'partial' keyword in C# is very good for project , what's the same thing in D?

[deadalnix via Digitalmars-d]

On Wednesday, 29 October 2014 at 07:41:41 UTC, FrankLike wrote:
> Hello,everyone,
> I've written some projects  in  C#,find the 'partial' keyword 
> is very userful,which lets the auto codes in another single 
> file,my codes are very easy to update.
> But  what the same thing in D?
>
> Thank you,every one.

What does it do ?