Macro to create a callable record with any arity

gistfile1.clj

(defmacro definvokerecord [invoke_fn & body]
  `(defrecord
     ~@body
     clojure.lang.IFn
     ~@(map (fn [n]
              (let [args (for [i (range n)] (symbol (str "arg" i)))]
                (if (empty? args)
                  `(~'invoke [this#]
                           (~invoke_fn this#))
                  `(~'invoke [this# ~@args]
                           (~invoke_fn this# ~@args))))) (range 21))
     (~'applyTo [this# args#]
                (apply ~invoke_fn this# args#))))

Good suggestion, I changed it.