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+;;  Copyright (c) Stephen C. Gilardi. All rights reserved.
+;;  The use and distribution terms for this software are covered by the
+;;  Common Public License 1.0 (http://opensource.org/licenses/cpl.php)
+;;  which can be found in the file CPL.TXT at the root of this distribution.
+;;  By using this software in any fashion, you are agreeing to be bound by
+;;  the terms of this license.
+;;  You must not remove this notice, or any other, from this software.
+;;
+;;  File: memoize.clj
+;;
+;;  scgilardi (gmail)
+;;  02 June 2008
+;;
+;;  Based on Common Lisp code from:
+;;  http://asymmetrical-view.com/talks/lisp-presentation/lisp-presentation.pdf
+
+(clojure/in-ns 'memoize)
+(clojure/refer 'clojure)
+
+(defn memoize
+  "Returns a memoized version of a referentially transparent function. The
+  memoized version of the function keeps a cache of the mapping from arguments
+  to results and, when calls with the same arguments are repeated often,  has
+  higher performance at the expense of higher memory use."
+  [function]
+  (let [cache (ref {})]
+    (fn [& args]
+      (if-let cached (@cache args)
+        cached
+        (let [result (apply function args)]
+          (dosync
+           (commute cache assoc args result))
+          result)))))