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copied!<p>Okay, I think you might want to rephrase your question as:</p> <p><strong>How can I extend Python's OOP to make inheritance work on the level of objects rather than classes?</strong></p> <p><em>First off - don't mess with the dicts:</em> If you are just copying the entries of the parent dict over to the child-dict, this works for instantiation, but changes in any of the dicts will not automagically update entries in all the other dicts. Assigning a new value to an attribute will simply create a new reference, so the attribute will not point to the same object any more. </p> <p>The solution is to tell python to look for the attribute in the right place using some Python magic ...</p> <pre><code>class ProxyMixin (object): def __init__(self, parent): self.parent = parent def __getattribute__(self, name): if name != 'parent' and hasattr(self.parent, name): return getattr(self.parent, name) else: return object.__getattribute__(self, name) def __setattr__(self, name, val): if name != 'parent' and hasattr(self.parent, name): setattr(self.parent, name) else: object.__setattr__(self, name, val) </code></pre> <p>(see the <a href="http://docs.python.org/reference/datamodel.html#attribute-access" rel="nofollow">python reference on attribute access</a>)</p> <p>Just add the ProxyMixin to your child class, and you will be fine.</p> <pre><code>class P: data = "shared data" def __init__(self, name): self.name = name def printname(self): print self.name class C(P, ProxyMixin): def __init__(self, parent=None): if parent: ProxyMixin.__init__(self, parent) </code></pre> <p>Now youn can dynamically rewire the parent object at any time using a simple assignment:</p> <pre><code>c.parent = newparent </code></pre>

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