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Diffstat (limited to 'lisp/life.el')
| -rw-r--r-- | lisp/life.el | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/lisp/life.el b/lisp/life.el new file mode 100644 index 00000000000..16b0e719b5b --- /dev/null +++ b/lisp/life.el @@ -0,0 +1,276 @@ +;; Conway's `Life' for GNU Emacs +;; Copyright (C) 1988 Free Software Foundation, Inc. +;; Contributed by Kyle Jones, talos!kjones@uunet.uu.net + +;; This file is part of GNU Emacs. + +;; GNU Emacs is free software; you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation; either version 1, or (at your option) +;; any later version. + +;; GNU Emacs is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with GNU Emacs; see the file COPYING. If not, write to +;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + +(provide 'life) + +(defconst life-patterns + [("@@@" " @@" "@@@") + ("@@@ @@@" "@@ @@ " "@@@ @@@") + ("@@@ @@@" "@@ @@" "@@@ @@@") + ("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@") + ("@@@@@@@@@@") + (" @@@@@@@@@@ " + " @@@@@@@@@@ " + " @@@@@@@@@@ " + "@@@@@@@@@@ " + "@@@@@@@@@@ ") + ("@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@" "@") + ("@ @" "@ @" "@ @" + "@ @" "@ @" "@ @" + "@ @" "@ @" "@ @" + "@ @" "@ @" "@ @" + "@ @" "@ @" "@ @") + ("@@ " " @@ " " @@ " + " @@ " " @@ " " @@ " + " @@ " " @@ " " @@ " + " @@ " " @@ " " @@ " + " @@ " " @@ " " @@ " + " @@") + ("@@@@@@@@@" "@ @ @" "@ @@@@@ @" "@ @ @ @" "@@@ @@@" + "@ @ @ @" "@ @@@@@ @" "@ @ @" "@@@@@@@@@")] + "Vector of rectangles containing some Life startup patterns.") + +;; Macros are used macros for manifest constants instead of variables +;; because the compiler will convert them to constants, which should +;; eval faster than symbols. +;; +;; The (require) wrapping forces the compiler to eval these macros at +;; compile time. This would not be necessary if we did not use macros +;; inside of macros, which the compiler doesn't seem to check for. +;; +;; Don't change any of the life-* macro constants unless you thoroughly +;; understand the `life-grim-reaper' function. +(require + (progn + (defmacro life-life-char () ?@) + (defmacro life-death-char () (1+ (life-life-char))) + (defmacro life-birth-char () 3) + (defmacro life-void-char () ?\ ) + + (defmacro life-life-string () (char-to-string (life-life-char))) + (defmacro life-death-string () (char-to-string (life-death-char))) + (defmacro life-birth-string () (char-to-string (life-birth-char))) + (defmacro life-void-string () (char-to-string (life-void-char))) + (defmacro life-not-void-regexp () (concat "[^" (life-void-string) "\n]")) + + ;; try to optimize the (goto-char (point-min)) & (goto-char (point-max)) + ;; idioms. This depends on goto-char's not griping if we underrshoot + ;; or overshoot beginning or end of buffer. + (defmacro goto-beginning-of-buffer () '(goto-char 1)) + (defmacro maxint () (lsh (lsh (lognot 0) 1) -1)) + (defmacro goto-end-of-buffer () '(goto-char (maxint))) + + (defmacro increment (variable) (list 'setq variable (list '1+ variable))) + 'life)) + +;; list of numbers that tell how many characters to move to get to +;; each of a cell's eight neighbors. +(defconst life-neighbor-deltas nil) + +;; window display always starts here. Easier to deal with than +;; (scroll-up) and (scroll-down) when trying to center the display. +(defconst life-window-start nil) + +;; For mode line +(defconst life-current-generation nil) +;; Sadly, mode-line-format won't display numbers. +(defconst life-generation-string nil) + +(defun abs (n) (if (< n 0) (- n) n)) + +(defun life (&optional sleeptime) + "Run Conway's Life simulation. +The starting pattern is randomly selected. Prefix arg (optional first arg +non-nil from a program) is the number of seconds to sleep between +generations (this defaults to 1)." + (interactive "p") + (or sleeptime (setq sleeptime 1)) + (life-setup) + (life-display-generation sleeptime) + (while t + (let ((inhibit-quit t)) + (life-grim-reaper) + (life-expand-plane-if-needed) + (life-increment-generation) + (life-display-generation sleeptime)))) + +(fset 'life-mode 'life) +(put 'life-mode 'mode-class 'special) + +(random t) + +(defun life-setup () + (let (n) + (switch-to-buffer (get-buffer-create "*Life*") t) + (erase-buffer) + (kill-all-local-variables) + (setq case-fold-search nil + mode-name "Life" + major-mode 'life-mode + truncate-lines t + life-current-generation 0 + life-generation-string "0" + mode-line-buffer-identification '("Life: generation " + life-generation-string) + fill-column (1- (window-width)) + life-window-start 1) + (buffer-flush-undo (current-buffer)) + ;; stuff in the random pattern + (life-insert-random-pattern) + ;; make