how to get all metadata of class、property、method

[b-xiang]

how to get all metadata of class、property、method from type

thanks!

[rainy-juzixiao]

You mean you want to get all the metadatas of type::get_properties(), and type::get_methods() returning object's metadata?I don't think RTTR allows you to obtain all the metadata information, even if it is technically feasible.

But to be honest, RTTR hasn't been updated for a long time. If you want to obtain all the metadata, I think you'll have to modify the code of RTTR (which might involve a lot of refactoring). But I don't think you have enough time to complete this task, especially if you are using the clang toolchain. Here, I used MSVC-Clang to test it, i can't compile it and the error reporting was very difficult. Also, let's be pessimistic and say that it's very likely that RTTR has actually stopped being maintained. Even a newer branch with version 0.9.7 still doesn't provide this functionality.

Btw, if you really want to obtain metadata, you can consider the meta project of the maintainer of entt, skypjack. It just like a separate library from the entt branch, it's a lightweight pure header library that allows you to get all the metadata's. But the meta project was abandoned some time ago and was marked as deprecated.

So, if you really want to obtain all the metadata, I'm sorry, these two solutions, if you prefer the traditional RTTR, then you either have to accept refactoring the code or use meta. And I think, even if reflection has been added to C++26, you still need time to migrate, and you can only obtain compile-time capabilities.

However, if you do consider making any modifications, in the src/rttr/detail/metadata/metadata_handler directory of RTTR, you will see this piece of code:

template<std::size_t Metadata_Count>
class metadata_handler
{
    public:
        RTTR_FORCE_INLINE metadata_handler(std::array<metadata, Metadata_Count> new_data) : m_metadata_list(std::move(new_data)) { }

        RTTR_INLINE variant get_metadata(const variant& key) const
        {
            // I don't expect that many data, so we iterate from start to end
            for (const auto& item : m_metadata_list)
            {
                if (item.get_key() == key)
                    return item.get_value();
            }

            return variant();
        }

    private:
        std::array<metadata, Metadata_Count> m_metadata_list;
};

You should be able to return an rttr::array_range for modification, and then follow the implementation of get_metadata, trace back and make the necessary changes. In theory, this should work. However, I cannot guarantee that it will definitely work.

[b-xiang]

thanks,I modified the source code and get all metadata of class、property、method !