What is a type error?

[Andreas Rossberg]

Marshall wrote:
> 
> After all, what are the alternatives? Purely-functional
> languages remove themselves from a large class of
> problems that I consider important: data management.

Maybe, but I have yet to see how second-class variables are really more 
adequate in dealing with it.

And note that even with second-class state you can still have aliasing 
issues - you just need mutable arrays and pass around indices. Keys in 
databases are a more general form of the same problem.

> I have explored the OO path to its bitter end and am
> convinced it is not the way. So what is left? Uniqueness
> types and logic programming, I suppose. I enjoy logic
> programming but it doesn't seem quite right. But notice:
> no pointers there!  And it doesn't seem to suffer from the
> lack.

Uh, aliasing all over the place! Actually, I think that logic 
programming, usually based on deep unification, brings by far the worst 
incarnation of aliasing issues to the table.

- Andreas

-- 
Andreas Rossberg, rossberg at ps.uni-sb.de