;; Die ersten drei Zeilen dieser Datei wurden von DrRacket eingefügt. Sie enthalten Metadaten
;; über die Sprachebene dieser Datei in einer Form, die DrRacket verarbeiten kann.
#reader(lib "DMdA-beginner-reader.ss" "deinprogramm")((modname cookie) (read-case-sensitive #f) (teachpacks ()) (deinprogramm-settings #(#f write repeating-decimal #f #t none explicit #f ())))
(: simple-choc chocolate-cookie)
(define simple-choc (make-chocolate-cookie 10 12))
(define double-choc (make-chocolate-cookie 20 12))

; Gewicht eines Schokokekses bestimmten
(: chocolate-cookie-weight (chocolate-cookie -> real))

(check-expect (chocolate-cookie-weight simple-choc) 22)
(check-expect (chocolate-cookie-weight double-choc) 32)

#;(define chocolate-cookie-weight
  (lambda (c)
    ...(chocolate-cookie-chocolate c)
    ...(chocolate-cookie-cookie c)
    ...))

(define chocolate-cookie-weight
  (lambda (c)
    (+ (chocolate-cookie-chocolate c)
       (chocolate-cookie-cookie c))))

; Aus einem Keks einen neuen mit doppelt so hohem Schokoladenanteil erzeugen
(: double-chocolate-in-cookie (chocolate-cookie -> chocolate-cookie))

(check-expect (double-chocolate-in-cookie simple-choc) double-choc)

#;(define double-chocolate-in-cookie
  (lambda (c)
    ...(chocolate-cookie-chocolate c)
    ...(chocolate-cookie-cookie c)
    ...))

; Ergebnis ist Cookie, daher Konstruktor:
#;(define double-chocolate-in-cookie
  (lambda (c)
    (make-chocolate-cookie
    ...(chocolate-cookie-chocolate c)
    ...(chocolate-cookie-cookie c)
    ...)))

; geschickte Kombination:
(define double-chocolate-in-cookie
  (lambda (c)
    (make-chocolate-cookie
      (* 2 (chocolate-cookie-chocolate c))
      (chocolate-cookie-cookie c))))