Import files contains implementation

[simendsjo]

On 12.08.2011 10:11, Jonathan M Davis wrote:
> On Friday, August 12, 2011 09:59:05 simendsjo wrote:
>> Why does the di files contain implementation?
>> Is it to allow CTFE from calling modules?
>>
>> l.d
>> ===
>> module l;
>> int f() { return 1; }
>>
>> l.di
>> ====
>> // D import file generated from 'l.d'
>> module l;
>> int f()
>> {
>> return 1;
>> }
>>
>> The documentation for this says "They can be used to hide the source
>> code", but this is a bit misleading.
>> http://www.d-programming-language.org/dmd-windows.html#interface_files
>
> In order for CTFE to work, you have to have the source of the function. Also,
> if you want inlining to work, you need the source of the function. You also
> have to have the source if it's a template.
>
> In this case, my guess is that the compiler automatically puts the source in
> the .di file if its small enough that it expects to inline it, but I don't
> know.
>
> Regardless, the web page isn't really misleading. You're free to get rid of
> the source if you want to. So, you can use it to hide the source code as much
> as you want (except for templates, which _have_ to have their source in the
> ..di file). It's just that apparently the compiler doesn't automatically hide
> all of the source that it could. You can edit them by hand if you want to hide
> more. But if it hid everything that it could by default, that would negatively
> impart performance.
>
> It's essentially the same situation as C++ header files. You _can_ hide
> function bodies in the cpp file if you want to (except for templates), but then
> you don't get inlining. So, you choose what you do and don't put in the header
> file. It's just that in the case of .di files, there's a tool to automatically
> generate them instead of forcing you to write the whole thing by hand.
>
> - Jonathan M Davis

Thanks.