[m-dev.] choice point deforestation

[Fergus Henderson]

On 22-Sep-1999, Simon Taylor <stayl at cs.mu.OZ.AU> wrote:
>  
> > By applying a deforestation-like "conjunctive partial deduction"
> > transformation to the conjunction `mymember(X, Data), test(X)',
> > we can push the pruning further in, to the point where we avoid
> > creating the choice points at all.
> 
> > Anyway, it seems to me that this optimization is quite similar to the
> > existing deforestation optimization.  Simon, how hard do you think it
> > would be to extend deforestation to handle cases like this?
>  	
> I did something like this last year, although it's probably not too clever
> about deciding when to do the optimization.
> See /home/mercury1/stayl/constraint/mercury.

What's the current status of that code?

Constraint propagation is similar to the optimization that I proposed,
but not quite the same.  The optimization that I proposed did not
involve reordering (well, no more reordering than is needed for
ordinary deforestation) which makes it a bit simpler.  You can apply
it even if the <Test> goal has outputs.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.
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