[mercury-users] Solver types and \=

[Peter Schachte]

> > Perhaps it would be better to leave '\=' undefined for solver types,
> > and leave the user to define a custom inequality predicate if it makes
> > sense?
> 
> Hmm, that sounds horribly warty to me.  Unfortunately, I think this is
> one of those situations where there is friction between Mercury's
> execution model and the use of solver types.  I don't think we should
> change Mercury's execution model.

I don't think it's the execution model, it's the assumption that
anything not free is ground.  Anyway, disallowing \= for any inst
variables seems wrong, because disequality constraints are perfectly
sensible.  Forbidding the most obvious expression of disequalities is
unneighborly when there's a reasonable way to allow them (ie, allowing
the solver writer to specify the method).

-- 
Peter Schachte              In order to become the master, the politician
schachte at cs.mu.OZ.AU        poses as the servant.
www.cs.mu.oz.au/~schachte/      -- Charles de Gaulle 
Phone: +61 3 8344 1338      
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