comp

comp.clj

;; The clojure comp cre function

;; Recursive
(defn my-comp
  ([] my-comp)
  ([f] f)
  ([f & fs]
   (fn [& args]
     (f (apply (apply my-comp fs) args)))))

;; Tail-recursive-esque, using loop and recur
(defn better-comp
  ([] identity)
  ([& fns]
   (fn [& args]
     (let [sorted-fns (reverse fns)
           first-f (apply (first sorted-fns) args)]
       (loop [initial-fn first-f
              remaining-fns (rest sorted-fns)]
         (if (empty? remaining-fns)
           initial-fn
           (let [future-fn (first remaining-fns)
                 remaining-fns (rest remaining-fns)]
             (recur (future-fn initial-fn) remaining-fns))))))))