Support for ranges, containers and types with tuple interface.

[Remotion]

Here is C++17 code add support for ranges, containers and types with tuple interface.

May this could be added to fmt in one or another way.

[Morwenn]

Just dropping a link to the Reddit discussion which has some interesting comments which might also be discussed here :)

[vitaut]

@Remotion, this is super cool!

May this could be added to fmt in one or another way.

Definitely. I think this can be added in a separate header such as fmt/ranges.h or something (naming ideas are welcome). Could you submit a PR?

[Remotion]

Yes I will prepare PR.

Do we also need structured binding support? But it will be a bit macro heavy for now.

[vitaut]

Do we also need structured binding support?

I'm not sure. How would structured building support look like from the user perspective?

[Remotion]

This way.
struct my_struct { std::string str_; }
int main() { my_struct st{}; fmt::print("{}\n", st); }

But I think it would be better first do ranges and may be then structured binding.

[vitaut]

Yeah, let's focus on ranges first.

[vitaut]

Closing since #735 has been merged. Thanks again!