C++: What is std::ranges::to_tuple (C++26)?

1#include <ranges>
2#include <tuple>
3
4std::vector<int> v = {1, 2, 3};
5
6// Convert to tuple
7auto t = std::views::all(v) | std::ranges::to_tuple();
8// t = std::tuple<int, int, int>(1, 2, 3)
9
10// Structured binding
11auto [a, b, c] = t;
12std::cout << a << " " << b << " " << c;  // 1 2 3
13
14// With transform
15std::string str = "hello";
16auto chars = str | std::views::all
17    | std::views::transform([](char c) { return std::toupper(c); })
18    | std::ranges::to_tuple();
19
20// From iota
21auto nums = std::views::iota(1, 4)
22    | std::ranges::to_tuple();
23// nums = (1, 2, 3)
24
25// Compile-time size
26static_assert(std::tuple_size_v<decltype(nums)> == 3);
27
28// Use with std::apply
29auto result = std::apply([](auto... args) {
30    return (args + ...);
31}, nums);
32// result = 6