;; Chain of responsibility folds into a sequence of handlers walked by some:
;; the chain stops at the first one that answers, with no next pointers

;; Handlers — each knows its code and what to do
(def rescuers
  [{:code 1 :to-help #(println "call firefighters")}
   {:code 2 :to-help #(println "call the police")}
   {:code 3 :to-help #(println "call an ambulance")}])

;; HandleRequest()
(defn help [code]
  (or (some (fn [r]
              (when (= code (:code r))
                ((:to-help r))
                true))
            rescuers)
      (println "nobody handles code" code)))

(help 1)  ; call firefighters
(help 3)  ; call an ambulance
(help 9)  ; nobody handles code 9 — the chain ran out