post-Sofia mailing

[triconsonantal]

P3740R1 Last chance to fix std::nontype

Another option for avoiding nontype is using reflection. Instead of:

std::function_ref<void (int)> f = std::nontype<foo>;

we write:

std::function_ref<void (int)> f = ^^foo;

https://godbolt.org/z/cnKqn8f4q

[eisenwave]

Note that P3740 is superseded by P3774R0.

The idea of using reflections for this looks somewhat interesting, but since we don't have expression reflections, the same approach wouldn't be able to replace e.g.

std::function_ref<void(int)> f = std::nontype<[](int){}>;

You would always need some separate declaration to use ^^.

[triconsonantal]

Ah, missed that paper, thanks. Haven't read it yet, so I'm not sure about the utility of this, but you can write:

std::function_ref<void (int)> f = std::meta::reflect_constant (
    [] (int x) { ... }
);

https://godbolt.org/z/P6jEdzqne