Insetion sort in clojure

insort.clj

(def v (shuffle (range 10)))

(defn swap-down [v i]
  (loop [j i w v]
     (if (> j 0) 
        (let [a (nth w (dec j)) b (nth w j)]
           (if (> a b)
              (recur (dec j) (assoc w (dec j) b j a))
              w))
         w)))
				    
(defn insertion-sort [v]
  (let [n (count v)]
    (loop [i 1 w v]
      (if (< i n)
        (recur (inc i) (swap-down w i))
        w))))
		
(defn swap-down! [w i]
  (loop [j i]
    (if (> j 0) 
      (let [a (nth w (dec j)) b (nth w j)]
        (if (> a b)
          (do
             (assoc! w (dec j) b j a)
             (recur (dec j))))))))
				    
				    
(defn insertion-sort! [v]
  (let [n (count v) w (transient v)]
    (loop [i 1] 
      (if (< i n)
        (do
          (swap-down! w i) 
          (recur (inc i)))
        (persistent! w)))))