passing one or both of the optional key args results in the error: No value supplied for key

gistfile1.clj

passing one or both of the optional key args results in the error: No value supplied for key, if I don't pass the optional map-destructured args all works swell. :)

(defmacro def-rest-resource
  "takes an unamed route and params as expected by defpage and a single body form,
optionally a map of the form {:nil-handler nil-handler-fn, :exception-handler exception-handler-fn}
where nil-handler-fn takes no arguments and exception-handler-fn takes an Exception as an argument"
  [route params body & {:keys [nil-handler exception-handler]
                        :or {nil-handler #(response/status 404 {:error "no results"})
                             exception-handler #(response/status 500 {:error (format "An error has occurred: %s" (.getMessage %))})}}]
  `(let [response-format-fn# response/json] ; make this dependent on request accept-type in the future, json for now
     (defpage ~route ~params
       (try
         (let [result# ~body]
           (response-format-fn# (if (nil? result#)
                                  (~nil-handler)
                                  result#)))
         (catch Exception exception#
           ((~exception-handler exception#)))))))