Merging Objects

[Michael Spencer]

Cloudthunder wrote:
> Sorry, I don't understand, how does this solve my problem?
> 
__getattr__ and __setattr__ allow you to set up dynamic delegation e.g.,

class Foo(object):
     def __init__(self, **kw):
         self.__dict__.update(kw)
     def methFoo(self, x):
         return "Foo.methFoo(%s,%s)" % (self,x)

class Bar(object):
     def __init__(self, **kw):
         self.__dict__.update(kw)
     def methBar(self, x):
         return "Foo.methFoo(%s,%s)" % (self,x)

class MultiDelegate(object):
     def __init__(self, *args):
         object.__setattr__(self,"_objects",args)
     def __getattr__(self, attr):
         for obj in self._objects:
             if attr in dir(obj):
                 return getattr(obj, attr)
         types = ",".join(obj.__class__.__name__ for obj in self._objects)
         raise AttributeError, "%s object has no attribute '%s'" % (types, attr)
     def __setattr__(self, attr, value):
         # but you could do something more useful here too
         raise TypeError, "Can't set attributes of MultiDelegate"

 >>> f = Foo(a=1)
 >>> b = Bar(b=2)
 >>> m = MultiDelegate(f,b)
 >>> m.a
1
 >>> m.b
2
 >>> m.methFoo(1)
'Foo.methFoo(<Untitled1.Foo object at 0x00A2A790>,1)'
 >>> m.methBar(1)
'Foo.methFoo(<Untitled1.Bar object at 0x00A2A330>,1)'
 >>>

HTH
Michael