>... In an object system, the way A's
>developer can achieve similar flexibility, but have it work, is to use
>normal object-oriented polymorphism. A can interact with objects that
>instantiate modules written after A was created, given that they implement
>subtypes of types A knows how to invoke. This flexibility, obtained through
>polymorphism, is in no conflict with static-only linking.
This means we would get a sub-type hierarchy whose depth is linear in the number of versions the implementation has been through. This is probably a Bad Thing.