gistfile1.clj

(defn xform [body [ns v]]
  (postwalk (fn [f]
              (if (= f ~(symbol v))
                `(var ~f)
                f)
              ) body))

(defmacro defparser [name & body]
  (try
    (eval `(def ~name ~@body))
    (catch clojure.lang.Compiler$CompilerException e
      (when-let [ec (.getCause e)]
        (when-let [parse #(next (re-matches #"Var (\S+)/(\S+) is unbound." %))]
          (if-let [ec (.getCause e)]
            (eval `(def ~name ~@(xform body (parse (.getMessage ec)))))
            (throw)))))))