Ben Cooley wrote:

> 
> Yes it certainly should support interop if there is any real intention of being
> a successor to Cpp.  

No it shouldn't. D is trying to break away from C++, not extend it.

> 
> And Yes, interop issues are part of the reason why the new .NET system is
> gaining ground against Java.  Both microsoft C# and Cpp have interop with
> eachother.  C# has unsafe code, which is completely compatible with C and Cpp,
> and Cpp has complete interop with the .NET world, including C#.

C# was designed from the beginning to run on CLI. CLI was designed so that multiple languages could share the same resources and talk to each other. D had no such design goals.

> 
> Outside of the D forums in the general programming world these issues are not
> really controversial.  They are considered self evident and obvious.  This is
> why D is not a real alternative to Cpp or C for most programmers.  

All of the D community comes from /outside/ of the D community, and most of us still live and work there. In my world, what you are saying just isn't true. You focus too much on C++, your circumstances, and the circumstances of people you know. The general programming world is much larger than that. I don't give a rat's ass about C++ interoperability. Most people I know wouldn't give a rat's ass about it either. I know C++ programmers who would happily switch over and use D for all of their new projects once their bosses approve it.

But why should would you stop with C++ interoperability? What all of the Java code bases out there? Surely they would be more likely to come to D if they could use their existing code. What about the C# programmers? Or the VB programmers? Why not just develop our own Common Language Interface? Because that's not the design goal behind D.

D isn't meant to just be a replacement for C++. It melds the features of several languages, along with new ideas, into something that is an excellent /alternative/ to many existing languages, not just C++. C++ interoperability would only be useful to a small subset of potential D users, not the masses to whom you claim it is self evident.

Obviously, D isn't going to be suited to every project. If you rely on a few million lines of C++, Java, or other code (besides C), then D isn't the best solution for leveraging that code base. But I just don't see how that is going to be a deal breaker for D's acceptance. I think the problem is much smaller than you let on.

Ben Cooley wrote:
>[snip]
> 
> And Yes, interop issues are part of the reason why the new .NET system is
> gaining ground against Java.  Both microsoft C# and Cpp have interop with
> eachother.  C# has unsafe code, which is completely compatible with C and Cpp,
> and Cpp has complete interop with the .NET world, including C#.
> 

C#'s unsafe code is not native or unmanaged code - it is managed code that allows the use of pointers into the GC heap.  C# only interops with C code through runtime marshalling.  It does not interop with native C++ code - such code has to be recompiled through Microsoft's "Managed Extensions for C++" compiler, after much tinkering albeit.

I'll bet that if you were to take the time to convert your existing C++ library over to .NET you'd find you'd spend the same amount of time as you would creating a C API wrapper around such code for D to use.

-- 
Regards,
James Dunne