Re: CLP(FD): Option list for labeling/2

Markus Triska wrote:

Other sets of options are also conceivable for the future (backjumping,
learning, posting CLP(Q) constraints, verification etc.), and I've
therefore so far been reluctant to introduce higher arities for
different categories. But maybe it wouldn't be much of a problem?
  

I agree, increasing the arity would not be a good idea for increasing set of options. The point that I think is adviceable is to have separate sets of options for the user, e.g., options for variable selection, value selection and so on, so that orthogonal procedures in labeling can be selected without allowing to mix them and therefore cuting possible user misunderstandings and errors. Maybe, a list of procedures/options can be used, as, e.g.:
[var_sel(+VarSPs), val_sel(+ValSPs), branching(+BPs)...]
This also allows to add further options and procedures/strategies.

Yes; one thing not considered so far is how options can be overridden if
we do away with the option list, i.e., labeling([ff,up|UserOptions], Vs).
Maybe this isn't a big problem? There probably aren't many programs that
use it that way, but it would be nice if it can still be supported.

  

As a user, with respect to those default options, I'd expect not to mix incompatible options when I state them and, if mixed, I would expect an exception. I dislike to allow to state incompatible or overridable options and let the system decide in terms of a given criteria (e.g., selecting the rightmost option). For instance: [ff,ffc] would raise an exception. But, obviously, this is only my personal point of view.
Best regards
Fernando

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Fernando Sáenz Pérez
Profesor Titular de Universidad / Associate Professor
Home Page: http://www.fdi.ucm.es/profesor/fernan
Tel: + 34 913947642. Fax: + 34 913947547
Despacho / Office: 435 (4ª planta / 4th floor)
Dept. Ingeniería del Software e Inteligencia Artificial / 
Department of Software Engineering and Artificial Intelligence
Universidad Complutense de Madrid
Facultad de Informática
C/Profesor José García Santesmases, s/n
E - 28040 Madrid. Spain
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