Hello everyone, I'm new to Jess and struggling with making one example work, based on problem from http://en.wikipedia.org/wiki/Backward_chaining
The goal is to find the pet's color if given that pet is a frog or a canary. I have defined such rules: =============== (do-backward-chaining color) (do-backward-chaining kind) (defrule print-Fritz-color (color ?name ?val) => (printout t "Color of " ?name " is " ?val crlf) ) (defrule frog-color (need-color ?name ?) (kind ?name frog) => (printout t "firing frog-color" crlf) (assert (color ?name "green")) ) (defrule pet-kind (need-kind ?name ?type) => (printout t "Pet name? ") (bind ?name (read)) (printout t "Pet kind? ") (bind ?type (read)) (assert (kind ?name ?type)) ) TRUE Jess> TRUE Jess> TRUE Jess> TRUE Jess> TRUE Jess> (reset) TRUE Jess> (agenda) [Activation: MAIN::pet-kind f-2, ; time=3 ; salience=0] For a total of 1 activations. Jess> (run) Pet name? Fritz Pet kind? frog 1 Jess> (facts) f-0 (MAIN::initial-fact) f-1 (MAIN::need-color nil nil) f-2 (MAIN::need-kind nil frog) f-3 (MAIN::kind Fritz frog) For a total of 4 facts. Jess> =================== Note that pet-kind rule fires, because it asks me about the pet name and type. What I don't get is why frog-color rule doesn't fire -- after all, it clearly has following facts asserted: f-1 (MAIN::need-color nil nil) f-3 (MAIN::kind Fritz frog) ..and the rule conditions defined: (defrule frog-color (need-color ?name ?) (kind ?name frog) Why doesn't the damn thing fire?? Regards, Marcin -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] --------------------------------------------------------------------
