Using vectors, this one's (life) function is about ~240 chars
after compacting whitespace.
;;;;;;;;;;;;;;;;;; 8< ;;;;;;;;;;;;;;;;;; 8< ;;;;;;;;;;;;;;;;;;
#lang racket
(define glider
'#(#(0 0 0 0 0 0 0 0 0 0)
#(0 0 0 0 0 0 0 0 0 0)
#(0 0 0 0 1 0 0 0 0 0)
#(0 0 0 0 0 1 0 0 0 0)
#(0 0 0 1 1 1 0 0 0 0)
#(0 0 0 0 0 0 0 0 0 0)
#(0 0 0 0 0 0 0 0 0 0)
#(0 0 0 0 0 0 0 0 0 0)
#(0 0 0 0 0 0 0 0 0 0)
#(0 0 0 0 0 0 0 0 0 0)))
(define (life board s)
(for/vector ([r s] [R board])
(for/vector ([c s] [C R])
(let* ([s (λ(b x) (in-vector b (max 0 (- x 1))(min s (+ x 2))))]
[n (for*/sum ([R (s board r)] [C (s R c)]) C)])
(if (if (positive? C)
(<= 3 n 4)
(= 3 n))
1 0)))))
12 minutes ago, Michael W wrote:
> Hey there! Inspired by this article, I tried (quite
> unsuccessfully) to make a very short, very contrived Game of
> Life just for fun.
> http://news.ycombinator.com/item?id=357938
>
> How can we make this shorter?
>
> ;;;;;;;;; 8< ;;;;;;;;;;;;;; 8< ;;;;;;;;;;;;;;
> #lang racket
>
> (define glider
> '((0 0 0 0 0 0 0 0 0 0)
> (0 0 0 0 0 0 0 0 0 0)
> (0 0 0 0 1 0 0 0 0 0)
> (0 0 0 0 0 1 0 0 0 0)
> (0 0 0 1 1 1 0 0 0 0)
> (0 0 0 0 0 0 0 0 0 0)
> (0 0 0 0 0 0 0 0 0 0)
> (0 0 0 0 0 0 0 0 0 0)
> (0 0 0 0 0 0 0 0 0 0)
> (0 0 0 0 0 0 0 0 0 0)))
>
> (define (life board s)
> (for/list ([r s])
> (for/list ([c s])
> (let* ([v (λ(r c) (list-ref (list-ref board (modulo r s))
> (modulo c s)))]
> [n (count positive
> (map (λ(y x)(v (- r y) (- c x)))
> '(-1 -1 -1 0 0 1 1 1)
> '(-1 0 1 -1 1 -1 0 1)))])
> (if (or (and (positive (v r c))
> (= 2 n))
> (= 3 n))
> 1 0)))))
>
--
Yell at me if you see me somewhere,
_mike
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