Clojure multimethods

(defmulti fill
          (fn [node value] (:tag node)))                    ; this is the dispatch function
(defmethod fill :div
  [node value]
  (assoc node :content [(str value)]))
(defmethod fill :input
  [node value]
  (assoc-in node [:attrs :value]
            (str value)))
;; tests
(fill {:tag :div} "hello")
(fill {:tag :input} "what")