[m-rev.] for discussion: subtypes documentation

[Fergus Henderson]

On 26-Nov-2002, Mark Brown <dougl at cs.mu.OZ.AU> wrote:
> Incidentally, how do I write an inst that covers some constructor
> containing existentially type data?  If I had the type
> 
> 	:- type foo
> 		--->	some [T] (f(T) => c(T))
> 		;	g(int).
> 
> how would I write the inst that covers only elements of foo whose top
> functor is f/1?

`bound(f(ground))'.

Existential type quantifiers and class constraints don't have any
effect on insts.

-- 
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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