[m-dev.] for review: the new debugger command set

[Erwan Jahier]

Tyson Dowd wrote:
> 
> On 18-Sep-1998, Zoltan Somogyi <zs at cs.mu.OZ.AU> wrote:
> >
> > > This rather strange to see a multi proc failing since it is supposed not
> > > to fail. Isn't that a bug in the tracer ?
> >
> > No, this is not a bug in the tracer, or in the code generator.
> >
> > "This rather strange to see a multi proc failing since it is supposed not
> > to fail" indicates a misconception. A multi proc is not supposed to fail
> > *without first producing a solution*. Once it has produced that solution,
> > and possibly other solutions, the multi proc is allowed to fail, and
> > must fail if it has no more solutions. The only difference between nondet
> > and multi is that multi promises at least one solution before failure.
> 
> I thinkg the problem is that our "quick summary" table in the language
> reference manual says "can fail?  no" for multi, and if you learn
> that table, you might answer the question "can multi ever fail?" with
> "no".

Indeed, that's the source of my "misconception".

> Perhaps what it should say is "can fail with no solutions?".

I think so.

-- 
R1.