core.clj

(defn recursive-take
  "Recursively take from a list based on the operation list
  For example [:h :l :l :h] will take using the following operations
  until the list is exhausted: first last last first."
  [col operations]
  (loop [c col ops (cycle operations) acc []]
    (if (empty? c)
      acc
      (let [op (first ops)
            [head-fn tail-fn] (if (= op :h)
                                [first rest]
                                [last drop-last])]
        (recur (tail-fn c) (rest ops) (concat [(head-fn c)] acc))))))