Fixed main.clj

; Also need to add (java.io StringReader) to :import at the top of the file

(defn- eval-opt
  "Evals expressions in str, prints each non-nil result using prn"
  [str]
  (let [eof (Object.) 
        reader (LineNumberingPushbackReader. (StringReader. str))]
      (loop [input (read reader false eof)]
        (when-not (= input eof)
          (let [value (eval input)]
            (when-not (nil? value)
              (prn value))
            (recur (read reader false eof)))))))