On Mon, 23 Aug 2010 12:00:22 -0400 [email protected] wrote: > > Hi all, > > I found a strange error on my gprolog coding, namely on the source: > > pred1([R-C-P|Ls], [R-C-P|Ls1]):- > memberchk(rel(_,X,Y), C), > memberchk(rel(_,Y,_), C), > nth(1,P,Z), > ... >
I see no cut in this code snip, implying the potential for backtracking either here or further on. From the manual: " member(Element, List) succeeds if Element belongs to the List. This predicate is re-executable on backtracking and can be thus used to enumerate the elements of List. memberchk/2 is similar to member/2 but only succeeds once. " Dhu _______________________________________________ Users-prolog mailing list [email protected] http://lists.gnu.org/mailman/listinfo/users-prolog
