From: Andrew Cheadle <amc4_at_...56...>

Date: Wed, 02 May 2007 21:16:28 +0100

Date: Wed, 02 May 2007 21:16:28 +0100

Hi Chuck, Can I give you a hint, what about defining a predicate 'disjunction': disjunction(X,Y) :- call(X). disjunction(X,Y) :- call(Y). Now, how about declaring 'disjunction' to be an infix operator, and obviously 'disjunction' should bind its arguments weakly: :- local op(1190, xfy, disjunction). I can now define the 'disjunction' predicate as: X disjunction Y :- call(X). X disjunction Y :- call(Y). try it out! Does that help ;-) Cheers Andy Lutz, Charles D wrote: > > Hi folks, > > I’m looking at the example for “Call” (Section 3.7.3 of “A Tutorial > Introduction”, > > v 21 Apr 2007) and I’m missing the point about how this defines > disjunction: > > X ; Y :- call(X). > > X ; Y :- call(Y). > > Each of these disjunction clauses seems to be formed by two other clauses, > > one just being “X” and the other being the implication of Y by either > a call(X) > > or call(Y). > > Or is it that the entire “left side” (“X ; Y”, for example) is implied > by the right > > side? As I am fairly new to ECLiPSe / Prolog, something of the syntax here > > escapes me. Any further explanation would be greatly appreciated. From a > > different text I thought I recalled that Prolog “Head :- Body” clauses > are Horn > > clauses, so there should only be one structure in the Head, but I could be > > wrong. > > Thanks! > > **Chuck Lutz** > > Lockheed Martin > > Systems of Systems Engineering > > BMC4I Modeling and Simulation > > Moorestown, NJ > > (856)638-7234 (office) > > charles.d.lutz@...53... <mailto:charles.d.lutz@...53...> > > “A graphic is never an end in itself; it is a moment > > in the process of decision making.” > - Jacques Bertin > > ------------------------------------------------------------------------ > > _______________________________________________ > ECLiPSe-Users mailing list > ECLiPSe-Users@...2... > http://www.crosscoreop.com/mailman/listinfo/eclipse-users > -- ********************************************************************* * Andrew Cheadle email: a.cheadle@...56... * * Department of Computing http://www.doc.ic.ac.uk/~amc4/ * * Imperial College London * *********************************************************************Received on Wed May 02 2007 - 21:16:37 CEST

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