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Task/Langtons-ant/EchoLisp/langtons-ant.echolisp

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+(lib 'plot)
+(lib 'types)
+
+(define (move iter x dir constant: plane turns cmax  width  xmax (cidx 0))
+	(while (> iter 0)
+	;; get color index of current square
+	(set! cidx (vector-ref plane x))
+
+	;; turn	
+	(if (vector-ref turns cidx)
+		(set! dir (if (= dir 3) 0 (1+ dir))) ;; right is #t
+		(set! dir (if (= dir 0) 3 (1- dir))))
+
+	;; rotate colors
+	(set! cidx (if (= cidx cmax) 0 (1+ cidx)))
+	(vector-set! plane x cidx)
+
+	;; move
+	;; x = v + h*width for a pixel at (h,v)
+	(set! x
+		(cond
+			((= dir 0) (1+ x))
+			((= dir 1) (+ x width))
+			((= dir 2) (1- x))
+			((= dir 3) (- x width))))
+		
+	(when (or (< x 0) (>= x xmax)) (set! iter -666)) ;; out of bounds
+	(set! iter (1- iter)))
+	iter)
+	
+;; a color table of 16 colors
+(define colors
+   (list 0 (rgb 1 1 1) (rgb 1 0 0) (rgb 0 1 0) (rgb 0 0 1) (rgb 1 1 0) (rgb 1 0 1) (rgb 0 1 1)))
+(define colors (list->vector (append colors colors)))
+
+;; transform color index into rgb color, using colors table.
+(define (colorize plane xmax)
+	(for ((x xmax))
+		(vector-set! plane x (vector-ref colors (vector-ref plane x))))
+	(vector->pixels plane)
+	xmax )
+	
+;; ant's patterns
+(define turns #(#t #t #f #f #f #t #f #f #f #t #t #t))   ;; RRLLLRLLLRRR
+;;(define turns #(#t #t #f #f #f #t #t #f)) ; RRLLLRRL
+;;(define turns #(#t #f)) ; RL : basic ant
+
+(define  (ant (iter 100000))
+	(plot-clear)
+	(define width (first (pixels-dim))) ;; plane dimensions
+	(define height (rest (pixels-dim)))
+	(define plane (pixels->uint32-vector))
+	(define x (+ (quotient width 2) (* width (quotient height 2)))) ;; middle of plane
+	(define xmax (* width height))
+	
+	(move iter  x 0 plane turns (1- (vector-length turns)) width xmax)
+	(colorize plane xmax))
+
+(ant) ;; run