DIP61: redone to do extern(C++,N) syntax

[Regan Heath via Digitalmars-d]

On Wed, 30 Apr 2014 10:20:22 +0100, Regan Heath <regan at netmail.co.nz>  
wrote:

Something else to think about.

C# has the same problem and has solved it the following way..

[main.cs]
using ..
using CSTest_Test1;
using CSTest_Test2;

namespace CSTest
{
     class Program
     {
         static void Main(string[] args)
         {
             Test1.GetLastError(); // class, not namespace required to call  
method
             Test2.GetLastError(); // class, not namespace required to call  
method
         }
     }
}

[Test1.cs]
using ..
namespace CSTest_Test1
{
     public static class Test1
     {
         [DllImport("coredll.dll", SetLastError = true)]
         public static extern Int32 GetLastError();
     }
}

[Test2.cs]
namespace CSTest_Test2
{
     public static class Test2
     {
         [DllImport("coredll.dll", SetLastError = true)]
         public static extern Int32 GetLastError();
     }
}

GetLastError() is always going to unambiguous here because it *must* live  
inside a C# class and that class name is *always* required in the call to  
it.

If D has replaced classes/namespaces with modules, then the answer to our  
problem may be to use the C++ namespace *only* to mangle the symbol, and  
*only* use the D module for lookup resolution.

module a;
extern(C++, std) class string {..}

module b:
extern(C++, std) class string {..}
extern(C++, std) class vector {..}

module userland;
import a;
import b;

void main()
{
   string x = new string();     //error ambiguous (same resolution as for D  
symbols)
   a.string x = new a.string(); //ok
   b.vector y = new b.vector(); //ok
}

Regan