Le 07/12/11 10:28, Matus Chochlik a écrit :
On Tue, Dec 6, 2011 at 2:37 PM, jinhua luo<ljh.home.king@gmail.com> wrote:
Hi, OK let me say this so you don't get me wrong: I welcome any attempt to add reflection to C++, I would very much like to have reflection in the C++ standard with the full support of the compiler, and I don't care on whose design it is based.
What I care about is that it is done properly, i.e. that it is not tailored for a specific goal ORM, Serialization, RPC, GUI geneation, parser generation, whatever .. but that it would support all of these and much more. It should provide as much meta-data as possible even if some of it might not be obviously usable in some scenario (it might be in others), etc.
It also should be compile-time because then you can use it with all the great meta-programming tools implemented in Boost and elsewhere. If you have a solid compile-time foundation you can implement run-time reflection even, dynamically loadable easily.
I have a quick look at the Mirror reflection utilities, although no deep investigation, I have some opinions about it: a) complex reflection declaration syntax (e.g. to describe the prototype of some method, it needs to use macro per parameter, but in my way, it's more easier and native: you just need to copy and parse the prototype from the class definition) The syntax is complex only if you need to specify all details manually. There are however the quick-registering macros that simplify the registering quite a lot.
I don't think that a compile-time reflection library is in competition with a run-time library. Both approaches are complementary, and I'm sure that the Boost community will appreciate both approaches if the library is well designed.
b) depends on C++11 features (as mentioned in the web site, It has been tested and is currently known to work with the gcc 4.5.1 and higher), but my way does not require new versions of C++ standards, so it supports VC7 or higher, and all gcc versions. C++11 is a standard now and Mirror (AFAICT) doesn't use anything gcc-specific. I know that the release cycles for compilers are quite long, but I hope that we'll get good if not full support for C++11 soon.
The fact that a library need c++11 support only restrict the compilers that can be used with. I guess that C++11 only libraries are welcome in Boost. Of course, if the library can be used on C++98 compilers with minor limitations, the number of potential users will be higher. So please, don't start a discussion stating that we need a compile-time/run-time or c++11/c++98 library. All the combinations have its usage, each one with its advantages and liabilities. Best, Vicente