;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
;; Knowledge Representation and Reasoning CSC 486/2506, Fall 2008
;;
;; Sample file for exercise 4, assignment 2 (Scheme implementation)
;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%




;; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
;; % (difference c1 c2)
;; %
;; % Computes the difference of C1 and C2, where C1 and C2 are
;; % represented in the format discussed in the guide
;; %
;; % You should implement this function
;; %
;; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

;; this implementation only prints the input
;;
(define (difference c1 c2) 
  (display c1)
  (display c2)
  'test
)





;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
;;          OBS: You should not modify anything below 
;;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

;; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
;; % (compDiff File): takes a file name, reads the two concepts in the file
;; % and prints the difference of the concepts
;; %
;; % This should work under MIT Scheme
;; %
;; % DO NOT CHANGE
;; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
(define (compDiff filename)
  (let* 
      ((idfile (open-input-file filename))
       (c1 (read idfile))
       (c2 (read idfile))
       (d (difference c1 c2)))
    (display "Difference= ")
    (display d)))