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1 | /*! |
2 | @file | |
3 | Defines `boost::hana::Comonad`. | |
4 | ||
5 | @copyright Louis Dionne 2013-2016 | |
6 | Distributed under the Boost Software License, Version 1.0. | |
7 | (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
8 | */ | |
9 | ||
10 | #ifndef BOOST_HANA_CONCEPT_COMONAD_HPP | |
11 | #define BOOST_HANA_CONCEPT_COMONAD_HPP | |
12 | ||
13 | #include <boost/hana/fwd/concept/comonad.hpp> | |
14 | ||
15 | #include <boost/hana/config.hpp> | |
16 | #include <boost/hana/core/default.hpp> | |
17 | #include <boost/hana/core/tag_of.hpp> | |
18 | #include <boost/hana/duplicate.hpp> | |
19 | #include <boost/hana/extend.hpp> | |
20 | #include <boost/hana/extract.hpp> | |
21 | ||
22 | ||
23 | BOOST_HANA_NAMESPACE_BEGIN | |
24 | template <typename W> | |
25 | struct Comonad { | |
26 | using Tag = typename tag_of<W>::type; | |
27 | static constexpr bool value = !is_default<extract_impl<Tag>>::value && | |
28 | (!is_default<duplicate_impl<Tag>>::value || | |
29 | !is_default<extend_impl<Tag>>::value); | |
30 | }; | |
31 | BOOST_HANA_NAMESPACE_END | |
32 | ||
33 | #endif // !BOOST_HANA_CONCEPT_COMONAD_HPP |