Thank you for this tip. It is not what I am trying to achieve, however. I must apologize if my original email was misunderstood.
My goal is to write a rule that would fire for any 'bag-of-items' fact whose item names, as listed in a multislot, are all represented by 'item' facts. The rule should not fire if one or more of these items are absent from the fact list: (item (name A)) (item (name B)) (bag-of-items (item-names A)) (bag-of-items (item-names A B)) (bag-of-items (item-names A B C)) In this example the two first 'bag-of-items' facts would fire my hypothetical rule, while the third would not, because there is no 'item' fact with name C. The 'forall' approach suggested by M. Friedman-Hill is quite close to this, however it seems that the rule will fire only if _all_ the 'bag-of-items' facts have all of their items represented by facts. I.e., in my example above it would not fire until I remove the third bag-of-items fact. Once again, it is close but no cigar. Best, Aurélien On Jul 30, 2013, at 10:54 AM, "Jason Morris" <jason.c.mor...@gmail.com> wrote: > Another "old skool" way of doing it using predicate constraints is... > > (clear) > (deftemplate item (slot name)) > (deftemplate bag-of-items (multislot item-names)) > > (defrule fire-for-all-members-in-bag > ; If you have a bag of item names ... > (bag-of-items (item-names $?item-names)) > ; and there is an item whose name is member of this bag ... > ?item <-(item (name ?name&:(member$ ?name $?item-names))) > => > ; ...then do something interesting > (printout t ?name " is in the bag!" crlf)) > > ;; Program > (reset) > (assert (item (name A))) > (assert (item (name B))) > (assert (item (name C))) > (assert (bag-of-items (item-names A B C))) > (run) > > *Jason C. Morris* > President, Principal Consultant > Morris Technical Solutions LLC > President, Rules Fest Association > Chairman, IntelliFest 2013: International Conference on Reasoning > Technologies -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' in the BODY of a message to majord...@sandia.gov, NOT to the list (use your own address!) List problems? Notify owner-jess-us...@sandia.gov. --------------------------------------------------------------------