;; The first three lines of this file were inserted by DrRacket. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-beginner-reader.ss" "lang")((modname structures) (read-case-sensitive #t) (teachpacks ((lib "universe.ss" "teachpack" "2htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "universe.ss" "teachpack" "2htdp")))))
;; Helene Martin, Garfield APCS++ 2010
;; Structure examples

;; A shoe is (make-shoe string string number number)
(define-struct shoe (brand color size price))

;; Some constants for testing
(define MY-SHOE (make-shoe "Nike" "red" 8.5 60))
(define YOUR-SHOE (make-shoe "Nike" "purple" 10 100))

;; Selectors access a single field
(check-expect (shoe-color MY-SHOE) "red")
(check-expect (shoe-size YOUR-SHOE) 10)

;; Template for a function over a shoe
;(define (shoe-func a-shoe)
;  ... (shoe-brand a-shoe) ...
;  ... (shoe-color a-shoe) ...
;  ... (shoe-size a-shoe) ...
;  ... (shoe-price a-shoe) ...

;; is-red? shoe -> boolean
;; Takes in a shoe and returns whether that shoe is red
(define (is-red? a-shoe)
  (string=? (shoe-color a-shoe) "red"))

(check-expect (is-red? MY-SHOE) true)
(check-expect (is-red? YOUR-SHOE) false)

;; discount-shoe shoe -> shoe
;; Takes in a shoe and returns one with a 50% discount
(define (discount-shoe a-shoe)
  (make-shoe (shoe-brand a-shoe)
             (shoe-color a-shoe)
             (shoe-size a-shoe)
             (* .5 (shoe-price a-shoe))))

(check-expect (discount-shoe MY-SHOE) (make-shoe "Nike" "red" 8.5 30))

;; same-size? shoe shoe -> boolean
;; Takes in two shoes and returns whether they are of the same size
(define (same-size? a-shoe another-shoe)
  (= (shoe-size MY-SHOE) (shoe-size YOUR-SHOE)))

(check-expect (same-size? MY-SHOE YOUR-SHOE) false)

;; An outfit is (make-outfit string shoe)
(define-struct outfit (color shoe))

(define MY-OUTFIT (make-outfit "red" MY-SHOE))
(define YOUR-OUTFIT (make-outfit "red" YOUR-SHOE))

;; matches? outfit -> boolean
;; Takes in an outfit and returns whether the color matches the shoes
(define (matches? an-outfit)
  (string=? (outfit-color an-outfit)
            (shoe-color (outfit-shoe an-outfit))))

(check-expect (matches? MY-OUTFIT) true)
(check-expect (matches? YOUR-OUTFIT) false)