sure (life-life-char) is used throughout + (goto-beginning-of-buffer) + (while (re-search-forward (life-not-void-regexp) nil t) + (replace-match (life-life-string) t t)) + ;; center the pattern horizontally + (goto-beginning-of-buffer) + (setq n (/ (- fill-column (save-excursion (end-of-line) (point))) 2)) + (while (not (eobp)) + (indent-to n) + (forward-line)) + ;; center the pattern vertically + (setq n (/ (- (1- (window-height)) + (count-lines (point-min) (point-max))) + 2)) + (goto-beginning-of-buffer) + (newline n) + (goto-end-of-buffer) + (newline n) + ;; pad lines out to fill-column + (goto-beginning-of-buffer) + (while (not (eobp)) + (end-of-line) + (indent-to fill-column) + (move-to-column fill-column) + (delete-region (point) (progn (end-of-line) (point))) + (forward-line)) + ;; expand tabs to spaces + (untabify (point-min) (point-max)) + ;; before starting be sure the automaton has room to grow + (life-expand-plane-if-needed) + ;; compute initial neighbor deltas + (life-compute-neighbor-deltas))) + +(defun life-compute-neighbor-deltas () + (setq life-neighbor-deltas + (list -1 (- fill-column) + (- (1+ fill-column)) (- (+ 2 fill-column)) + 1 fill-column (1+ fill-column) + (+ 2 fill-column)))) + +(defun life-insert-random-pattern () + (insert-rectangle + (elt life-patterns (% (abs (random)) (length life-patterns)))) + (insert ?\n)) + +(defun life-increment-generation () + (increment life-current-generation) + (setq life-generation-string (int-to-string life-current-generation))) + +(defun life-grim-reaper () + ;; Clear the match information. Later we check to see if it + ;; is still clear, if so then all the cells have died. + (store-match-data nil) + (goto-beginning-of-buffer) + ;; For speed declare all local variable outside the loop. + (let (point char pivot living-neighbors list) + (while (search-forward (life-life-string) nil t) + (setq list life-neighbor-deltas + living-neighbors 0 + pivot (1- (point))) + (while list + (setq point (+ pivot (car list)) + char (char-after point)) + (cond ((eq char (life-void-char)) + (subst-char-in-region point (1+ point) + (life-void-char) 1 t)) + ((< char 3) + (subst-char-in-region point (1+ point) char (1+ char) t)) + ((< char 9) + (subst-char-in-region point (1+ point) char 9 t)) + ((>= char (life-life-char)) + (increment living-neighbors))) + (setq list (cdr list))) + (if (memq living-neighbors '(2 3)) + () + (subst-char-in-region pivot (1+ pivot) + (life-life-char) (life-death-char) t)))) + (if (null (match-beginning 0)) + (life-extinct-quit)) + (subst-char-in-region 1 (point-max) 9 (life-void-char) t) + (subst-char-in-region 1 (point-max) 1 (life-void-char) t) + (subst-char-in-region 1 (point-max) 2 (life-void-char) t) + (subst-char-in-region 1 (point-max) (life-birth-char) (life-life-char) t) + (subst-char-in-region 1 (point-max) (life-death-char) (life-void-char) t)) + +(defun life-expand-plane-if-needed () + (catch 'done + (goto-beginning-of-buffer) + (while (not (eobp)) + ;; check for life at beginning or end of line. If found at + ;; either end, expand at both ends, + (cond ((or (eq (following-char) (life-life-char)) + (eq (progn (end-of-line) (preceding-char)) (life-life-char))) + (goto-beginning-of-buffer) + (while (not (eobp)) + (insert (life-void-char)) + (end-of-line) + (insert (life-void-char)) + (forward-char)) + (setq fill-column (+ 2 fill-column)) + (scroll-left 1) + (life-compute-neighbor-deltas) + (throw 'done t))) + (forward-line))) + (goto-beginning-of-buffer) + ;; check for life within the first two lines of the buffer. + ;; If present insert two lifeless lines at the beginning.. + (cond ((search-forward (life-life-string) + (+ (point) fill-column fill-column 2) t) + (goto-beginning-of-buffer) + (insert-char (life-void-char) fill-column) + (insert ?\n) + (insert-char (life-void-char) fill-column) + (insert ?\n) + (setq life-window-start (+ life-window-start fill-column 1)))) + (goto-end-of-buffer) + ;; check for life within the last two lines of the buffer. + ;; If present insert two lifeless lines at the end. + (cond ((search-backward (life-life-string) + (- (point) fill-column fill-column 2) t) + (goto-end-of-buffer) + (insert-char (life-void-char) fill-column) + (insert ?\n) + (insert-char (life-void-char) fill-column) + (insert ?\n) + (setq life-window-start (+ life-window-start fill-column 1))))) + +(defun life-display-generation (sleeptime) + (goto-char life-window-start) + (recenter 0) + (sit-for sleeptime)) + +(defun life-extinct-quit () + (life-display-generation 0) + (signal 'life-extinct nil)) + +(put 'life-extinct 'error-conditions '(life-extinct quit)) +(put 'life-extinct 'error-message "All life has perished") + + |