[m-dev.] Foreign type compare and unification

[Fergus Henderson]

On 21-May-2002, Ralph Becket <rafe at cs.mu.OZ.AU> wrote:
> Mark Brown, Tuesday, 21 May 2002:
> > 
> > What I'm saying is that the behaviour of the program should not depend on
> > a closed world assumption about the members of a typeclass.
> 
> This is what will happen anyway with generic predicates that use dynamic
> type class casts.

Not necessarily.

Earlier we discussed the possibility of "not_instance" declarations
(or something like that) to specify that a type wasn't an instance of a
type class, for use with dynamic type class casts, to avoid relying on
a closed world assumption.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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