Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!uoregon!novick
From: novick@uoregon.uoregon.edu (David G. Novick)
Newsgroups: comp.lang.prolog
Subject: Re: Forward chaining production systems on Prolog?
Message-ID: <3891@uoregon.uoregon.edu>
Date: 20 Feb 89 18:55:03 GMT
Organization: University of Oregon, Computer Science.  Eugene OR
Lines: 28

Yasusi Kanada has inquired about other references to forward-chaining
productions systems in Prolog.

As noted in earlier articles, backward-chaining systems are very
straight-forward in Prolog.  Forward-chaining systems, while not
quite as directly implementable, are nevertheless fairly easy to
write in Prolog.  As part of my doctoral work, I wrote a forward-
chaining system on top of SICTStus Prolog.  A complete listing of
the system is available as an appendix in Novick, D. G. 1988. "Control
of mixed-initiative discourse through meta-locutionary acts: A
computational model,"  Tech. Rep. CIS-TR-88-18, Department of Computer
and Information Science, University of Oregon.  This work relied on 
my earlier Lisp-based contributions to the ORBS system.

Some of the nice feature of writing a rule-based system in
Prolog are that (1) conflict resolution can be described in predicate
form, so CR strategies can be domain-customized rather easily, 
(2) most of the unification chores are handled by the language, (3) it
is trivial to add control information to rules, and (4) there is a
good correspondence between "test" clauses in a rule and the idea that
something is provable.

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David G. Novick			  |  internet: novick@cs.uoregon.edu
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