(defun pr (x)
  (print x))
(defun pr1 (x)
  (prin1 x))
  
;(setq db (list ""))
;(setq db '())
(defun fd1 ()
	(setq rb '())
	(loadrules)
	(setq db '())
	(filldb)
	(setq L rb)
	(interprit)
	(pr1 "[final result:]")
	(pr1 (last db) ))
#|
to forward1
 m "rb []
 loadrules
 pr [enter facts into data base]
 m "db []
 filldb
 interpret :rb
 (pr [final result:] last :db)
end
|#
(defun filldb ()
	(pr1 "next fact:")
	(setq n (read-line))
	(cond ((string= n "*") nil)
		  ((string= n "") (filldb))
		  ;(t (progn (setq db (cons db (list n)))(filldb))) ))
		  (t (progn (setq db (append db (list n)))(filldb))) ))

(setq rb '())
(defun loadrules ()
	(pr1 "[enter next rule]")
	(pr1 "condition")
	(setq c (read-line))
	(cond ((string= c "*") (progn (setq rb (nreverse rb)) nil))
		  (t (progn 
				(pr1 "action")
				(setq a (read-line))
				(setq rb (cons (list c a) rb))
				(loadrules)))) )	
(defun member$ (item lst)
  (if (null lst) nil
	(if (equal (car lst) item)
		lst
	  (member$ item (cdr lst))
	  )))

(defun fire ()
	(setq db (append db (last L1)))
	(pr1 "[deduced:]")
	(pr1 (last L1)))
			
(defun check (x L)
	(if (null L) nil
		(if (string= x (car L)) t
			(check x (cdr L)))))
			
(setq L  '(("b" "c")("a" "b"))) 
(setq L  '(("a" "b"))) 
(setq L  '(("a" "b") ("b" "c"))) 
(setq rb '(("a" "b") ("b" "c"))) 
(setq db '("a"))

(defun interprit ()
	(if (null L) nil
		(progn 
			(setq L1 (car L))
			(setq c  (car L1)) ))
		
	(if (and (check c db) (not (member$ (car (last L1)) db)) ) (progn (fire)(interprit))
		(progn (setq L (cdr L)) (pr1 "2")(pr1 L)) )
	
	(if (null L) nil
		(interprit)) )