;; 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-intermediate-reader.ss" "lang")((modname |22.3|) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp")))))
;;Model

;build-number : (listof number) -> number
;Given alon which represent the digits of a number, with the first digit representing the most significant digit, return the number alon represents.

;x10add : number number -> number
;Given n1 and n2, multiply n2 by 10 (ie, x10) then add to n1 (ie, add).

(define (build-number alon)
  (local ((define (x10add n1 n2)
            (+ (* n2 10) n1)))
    (foldl x10add 0 alon)))

;;View

(define a-msg (make-message "Please choose 3 digits"))

;;DIGITS is a list of gui-items [choice]
(define DIGITS (local ((define (create-choice-gui colnum)
                         (make-choice (build-list 10 number->string))))
                 (build-list 3 create-choice-gui)))

;;list-of-digit-choices : number -> gui-item [choice]


;;Controller

(define (submit-digits event)
  (draw-message a-msg (number->string (build-number (map choice-index DIGITS)))))

(create-window (list DIGITS
                     (list a-msg)
                     (list (make-button "Submit digits" submit-digits))))