Thoughts on Variant creation

[Andrew Potter <agpotter gmail com>]

I've been thinking about how we create variants in glibmm and why its more of a pain than in C. The common case ultimate goal of variants is to throw a data structure into a tuple. In C, you can use g_variant_new() and a format string, and hand it pointers to your hard data. 1 method returns the desired result if you don't need to build a container variant. 

However, currently in glibmm you have to call a ::create() method for each individual data element before you can call create_tuple(). It is relatively cumbersome for nontrivial tuples.

There are a lot of possible solutions, but I have no idea which is the best. We could make a really bare wrapper g_variant_new() that passes all the arguments through and just Glib::wrap()s the result into a Glib::VariantContainerBase. Or, we could parse the format string ourselves and call the appropriate ::create() methods.

Maybe we could break ground with a C++11 std::tuple constructor. It'd be really, really nice if you could just:

auto vtuple = VariantContainerBase::create_tuple({(int) item1, (float) item2, (std::map) item3});

Thoughts?

Also, what is the motivation to provide only ::create() methods and not do a constructor, e.g.:

int i = 5;

Variant<int> vint(i); 

Thanks for your time