;;; $Id: length.scm,v 1.1 2004/01/29 00:19:34 leavens Exp $
;;; AUTHOR: Brian Dorn and Gary T. Leavens

(deftype length (forall (t) (-> ((list-of t)) number)))
(define length
  (lambda (l)
    ;; ENSURES: Result is the length of l
    (if (null? l) 
	0
	(+ 1 (length (cdr l))))))