an example of Clojure 1.4 reader literals

gistfile1.clj

(defn defn-reader [body]
  (let [name (symbol (name (first (keys (dissoc (meta body) :tag)))))
        args (read-string (:tag (meta body)))]
    `(defn ~name ~args ~(seq body))))

(.bindRoot #'default-data-readers {'defn #'defn-reader})

#defn ^:fact ^"[x]"
[
  if (= x 0)
   1
   (* x (fact (dec x)))
]

(fact 10) ;=> 3628800