[m-dev.] Dependent insts

[Thomas Charles Conway]

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.

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