Auto ref function : How is this possible ?

[matovitch via Digitalmars-d-learn]

Hi,

I just learn about auto ref functions and tried this :

import std.stdio;

auto ref foo(int i, ref float f)
{
          if (i < f)
          {
              return i;
          }
          else
          {
              return f;
          }
}

void main()
{
          int i = 1;
          float f1 = 1.1;
          float f2 = 0.9;
          writeln(foo(i, f1));
          writeln(foo(i, f2));
}

Tricky questions : Does it compiles ? If yes what does it do ?
Then my question : How is this possible ?