背景⌗

ranges 表示可迭代序列，比如 array、vector、initialized_list。

The ranges library is an extension and generalization of the algorithms and iterator libraries that makes them more powerful by making them composable and less error-prone.

使用⌗

int range_example() {
  auto const ints = {0, 1, 2, 3, 4, 5};
  auto even = [](int i) { return 0 == i % 2; };

  std::cout << *std::ranges::begin(ints) << std::endl;

  // Traditional functional composing syntax:
  for (int i : std::ranges::filter_view(ints, even)) {
    std::cout << i << '\n';
  }

  // Pipe syntax of composing the views:
  for (int i : ints | std::views::filter(even)) {
    std::cout << i << '\n';
  }

  return 0;
}

Good Resources⌗

C++ 20’s Ranges: A Quick Start:

A Simple String Split in C++:

constexpr auto Split(const std::string_view &str) {
  auto split_strings = str | std::ranges::views::split(' ');
  return split_strings;
}

int main(int argc, char **argv) {
  range_example();
  for (const auto &str : Split("hello world")) {
    std::cout << std::string_view{str.begin(), str.end()} << '\n';
  }

  return 0;
}

Reference⌗

  1. Ranges