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

[Steven Schveighoffer via Digitalmars-d]

On Tue, 29 Apr 2014 12:03:02 -0400, Timon Gehr <timon.gehr at gmx.ch> wrote:

> On 04/29/2014 05:52 PM, Steven Schveighoffer wrote:
>> I am not familiar with the rules.
>>
>> Perhaps you can just outline for me:
>>
>> module bar;
>>
>> extern(C++, foo) void func();
>>
>> module prog;
>>
>> import bar;
>>
>> void main()
>> {
>>     foo.func(); // works?
>> }
>>
>> If this works, then we have a problem.
>
> It does work. What happens is analogous to:
>
> module bar;
>
> void func(){}
>
> module prog;
> import bar;
>
> void func(){}
>
> void main(){
>      func();
> }
>
> I.e. if you add a new symbol to your own module, then this identifier  
> will be hidden, no questions asked. Importing a module adds a new symbol  
> of its name to your module. I'm not sure why you see this as a problem.  
> The name lookup rules are designed such that changes in one module  
> cannot silently change name lookup in _another_ module, but anything may  
> happen to lookup in the same module.

OK, so you are saying that from a module different than the one that  
defines the namespace/function, I can call it via it's full namespace.

But what happens when you add another import that conflicts?

module foo;

void func() {}

module prog; // updated
import bar;
import foo;

void main(){
    foo.func(); // now calls foo.func, and not bar.func as it originally  
did, right?
}

So by importing from another module, we have silently and drastically  
changed the behavior. Have I missed something?

Why is this not a problem?

-Steve