-- tail recursion
module test009;

import Stdlib.Prelude open;

sum' (acc : Nat) : Nat → Nat
  | zero := acc
  | (suc x) := sum' (suc x + acc) x;

sum : Nat → Nat := sum' 0;

fact' (acc : Nat) : Nat → Nat
  | zero := acc
  | (suc x) := fact' (acc * suc x) x;

fact : Nat → Nat := fact' 1;

main : Nat := sum 10000 + fact 5 + fact 10 + fact 12;