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6594deb0 ER |
1 | ;;; life.el --- John Horton Conway's `Life' game for GNU Emacs |
2 | ||
b0778a31 | 3 | ;; Copyright (C) 1988, 2001 Free Software Foundation, Inc. |
3a801d0c | 4 | |
4228277d | 5 | ;; Author: Kyle Jones <kyleuunet.uu.net> |
e9571d2a | 6 | ;; Keywords: games |
e5167999 | 7 | |
80a677d9 JA |
8 | ;; This file is part of GNU Emacs. |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
11 | ;; it under the terms of the GNU General Public License as published by | |
e5167999 | 12 | ;; the Free Software Foundation; either version 2, or (at your option) |
80a677d9 JA |
13 | ;; any later version. |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
b578f267 EN |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
23 | ;; Boston, MA 02111-1307, USA. | |
80a677d9 | 24 | |
e41b2db1 ER |
25 | ;;; Commentary: |
26 | ||
27 | ;; A demonstrator for John Horton Conway's "Life" cellular automaton | |
28 | ;; in Emacs Lisp. Picks a random one of a set of interesting Life | |
eb8c3be9 | 29 | ;; patterns and evolves it according to the familiar rules. |
e41b2db1 | 30 | |
e5167999 ER |
31 | ;;; Code: |
32 | ||
80a677d9 JA |
33 | (defconst life-patterns |
34 | [("@@@" " @@" "@@@") | |
35 | ("@@@ @@@" "@@ @@ " "@@@ @@@") | |
36 | ("@@@ @@@" "@@ @@" "@@@ @@@") | |
37 | ("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@") | |
38 | ("@@@@@@@@@@") | |
39 | (" @@@@@@@@@@ " | |
40 | " @@@@@@@@@@ " | |
41 | " @@@@@@@@@@ " | |
42 | "@@@@@@@@@@ " | |
43 | "@@@@@@@@@@ ") | |
44 | ("@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@") | |
45 | ("@ @" "@ @" "@ @" | |
46 | "@ @" "@ @" "@ @" | |
47 | "@ @" "@ @" "@ @" | |
48 | "@ @" "@ @" "@ @" | |
49 | "@ @" "@ @" "@ @") | |
50 | ("@@ " " @@ " " @@ " | |
51 | " @@ " " @@ " " @@ " | |
52 | " @@ " " @@ " " @@ " | |
53 | " @@ " " @@ " " @@ " | |
54 | " @@ " " @@ " " @@ " | |
55 | " @@") | |
a1506d29 | 56 | ("@@@@@@@@@" "@ @ @" "@ @@@@@ @" "@ @ @ @" "@@@ @@@" |
80a677d9 JA |
57 | "@ @ @ @" "@ @@@@@ @" "@ @ @" "@@@@@@@@@")] |
58 | "Vector of rectangles containing some Life startup patterns.") | |
59 | ||
60 | ;; Macros are used macros for manifest constants instead of variables | |
61 | ;; because the compiler will convert them to constants, which should | |
62 | ;; eval faster than symbols. | |
63 | ;; | |
80a677d9 JA |
64 | ;; Don't change any of the life-* macro constants unless you thoroughly |
65 | ;; understand the `life-grim-reaper' function. | |
e8a57935 JB |
66 | |
67 | (defmacro life-life-char () ?@) | |
68 | (defmacro life-death-char () (1+ (life-life-char))) | |
69 | (defmacro life-birth-char () 3) | |
70 | (defmacro life-void-char () ?\ ) | |
71 | ||
72 | (defmacro life-life-string () (char-to-string (life-life-char))) | |
73 | (defmacro life-death-string () (char-to-string (life-death-char))) | |
74 | (defmacro life-birth-string () (char-to-string (life-birth-char))) | |
75 | (defmacro life-void-string () (char-to-string (life-void-char))) | |
76 | (defmacro life-not-void-regexp () (concat "[^" (life-void-string) "\n]")) | |
77 | ||
44fad123 | 78 | (defmacro life-increment (variable) (list 'setq variable (list '1+ variable))) |
e8a57935 | 79 | |
80a677d9 JA |
80 | |
81 | ;; list of numbers that tell how many characters to move to get to | |
82 | ;; each of a cell's eight neighbors. | |
83 | (defconst life-neighbor-deltas nil) | |
84 | ||
85 | ;; window display always starts here. Easier to deal with than | |
86 | ;; (scroll-up) and (scroll-down) when trying to center the display. | |
87 | (defconst life-window-start nil) | |
88 | ||
89 | ;; For mode line | |
90 | (defconst life-current-generation nil) | |
91 | ;; Sadly, mode-line-format won't display numbers. | |
92 | (defconst life-generation-string nil) | |
93 | ||
44fad123 RS |
94 | (defvar life-initialized nil |
95 | "Non-nil if `life' has been run at least once.") | |
80a677d9 | 96 | |
e8a57935 | 97 | ;;;###autoload |
80a677d9 JA |
98 | (defun life (&optional sleeptime) |
