[cap-talk] Type systems

[David Hopwood]

John Carlson wrote:
> The problem with static and dynamic type systems is that you have  
> distinct types.  We need fuzzy type systems, where each object is  
> it's own type.

Why?

> How would you create a capability system out of a language like Self?
> Or is it naturally capability based?

Self is not capability-based because it does not support encapsulation:
instance variables are publically accessible. Also, it's practically
impossible to build defensively consistent abstractions when using
dynamic delegation, because a client can provide the implicit 'self'
argument independently on each call, and an object would normally have
to trust 'self'.

Static delegation, where an object's delegates are fixed at the time
it is created, is safer than dynamic delegation.

-- 
David Hopwood