptype, new_pinstance)
    def __getattr__(self, name):
        return getattr(self.pinstance, name)
    ## TODO: setattr, repr, etc

# Root object
Object = PObject().clone('Object')

### Example
person = Object.clone('person')
person.name = 'John Doe'
person.arms = 2

# Anna retains the number of arms of its parent
person1 = person.clone('person1')
person1.name = 'Anna Doe'