(DEFPROP LOOKUP
 (LAMBDA(MKX)
  (PROG	(PT)
	(SETQ PT PRINTTABLE)
   LOOP	(COND ((NULL PT) (SYSTEMERROR))
	      ((EQ MKX (CAAR PT)) (RETURN (CDAR PT)))
	      (T (SETQ PT (CDR PT)) (GO LOOP)))))
EXPR)
