#|
*******************************************************************************
PRODIGY Version 2.01  
Copyright 1989 by Alicia Perez

The PRODIGY System was designed and built by Steven Minton, Craig Knoblock,
Dan Kuokka and Jaime Carbonell.  Additional contributors include Henrik Nordin,
Yolanda Gil, Manuela Veloso, Robert Joseph, Santiago Rementeria, Alicia Perez, 
Ellen Riloff, Michael Miller, and Dan Kahn.

The PRODIGY system is experimental software for research purposes only.
This software is made available under the following conditions:
1) PRODIGY will only be used for internal, noncommercial research purposes.
2) The code will not be distributed to other sites without the explicit 
   permission of the designers.  PRODIGY is available by request.
3) Any bugs, bug fixes, or extensions will be forwarded to the designers. 

Send comments or requests to: prodigy@cs.cmu.edu or The PRODIGY PROJECT,
School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213.
*******************************************************************************|#



;;;
;;; This is an unstable version; new control rules are being tested and added,
;;; and the operators can also change.
;;;
;;; If you have any suggestion or question, please send mail to aperez@cs
;;;

(defun loc-in-room (x y room)
    (cond ((or (is-variable x)
	       (is-variable y))
	   'no-match-attempted)
	  ((is-variable room)
	   `(((,room ,(convert-loc-to-room x y)))))
	  ((atom room)(eq room (convert-loc-to-room x y)))
	  (t (error "Room is not a variable or an atom"))))

(defun convert-loc-to-room (x y)
  (cond ((and (<= y 5)
	      (>= y 1))
	 (cond ((and (<= x 4)
		     (>= x 3))
		'rpdp)
	       ((and (<= x 9)
		     (>= x 5))
		'rclk)
	       ((and (<= x 12)
		     (>= x 10))
		'rril)
	       (t (error "Invalid x room coordinate"))))
	((and (<= y 10)
	      (>= y 6))
	 (cond ((and (<= x 2)
		     (>= x 1))
		'runi)
	       ((and (<= x 6)
		     (>= x 3))
		'rmys)
	       ((and (<= x 9)
		     (>= x 7))
		'rram)
	       ((and (<= x 12)
		     (>= x 10))
		'rhal)
	       (t (error "Invalid x room coordinate"))))
	(t (error "Invalid y room coordinate"))))

(defun equal-p (first-arg second-arg)
  "Check if the two arguments are equal. It is not a generator"

  (equal first-arg second-arg))


(defun less-than (x y)
  "returns t or nil depending on whether x is less than y; return 
   'not-match-attempted when either x or y are variables"

  (cond ((is-variable x) 'no-match-attempted)   
	((is-variable y) 'no-match-attempted)	
	((<= x y) t)))


(defun is-sum (x y sum)
  "returns in its third argument the sum of the first and second ones.
  Can act as a generator for any of the arguments"

  (let* ((num 0)
	 (number-of-variables
	  (dolist (v (list x y sum) num)
	    (cond ((is-variable v)(incf num))
		  (t nil)))))

    (cond ((>= number-of-variables 2) 'no-match-attempted)
	  ((zerop number-of-variables) (equal (+ x y) sum))
	  ((is-variable sum) (list (list (list sum (+ x y)))))
	  ((is-variable x) (list (list (list x (- sum y)))))
	  (t (list (list (list y (- sum x))))))))      ;(is-variable y)