Chain of handlers

gistfile1.clj

;; raek's idea

(defn cool? [w]
  true) ;; all words are cool

(def handlers
  [[#(and (:small-word %)
          (:first-word %)) #(.toUpperCase %)]
   ; you can even use functions as your predicate
   [cool? #(.toLowerCase %)]])

(defn chain [handlers [word tags]]
  (loop [h handlers]
    (if (empty? h)
      word
      (let [[pred? action] (first h)]
        (if (pred? tags)
          (action word)
          (recur (rest h)))))))

(chain handlers
       ["hello" {:small-word true
                 :first-word true}])
;; user=> "HELLO"

(map (partial chain handlers)
     [["hello" {:small-word true
                :first-word true}]
      ["wOrLd" {}]])
;; user=> ("HELLO" "world")