A few weeks ago I realized there was reason in principle that ^^^^^^^^^^ Did you mean "was no reason"???
So did you?
declaring a class satisfies an interface shouldn't just amount to adding the interface to the class' __bases__ (as Guido has been suggesting all along).
Why not? Am we missing somethings?
We'd need a trick to deny an interface that would be inherited by default. Something like private inheritance.
I think it's more than that. You might need to "uninherit": Say Interface A begets class B which begets class C. What if C doesn't fulfill A?
Sorry, I meant to include that case. How do you do that in C++? Inherit privately from B and publicly from A, and making A virtual base everywhere?
There's also the ambiguity of inheriting from a single interface: does that create a sub-interface or an implementation of the interface? Of course with your C++ hat on you probably don't care. On Mondays, Wednesdays, Fridays and alternating Sundays I don't care either.
With my C++ hat on I can't even imagine this. In C++ we don't express interfaces in code: they're written down as "concepts" in the some documentation somewhere (no, I don't think an abstract class in C++ is a good analogy for these Python interfaces).
What's the difference between an abstract class and an interface in C++? --Guido van Rossum (home page: http://www.python.org/~guido/)