;; The first three lines of this file were inserted by DrScheme. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-advanced-reader.ss" "lang")((modname |40.1|) (read-case-sensitive #t) (teachpacks ((lib "guess-gui.ss" "teachpack" "htdp") (lib "guess.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp") (lib "draw.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #t #t none #f ((lib "guess-gui.ss" "teachpack" "htdp") (lib "guess.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp") (lib "draw.ss" "teachpack" "htdp")))))
#|
Exercise 40.1.3.   Show how to implement the following structure definitions as functions:

   1. (define-struct movie (title producer))
   2. (define-struct boyfriend (name hair eyes phone))
   3. (define-struct cheerleader (name number))
   4. (define-struct CD (artist title price))
   5. (define-struct sweater (material size producer))

Pick one and demonstrate that the expected laws hold.    Solution
|#

(define (make-movie title producer)
  (local ((define title0 title)
          (define producer0 producer)
          (define (service-manager msg)
            (cond
              [(equal? msg 'title) title0]
              [(equal? msg 'producer) producer0])))
    service-manager))

(define (movie-title amovie)
  (amovie 'title))

(define (movie-producer amovie)
  (amovie 'producer))

(define SciFi (make-movie 'StarWars 'GeorgeLucas))
(movie-title SciFi)
(movie-producer SciFi)

(define (make-boyfriend name hair eyes phone)
  (lambda (selector)
    (selector name hair eyes phone)))
(define (boyfriend-name aboyfriend)
  (aboyfriend (lambda (name hair eyes phone) name)))
(define (boyfriend-hair aboyfriend)
  (aboyfriend (lambda (name hair eyes phone) hair)))
(define (boyfriend-eyes aboyfriend)
  (aboyfriend (lambda (name hair eyes phone) eyes)))
(define (boyfriend-phone aboyfriend)
  (aboyfriend (lambda (name hair eyes phone) phone)))

(define Aaron (make-boyfriend 'Aaron 'black 'black 715))
(boyfriend-name Aaron)
(boyfriend-hair Aaron)
(boyfriend-eyes Aaron)
(boyfriend-phone Aaron)

(define (make-cheerleader name number)
  (lambda (selector)
    (selector name number)))
(define (cheerleader-name acheerleader)
  (acheerleader (lambda (name number) name)))
   
(define (cheerleader-number acheerleader)
  (acheerleader (lambda (name number) number)))

(define Abbo (make-cheerleader 'Abbo 53535))
(cheerleader-name Abbo)
(cheerleader-number Abbo)

(define (make-CD artist title price)
  (local ((define artist0 artist)
          (define title0 title)
          (define price0 price)
          (define (service-manager msg)
            (cond
              [(equal? msg 'artist) artist0]
              [(equal? msg 'title) title0]
              [(equal? msg 'price) price0])))
    service-manager))

(define (CD-artist aCD)
  (aCD 'artist))

(define (CD-title aCD)
  (aCD 'title))

(define (CD-price aCD)
  (aCD 'price))

(define BeeGees (make-CD 'BeeGees 'SaturdayNightFever 9.99))
(CD-artist BeeGees)
(CD-title BeeGees)
(CD-price BeeGees)

(define (make-sweater material size producer)
  (lambda (selector)
    (selector material size producer)))
(define (sweater-material asweater)
  (asweater (lambda (material size producer) material)))
(define (sweater-size asweater)
  (asweater (lambda (material size producer) size)))
(define (sweater-producer asweater)
  (asweater (lambda (material size producer) producer)))

(define YellowJacket (make-sweater 'Cotton 'Large 'Unknown))
(sweater-material YellowJacket)
(sweater-size YellowJacket)
(sweater-producer YellowJacket)