;; SICP 4.2.3
(require 'stdlib)

(define (cons. x y)
  (lambda (m) (m x y)))

(define (car. z)
  (cond ((null z) nil)
        (t (z (lambda (p q) p)))))

(define (cdr. z)
  (cond ((null z) nil)
        (t (z (lambda (p q) q)))))

(define (list. #!rest args)
  (cond ((null args) nil)
        (t (cons. (car. args) (list. (cdr. args))))))

(define (list-ref items n)
  (if (= n 0)
      (car. items)
    (list-ref (cdr. items) (- n 1))))

(define (map. proc items)
  (if (null items)
      '()
    (cons. (proc (car. items))
           (map. proc (cdr. items)))))

(define (scale-list items factor)
  (map. (lambda (x) (* x factor))
       items))

(define (add-lists list1 list2)
  (cond ((null list1) list2)
        ((null list2) list1)
        (t (cons. (+ (car. list1) (car. list2))
                  (add-lists (cdr. list1) (cdr. list2))))))

;;(define ones (cons. 1 ones))
;;(define integers (cons. 1 (add-lists ones integers)))