Newbie initial comments on D language - RTTI and run-time reflection

[Edward Diener]

Robert Fraser wrote:
> Edward Diener wrote:
>> But that is still only half the story. Run-time reflection in a RAD 
>> environment needs the ability to be able to create an object directly 
>> from the type of that object, and the type of an object must itself be 
>> instantiable as an object. This final ability is in Java, Python, 
>> .Net, and C++ Builder/Delphi. I can only encourage D to have this 
>> ability also.
> 
>  From http://www.digitalmars.com/d/2.0/abi.html :
> 
> The class definition:
> 
> class XXXX
> {
>     ....
> };
> 
> Generates the following:
> 
>     * An instance of Class called ClassXXXX.
> [...]
> 
> And from http://www.digitalmars.com/d/2.0/phobos/object.html :
> 
> class ClassInfo;
>     Runtime type information about a class. Can be retrieved for any 
> class type or instance by using the .classinfo property. A pointer to 
> this appears as the first entry in the class's vtbl[].
> 
>     byte[] init;
>         class static initializer (init.length gives size in bytes of class)
> 
>     string name;
>         class name
> 
>     void*[] vtbl;
>         virtual function pointer table
> 
>     Interface[] interfaces;
>         interfaces this class implements
> 
>     ClassInfo base;
>         base class
> 
>     static ClassInfo find(string classname);
>         Search all modules for ClassInfo corresponding to classname.
> 
>         Returns:
>         null if not found
> 
>     Object create();
>         Create instance of Object represented by 'this'.
> 
>     const(MemberInfo[]) getMembers(string name);
>         Search for all members with the name 'name'. If name[] is null, 
> return all members.

That is start, but it looks like I will wait for 2.0 to be done before I 
investigate further.

BTW I do realize what a major effort it is to provide metaclass 
information such as ClassInfo and further facilities so that full 
run-time reflection can be done. I would not be disappointed if D did 
not fully offer such facilities, but my argument here is not that I do 
not understand the huge effort but that once D offers that sort of 
facility it becomes possible do to some amazing thing with it and would 
be worth it.