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6594deb0 ER |
1 | ;;; life.el --- John Horton Conway's `Life' game for GNU Emacs |
2 | ||
3a801d0c ER |
3 | ;; Copyright (C) 1988 Free Software Foundation, Inc. |
4 | ||
e5167999 | 5 | ;; Author: Kyle Jones <talos!kjones@uunet.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 | |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to | |
22 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | ||
e41b2db1 ER |
24 | ;;; Commentary: |
25 | ||
26 | ;; A demonstrator for John Horton Conway's "Life" cellular automaton | |
27 | ;; in Emacs Lisp. Picks a random one of a set of interesting Life | |
28 | ;; patterns and avolves it according to the familiar rules. | |
29 | ||
e5167999 ER |
30 | ;;; Code: |
31 | ||
80a677d9 JA |
32 | (defconst life-patterns |
33 | [("@@@" " @@" "@@@") | |
34 | ("@@@ @@@" "@@ @@ " "@@@ @@@") | |
35 | ("@@@ @@@" "@@ @@" "@@@ @@@") | |
36 | ("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@") | |
37 | ("@@@@@@@@@@") | |
38 | (" @@@@@@@@@@ " | |
39 | " @@@@@@@@@@ " | |
40 | " @@@@@@@@@@ " | |
41 | "@@@@@@@@@@ " | |
42 | "@@@@@@@@@@ ") | |
43 | ("@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@") | |
44 | ("@ @" "@ @" "@ @" | |
45 | "@ @" "@ @" "@ @" | |
46 | "@ @" "@ @" "@ @" | |
47 | "@ @" "@ @" "@ @" | |
48 | "@ @" "@ @" "@ @") | |
49 | ("@@ " " @@ " " @@ " | |
50 | " @@ " " @@ " " @@ " | |
51 | " @@ " " @@ " " @@ " | |
52 | " @@ " " @@ " " @@ " | |
53 | " @@ " " @@ " " @@ " | |
54 | " @@") | |
55 | ("@@@@@@@@@" "@ @ @" "@ @@@@@ @" "@ @ @ @" "@@@ @@@" | |
56 | "@ @ @ @" "@ @@@@@ @" "@ @ @" "@@@@@@@@@")] | |
57 | "Vector of rectangles containing some Life startup patterns.") | |
58 | ||
59 | ;; Macros are used macros for manifest constants instead of variables | |
60 | ;; because the compiler will convert them to constants, which should | |
61 | ;; eval faster than symbols. | |
62 | ;; | |
80a677d9 JA |
63 | ;; Don't change any of the life-* macro constants unless you thoroughly |
64 | ;; understand the `life-grim-reaper' function. | |
e8a57935 JB |
65 | |
66 | (defmacro life-life-char () ?@) | |
67 | (defmacro life-death-char () (1+ (life-life-char))) | |
68 | (defmacro life-birth-char () 3) | |
69 | (defmacro life-void-char () ?\ ) | |
70 | ||
71 | (defmacro life-life-string () (char-to-string (life-life-char))) | |
72 | (defmacro life-death-string () (char-to-string (life-death-char))) | |
73 | (defmacro life-birth-string () (char-to-string (life-birth-char))) | |
74 | (defmacro life-void-string () (char-to-string (life-void-char))) | |
75 | (defmacro life-not-void-regexp () (concat "[^" (life-void-string) "\n]")) | |
76 | ||
77 | ;; try to optimize the (goto-char (point-min)) & (goto-char (point-max)) | |
78 | ;; idioms. This depends on goto-char's not griping if we underrshoot | |
79 | ;; or overshoot beginning or end of buffer. | |
80 | (defmacro goto-beginning-of-buffer () '(goto-char 1)) | |
81 | (defmacro maxint () (lsh (lsh (lognot 0) 1) -1)) | |
82 | (defmacro goto-end-of-buffer () '(goto-char (maxint))) | |
83 | ||
84 | (defmacro increment (variable) (list 'setq variable (list '1+ variable))) | |
85 | ||
80a677d9 JA |
86 | |
87 | ;; list of numbers that tell how many characters to move to get to | |
88 | ;; each of a cell's eight neighbors. | |
89 | (defconst life-neighbor-deltas nil) | |
90 | ||
91 | ;; window display always starts here. Easier to deal with than | |
92 | ;; (scroll-up) and (scroll-down) when trying to center the display. | |
93 | (defconst life-window-start nil) | |
94 | ||
95 | ;; For mode line | |
96 | (defconst life-current-generation nil) | |
97 | ;; Sadly, mode-line-format won't display numbers. | |
98 | (defconst life-generation-string nil) | |
99 | ||
100 | (defun abs (n) (if (< n 0) (- n) n)) | |
101 | ||
