-- local functions with free variables
module test015;

import Stdlib.Prelude open;

terminating
f : Nat → Nat → Nat
  | x :=
    let
      g (y : Nat) : Nat := x + y;
    in if
      (x == 0)
      (f 10)
      (if (x < 10) λ {y := g (f (sub x 1) y)} g);

g (x : Nat) (h : Nat → Nat) : Nat := x + h x;

terminating
h : Nat → Nat
  | zero := 0
  | (suc x) := g x h;

main : Nat :=
  f 100 500
    + -- 600
      f
      5
      0
    + -- 25
      f
      5
      5
    + -- 30
      h
      10
    + -- 45
      g
      10
      h
    + -- 55
      g
      3
      (f 10);