On Mon, 26 Apr 2010, Alexandre Saidi wrote: > Hi all, > another way is to test : > not (not (foo(X)). > > since "not not P = P" and that WITHOUT variable binding. > > Please adapt « not » (eg. use « \+" if necessary). That brings us back to where we started. "david" asked specifically about a test that would check asserted facts like foo(bar). without succeeding on clauses with more general heads like foo(X) that could be unified with foo(bar). Using "not not" doesn't work for his purpose; it succeeds when foo(X) exists. The question of whether or not to bind X when such a thing does succeed, is a different question. As I said: > > depending on just what you want to query for. Note that all of these > > break the logic programming model and you probably should think hard about > > whether what you're attempting to do is *really* a good idea. -- Matthew Skala, postdoctoral researcher, Universities of Toronto and Waterloo mskala_at_cs.toronto.edu mskala_at_cs.uwaterloo.ca mskala_at_ansuz.sooke.bc.caReceived on Mon Apr 26 2010 - 17:37:15 CEST
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