RPN i Clojure

rpn.clj

(defn rpn [expr]
  (let [head (first expr) 
	     tail (rest expr)]
	     (cond
	      (nil? head) (fn [n] n)
	      (number? head) ((rpn tail) head)
	      :else (let [restex (rpn tail)] 
					    (fn [n]
						(fn [m]
						    (restex ((resolve (symbol head)) m n))
						    )
						)
					    )
	      )
	     )
    )

(defn lex [input]
  (map (fn [t]
	   (cond
	    (re-matches #"\d+" t) (Integer/parseInt t)
	    :else (symbol t)
	    )
	   ) (re-seq #"\S+" input)
       )
  )

(while true (println (rpn (lex (read-line)))))