99 | "Run Conway's Life simulation. | |
e3f99b91 JB |
100 | The starting pattern is randomly selected. Prefix arg (optional first |
101 | arg non-nil from a program) is the number of seconds to sleep between | |
80a677d9 JA |
102 | generations (this defaults to 1)." |
103 | (interactive "p") | |
44fad123 RS |
104 | (or life-initialized |
105 | (random t)) | |
106 | (setq life-initialized t) | |
80a677d9 JA |
107 | (or sleeptime (setq sleeptime 1)) |
108 | (life-setup) | |
e8a57935 JB |
109 | (catch 'life-exit |
110 | (while t | |
111 | (let ((inhibit-quit t)) | |
b0778a31 | 112 | (life-display-generation sleeptime) |
e8a57935 JB |
113 | (life-grim-reaper) |
114 | (life-expand-plane-if-needed) | |
b0778a31 | 115 | (life-increment-generation))))) |
80a677d9 | 116 | |
31e1d920 | 117 | (defalias 'life-mode 'life) |
80a677d9 JA |
118 | (put 'life-mode 'mode-class 'special) |
119 | ||
80a677d9 JA |
120 | (defun life-setup () |
121 | (let (n) | |
122 | (switch-to-buffer (get-buffer-create "*Life*") t) | |
123 | (erase-buffer) | |
124 | (kill-all-local-variables) | |
125 | (setq case-fold-search nil | |
126 | mode-name "Life" | |
127 | major-mode 'life-mode | |
128 | truncate-lines t | |
129 | life-current-generation 0 | |
130 | life-generation-string "0" | |
131 | mode-line-buffer-identification '("Life: generation " | |
132 | life-generation-string) | |
133 | fill-column (1- (window-width)) | |
134 | life-window-start 1) | |
135 | (buffer-disable-undo (current-buffer)) | |
136 | ;; stuff in the random pattern | |
137 | (life-insert-random-pattern) | |
138 | ;; make sure (life-life-char) is used throughout | |
44fad123 | 139 | (goto-char (point-min)) |
80a677d9 JA |
140 | (while (re-search-forward (life-not-void-regexp) nil t) |
141 | (replace-match (life-life-string) t t)) | |
142 | ;; center the pattern horizontally | |
44fad123 | 143 | (goto-char (point-min)) |
80a677d9 JA |
144 | (setq n (/ (- fill-column (save-excursion (end-of-line) (point))) 2)) |
145 | (while (not (eobp)) | |
146 | (indent-to n) | |
147 | (forward-line)) | |
148 | ;; center the pattern vertically | |
149 | (setq n (/ (- (1- (window-height)) | |
150 | (count-lines (point-min) (point-max))) | |
151 | 2)) | |
44fad123 | 152 | (goto-char (point-min)) |
80a677d9 | 153 | (newline n) |
44fad123 | 154 | (goto-char (point-max)) |
80a677d9 JA |
155 | (newline n) |
156 | ;; pad lines out to fill-column | |
44fad123 | 157 | (goto-char (point-min)) |
80a677d9 JA |
158 | (while (not (eobp)) |
159 | (end-of-line) | |
160 | (indent-to fill-column) | |
161 | (move-to-column fill-column) | |
162 | (delete-region (point) (progn (end-of-line) (point))) | |
163 | (forward-line)) | |
164 | ;; expand tabs to spaces | |
165 | (untabify (point-min) (point-max)) | |
166 | ;; before starting be sure the automaton has room to grow | |
167 | (life-expand-plane-if-needed) | |
168 | ;; compute initial neighbor deltas | |
169 | (life-compute-neighbor-deltas))) | |
170 | ||
171 | (defun life-compute-neighbor-deltas () | |
172 | (setq life-neighbor-deltas | |
173 | (list -1 (- fill-column) | |
174 | (- (1+ fill-column)) (- (+ 2 fill-column)) | |
175 | 1 fill-column (1+ fill-column) | |
176 | (+ 2 fill-column)))) | |
177 | ||
178 | (defun life-insert-random-pattern () | |
179 | (insert-rectangle | |
6b6d5edf | 180 | (elt life-patterns (random (length life-patterns)))) |
80a677d9 JA |
181 | (insert ?\n)) |
182 | ||
183 | (defun life-increment-generation () | |
44fad123 | 184 | (life-increment life-current-generation) |
80a677d9 JA |
185 | (setq life-generation-string (int-to-string life-current-generation))) |
186 | ||
187 | (defun life-grim-reaper () | |
188 | ;; Clear the match information. Later we check to see if it | |
189 | ;; is still clear, if so then all the cells have died. | |
ac092f22 | 190 | (set-match-data nil) |
44fad123 | 191 | (goto-char (point-min)) |
80a677d9 JA |
192 | ;; For speed declare all local variable outside the loop. |
193 | (let (point char pivot living-neighbors list) | |
