// Copyright Louis Dionne 2013-2017 // Distributed under the Boost Software License, Version 1.0. // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) #include #include #include #include #include namespace hana = boost::hana; auto to_string = [](auto x) { std::ostringstream ss; ss << x; return ss.str(); }; int main() { auto f = [=](auto element, std::string s) { return "f(" + to_string(element) + ", " + s + ")"; }; // with an initial state BOOST_HANA_RUNTIME_CHECK( hana::fold_right(hana::make_tuple(1, '2', 3.0, 4), "5", f) == "f(1, f(2, f(3, f(4, 5))))" ); // without initial state BOOST_HANA_RUNTIME_CHECK( hana::fold_right(hana::make_tuple(1, '2', 3.0, 4, "5"), f) == "f(1, f(2, f(3, f(4, 5))))" ); }