memoization with invalidation in clojure

gistfile1.clj

(defn memoize*
	"Like clojure.core/memoize, but the returned function's metadata contains an :invalidate function which completely resets the memory in the 0-ary form, or accepts the argument sequence for which to invalidate as its only argument."
	[f]
	(let [memo (atom {})]
		(with-meta
			(fn memoized [& args]
				(if-let [e (find @memo args)]
					(val e)
					(let [ret (apply f args)]
						(swap! memo assoc args ret)
						ret)))
			{:invalidate
				(fn memo-invalidate
					; invalidate all
					([]
						(reset! memo {}))
					([args]
						(swap! memo dissoc (seq args))))})))