gistfile1.clj

(defn until
  [p]
  (fn [rf]
    (let [p? (volatile! false)]
      (fn
        ([x] (rf x))
        ([x y]
         (if @p?
           x
           (do
             (when (p y)
               (vreset! p? true))
             (rf x y))))))))

(into []
      (until #(re-find #"\." %))
      ["ciao" "mi" "piace" "clojure." "Ed" "altro"])

(sequence (until #(re-find #"\." %))
          ["ciao" "mi" "piace" "clojure." "Ed" "altro"])

(transduce (until #(re-find #"\." %))
           conj
           ["ciao" "mi" "piace" "clojure." "Ed" "altro"])