View difference between Paste ID: 5g3fjeN0 and BGFs91sK

 ;; Backward Chaining
 
 (ns backward)
 (import '(java.util.concurrent Executors ExecutorCompletionService))
 
 (declare start solve-goal solve-rule collect unify)
 
 ; Choose between using parallel collect or sequential collect.
 (def use-parallel-collect true)
 
 (def completion-service (ExecutorCompletionService.
 	(Executors/newCachedThreadPool)))
 
 (defn start []
-	(print "Enter query: ") (flush)
+	(loop []
-	(let [query (read-line)
+		(print "Enter query: ") (flush)
-		  truth (solve-goal (symbol query))]
+		(let [query (read-line)
-		(printf "Answer is: %s\n" truth)))
+			truth (solve-goal (symbol query))]
 			(printf "Answer is: %s\n" truth))
 		(recur)))
 
 (defn fetch-rules [goal]
-		a '[[]]
+
-		b '[[]]
+
-		c '[[]]
+		a '[[e,f]]
-		d '[[]]
+		b '[[c,d,e,f]]
 		c '[[e,f]]
 		d '[[e,f]]
 		e '[[]]
 		f '[[]]
 		true (throw (Exception. "No applicable rule"))))
 
 (defn solve-goal [goal]
 	(let [rules (fetch-rules goal)]
 		(if (some empty? rules)
 			1.0		; return a truth value
 			(do
 				(doseq [rule rules]
 					(.submit completion-service #(solve-rule rule)))
 				(.get (.take completion-service))))))
 
 ; Move minimization logic here from collect.
-		(apply min truths)))
+
 	(let [truths (collect solve-goal rule-tail)]
 		(apply + truths)))
 
 ; Accumulate results
 (def collect (if use-parallel-collect pmap map))