What is Expressiveness in a Computer Language

[rossberg at ps.uni-sb.de]

Scott David Daniels wrote:
> rossberg at ps.uni-sb.de wrote:
> > Huh? There is a huge, fundamental difference: namely whether a type
> > system is sound or not. A soundness proof is obligatory for any serious
> > type theory, and failure to establish it simply is a bug in the theory.
>
> So you claim Java and Objective C are "simply bugs in the theory."

You're misquoting me. What I said is that lack of soundness of a
particular type theory (i.e. a language plus type system) is a bug in
that theory.

But anyway, Java in fact is frequently characterised as having a bogus
type system (e.g. with respect to array subtyping). Of course, in a
hybrid language like Java with its dynamic checks it can be argued
either way.

Naturally, the type system of Objective-C is as broken as the one of
plain C.

- Andreas