I made a module that looped for a while in compile time (since you can't sleep during compile time), to see if I could pre-compile the module, and thus save time compiling the main application. It didn't work at first, because any file that depended on the module would import it, and importing it would execute the compile time code again, thus taking a long time to compile... twice.

But then I remembered about the rarely used -H option for dmd. -H outputs a stripped down version of the source file being compiled, with all the function definitions replaced with declarations. So if your expensive to compile code is encapsulated within a function... it doesn't appear in the -H output.

So uh... git://critter.cloudns.org/test-dlang-encapsulation I guess. It might be a neat trick to speed up compilation, if you have a lot of complicated code that can be hidden behind a simple interface.

On 28/08/2016 6:34 AM, cy wrote:
> I made a module that looped for a while in compile time (since you can't
> sleep during compile time), to see if I could pre-compile the module,
> and thus save time compiling the main application. It didn't work at
> first, because any file that depended on the module would import it, and
> importing it would execute the compile time code again, thus taking a
> long time to compile... twice.
>
> But then I remembered about the rarely used -H option for dmd. -H
> outputs a stripped down version of the source file being compiled, with
> all the function definitions replaced with declarations. So if your
> expensive to compile code is encapsulated within a function... it
> doesn't appear in the -H output.
>
> So uh... git://critter.cloudns.org/test-dlang-encapsulation I guess. It
> might be a neat trick to speed up compilation, if you have a lot of
> complicated code that can be hidden behind a simple interface.

Sounds like a use case for creating a source file in a pregeneration step.