[Cs254f11] Help me fix this loop

[Maxwell William Fair Levit]

Hey all, I'm writing code that takes turns placing black and white (1 and 2)
pieces on a Go board. I'm running into trouble with the loop that is supposed
to actually place a bunch of pieces.

(def board
  (atom
    (zipmap
      (reduce concat
              (for [y (range 19)]
                (map vector (repeat 19 y )
                     (for [x (range 19)] x))))
      (vec (repeat 361 0)))))

;; defines a 19x19 board with all 361 entires set to 0.


(defn place-peice
  [x y z]
  (swap! board update-in [[x y]] (fn [j] z) ))

;;Sets the value of the space with coordinates [x y] to z.

(loop [c 1 x (rand-int 19) y (rand-int 19)]
  (if (and (< c 3) (zero? (get @board x y)))
    (do (place-peice x y (if (even? x) 1 2))
        (recur (inc c) (rand-int 19) (rand-int 19)))
    (recur c (rand-int 19) (rand-int 19))))

This just crashes clooj, presumably because its going infinitely, since I set
the number of iterations low enough that it shouldn't just be an efficiency
issue.

The other setup I had which gave me a "Must recur from tail position" error. was
this.



(loop [c 1 x (rand-int 19) y (rand-int 19)]
  (if (and (< c 3) (zero? (get @board x y)))
    (place-peice x y (if (even? x) 1 2))
    (recur c (rand-int 19) (rand-int 19)))
  (recur (inc c) (rand-int 19) (rand-int 19)))

Can someone tell me why these don't work and/or how to fix them?


Thanks,

-Max