Pig-Latin in Clojure

pig-latin.clj

(defn pig-latin [word]
  (let [first-letter (first word) remaining (apply str (rest word)) vowel? (set "aeiou")]
    (if (vowel? (first remaining))
      (str remaining first-letter "ay")
      (recur (str remaining first-letter)))))

was right the first time. using the set function converts the string to chars. using the literal requires using the char syntax: #{\a \e \i \o \u}