I am testing some of the fancy new c++ features, one of which is ranges and the associated views. I find it particularly interesting that you can chain what you wish to do with a container.
You can use the binary operator|() to chain things, which is really nice. I noticed that you can chain into std::views::take(int), std::views::transform() with a lambda or function pointer, std::views::filter() with a lambda or function pointer. The only thing you can't use is std::views::reverse. That one can only be used by putting a range into it's argument. Why it that? Is there an alternative?
#include <iostream>
#include <vector>
#include <string>
#include <ranges>
int main()
{
using std::string;
using std::cout, std::endl;
const std::vector<string> vec = { "A", "B", "a", "b", "b2", "a2", "a3", "b3", "b4" };
for (auto const& val : std::views::reverse(vec) // ok
| std::views::take_while([](const string& s) {return s.size() > 0 && s[0] == 'b'; })
// | std::views::reverse() // Error?!
)
{
cout << val << endl;
}
}
Compile with g++ -std=c++20 main.cpp -o main
How would I get b3, b4 in that situation using the syntax above?