1 ;; The first three lines of this file were inserted by DrScheme. They record metadata
2 ;; about the language level of this file in a form that our tools can easily process.
3 #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")))))
4 ;;Model
5 
6 ;build-number : number number -> number
7 ;Given new and previous, multiply previous by 10 and add new to build a new number for display in the calculator.
8 
9 (define (build-number new previous)
10   (+ (* 10 previous) new))
11 
12 ;A cell is either
13 ;1. a number or
14 ;2. a symbol.
15 
16 ;A gui-table is a (listof (listof cell)).
17 
18 
19 (define pad1 '((1 2 3)
20                (4 5 6)
21                (7 8 9)
22                ("#" 0 "*")))
23 (define pad2 '((1 2 3 "+")
24                (4 5 6 "-")
25                (7 8 9 "*")
26                (0 "=" "." "/")))
27 
28 
29 ;;View
30 
31 ;pad->gui : string gui-table -> (listof (listof gui-items))
32 ;Given title and a-gui-table, return a (listof (listof gui-items)) that can be used by create-window to create a phone or calculator pad.  pad->gui first creates a message gui-item with the string from title, then a message gui-item repeating the last item entered, and finally an array of button gui-items.
33 
34 (define (pad->gui title a-gui-table)
35   (append (list (list (make-message title))
36                 (list (make-message "")))
37           (map loc->lob a-gui-table)))
38 
39 
40 
41 ;;Controller
42 
43 ;cell->button : cell -> gui-item [button]
44 ;Given acell, create a gui-item [button].
45 
46 ;gen-button : string -> gui-item [button]
47 
48 ;pad-callback : event -> true
49 ;Draws acell (the text associated with the button) into title.
50 
51 (define (cell->button acell)
52   (local ((define (gen-button cell-text)
53             (make-button cell-text pad-callback))
54           (define (pad-callback event) 
55             (draw-text (convert->string acell))))
56     (gen-button (convert->string acell))))
57 
58 ;draw-text : string -> true
59 ;Given a-string, draw it into the title and return true.
60 
61 (define (draw-text a-string)
62   (draw-message (list-ref (list-ref phonepad 1) 0) a-string))
63 
64 ;convert->string : X -> string
65 
66 (define (convert->string a-datum)
67   (cond
68     [(number? a-datum) (number->string a-datum)]
69     [else a-datum]))
70 
71 ;loc->lob : (listof cell)
72 ;[(listof cells) to (listof buttons)] Given aloc, convert them to a lob.
73 
74 (define (loc->lob aloc)
75   (map cell->button aloc))
76 
77 (define phonepad (pad->gui "Phone" pad1))
78 (define calcpad (pad->gui "Calculator" pad2))
79 
80 (create-window phonepad)