gcc/testsuite/algol68/execute/manorboy.a68

begin proc a = (int in_k, proc int x1, x2, x3, x4, x5) int:
         (int k := in_k;
          proc b = int: a (k -:= 1, b, x1, x2, x3, x4);
          (k <= 0 | x4 + x5 | b));

      assert (a (10, int:1, int:-1, int:-1, int:1, int:0) = -67)
end