Re: Is Prolog a good language for generating semi-random, constrained solutions?

>We only have a brought id of your latest ninja code :-) I think that

>Prolog adds two things to tackle the case where naive generate-and-test
>proves to be too slow: constraints and easy integration of DSLs.
>Constraints provide a neat way to merge testing inside the generator,
>such that it is executed as early as possible. In a sense, I guess we
>can see that as a form of `aspect programming'. Instead of
>
>    generate, test
>
>you  get
>
>    set_constraints, generate, test
>
>where test can also become empty. In addition constraints allow to
>reason about the domains of variables and avoid brute force generate and
>test. DSLs allow you to express your problem natively and generate the
>dirty stuff in the generate routine automatically, or do simple things
>such as goal reordering to reduce backtracking.



I completely endorse this approach.

>  Cheers --- Jan

> P.s.    When I was in Vienna, Markus and I chatted briefly about the
>    idea to have a Prolog thread `fork', i.e., a call that creates
>    a new thread as a copy of the running one.  This would require
>    some restrictions, i.e., we cannot fork if Prolog is called
>    from C in an arbitrary way.  Is that worth investigating at
>    some point?

Can you have it sync-up?  It shouldn't matter to C if Prolog forks off a thread and then closes it before returning to caller.
Or, you could return to caller but only the first thread ; all others terminate.  I think this construct is useful:

first_to_complete(List of Callables) is semidet.

Alan Baljeu
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