map-all.clj

(defn map-all
  "Like map but if given multiple collections will call the function f
   with as many arguments as there are elements still left."
  ([f] (map f))
  ([f coll] (map f coll))
  ([f c1 & colls]
   (let [step (fn step [cs]
                (lazy-seq
                  (let [ss (keep seq cs)]
                    (when (seq ss)
                      (cons (map first ss)
                            (step (map rest ss)))))))]
     (map #(apply f %) (step (conj colls c1))))))