Data commit

Task/Church-numerals/Clojure/church-numerals.clj

@@ -0,0 +1,18 @@
+(defn zero [f] identity)
+(defn succ  [n]   (fn [f] (fn [x] (f ((n f) x)))))
+(defn add   [n,m] (fn [f] (fn [x] ((m f)((n f) x)))))
+(defn mult  [n,m] (fn [f] (fn [x] ((m (n f)) x))))
+(defn power [b,e] (e b))
+
+(defn to-int [c] ((c inc) 0))
+
+(defn from-int [n]
+  (letfn [(countdown [i] (if (zero? i) zero (succ (countdown (- i 1)))))]
+  (countdown n)))
+
+(def three (succ (succ (succ zero))))
+(def four (from-int 4))
+
+(doseq [n [(add three four)   (mult three four)
+           (power three four) (power four three)]]
+    (println (to-int n)))