Kata from http://programmingpraxis.com/2010/10/12/rotate-an-array/

onlisp.clj

;idea from the book onlisp, pag 30
(defn rev [nums]
  (let [f (fn [coll res]
	    (if (empty? coll)
	      res
	      (recur (drop-last coll) (conj res (last coll)))))]
    
    (f nums [])))

rotation.clj

(defn rotate [arr op]
  (loop [elem arr
  	 left (mod op (count arr))]
    
    (if (> left 0)
      (recur
	(conj (drop-last elem) (last elem)) 
        (dec left))

      elem)))

rotation2.clj

;different approach, cycling sequence 
(defn rotate [arr times]
  (let [size (count arr)
        op (mod times size)]
    
    (take 
      size 
      (drop op 
        (cycle arr)))))

DONE: find a better way to append an element to a collection. The place where conj will add the element is implementation dependent.
(elements are added at the beginning, so function starts from last element)