(define is-cond-expression?
  (lambda (v)
   (if (pair? v)
    (if (equal? (car v) 'cond)
     (if (equal? (cadr v) 'else)
      (is-expression? (list-ref v 2))
      (letrec ([visit (trace-lambda cunt (x)
			 (if (equal? (car x) 'else)
			      (is-expression? (cdr x)))
			      (and (is-cond-clause? (car x))
				(visit (cdr x))))])
      (visit (cdr v))))
     #f)
   #f)))

(define is-cond-clause?
  (lambda (v)
   (if (not (null? v))
    (if (proper-list-of-given-length? v 2)
     (and (is-expression? (list-ref v 0))
     	  (is-expression? (list-ref v 1)))
    (if (proper-list-of-given-length? v 3)
      (and (is-expression? (list-ref v 0))
      	   (equal? (list-ref v 1) '=>)
	   (is-expression? (list-ref v 2)))
      #f))
    #t)))