(ns devon.demo)

(defprotocol Show
  (show [this]))

(extend-protocol Show
   java.lang.String
     (show [this] (println this))
   some-ns.Person
     (show [this] (println this.toString)))

(show "Hello") ;console: "Hello", return-val: nil
(show (Person. "Name")) ; console: "Name", return-val: nil