#include <https://raw.githubusercontent.com/martinmoene/optional-lite/master/include/nonstd/optional.hpp>
#include <iostream>
#include <string>

int main()
{
    nonstd::optional<std::string> s;
    s = "test";
    std::cout << (*s == "test") << std::endl;
    std::cout << (s.value_or("") == "test") << std::endl; // comment this line
    std::cout << (s->empty()) <<  std::endl;
}