One thing that would be a huge plus for D compared to any other language
would be good C++ interoperability of some kind. Playing well with C is a
requirement for any serious language. My bet is playing well with C++ will
be just as important in the future, if not already.
Java has a useful but fairly clunky interface to C++ (JNI) and C# has
Managed Extensions to C++ (though I don't know any details about it). D
doesn't seem to have anything planned here or a story to tell users. Any
time C++ code wants to talk to D code or vice-versa you have to go through
C.

I noticed the dmd source code has a linkage enum entry for C++ (in addition to the C, Pascal, D and Windows options already implemented). What are the major obstacles to implementing it?

-Ben

"Ben Hinkle" <bhinkle4@juno.com> wrote in message news:c0dugh$enh$1@digitaldaemon.com...
> One thing that would be a huge plus for D compared to any other language
> would be good C++ interoperability of some kind. Playing well with C is a
> requirement for any serious language. My bet is playing well with C++ will
> be just as important in the future, if not already.
> Java has a useful but fairly clunky interface to C++ (JNI) and C# has
> Managed Extensions to C++ (though I don't know any details about it). D
> doesn't seem to have anything planned here or a story to tell users. Any
> time C++ code wants to talk to D code or vice-versa you have to go through
> C.
>
> I noticed the dmd source code has a linkage enum entry for C++ (in
addition
> to the C, Pascal, D and Windows options already implemented). What are the major obstacles to implementing it?

The problem is the layout of the vtbl[]. To get that right, you have to build part of a C++ compiler.

Walter wrote:
> "Ben Hinkle" <bhinkle4@juno.com> wrote in message
> news:c0dugh$enh$1@digitaldaemon.com...
> 
>>One thing that would be a huge plus for D compared to any other language
>>would be good C++ interoperability of some kind. Playing well with C is a
>>requirement for any serious language. My bet is playing well with C++ will
>>be just as important in the future, if not already.
>>Java has a useful but fairly clunky interface to C++ (JNI) and C# has
>>Managed Extensions to C++ (though I don't know any details about it). D
>>doesn't seem to have anything planned here or a story to tell users. Any
>>time C++ code wants to talk to D code or vice-versa you have to go through
>>C.
>>
>>I noticed the dmd source code has a linkage enum entry for C++ (in
> 
> addition
> 
>>to the C, Pascal, D and Windows options already implemented). What are the
>>major obstacles to implementing it?
> 
> 
> The problem is the layout of the vtbl[]. To get that right, you have to
> build part of a C++ compiler.
> 

If I understand this right, it _can_ be done, but implementing C++ interoperability would to a large extent undo the advantages of the D design for clean compiler code, and the added complexity would not be in proportion to what is needed to compile plain D.

As much as it would be a pain for all of you putting so much effort in getting rid of C++ badness, would not it be doable to have two flavors of D compilers? One that does clean D and takes full advantage of its design, and an other that provides C++ interoperability, however cludgy?
You would use the beautiful pure D compiler whenever possible, and the bulky ugly one when you need interoperability with C++.

The D.gnu newsgroup is showing promising results recently, and since GCC already compiles C++, would it be possible to use the vtbl[] stuff that is already there? Also DM has a C++ compiler, which I hope means that relevant parts can be glued into its D compiler...? Not that this would be trivial, but probably not as bad as having to build part of a C++ compiler (from scratch) either.

I am not in the same leage as most of you, and I have great respect for the work being done here. But I had to mention this --- I hope it makes sence :-)

Bastiaan.

On Wed, 11 Feb 2004 20:18:02 -0800, Walter <walter@digitalmars.com> wrote:

> The problem is the layout of the vtbl[]. To get that right, you have to
> build part of a C++ compiler.

Well, you have a nice C++ compiler at hand. I wouldn't mind if I only can link it with DMC++ compiled code. At least this would makes bootstrapping D projects much simpler. Over time D libraries will develop and replace more and more C++ libaries.

I would add DMC++ compatibility.

-- 
Robert M. Münch
Management & IT Freelancer
http://www.robertmuench.de

"Walter" <walter@digitalmars.com> wrote in message news:c0ev8k$24q3$1@digitaldaemon.com...
|
| "Ben Hinkle" <bhinkle4@juno.com> wrote in message
| news:c0dugh$enh$1@digitaldaemon.com...
| > One thing that would be a huge plus for D compared to any other language
| > would be good C++ interoperability of some kind. Playing well with C is a
| > requirement for any serious language. My bet is playing well with C++ will
| > be just as important in the future, if not already.
| > Java has a useful but fairly clunky interface to C++ (JNI) and C# has
| > Managed Extensions to C++ (though I don't know any details about it). D
| > doesn't seem to have anything planned here or a story to tell users. Any
| > time C++ code wants to talk to D code or vice-versa you have to go through
| > C.
| >
| > I noticed the dmd source code has a linkage enum entry for C++ (in
| addition
| > to the C, Pascal, D and Windows options already implemented). What are the
| > major obstacles to implementing it?
|
| The problem is the layout of the vtbl[]. To get that right, you have to
| build part of a C++ compiler.
|

Would it be possible to have an API to use D objects from C++ (instead of the other way around)? I notice the D spec describes the object layout and vtbl, so that is a start. Some way to call constructors would probably be needed.

