[Haskell-cafe] Re: US Homeland Security program language security risks

[Daniel Fischer]

Am Sonntag, 6. Januar 2008 15:54 schrieb Achim Schneider:
> Daniel Fischer <daniel.is.fischer at web.de> wrote:
> > Am Sonntag, 6. Januar 2008 15:18 schrieb Andrew Coppin:
> > > Daniel Fischer wrote:
> > > > Just because I don't know:
> > > > what bugs would be possible in a language having only the
> > > > instruction return ()
> > >
> > > Bug #1: You cannot write any nontrivial programs. ;-)
> >
> > That's not a bug, that's a feature.
>
> That's an interesting task: Design a non-touring complete,
> restricted language in which every expression is decidable, without
> making the language unusable for usual programming problems.

I'm not a logician, but didn't Gödel prove that you couldn't express the 
(full) arithmetic of natural numbers in such a language?
Of course it might be possible to express a sufficiently interesting part of 
it, but I should be surprised.