Clojure merge sort

merges.clj

(ns misc.merges
  (:require [joy.qs :refer [rand-ints]]))

(defn merge-sort [xs]
  (if (<= (count xs) 1)
    xs
    (let [[left right] (split-at (/ (count xs) 2) xs)]
      (mrge (merge-sort left) (merge-sort right)))))

(defn mrge [xs ys]
  (loop [xs xs, ys ys, acc []]
    (if (or (empty? xs) (empty? ys))
      (concat acc xs ys)
      (let [x (first xs)
            y (first ys)]
        (if (< x y)
          (recur (next xs) ys (vec (conj acc x)))
          (recur xs (next ys) (vec (conj acc y))))))))