Commit | Line | Data |
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80a677d9 JA |
1 | ; |
2 | ; hanoi - towers of hanoi in GNUmacs | |
3 | ; | |
4 | ; Author (a) 1985, Damon Anton Permezel | |
5 | ; | |
6 | ||
7 | ;;; | |
8 | ;;; hanoi-topos - direct cursor addressing | |
9 | ;;; | |
10 | (defun hanoi-topos (row col) | |
11 | (goto-line row) | |
12 | (beginning-of-line) | |
13 | (forward-char col)) | |
14 | ||
15 | ;;; | |
16 | ;;; hanoi - user callable Towers of Hanoi | |
17 | ;;; | |
f9f9507e | 18 | ;;;###autoload |
80a677d9 JA |
19 | (defun hanoi (nrings) |
20 | "Towers of Hanoi diversion. Argument is number of rings." | |
21 | (interactive | |
22 | (list (if (null current-prefix-arg) | |
23 | 3 | |
24 | (prefix-numeric-value current-prefix-arg)))) | |
25 | (if (<= nrings 0) (error "Negative number of rings")) | |
26 | (let (pole-spacing | |
27 | floor-row | |
28 | fly-row | |
29 | (window-height (window-height (selected-window))) | |
30 | (window-width (window-width (selected-window)))) | |
31 | (let ((h (+ nrings 2)) | |
32 | (w (+ (* (1- nrings) 6) 2 5))) | |
33 | (if (not (and (>= window-width h) | |
34 | (> window-width w))) | |
35 | (progn | |
36 | (delete-other-windows) | |
37 | (if (not (and (>= (setq window-height | |
38 | (window-height (selected-window))) h) | |
39 | (> (setq window-width | |
40 | (window-width (selected-window))) w))) | |
41 | (error "Screen is too small (need at least %dx%d)" w h)))) | |
42 | (setq pole-spacing (/ window-width 6)) | |
43 | (if (not (zerop (logand pole-spacing 1))) | |
44 | ;; must be even | |
45 | (setq pole-spacing (1+ pole-spacing))) | |
46 | (setq floor-row (if (> (- window-height 3) h) | |
47 | (- window-height 3) window-height))) | |
48 | (let ((fly-row (- floor-row nrings 1)) | |
49 | ;; pole: column . fill height | |
50 | (pole-1 (cons pole-spacing floor-row)) | |
51 | (pole-2 (cons (* 3 pole-spacing) floor-row)) | |
52 | (pole-3 (cons (* 5 pole-spacing) floor-row)) | |
53 | (rings (make-vector nrings nil))) | |
54 | ;; construct the ring list | |
55 | (let ((i 0)) | |
56 | (while (< i nrings) | |
57 | ;; ring: [pole-number string empty-string] | |
58 | (aset rings i (vector nil | |
59 | (make-string (+ i i 3) (+ ?0 i)) | |
60 | (make-string (+ i i 3) ?\ ))) | |
61 | (setq i (1+ i)))) | |
62 | ;; | |
63 | ;; init the screen | |
64 | ;; | |
65 | (switch-to-buffer "*Hanoi*") | |
66 | (setq buffer-read-only nil) | |
67 | (buffer-disable-undo (current-buffer)) | |
68 | (erase-buffer) | |
69 | (let ((i 0)) | |
70 | (while (< i floor-row) | |
71 | (setq i (1+ i)) | |
72 | (insert-char ?\ (1- window-width)) | |
73 | (insert ?\n))) | |
74 | (insert-char ?= (1- window-width)) | |
75 | ||
76 | (let ((n 1)) | |
77 | (while (< n 6) | |
78 | (hanoi-topos fly-row (* n pole-spacing)) | |
79 | (setq n (+ n 2)) | |
80 | (let ((i fly-row)) | |
81 | (while (< i floor-row) | |
82 | (setq i (1+ i)) | |
83 | (next-line 1) | |
84 | (insert ?\|) | |
85 | (delete-char 1) | |
86 | (backward-char 1))))) | |
87 | ;(sit-for 0) | |
88 | ;; | |
89 | ;; now draw the rings in their initial positions | |
90 | ;; | |
91 | (let ((i 0) | |
92 | ring) | |
93 | (while (< i nrings) | |
94 | (setq ring (aref rings (- nrings 1 i))) | |
95 | (aset ring 0 (- floor-row i)) | |
96 | (hanoi-topos (cdr pole-1) | |
97 | (- (car pole-1) (- nrings i))) | |
