On Fri, 02 May 2014 01:22:12 +0100, deadalnix <deadal...@gmail.com> wrote:
On Thursday, 1 May 2014 at 10:03:21 UTC, Regan Heath wrote:
On Wed, 30 Apr 2014 20:56:15 +0100, Timon Gehr <timon.g...@gmx.ch>
wrote:
If this is a problem, I guess the most obvious alternatives are to:
1. Get rid of namespace scopes. Require workarounds in the case of
conflicting definitions in different namespaces in the same file. (Eg.
use a mixin template.) I'd presume this would not happen often.
2. Give the global C++ namespace a distinctive name and put all other
C++ namespaces below it. This way fully qualified name lookup will be
reliable.
3. Use the C++ namespace for mangling, but not lookup. C++ symbols
will belong in the module they are imported into, and be treated
exactly the same as a D symbol, e.g.
1. The whole point of C++ namespace is to avoid that. That is going to
happen. Probably less in D as we have module scoping. But that makes it
impossible to port many C++ headers.
2. Creating a new name lookup mechanism is the kind of idea that sound
good but ends up horribly backfiring. There is all kind of implications
and it affect every single identifier resolution. You don't want to mess
with that (especially since it is already quite badly defined in the
first place).
3. That makes it impossible to port some C++ headers just as 1.
#1 and #3 are essentially the same thing, and are how C# interfaces with
.. well C, not C++ granted. But, how does this make it impossible to port
some C++ headers?
Were you thinking..
[a.cpp/h]
namespace a {
void foo();
}
[b.cpp/h]
namespace b {
void foo();
}
[header.h] <- header to import
#include "a.h"
#include "b.h"
[my.d] <- our port
extern(c++, a) foo();
extern(c++, b) foo(); // oh, oh!
?
Because the solution is..
[a.d]
extern(c++, a) foo();
[b.d]
extern(c++, b) foo();
[my.d]
import a;
import b;
// resolve the conflict using the existing D mechanisms, or call them
using a.foo, b.foo.
In essence we're re-defining the C++ namespace(s) as a D one(s) and we
have complete flexibility about how we do it. We can expose C++ symbols
in any D namespace we like, we can hide/pack others away in a cpp or util
namespace if we prefer.
R
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