Re: ada binding

[sg <alpha@skynet.org.pl_WITHOUT>]

Martin Krischik napisał(a):
> Szymon Guz wrote:
> 
>> Martin Krischik napisa?(a):
>>> Szymon Guz wrote:
>>>
>>>> Maciej Sobczak napisa?(a):
>>>>> Szymon Guz wrote:
>>>>>
>>>>>> how to make an Ada binding for a "C++" class using this C layer ?
>>>>> Basically, if the C++ class is not a template, but just plain "classic"
>>>>> OO stuff, then you can write a wrapper around it in C, which will still
>>>>> be OO, but without the syntax sugar of real class. Something along
>>>>> this:
>>>>>
>>>>> // an existing C++ class:
>>>>> class MyClass
>>>>> {
>>>>> public:
>>>>>     void myFun();
>>>>> };
>>>>>
>>>>> // a C wrapper:
>>>>> extern "C"
>>>>> void * MyClass_new()
>>>>> {
>>>>>     return new MyClass;
>>>>> }
>>>>>
>>>>> extern "C"
>>>>> void MyClass_delete(void *p)
>>>>> {
>>>>>     delete static_cast<MyClass*>(p);
>>>>> }
>>>>>
>>>>> extern "C"
>>>>> void MyClass_myFun(void *vp)
>>>>> {
>>>>>     MyClass *mcp = static_cast<MyClass*>(vp);
>>>>>     mcp->myFun();
>>>>> }
>>>>>
>>>>> // and so on.
>>>>>
>>>>> Depending on the level of isolation that you want to achieve and the
>>>>> level of type safety that you want to retain, hiding the object behind
>>>>> void* might or might not be the best choice, but this is to give you
>>>>> the idea. Above, MyClass_new, MyClass_delete and MyClass_myFun are
>>>>> plain C functions (you can extract their declarations to separate
>>>>> header file) and you can interface them from just about any sensible
>>>>> language in existence and from Ada in particular.
>>>>>
>>>>>
>>>> OK, but what about using the class fields :
>>>>
>>>> class MyClass
>>>> {
>>>> public:
>>>>    int X;
>>>>    int *p_X;
>>>> }
>>>>
>>>> and what about inheriting this from the class in Ada, is it possible ?
>>> If you are planning to inheriting  then you need to directly bind to the
>>> C++ class. Only one compiler offers that (GNAT). Start reading here:
>>>
>>> http://gcc.gnu.org/onlinedocs/gcc-4.0.2/gnat_rm/Pragma-CPP_005fClass.html
>>>
>>> Martin
>> I know but I wander if I can do that using other compilers and with the
>> middle layer written in C.
> 
> You would need to use proxy classes then. Just as much work :-(
> 
> Martin
> 

Well... if this is the only way, so I think that there a very little 
chance for having the wxWindows Ada binding

Szymon Guz