# Conway's Game of Life implemented in Emacs org-mode tables

Evaluate the code in the first source block (`C-c C-c`

), then keep
evaluating the second block for each iteration of the rules.

#+BEGIN_SRC emacs-lisp :results silent (require 'cl) ; for loop (defvar *empty* "") (defvar *live* "o") (defun make-empty-board (nrow ncol) (loop for r from 0 below nrow collect (loop for c from 0 below ncol collect *empty*))) (defun get-cell (r c nrow ncol board) (cond ((and (< -1 r nrow) (< -1 c ncol)) (elt (elt board r) c)) (:else *empty*))) (defun set-cell (r c val board) (setf (elt (elt board r) c) val)) (defun count-neighbors (r c nrow ncol board) (loop for x from (1- r) to (1+ r) sum (loop for y from (1- c) to (1+ c) sum (cond ((and (= x r) (= y c)) 0) ((equal *live* (get-cell x y nrow ncol board)) 1) (:else 0))))) (defun cell-at-next-gen (current neighbors) (cond ((= 3 neighbors) *live*) ((and (= 2 neighbors) (equal *live* current)) *live*) (:else *empty*))) (defun iter-life (board) (let* ((nrow (length board)) (ncol (length (car board))) (next-board (make-empty-board nrow ncol))) (loop for r from 0 below nrow do (loop for c from 0 below ncol do (set-cell r c (cell-at-next-gen (get-cell r c nrow ncol board) (count-neighbors r c nrow ncol board)) next-board))) next-board)) #+END_SRC #+BEGIN_SRC emacs-lisp :var board=board :results table (iter-life board) #+END_SRC #+NAME:board #+RESULTS: | | o | | | | | | | | | | o | | | | | | | o | o | o | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |