(e! filter-fn screen-object & args)

Associates values to the entities in screen-object that match the supplied function. Returns the entities that were changed.

(e! :player? main-screen :health 10)
Source
(defn e!
  [filter-fn screen-object & args]
  (swap! (:entities screen-object)
         (fn [entities]
           (vec (for [e entities]
                  (if (filter-fn e)
                    (apply assoc e args)
                    e)))))
  (e filter-fn screen-object))