colored.clj

(ns colored-lti-clj.core)

(defalias List
  (TFn [a]
    '{:match (All [b] [(ListVisitor a b) :-> b])}))

(defalias ListVisitor
  (TFn [a b]
    '{:caseNil (All [:-> b])
      :caseCons (All [a (List a) :-> b])}))

(ann Nil (All [a] [:-> (List a)]))
(defn Nil []
  {:match (fn [v] ((:caseNil v)))})

(ann Cons (All [a] [a (List a) :-> (List a)]))
(defn Cons [x xs]
  {:match (fn [v] ((:caseCons v) x xs))})

(ann append (All [c] [(List c) (List c) :-> (List c)]))
(defn append [xs ys]
  ((:match xs)
   {:caseNil (fn [] ys)
    :caseCons (fn [x xs1]
                (Cons x (append xs1 ys)))}))