/*! @file Defines `boost::hana::Monoid`. @copyright Louis Dionne 2013-2016 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) */ #ifndef BOOST_HANA_CONCEPT_MONOID_HPP #define BOOST_HANA_CONCEPT_MONOID_HPP #include <boost/hana/fwd/concept/monoid.hpp> #include <boost/hana/config.hpp> #include <boost/hana/core/default.hpp> #include <boost/hana/core/tag_of.hpp> #include <boost/hana/detail/integral_constant.hpp> #include <boost/hana/plus.hpp> #include <boost/hana/zero.hpp> BOOST_HANA_NAMESPACE_BEGIN template <typename M> struct Monoid : hana::integral_constant<bool, !is_default<zero_impl<typename tag_of<M>::type>>::value && !is_default<plus_impl<typename tag_of<M>::type, typename tag_of<M>::type>>::value > { }; BOOST_HANA_NAMESPACE_END #endif // !BOOST_HANA_CONCEPT_MONOID_HPP