foo.hy

(import [collections [OrderedDict]])

(defn lru-cache [&optional [limit 100]]
  (defn inner [func]
    (setv cache (OrderedDict))
    (defn cached-fn [&rest args]
      (let [[result nil]]
        (try
         (setv result (.pop cache args))
         (catch [e KeyError]
           (setv result (apply func args))
           (if (> (len cache) limit)
             (.popitem cache 0))))
        (print "cache len" (len cache))
        (setv (get cache args) result)
        result))
    cached-fn)
  inner)

(with-decorator (lru-cache 100)
  (defn foo [&rest args]
    (print "in foo, " args)))

(foo 1 2)
(foo 1 2)
(foo 2 3)