The C++ compatibility provided in D 2.0 is a huge step forward.  However, if my understanding is correct, the biggest limitation with it is that D's classes are not ABI compatible with C++ classes.  This means that non-static member functions can't be called between D and C++.

To remedy this issue, I propose that we allow extern C++ declarations on classes.  This would mean that the class behaves like a C++ class (doesn't inherit Object, no GC by default, only polymorphic if it contains virtual functions, etc.)

I realize this may require a moderate amount of Walter's time.  I therefore would propose this as perhaps a D 3.0 feature.

What issues would arise that I am forgetting to address?  Does anyone have a better solution for this?

-Craig 

Craig Black wrote:
> The C++ compatibility provided in D 2.0 is a huge step forward.  However, if my understanding is correct, the biggest limitation with it is that D's classes are not ABI compatible with C++ classes.  This means that non-static member functions can't be called between D and C++.
> 
> To remedy this issue, I propose that we allow extern C++ declarations on classes.  This would mean that the class behaves like a C++ class (doesn't inherit Object, no GC by default, only polymorphic if it contains virtual functions, etc.)
> 
> I realize this may require a moderate amount of Walter's time.  I therefore would propose this as perhaps a D 3.0 feature.
> 
> What issues would arise that I am forgetting to address?  Does anyone have a better solution for this?

You can already call C++ member functions declared with extern(C++). The problems, however, stem from C++ constructors, destructors, and special functions.

"Walter Bright" <newshound1@digitalmars.com> wrote in message news:fssh36$8sl$1@digitalmars.com...
> Craig Black wrote:
>> The C++ compatibility provided in D 2.0 is a huge step forward.  However, if my understanding is correct, the biggest limitation with it is that D's classes are not ABI compatible with C++ classes.  This means that non-static member functions can't be called between D and C++.
>>
>> To remedy this issue, I propose that we allow extern C++ declarations on classes.  This would mean that the class behaves like a C++ class (doesn't inherit Object, no GC by default, only polymorphic if it contains virtual functions, etc.)
>>
>> I realize this may require a moderate amount of Walter's time.  I therefore would propose this as perhaps a D 3.0 feature.
>>
>> What issues would arise that I am forgetting to address?  Does anyone have a better solution for this?
>
> You can already call C++ member functions declared with extern(C++). The problems, however, stem from C++ constructors, destructors, and special functions.

But that only works for virtual functions declared using interfaces, right? That is somewhat limiting.  It would be nice to take it a step further.

-Craig