Reify a protocol by giving a generic implementation function that will be called for all protocol methods. Like a proxy.

reify_generic.clj

(ns reify-generic
  "reify a protocol such that every method is delegated to a specified method")

(defmacro reify-generic
  "Reify the given protocols. Every method of any protocol is implemented such
   that f is called as (apply f protocol-method args)

   Example:

  (defprotocol Calculator
    (add [this x y])
    (sub [this x y])
    (mul [this x y])
    (div [this x y]))

  (defn test-run []
    (let [printer (reify-generic (fn [method this & args] (apply println method args)) Calculator)]
      (add printer 1 2)
      (sub printer 1 3)))
  "
  [f & protocols]
  `(reify
    ~@(apply seq (map (fn [proto]
			(apply concat [proto]
			       (map (fn [{name :name arglists :arglists}]
				      (map (fn [arglist] `(~name ~arglist (~f ~(keyword name) ~@arglist)))
					   arglists))
				    (-> proto resolve deref :sigs vals))))
		      protocols))))