wrapping.clj

;; 'wrap' any function to print the arguments
;; with the intention of visualizing what happens
;; when you pass a function to reduce

;; first version
(defn wrap [f & args]
  (println args)
  (apply f args))

(wrap + 4 5)

(reduce (fn [a b] (wrap + a b)) numbers)

;; how to rewrite so i can call like this?
(reduce (wrap +) numbers)

;; hmm...
(defn wrap [f]
  (fn [& args]
    (println args)
    (apply f args)))

;;accept arbitrary wrapper fn?
(defn wrap [f w]
  (fn [& args]
    (apply w args)
    (apply f args)))

;; accept collection of wrappers using comp
(defn wrap [f w]
  (fn [& args]
    ((apply comp w) args)
    (apply f args)))