Re: [boost] Library Proposal: Reflection for C++

From: Edward Diener (eddielee_at_[hidden])
Date: 2006-02-01 12:27:40

David Abrahams wrote:
> Stefan Roiser <stefan.roiser_at_[hidden]> writes:
> 
>> On 31 Jan 2006, at 19:40, David Abrahams wrote:
>>
>>> Stefan Roiser <stefan.roiser_at_[hidden]> writes:
>>>
>>>> On 30 Jan 2006, at 17:08, Stefan Seefeld wrote:
>>>>
>>>> With interaction with objects I meant e.g. through the meta-level
>>>> instantiate a class, get/set the data member values, call a function
>>>> on that instance, retrieve the function's return value and so on. I
>>>> may have missed that, but I couldn't find examples on the synopsis
>>>> page for this functionality.
>>>>
>>>> Reflex code for this would look something like
>>>>
>>>> Type t = Type::ByName("foo");
>>>> Object instance = t.Construct();
>>>> Object ret_obj = instance.Invoke("myFunction");
>>> Very interesting.  Where do you get the object code for
>>> foo::myFunction?  Or have you implemented a full C++ interpreter?
>> foo::myFunction will be invoked through a stub function which is part  
>> of the dictionary library for class foo. A dictionary library may be  
>> dynamically loaded in a program.
> 
> Soooo.... what about templates?  Do you have to do something to
> manually instantiate them?  Or do you do some kind of on-the-fly
> compilation?

Since templates are not types, I would leave out the instantiation of 
templates into types, which is a compile-time mechanism, from a run-time 
reflection system, and concentrate instead on finding information about 
types ( and objects ), and invoking objects from types. Of course an 
already instantiated template class or template function is a type, and 
should be subject to run-time reflection like any other type.