Ibid.cljs

(def in ["a" "ibid" "ibid" "b"])

(defn ibid 
  ([in]
   (ibid (vec (first in)) (rest in))
  ([left right]
   (println left right)
   (if (empty? right)
     ; done
     left
     ; else recurse
     (if (= "ibid" (first right))
       ; repeat last left
       (ibid (conj left (last left))
             (rest right)
       (ibid (conj left (first right))
             (rest right))))
             

(defn fib
  [n]
  (if (= 1 n)
    1
  	(+ n (fib (dec n))))