rpn.clj

(defn process [socket]
  (let [ in (java.io.PushbackReader. (make-reader (. socket getInputStream)))
         out (java.io.PrintWriter. (make-writer (. socket getOutputStream)))]
    (loop [stack ()]
      (let [form (read in)]
        (println "STACK:\t" stack)
        (println "READ:\t" form)
        (cond
          (number? form) (recur (conj stack form))
          (= 'quit form) (do
            (. out println "Connection closed by client, closing socket")
            (. out flush)
            (. socket close))
          :else (do
            (. out println "Syntax error: unrecognized form" form)
            (. out flush)
            (. socket close)))))))