partition-with.clj

(defn partition-with
  "Applies f to each value in coll, splitting it each time f returns true.
  Returns a lazy seq of partitions."
  [f coll]
  (lazy-seq
   (when-let [s (seq coll)]
     (let [[head tail] (split-with (complement f) (rest coll))]
       (cons (cons (first coll) head)
             (partition-with f tail))))))