• Cecil Ward (26/26) Nov 02 2018 Considering the syntax
• Paul Backus (11/18) Nov 02 2018 Use a separate module:
• Jonathan M Davis (11/33) Nov 03 2018 Yeah, pretty much the entire point of the new syntax was to make it so t...

Cecil Ward <d cecilward.com> writes:

Considering the syntax

     extern( C++, "myCppNamespace" ) void cppFunc();

If you want to still be able to use the namespace-qualified form 
myCppNamespace.cppFunc() in your D, even with the string type of 
reference, what about something like

     extern( C++, "myCppNamespace" alias myCppNamespaceAlias ) 
void cppFunc();

which declares that the name myCppNamespaceAlias is an alias in D 
for the C++ namespace myCppNamespace, and so would then permit 
the use of myCppNamespaceAlias.cppFunc().

Would such a thing even be a worthwhile enhancement?

That could get very repetitive though, so it would be better to 
be able to declare an association between the C++ namespace 
string and its alias just once. There are many many possible ways 
that might be done. Perhaps something such as :

     alias myCppNamespaceAlias = extern( C++, "myCppNamespace" );
     /*either */ extern( C++, "myCppNamespace" ) void cppFunc();
     /* or */      extern( C++, myCppNamespaceAlias ) void 
cppFunc();

Or merely:

     extern( C++, "myCppNamespace" alias myCppNamespaceAlias );
     /*either */ extern( C++, "myCppNamespace" ) void cppFunc();
     /* or */      extern( C++, myCppNamespaceAlias ) void 
cppFunc();

Any thoughts?

Would such a thing even be a worthwhile enhancement?

Paul Backus <snarwin gmail.com> writes:

On Saturday, 3 November 2018 at 05:49:53 UTC, Cecil Ward wrote:
 Considering the syntax

     extern( C++, "myCppNamespace" ) void cppFunc();

 If you want to still be able to use the namespace-qualified 
 form myCppNamespace.cppFunc() in your D, even with the string 
 type of reference, what about something like

     extern( C++, "myCppNamespace" alias myCppNamespaceAlias ) 
 void cppFunc();

Use a separate module:

--- myCppNamespace.d
module myCppNamespace;

extern(C++, "myCppNamespace") void cppFunc();

--- main.d
static import myCppNamespace;

void main()
{
     myCppNamespace.cppFunc();
}

Jonathan M Davis <newsgroup.d jmdavisprog.com> writes:

On Saturday, November 3, 2018 12:02:19 AM MDT Paul Backus via Digitalmars-d 
wrote:
 On Saturday, 3 November 2018 at 05:49:53 UTC, Cecil Ward wrote:
 Considering the syntax

     extern( C++, "myCppNamespace" ) void cppFunc();

 If you want to still be able to use the namespace-qualified
 form myCppNamespace.cppFunc() in your D, even with the string
 type of reference, what about something like

     extern( C++, "myCppNamespace" alias myCppNamespaceAlias )

 void cppFunc();

 Use a separate module:

 --- myCppNamespace.d
 module myCppNamespace;

 extern(C++, "myCppNamespace") void cppFunc();

 --- main.d
 static import myCppNamespace;

 void main()
 {
      myCppNamespace.cppFunc();
 }

Yeah, pretty much the entire point of the new syntax was to make it so that
extern(C++) was _only_ about name mangling, just like extern(C) is only
about name mangling. You can use D's module system to full effect if you
want to organize the symbols rather than stick the entire namespace in the
same file - or you can just use the old extern(C++) syntax. Basically, with
the new extern(C++) syntax, you can organize C++ symbols like you would D
symbols, and that includes using stuff like static imports if that's what
you prefer.

- Jonathan M Davis