gameoflife.scm

(define @matrix-w)
(define @matrix-h)
(define *matrix-neighbors)
(define *matrix-life)



; retrieve location on matrix by x/y
(define (matrix-pos M x y)
  (if (or (< x 0)
          (< y 0)
          (>= x @matrix-w)
          (>= y @matrix-h))
      0
      (list-ref (list-ref M y) x)))

; iterate row
(define (matrix-map~r R x y A f)
  (if (null? R)
      (reverse A)
      (matrix-map~r (cdr R)
                    (+ x 1)
                    y
                    (cons (f (car R) x y)
                          A)
                    f)))
; iterate matrix
(define (matrix-map~ M y A f)
  (if (null? M)
      (reverse A)
      (matrix-map~ (cdr M)
                   (+ y 1)
                   (cons (matrix-map~r (car M) 0 y '() f)
                         A)
                   f)))
; like map function but with matrix
(define (matrix-map f M)
  (matrix-map~ M 0 '() f))

; tile display
(define (matrix-tile q)
  (if (= q 1)
      "()"
      ". "))

; display matrix
(define (matrix-display M)
  (for-each (lambda (row)
                      (do (display (apply string-append
                                          (map matrix-tile row)))
                          (newline)))
            M))


; retrieve number of alive neighbor cells
(define (neighbors M x y)
  (+ (matrix-pos M (- x 1) y)
     (matrix-pos M (- x 1) (- y 1))
     (matrix-pos M (- x 1) (+ y 1))
     (matrix-pos M (+ x 1) y)
     (matrix-pos M (+ x 1) (- y 1))
     (matrix-pos M (+ x 1) (+ y 1))
     (matrix-pos M x (+ y 1))
     (matrix-pos M x (- y 1))))

; populate *matrix-neighbors list with data
(define (populate-neighbors)
  (define *matrix-neighbors
          (matrix-map (lambda (t x y)
                        (neighbors *matrix-life x y))
                      *matrix-life)))
                      
; update cells based on neighbor data
(define (update-life)
  (define *matrix-life
          (matrix-map (lambda (t x y)
                        (cond ((or (< t 2)
                                   (> t 3))
                               0)
                              ((= t 3)
                               1)
                              (else (matrix-pos *matrix-life x y))))
                      *matrix-neighbors)))
                      
; display life
(define (display-life)
  (do (matrix-display *matrix-life)
      (newline)))
      
; do it all
(define (life)
  (do (display-life)
      (populate-neighbors)
      (update-life)))

; repeat utility
(define (repeat f times)
  (if (<= times 0)
      #!void
      (do (f)
          (repeat f (- times 1)))))


; example
(define *matrix-life '((0 1 0 0 0 0 0 0 0 0 0)
                       (0 0 1 0 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 1 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 0 0 0 0 0 0)
                       (0 0 0 0 0 0 0 0 0 0 0)))

; get size for later use
(define @matrix-w (length (car *matrix-life)))
(define @matrix-h (length *matrix-life))


; go!
(define (life-loop)
  (do (life)
      (if (eq? (read) "q")
          #!void
          (life-loop))))
(life-loop)