e8a57935 | 102 | ;;;###autoload |
80a677d9 JA |
103 | (defun life (&optional sleeptime) |
104 | "Run Conway's Life simulation. | |
e3f99b91 JB |
105 | The starting pattern is randomly selected. Prefix arg (optional first |
106 | arg non-nil from a program) is the number of seconds to sleep between | |
80a677d9 JA |
107 | generations (this defaults to 1)." |
108 | (interactive "p") | |
109 | (or sleeptime (setq sleeptime 1)) | |
110 | (life-setup) | |
111 | (life-display-generation sleeptime) | |
e8a57935 JB |
112 | (catch 'life-exit |
113 | (while t | |
114 | (let ((inhibit-quit t)) | |
115 | (life-grim-reaper) | |
116 | (life-expand-plane-if-needed) | |
117 | (life-increment-generation) | |
118 | (life-display-generation sleeptime))))) | |
80a677d9 | 119 | |
31e1d920 | 120 | (defalias 'life-mode 'life) |
80a677d9 JA |
121 | (put 'life-mode 'mode-class 'special) |
122 | ||
123 | (random t) | |
124 | ||
125 | (defun life-setup () | |
126 | (let (n) | |
127 | (switch-to-buffer (get-buffer-create "*Life*") t) | |
128 | (erase-buffer) | |
129 | (kill-all-local-variables) | |
130 | (setq case-fold-search nil | |
131 | mode-name "Life" | |
132 | major-mode 'life-mode | |
133 | truncate-lines t | |
134 | life-current-generation 0 | |
135 | life-generation-string "0" | |
136 | mode-line-buffer-identification '("Life: generation " | |
137 | life-generation-string) | |
138 | fill-column (1- (window-width)) | |
139 | life-window-start 1) | |
140 | (buffer-disable-undo (current-buffer)) | |
141 | ;; stuff in the random pattern | |
142 | (life-insert-random-pattern) | |
143 | ;; make sure (life-life-char) is used throughout | |
144 | (goto-beginning-of-buffer) | |
145 | (while (re-search-forward (life-not-void-regexp) nil t) | |
146 | (replace-match (life-life-string) t t)) | |
147 | ;; center the pattern horizontally | |
148 | (goto-beginning-of-buffer) | |
149 | (setq n (/ (- fill-column (save-excursion (end-of-line) (point))) 2)) | |
150 | (while (not (eobp)) | |
151 | (indent-to n) | |
152 | (forward-line)) | |
153 | ;; center the pattern vertically | |
154 | (setq n (/ (- (1- (window-height)) | |
155 | (count-lines (point-min) (point-max))) | |
156 | 2)) | |
157 | (goto-beginning-of-buffer) | |
158 | (newline n) | |
159 | (goto-end-of-buffer) | |
160 | (newline n) | |
161 | ;; pad lines out to fill-column | |
162 | (goto-beginning-of-buffer) | |
163 | (while (not (eobp)) | |
164 | (end-of-line) | |
165 | (indent-to fill-column) | |
166 | (move-to-column fill-column) | |
167 | (delete-region (point) (progn (end-of-line) (point))) | |
168 | (forward-line)) | |
169 | ;; expand tabs to spaces | |
170 | (untabify (point-min) (point-max)) | |
171 | ;; before starting be sure the automaton has room to grow | |
172 | (life-expand-plane-if-needed) | |
173 | ;; compute initial neighbor deltas | |
174 | (life-compute-neighbor-deltas))) | |
175 | ||
176 | (defun life-compute-neighbor-deltas () | |
177 | (setq life-neighbor-deltas | |
178 | (list -1 (- fill-column) | |
179 | (- (1+ fill-column)) (- (+ 2 fill-column)) | |
180 | 1 fill-column (1+ fill-column) | |
181 | (+ 2 fill-column)))) | |
182 | ||
183 | (defun life-insert-random-pattern () | |
184 | (insert-rectangle | |
185 | (elt life-patterns (% (abs (random)) (length life-patterns)))) | |
186 | (insert ?\n)) | |
187 | ||
188 | (defun life-increment-generation () | |
189 | (increment life-current-generation) | |
190 | (setq life-generation-string (int-to-string life-current-generation))) | |
191 | ||
192 | (defun life-grim-reaper () | |
193 | ;; Clear the match information. Later we check to see if it | |
194 | ;; is still clear, if so then all the cells have died. | |
195 | (store-match-data nil) | |
196 | (goto-beginning-of-buffer) | |
197 | ;; For speed declare all local variable outside the loop. | |
