Head Const

[Ola Fosheim Grøstad via Digitalmars-d]

On Tuesday, 16 February 2016 at 09:04:48 UTC, Daniel Murphy wrote:
> I'm starting to think we should give up on implementing C++ 
> support in the language and move it to the library.
>
> eg
>
> mixin(cppFunctionBinding("unsigned long long 
> NameSpace::myFunc(char * const && x, long double y)");
>
> expands to some combination of pragma(mangle) and extern(C++)
>
> With the limitation that only declarations can be parsed, it's 
> not that bad to implement a ctfe C++ parser, and we can stop 
> the creep of C++ features and hack into D.
>
> As a bonus, it could generate wrappers when we really can't 
> match the semantics well enough.

I agree with the principle, but not as a library function, 
because:

1. you want virtual functions to work out ok

2. making D more reliant on macroish string processing is not good


You would need something along the lines of:

1. «extern "C++"» the essence of the class definition in plain 
C++ syntax

2. add to this syntax a translation for each parameter what it 
means in D.


E.g.

extern "C++" {

class X {
   mutable int rc;
   virtual func1(const A* ptr); @reinterpret(ptr, head_const_ptr!A)
   virtual func2(const A* ptr); @reinterpret(ptr, const A*)
   virtual func3(A* ptr);
   virtual func4(const A* ptr); @reinterpret(ptr, const_rc!A*)
};

}