Using D without libphobos

[Radu]

On Thursday, 26 April 2018 at 03:04:55 UTC, A. Nicholi wrote:
> Hello,
>
> I am working on a large cross-platform project, which will be 
> written primarily in D, interfacing to C as necessary. To get 
> finer control over memory safety, binary size, and use of the 
> GC, we would like to disclude libphobos as a dependency in lieu 
> of our own code. The project is compiled using LDC.
>
> I am not sure if this is possible though, as it seems there are 
> certain things in libphobos that are tightly coupled into the D 
> runtime. There are several things in the core namespace that 
> would be helpful for us (SIMD, C bindings, etc), but I am not 
> sure if that is not also part of libphobos along with the other 
> namespaces.
>
> How do I remove libphobos as a runtime dependency with ld and 
> MSVC’s link.exe? Is it possible to decouple core from other 
> parts of the runtime, and if so, how?
>
> Regards,
> A. Nicholi

LDC allows specifying default libs, something like 
`-defaultlib=phobos2-ldc,druntime-ldc`; you can remove phobos 
from the list.

I think you can use any symbol that is compile time only from 
phobos (like std.traits and std.meta), and you can take stuff 
from phobos and adapt it to your own needs. I use the compiler 
explorer (https://d.godbolt.org/) to check the generate code for 
symbols added.

LDC is flexible enough, from my experience, to allow certain 
degree of customization. You can override the default C compiler 
and add your own paths, or you can create a custom C compiler 
driver that overrides defaults. Check the ldc command line spec 
for inspiration https://wiki.dlang.org/Using_LDC

Something to remember though, if you intend to commit to serious 
commercial use, you should be prepared to dig in and fix stuff 
that doesn't work, or add new functionality, or sponsor the 
foundation for support. D and LDC are opensource projects, and 
they have mostly good quality implementation, but they are not 
commercial grade top of the line products.