Said compiler must somehow work together with the D compiler here, which should lead to god-awful memory use, compilation time, and error messages.
So you have a C++ file that uses vector<int>, vector<struct c_struct>, vector<CppClass>, vector<DClass>, etc. once and then you can link to them from D code.
The only case where that doesn't work is when you have lots of one-off instantiations, where requiring an instantiation in C++ code for each use in D would get annoying quickly.
Do you have to write some kind of D header file for foreign C++ functions? Otherwise, how would D even know about the existence of e.g. vector<int>::push?
You will need to recreate the C++ function definitions in D and mark them extern(C++), but that's about it.
Let's be clear a compiler builds a object files that have to be linked to create a executable binary. IE compiler makes .o files. Linker takes output object files from the compiler an puts them (.o,.so/.dll,.a) together, to make .exe files.
This all works because you are linking to the C/C++ library binaries (the .o, .so, .a, .dll) files generated by a C/C++ compiling/linking. In most cases this is shared object library/dll provided by the operating system or pre-built library you install on the system. There is no need to compile it because it is pre-built. if you do compile the library yourself, it is a one time thing.
In D you create a .d file that describes what is in a C++ library .o/.so/.a/.dll file. So that upon linking, you take your D code's .o files + the C/C++ .o files to put together a full executable binary.
Templates are delivered as C++ include files (i.e. source code). When you use them, the compiler fills in the types you want and compiles the result.
For example, there's the std::vector<> template. You can fill in any type that meets the specific requirements of the template and use it like std::vector<int> or std::vector<YourC++ClassType>.
However, you probably won't be able to do std::vector<YourDClassType>. ABI compatibility is not enough to do this as you would be effectively mixing C++ and D source code here.
I think this should be working. You don't have to 'mix source code', you can implement YourDClassType in D and use it in C++. You simply have to write a C++ header describing the class. Then write a D file describing the external C++ sdt::vector<YourDClassType> file and link everything together.
Not sure if anybody actively tested this though ;-)
Also if your "library" is all templates, it's not a library, it's a framework that uses other libraries. There still has to be at some point tangible code that is compiled to an object file to be linked. You will have to find all of the dependancies and make sure that they are also described in a .d file.
This might mean you have a bunch of work that you need to do in order use the c++ code you want to bring in into D. But then again, if it's a public/open source library, and you go down that rabbit hole and make it work, you just made D even better.
please see https://dlang.org/spec/cpp_interface.html#cpp-templates for more details.
TIL STL is not a library.
How does it work in practice ? C++ name mangling is not standardized and so every compiler can implement its own scheme. So does it mean there is a list of D compatible c++ compiler somewhere ? I have the feeling that if you are using some exotic proprietary c++ compiler it won't work well.
That's right, and the D compiler deals with that by customizing the C++ mangling for every platform.
What is ABI compatiblity? in a nutshell it let's you use libraries from another programming language. In D, all you need is a D file that describes the C/C++ library as a wrapper so the D compiler knows what you are using.
This means D will build upon everything that already exists for C/C++. You can intermix C/C++ and D in the same project if you so choose to. Which is really a big deal because you don't necessarily have to stop and rewrite years of code you might already have to start using D.
Syntax wise D is a kin to C#/Java, so if you know C# or Java, jumping over to using D is just a matter of learning the language specific Gotchas and core libraries. So the learning curve is quite low if you know C/C++,C#, or Java.
to see what D libraries are out there I suggest looking at http://code.dlang.org/