1 /*=============================================================================
2 Copyright (c) 2001-2013 Joel de Guzman
3 Copyright (c) 2018 Kohei Takahashi
5 Distributed under the Boost Software License, Version 1.0. (See accompanying
6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 ==============================================================================*/
8 #if !defined(BOOST_FUSION_MAP_DETAIL_VALUE_AT_KEY_IMPL_02042013_0821)
9 #define BOOST_FUSION_MAP_DETAIL_VALUE_AT_KEY_IMPL_02042013_0821
11 #include <boost/fusion/support/config.hpp>
12 #include <boost/utility/declval.hpp>
14 namespace boost { namespace fusion
20 template <typename Tag>
21 struct value_at_key_impl;
24 struct value_at_key_impl<map_tag>
26 template <typename Sequence, typename Key>
27 struct apply : BOOST_FUSION_DECLTYPE_N3031((
28 boost::declval<Sequence>().get_val(mpl::identity<Key>())