98 | (hanoi-draw-ring ring t nil) | |
99 | (setcdr pole-1 (1- (cdr pole-1))) | |
100 | (setq i (1+ i)))) | |
101 | (setq buffer-read-only t) | |
102 | (sit-for 0) | |
103 | ;; | |
104 | ;; do it! | |
105 | ;; | |
106 | (hanoi0 (1- nrings) pole-1 pole-2 pole-3) | |
107 | (goto-char (point-min)) | |
108 | (message "Done") | |
109 | (setq buffer-read-only t) | |
110 | (set-buffer-modified-p (buffer-modified-p)) | |
111 | (sit-for 0)))) | |
112 | ||
113 | ;;; | |
114 | ;;; hanoi0 - work horse of hanoi | |
115 | ;;; | |
116 | (defun hanoi0 (n from to work) | |
117 | (cond ((input-pending-p) | |
118 | (signal 'quit (list "I can tell you've had enough"))) | |
119 | ((< n 0)) | |
120 | (t | |
121 | (hanoi0 (1- n) from work to) | |
122 | (hanoi-move-ring n from to) | |
123 | (hanoi0 (1- n) work to from)))) | |
124 | ||
125 | ;;; | |
126 | ;;; hanoi-move-ring - move ring 'n' from 'from' to 'to' | |
127 | ;;; | |
128 | ;;; | |
129 | (defun hanoi-move-ring (n from to) | |
130 | (let ((ring (aref rings n)) ; ring <- ring: (ring# . row) | |
131 | (buffer-read-only nil)) | |
132 | (let ((row (aref ring 0)) ; row <- row ring is on | |
133 | (col (- (car from) n 1)) ; col <- left edge of ring | |
134 | (dst-col (- (car to) n 1)) ; dst-col <- dest col for left edge | |
135 | (dst-row (cdr to))) ; dst-row <- dest row for ring | |
136 | (hanoi-topos row col) | |
137 | (while (> row fly-row) ; move up to the fly row | |
138 | (hanoi-draw-ring ring nil t) ; blank out ring | |
139 | (previous-line 1) ; move up a line | |
140 | (hanoi-draw-ring ring t nil) ; redraw | |
141 | (sit-for 0) | |
142 | (setq row (1- row))) | |
143 | (setcdr from (1+ (cdr from))) ; adjust top row | |
144 | ;; | |
145 | ;; fly the ring over to the right pole | |
146 | ;; | |
147 | (while (not (equal dst-col col)) | |
148 | (cond ((> dst-col col) ; dst-col > col: right shift | |
149 | (end-of-line 1) | |
150 | (delete-backward-char 2) | |
151 | (beginning-of-line 1) | |
152 | (insert ?\ ?\ ) | |
153 | (sit-for 0) | |
154 | (setq col (1+ (1+ col)))) | |
155 | ((< dst-col col) ; dst-col < col: left shift | |
156 | (beginning-of-line 1) | |
157 | (delete-char 2) | |
158 | (end-of-line 1) | |
159 | (insert ?\ ?\ ) | |
160 | (sit-for 0) | |
161 | (setq col (1- (1- col)))))) | |
162 | ;; | |
163 | ;; let the ring float down | |
164 | ;; | |
165 | (hanoi-topos fly-row dst-col) | |
166 | (while (< row dst-row) ; move down to the dest row | |
167 | (hanoi-draw-ring ring nil (> row fly-row)) ; blank out ring | |
168 | (next-line 1) ; move down a line | |
169 | (hanoi-draw-ring ring t nil) ; redraw ring | |
170 | (sit-for 0) | |
171 | (setq row (1+ row))) | |
172 | (aset ring 0 dst-row) | |
173 | (setcdr to (1- (cdr to)))))) ; adjust top row | |
174 | ||
175 | ;;; | |
176 | ;;; draw-ring - draw the ring at point, leave point unchanged | |
177 | ;;; | |
178 | ;;; Input: | |
179 | ;;; ring | |
180 | ;;; f1 - flag: t -> draw, nil -> erase | |
181 | ;;; f2 - flag: t -> erasing and need to draw ?\| | |
182 | ;;; | |
183 | (defun hanoi-draw-ring (ring f1 f2) | |
184 | (save-excursion | |
185 | (let* ((string (if f1 (aref ring 1) (aref ring 2))) | |
186 | (len (length string))) | |
187 | (delete-char len) | |
188 | (insert string) | |
189 | (if f2 | |
190 | (progn | |
191 | (backward-char (/ (+ len 1) 2)) | |
192 | (delete-char 1) (insert ?\|)))))) | |
193 |