[m-dev.] Dependent insts

[Thomas Charles Conway]

On Thu, Mar 11, 1999 at 09:17:55AM EST, Fergus Henderson wrote:
> On 11-Mar-1999, Thomas Charles Conway <conway at hydra.cs.mu.oz.au> wrote:
> > On Wed, Mar 10, 1999 at 11:15:49PM EST, Fergus Henderson wrote:
> > > The complicated cases come where you have things like
> > > 
> > > 	:- inst isspecial = bound((
> > > 			(bound("builtin") / bound("solutions"))
> > > 		;	(bound("float") / bound("plus"))
> > > 		)).
> > > 
> > > 	:- mode p(out(isspecial)).
> > > 	:- mode q(out(isspecial)).
> > > 
> > > 	p(X) :-
> > > 		q(X0),
> > > 		X0 = Y0/Z0,
> > > 		...
> > > 		X = Y0/Z0.
> > > 
> > > Here it's not sufficient to keep track of the inst of each variable;
> > > because if you just look at the insts of Y0 and Z0, you can't tell
> > > that X won't be bound to `"float"/"solutions"'.
> > 
> > Sounds like an aliasing problem to me.
> 
> Well, suffice it to say that it is a problem.
> 
> If you think the solution is simple, you're welcome to go ahead
> and implement it.  Personally, however, I suspect it would not
> be at all simple.
> 

I don't recall saying it would be simple, just useful.

-- 
Thomas Conway <conway at cs.mu.oz.au> )O+
To a killer whale, otters are like hairy popcorn -- Paul Dayton