inner functions calling each other - how to do this with inner struct?

[Ivan Kazmenko via Digitalmars-d-learn]

On Wednesday, 3 February 2016 at 15:09:35 UTC, Adam D. Ruppe 
wrote:
> Read my post here:
>
> http://stackoverflow.com/questions/34398408/struct-declaration-order/34398642#34398642
>
> then see if you can use the same reasoning on your problem.

This indeed works without any other tricks such as compile-time 
parameters:

-----
import std.stdio;

void outerFun () {
     struct Holder {
         static struct S {
             void fun2 (int x) {
                 writeln (x);
                 if (x > 0) fun1 (x - 1);
             }
         }

         static S s;

         static void fun1 (int y) {
             writeln (y);
             if (y > 1) s.fun2 (y - 2);
         }
     }

     Holder.fun1 (10);
}

void main () {outerFun ();}
-----

Thank you!

Ivan Kazmenko.