Any plans to support STL value types?

[Timon Gehr via Digitalmars-d]

On 05/15/2015 09:44 PM, Jonathan M Davis wrote:
> On Friday, 15 May 2015 at 18:42:31 UTC, Kagamin wrote:
>> Many STL types inherit from base classes, yet they are used as value
>> types: std::string, std::vector etc. Are there plans to support C++
>> types with inheritance as proper value types in D frontend?
>
> Given that the inheritance they have is actually undesirable when they
> are treated as value types, I doubt that there's much need. If you're
> using inheritance in C++, you're putting your class on the heap and
> accessing it via pointers,> in which case, accessing them in D as classes
> makes sense. And if you're using these STL types as value types on the
> stack, then they can be treated as value types. Doing otherwise just
> risks object slicing, which is not desirable in the least.
>
> So, while I don't know how we're going to be handling STL types (I don't
> even know what the current state of C++ state support is, since it keeps
> improving), I really don't see why there's value in supported
> inheritance with value types. It would just be begging for bugs - which
> is why native D types don't support it.
>
> - Jonathan M Davis

He didn't ask about support for object slicing, just support for proper 
interfacing to value types that happen to use implementation inheritance.


   template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
     class vector : protected _Vector_base<_Tp, _Alloc>
     {


vector is a value type. You won't accidentally slice it, as the parent 
class is not accessible. _Vector_base is there to make exception safety 
easier AFAIK. It's basically an implementation detail. (Does anyone know 
why they are using protected inheritance instead of private inheritance?)