count.clj

;; Clojure vs Erlang on counter recursion

;; Clojure version
(ns count)

(defn down
  [x]
  (if (zero? x) (prn "blastoff!")
      (do
        (prn x)
        (recur (dec x)))))

(defn up
  [x]
  (loop [c 1 x x]
    (if (> c x) (prn "Finished!")
        (do
          (prn c)
          (recur (inc c) x)))))

------------------------------------------------------------

;; Erlang version
-module(count).
-export([countdown/1, countup/1]).

countdown(From) when From > 0 ->
  io:format("~w!~n", [From]),
  countdown(From-1);

countdown(From) ->
  io:format("blastoff!~n").

countup(Limit) ->
  countup(1, Limit).

countup(Count,Limit) when Count =< Limit ->
  io:format("~w!~n", [Count]),
  countup(Count+1, Limit);

countup(Count, Limit) ->
  io:format("Finally!~n").