(load "for.ss")
(load "listprocs.ss")

(define mystery 
  (lambda (null? if list)
    (if (null? list) list 3)))

(define nest 
  (lambda (x)
    (lambda (x)
      (+ x x))))

(define x 0)

(define (nextx)
  (set! x (+ x 1))
  x)

(define (make-letter-tallys)
  (for (char->integer #\a) 
       (char->integer #\z) 
       (lambda (accum cno) 
         (append accum (list (cons (integer->char cno) 0))))
       null))
                                           
(define (count-letters msg)
  (let ((letter-uses (make-letter-tallys)))
    (map (lambda (c) 
           (insertlg 
            (lambda (thisletter foundit)
              (if foundit foundit 
                  (if (eq? (car thisletter) c) 
                      (begin (set-cdr! thisletter (+ (cdr thisletter) 1)) #t)
                      #f)))          
            letter-uses
            #f))
         (string->list msg))
    letter-uses))