extern(C++, ns)

[Marc Schütz via Digitalmars-d]

On Wednesday, 20 January 2016 at 17:25:56 UTC, JohnCK wrote:
> On Wednesday, 20 January 2016 at 16:38:19 UTC, Marc Schütz 
> wrote:
> I think the first error is correct:
>
>>     bar();      // Error: b.bar at b.d(6) conflicts with 
>> a.ns.bar at a.d(5)
>

Yes, I put this one in to show why the next lines are sometimes 
necessary.

> So you have two functions bar() one inside 'ns' in module a and 
> "outside" 'ns' in module b.
>
> Now, the last 2 errors, Mark Schutz said:
>
>>     a.ns.bar(); // works, but requires superfluous `a`, even 
>> though
>>                 // `ns` already makes it unambiguous
>
> Question: What happens if you do this: using "ns1" in "module 
> a" and "ns2" in "module b" and do:
>
> ns1.bar();
>
> ?

There'd be no collision anymore, but...

>
> Because you can't have more than one namespaces with the same 
> name in C++, right?

You can:

namespace ns {
     void foo();
}
namespace ns {
     void bar();
}
int main() {
     ns::bar();
     return 0;
}

More realistically, the namespace declarations would appear in 
different header files, all #included into the same cpp file. 
These different header files would naturally be mapped to 
different D modules.