core.logic

(ns test                                                                                                                                                                          
  (:refer-clojure :exclude [==])                                                                                                                                                  
  (:require                                                                                                                                                                       
   [clojure.core.logic :refer :all]))                                                                                                                                             

;; This expression should evaluate to true, but it does not, 
;; because the second run* returns (2 1) instead of (1 2).
                                                                                                                                                                                  
(= (run* [q]                                                                                                                                                                      
     (conde                                                                                                                                                                       
       [(== q 1)]                                                                                                                                                                 
       [(== q 2)]))                                                                                                                                                               
   (run* [q]                                                                                                                                                                      
     (conde                                                                                                                                                                       
       [(fresh [a] (== q 1))]                                                                                                                                                     
       [(== q 2)])))