198 | (let (point char pivot living-neighbors list) | |
199 | (while (search-forward (life-life-string) nil t) | |
200 | (setq list life-neighbor-deltas | |
201 | living-neighbors 0 | |
202 | pivot (1- (point))) | |
203 | (while list | |
204 | (setq point (+ pivot (car list)) | |
205 | char (char-after point)) | |
206 | (cond ((eq char (life-void-char)) | |
207 | (subst-char-in-region point (1+ point) | |
208 | (life-void-char) 1 t)) | |
209 | ((< char 3) | |
210 | (subst-char-in-region point (1+ point) char (1+ char) t)) | |
211 | ((< char 9) | |
212 | (subst-char-in-region point (1+ point) char 9 t)) | |
213 | ((>= char (life-life-char)) | |
214 | (increment living-neighbors))) | |
215 | (setq list (cdr list))) | |
216 | (if (memq living-neighbors '(2 3)) | |
217 | () | |
218 | (subst-char-in-region pivot (1+ pivot) | |
219 | (life-life-char) (life-death-char) t)))) | |
220 | (if (null (match-beginning 0)) | |
221 | (life-extinct-quit)) | |
222 | (subst-char-in-region 1 (point-max) 9 (life-void-char) t) | |
223 | (subst-char-in-region 1 (point-max) 1 (life-void-char) t) | |
224 | (subst-char-in-region 1 (point-max) 2 (life-void-char) t) | |
225 | (subst-char-in-region 1 (point-max) (life-birth-char) (life-life-char) t) | |
226 | (subst-char-in-region 1 (point-max) (life-death-char) (life-void-char) t)) | |
227 | ||
228 | (defun life-expand-plane-if-needed () | |
229 | (catch 'done | |
230 | (goto-beginning-of-buffer) | |
231 | (while (not (eobp)) | |
232 | ;; check for life at beginning or end of line. If found at | |
233 | ;; either end, expand at both ends, | |
234 | (cond ((or (eq (following-char) (life-life-char)) | |
235 | (eq (progn (end-of-line) (preceding-char)) (life-life-char))) | |
236 | (goto-beginning-of-buffer) | |
237 | (while (not (eobp)) | |
238 | (insert (life-void-char)) | |
239 | (end-of-line) | |
240 | (insert (life-void-char)) | |
241 | (forward-char)) | |
242 | (setq fill-column (+ 2 fill-column)) | |
243 | (scroll-left 1) | |
244 | (life-compute-neighbor-deltas) | |
245 | (throw 'done t))) | |
246 | (forward-line))) | |
247 | (goto-beginning-of-buffer) | |
248 | ;; check for life within the first two lines of the buffer. | |
249 | ;; If present insert two lifeless lines at the beginning.. | |
250 | (cond ((search-forward (life-life-string) | |
251 | (+ (point) fill-column fill-column 2) t) | |
252 | (goto-beginning-of-buffer) | |
253 | (insert-char (life-void-char) fill-column) | |
254 | (insert ?\n) | |
255 | (insert-char (life-void-char) fill-column) | |
256 | (insert ?\n) | |
257 | (setq life-window-start (+ life-window-start fill-column 1)))) | |
258 | (goto-end-of-buffer) | |
259 | ;; check for life within the last two lines of the buffer. | |
260 | ;; If present insert two lifeless lines at the end. | |
261 | (cond ((search-backward (life-life-string) | |
262 | (- (point) fill-column fill-column 2) t) | |
263 | (goto-end-of-buffer) | |
264 | (insert-char (life-void-char) fill-column) | |
265 | (insert ?\n) | |
266 | (insert-char (life-void-char) fill-column) | |
267 | (insert ?\n) | |
268 | (setq life-window-start (+ life-window-start fill-column 1))))) | |
269 | ||
270 | (defun life-display-generation (sleeptime) | |
271 | (goto-char life-window-start) | |
272 | (recenter 0) | |
e8a57935 JB |
273 | |
274 | ;; Redisplay; if the user has hit a key, exit the loop. | |
275 | (or (eq t (sit-for sleeptime)) | |
276 | (throw 'life-exit nil))) | |
80a677d9 JA |
277 | |
278 | (defun life-extinct-quit () | |
279 | (life-display-generation 0) | |
280 | (signal 'life-extinct nil)) | |
281 | ||
282 | (put 'life-extinct 'error-conditions '(life-extinct quit)) | |
283 | (put 'life-extinct 'error-message "All life has perished") | |
49116ac0 JB |
284 | |
285 | (provide 'life) | |
286 | ||
6594deb0 | 287 | ;;; life.el ends here |