> > Tell me if I'm wrong, but from a type point of view, delegation is
                              ^^^^^^^^^^^^^^^^^^^^^^^^^
> What?  Half of the Design Patterns book is about how to use
> composition & delegation instead of inheritance.
I don't say that delegation does not exist outside duck-typing. And I never 
said that only inheritance is usable from an *engineering* point of view.

However, the "model(a) == model(b)" comparison does NOT cooperate well with 
delegation unless your definition of model is the duck-typing one (for 
instance if you define the type as the class of the object).

Sylvain