properties.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from __future__ import print_function
from functools import partial
import random


__author__ = 'Alexey "Averrin" Nabrodov'
__version__ = '0.0.0'
                
def addBinding(obj1, prop1, obj2, prop2, one_way=False):
    class WProperty(object):
        def __init__(self, name):
            self.name = name
            self.owner = None
            self.onSet = []

        def __get__(self, obj, objtype=None):
            return getattr(obj, "__" + self.name, None)
    
        def __set__(self, obj, value):
            setattr(obj, "__" + self.name, value)
            self.owner = obj
            for handler in self.onSet:
                handler(obj, value)
    
        def addHandler(self, handler):
            self.onSet.append(handler)
    
        def addBinding(self, prop, one_way=False):
            prop.addHandler(lambda o, x: setattr(self.owner, "__" + self.name, x))
            if not one_way:
                self.addHandler(lambda o, x: setattr(prop.owner, "__" + self.name, x))            
            
    val1 = getattr(obj1, prop1)
    p1 = WProperty(prop1)
    rp1 = prop1 + str(random.randint(0,9999))
    obj1.__props[prop1] = rp1
    setattr(type(obj1), rp1, p1)
    setattr(obj1, prop1 + "Property", p1)
    p1.__set__(obj1, val1)
    
    val2 =  getattr(obj2, prop2)
    p2 = WProperty(prop2)
    rp2 = prop2 + str(random.randint(0,9999))
    obj2.__props[prop2] = rp2
    setattr(type(obj2), rp2, p2)
    setattr(obj2, prop2 + "Property", p2)
    p2.__set__(obj2, val2)

    
    p1.addBinding(p2, one_way)
    
class SadObject(object):
    def __getattribute__(self, key):
        props = object.__getattribute__(self, "__props")
        if key in props:
            key = props[key]
            pv = type(self).__dict__[key].__get__(self, key)
            return pv
        return object.__getattribute__(self, key)

    def __setattr__(self, key, value):
        if not hasattr(self, "__props"):
            object.__setattr__(self, "__props", {})    
        if key in object.__getattribute__(self, "__props"):
            key = object.__getattribute__(self, "__props")[key]
            type(self).__dict__[key].__set__(self, value)
        else:
            object.__setattr__(self, key, value)
        


def main():
    class A(SadObject): pass
    class B(SadObject): pass
    obj = A()
    obj2 = B()
    obj3 = B()
    obj.a = "a"
    obj2.a = "b"
    obj3.a = "z"

    print(obj.a, obj2.a, obj3.a)
    addBinding(obj, "a", obj2, "a")
    
    print(obj.a, obj2.a, obj3.a)
    obj.a = "c"
    
    print(obj.a, obj2.a, obj3.a)
    obj2.a = "d"
    print(obj.a, obj2.a, obj3.a)


if __name__ == '__main__':
    main()