2022-04-07 18:43:21 +02:00

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;; In Emacs, open this file in -*- Scheme -*- mode.
;; Conway's game of life
;; (https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life)
;; Notice that this program uses:
;; - ANSI escape sequences, and so require a compatible terminal,
;; - Unicode Block Elements [1], and so require a font supporting them.
;;
;; [1] https://unicode-table.com/en/blocks/block-elements/
(def board-make@3
(fun (w h c)
(let ((b (@block-alloc-100 3)))
(@block-set! b 0 w)
(@block-set! b 1 h)
(@block-set! b 2 c)
b)))
(def board-make@2
(fun (w h)
(board-make w h (vector-make (* w h) #f))))
(def board-width
(fun (b) (@block-get b 0)))
(def board-height
(fun (b) (@block-get b 1)))
(def board-cells
(fun (b) (@block-get b 2)))
(def board-cell-index
(fun (b x y)
(let ((x1 (%f x (board-width b)))
(y1 (%f y (board-height b))))
(+ x1 (* y1 (board-width b))))))
(def board-get
(fun (b x y)
(vector-get (board-cells b) (board-cell-index b x y))))
(def board-get/int
(fun (b x y)
(if (board-get b x y) 1 0)))
(def board-set!
(fun (b x y v)
(vector-set! (board-cells b) (board-cell-index b x y) v)))
(def live-neighbors-count
(let ((offsets (list-make (pair-make -1 -1)
(pair-make -1 0)
(pair-make -1 1)
(pair-make 0 -1)
(pair-make 0 1)
(pair-make 1 -1)
(pair-make 1 0)
(pair-make 1 1))))
(fun (b x y)
(list-fold-left
(fun (c os)
(+ c
(board-get/int b (+ x (pair-fst os)) (+ y (pair-snd os)))))
0
offsets))))
(def evolve-board
(fun (b)
(let ((b1 (board-make (board-width b) (board-height b))))
(rec loop ((x (- (board-width b) 1))
(y (- (board-height b) 1)))
(let* ((n (live-neighbors-count b x y))
(s (or (= n 3) (and (= n 2) (board-get b x y)))))
(board-set! b1 x y s)
(cond ((> y 0) (loop x (- y 1)))
((> x 0) (loop (- x 1) (- (board-height b) 1)))
(#t b1)))))))
(def draw-board
(let ((code " ▗▖▄▝▐▞▟▘▚▌▙▀▜▛█"))
(fun (b)
(rec loop ((y 0) (x 0))
(let* ((b0 (board-get/int b (+ x 1) (+ y 1)))
(b1 (board-get/int b x (+ y 1)))
(b2 (board-get/int b (+ x 1) y))
(b3 (board-get/int b x y))
(i (int-bitwise-or
(int-shift-left b3 3)
(int-shift-left b2 2)
(int-shift-left b1 1)
(int-shift-left b0 0))))
(char-print (string-get code i))
(cond ((< x (- (board-width b) 1))
(loop y (+ x 2)))
((< y (- (board-height b) 1))
(newline-print)
(loop (+ y 2) 0))
(#t
(newline-print))))))))
(defrec animate-life
(fun (b n)
(string-print "") ;clear screen
(string-print "") ;set black background, white foreground
(string-print "[?25l") ;hide cursor
(rec loop ((b b) (n n))
(string-print "") ;move to top-left
(draw-board b)
(if (> n 0)
(loop (evolve-board b) (- n 1))))))
(def b (board-make 158 68))
(def glider-ul
(fun (b x y)
(board-set! b (+ x 1) (+ y 2) #t)
(board-set! b (+ x 2) (+ y 1) #t)
(board-set! b (+ x 0) (+ y 0) #t)
(board-set! b (+ x 1) (+ y 0) #t)
(board-set! b (+ x 2) (+ y 0) #t)))
(def glider-dr
(fun (b x y)
(board-set! b (+ x 1) (+ y 0) #t)
(board-set! b (+ x 2) (+ y 1) #t)
(board-set! b (+ x 0) (+ y 2) #t)
(board-set! b (+ x 1) (+ y 2) #t)
(board-set! b (+ x 2) (+ y 2) #t)))
(glider-dr b 4 4)
(glider-dr b 10 5)
(glider-ul b 13 15)
(glider-ul b 5 20)
(glider-ul b 17 22)
(glider-ul b 23 5)
(glider-ul b 2 7)
(glider-ul b 19 33)
(animate-life b 5000)