std::vector<std::string> str = { "Value1", "Value2", "Value3" };
from(str)
        >> select([](auto&& s, auto&& i) { return std::make_pair(i, s); })
        >> for_each([](auto&& s) { std::cout << s.first << " = " << s.second << "\n"; });

0 = Value1
1 = Value2
2 = Value3