So what does (inout int = 0) do?

[QAston via Digitalmars-d]

On Friday, 15 April 2016 at 03:10:12 UTC, Andrei Alexandrescu 
wrote:
> Consider:
>
> https://github.com/D-Programming-Language/phobos/blob/master/std/range/primitives.d#L152
>
> There is no explanation to it in the source code, and the line 
> blames to 
> https://github.com/D-Programming-Language/phobos/pull/2661 
> (irrelevant).
>

I've been wondering what that is myself, so I've just 
cargo-cult-copied it into my code. Thanks for the post.