/*! @file Defines `boost::hana::monadic_compose`. @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_MONADIC_COMPOSE_HPP #define BOOST_HANA_MONADIC_COMPOSE_HPP #include <boost/hana/fwd/monadic_compose.hpp> #include <boost/hana/chain.hpp> #include <boost/hana/concept/monad.hpp> #include <boost/hana/config.hpp> #include <boost/hana/core/dispatch.hpp> #include <boost/hana/functional/partial.hpp> BOOST_HANA_NAMESPACE_BEGIN namespace detail { struct monadic_compose_helper { template <typename F, typename G, typename X> constexpr decltype(auto) operator()(F&& f, G&& g, X&& x) const { using M = typename hana::tag_of<decltype(g(x))>::type; #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS static_assert(hana::Monad<M>::value, "hana::monadic_compose(f, g) requires 'g' to return a monadic value"); #endif return hana::chain(static_cast<G&&>(g)(static_cast<X&&>(x)), static_cast<F&&>(f)); } }; } //! @cond template <typename F, typename G> constexpr auto monadic_compose_t::operator()(F&& f, G&& g) const { return hana::partial(detail::monadic_compose_helper{}, static_cast<F&&>(f), static_cast<G&&>(g) ); } //! @endcond BOOST_HANA_NAMESPACE_END #endif // !BOOST_HANA_MONADIC_COMPOSE_HPP