IO Monads in C++

IOMonads.cpp

#include <iostream>
#include <string>
#include <tuple>
auto getString = [] {
    return []() {
        std::string string;
        getline(std::cin, string);
        return string;
    };
};

auto putString = [](std::string string) {
    return [string]() {
        std::cout << string << "\n";
        return std::make_tuple();
    };
};

template <typename Monad, typename Functor>
constexpr auto operator>>(Monad monad, Functor functor)
{
    return [monad, functor] {
        return functor(monad())();
    };
}

auto result = getString() >> [](std::string str) {
    return getString() >> [str](std::string str2) {
        return putString(str + str2);
    };
};

int main()
{
    result();
    return 0;
}