drop-between.clj

(defn drop-between [start? pred? stop?]
  (fn [rf]
    (let [drop? (volatile! false)]
      (fn
        ([] (rf))
        ([result] (rf result))
        ([result input]
         (when (stop? input)
           (vreset! drop? false))
         (when (start? input)
           (vreset! drop? true))
         (if (and @drop? (pred? input))
           result
           (rf result input)))))))