194 | (while (search-forward (life-life-string) nil t) | |
195 | (setq list life-neighbor-deltas | |
196 | living-neighbors 0 | |
197 | pivot (1- (point))) | |
198 | (while list | |
199 | (setq point (+ pivot (car list)) | |
200 | char (char-after point)) | |
201 | (cond ((eq char (life-void-char)) | |
202 | (subst-char-in-region point (1+ point) | |
203 | (life-void-char) 1 t)) | |
204 | ((< char 3) | |
205 | (subst-char-in-region point (1+ point) char (1+ char) t)) | |
206 | ((< char 9) | |
207 | (subst-char-in-region point (1+ point) char 9 t)) | |
208 | ((>= char (life-life-char)) | |
44fad123 | 209 | (life-increment living-neighbors))) |
80a677d9 JA |
210 | (setq list (cdr list))) |
211 | (if (memq living-neighbors '(2 3)) | |
212 | () | |
213 | (subst-char-in-region pivot (1+ pivot) | |
214 | (life-life-char) (life-death-char) t)))) | |
215 | (if (null (match-beginning 0)) | |
216 | (life-extinct-quit)) | |
217 | (subst-char-in-region 1 (point-max) 9 (life-void-char) t) | |
218 | (subst-char-in-region 1 (point-max) 1 (life-void-char) t) | |
219 | (subst-char-in-region 1 (point-max) 2 (life-void-char) t) | |
220 | (subst-char-in-region 1 (point-max) (life-birth-char) (life-life-char) t) | |
221 | (subst-char-in-region 1 (point-max) (life-death-char) (life-void-char) t)) | |
222 | ||
223 | (defun life-expand-plane-if-needed () | |
224 | (catch 'done | |
44fad123 | 225 | (goto-char (point-min)) |
80a677d9 JA |
226 | (while (not (eobp)) |
227 | ;; check for life at beginning or end of line. If found at | |
228 | ;; either end, expand at both ends, | |
229 | (cond ((or (eq (following-char) (life-life-char)) | |
230 | (eq (progn (end-of-line) (preceding-char)) (life-life-char))) | |
44fad123 | 231 | (goto-char (point-min)) |
80a677d9 JA |
232 | (while (not (eobp)) |
233 | (insert (life-void-char)) | |
234 | (end-of-line) | |
235 | (insert (life-void-char)) | |
236 | (forward-char)) | |
237 | (setq fill-column (+ 2 fill-column)) | |
238 | (scroll-left 1) | |
239 | (life-compute-neighbor-deltas) | |
240 | (throw 'done t))) | |
241 | (forward-line))) | |
44fad123 | 242 | (goto-char (point-min)) |
80a677d9 JA |
243 | ;; check for life within the first two lines of the buffer. |
244 | ;; If present insert two lifeless lines at the beginning.. | |
245 | (cond ((search-forward (life-life-string) | |
246 | (+ (point) fill-column fill-column 2) t) | |
44fad123 | 247 | (goto-char (point-min)) |
80a677d9 JA |
248 | (insert-char (life-void-char) fill-column) |
249 | (insert ?\n) | |
250 | (insert-char (life-void-char) fill-column) | |
251 | (insert ?\n) | |
252 | (setq life-window-start (+ life-window-start fill-column 1)))) | |
44fad123 | 253 | (goto-char (point-max)) |
80a677d9 JA |
254 | ;; check for life within the last two lines of the buffer. |
255 | ;; If present insert two lifeless lines at the end. | |
256 | (cond ((search-backward (life-life-string) | |
257 | (- (point) fill-column fill-column 2) t) | |
44fad123 | 258 | (goto-char (point-max)) |
80a677d9 JA |
259 | (insert-char (life-void-char) fill-column) |
260 | (insert ?\n) | |
261 | (insert-char (life-void-char) fill-column) | |
262 | (insert ?\n) | |
263 | (setq life-window-start (+ life-window-start fill-column 1))))) | |
264 | ||
265 | (defun life-display-generation (sleeptime) | |
266 | (goto-char life-window-start) | |
267 | (recenter 0) | |
a1506d29 | 268 | |
e8a57935 JB |
269 | ;; Redisplay; if the user has hit a key, exit the loop. |
270 | (or (eq t (sit-for sleeptime)) | |
271 | (throw 'life-exit nil))) | |
80a677d9 JA |
272 | |
273 | (defun life-extinct-quit () | |
274 | (life-display-generation 0) | |
275 | (signal 'life-extinct nil)) | |
276 | ||
277 | (put 'life-extinct 'error-conditions '(life-extinct quit)) | |
278 | (put 'life-extinct 'error-message "All life has perished") | |
49116ac0 JB |
279 | |
280 | (provide 'life) | |
281 | ||
6b61353c | 282 | ;;; arch-tag: e9373544-755e-42f5-a9a1-4d4c422bb97a |
6594deb0 | 283 | ;;; life.el ends here |