tap implementation for C++11

tap.cpp

/** tap implementation for C++11 */
template<typename T, typename F>
T tap(T &&obj, F const &fn) {
    fn(obj);
    return obj;
}

// usage
tap(new User(params), [](User *u) {
    if (u->isValid()) {
        userMailer.deliverWelcomeEmail(*u);
    }
});