Also it occurred to me that COM provides a basic story on win32. For other platforms maybe CORBA could help (though that would probably bring a lot of infrastructure). It wouldn't be as nice as seemlessly interoperating but it is a step beyond "extern (C)".

-Ben

I vote no

"Bastiaan Veelo" <Bastiaan.N.Veelo@ntnu.no> wrote in message news:c0fija$35n$1@digitaldaemon.com...
> Walter wrote:
> > "Ben Hinkle" <bhinkle4@juno.com> wrote in message news:c0dugh$enh$1@digitaldaemon.com...
> >
> >>One thing that would be a huge plus for D compared to any other language would be good C++ interoperability of some kind. Playing well with C is
a
> >>requirement for any serious language. My bet is playing well with C++
will
> >>be just as important in the future, if not already.
> >>Java has a useful but fairly clunky interface to C++ (JNI) and C# has
> >>Managed Extensions to C++ (though I don't know any details about it). D
> >>doesn't seem to have anything planned here or a story to tell users. Any
> >>time C++ code wants to talk to D code or vice-versa you have to go
through
> >>C.
> >>
> >>I noticed the dmd source code has a linkage enum entry for C++ (in
> >
> > addition
> >
> >>to the C, Pascal, D and Windows options already implemented). What are
the
> >>major obstacles to implementing it?
> >
> >
> > The problem is the layout of the vtbl[]. To get that right, you have to build part of a C++ compiler.
> >
>
> If I understand this right, it _can_ be done, but implementing C++ interoperability would to a large extent undo the advantages of the D design for clean compiler code, and the added complexity would not be in proportion to what is needed to compile plain D.
>
> As much as it would be a pain for all of you putting so much effort in getting rid of C++ badness, would not it be doable to have two flavors of D compilers? One that does clean D and takes full advantage of its design, and an other that provides C++ interoperability, however cludgy? You would use the beautiful pure D compiler whenever possible, and the bulky ugly one when you need interoperability with C++.
>
> The D.gnu newsgroup is showing promising results recently, and since GCC already compiles C++, would it be possible to use the vtbl[] stuff that is already there? Also DM has a C++ compiler, which I hope means that relevant parts can be glued into its D compiler...? Not that this would be trivial, but probably not as bad as having to build part of a C++ compiler (from scratch) either.
>
> I am not in the same leage as most of you, and I have great respect for the work being done here. But I had to mention this --- I hope it makes sence :-)
>
> Bastiaan.
>

Robert M. Münch wrote:

> On Wed, 11 Feb 2004 20:18:02 -0800, Walter <walter@digitalmars.com> wrote:
> 
>> The problem is the layout of the vtbl[]. To get that right, you have to
>> build part of a C++ compiler.
> 
> Well, you have a nice C++ compiler at hand. I wouldn't mind if I only can link it with DMC++ compiled code. At least this would makes bootstrapping D projects much simpler. Over time D libraries will develop and replace more and more C++ libaries.
> 
> I would add DMC++ compatibility.

I think it would add too much complexity to the D compiler implementation.  I vote no.


Sean

I don't have a good knowledge about compilation, but I thought if it is
possible
to write a tool that automatically generate from a c++ library a interface
for use it.

I'm sorry for my english, what i mean is that the tool write a D module that
define
a class.
This class has all the public methos of the original class in the c++
library.
When someone calls a method from this class, it will do all the necessary
operations
(I don't know what) and after it executes the original method ( I assume we
can know where
the method is from the vtbl).
Please tell me if something lime this is possible.

"Walter" <walter@digitalmars.com> wrote in message news:c0ev8k$24q3$1@digitaldaemon.com...
>
> "Ben Hinkle" <bhinkle4@juno.com> wrote in message news:c0dugh$enh$1@digitaldaemon.com...
> > One thing that would be a huge plus for D compared to any other language would be good C++ interoperability of some kind. Playing well with C is
a
> > requirement for any serious language. My bet is playing well with C++
will
> > be just as important in the future, if not already.
> > Java has a useful but fairly clunky interface to C++ (JNI) and C# has
> > Managed Extensions to C++ (though I don't know any details about it). D
> > doesn't seem to have anything planned here or a story to tell users. Any
> > time C++ code wants to talk to D code or vice-versa you have to go
through
> > C.
> >
> > I noticed the dmd source code has a linkage enum entry for C++ (in
> addition
> > to the C, Pascal, D and Windows options already implemented). What are
the
> > major obstacles to implementing it?
>
> The problem is the layout of the vtbl[]. To get that right, you have to build part of a C++ compiler.
>
>