1/*!
2@file
3Defines `boost::hana::contains` and `boost::hana::in`.
4
5Copyright Louis Dionne 2013-2022
6Distributed 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_CONTAINS_HPP
11#define BOOST_HANA_CONTAINS_HPP
12
13#include <boost/hana/fwd/contains.hpp>
14
15#include <boost/hana/any_of.hpp>
16#include <boost/hana/concept/searchable.hpp>
17#include <boost/hana/config.hpp>
18#include <boost/hana/core/dispatch.hpp>
19#include <boost/hana/equal.hpp>
20
21
22namespace boost { namespace hana {
23 //! @cond
24 template <typename Xs, typename Key>
25 constexpr auto contains_t::operator()(Xs&& xs, Key&& key) const {
26 using S = typename hana::tag_of<Xs>::type;
27 using Contains = BOOST_HANA_DISPATCH_IF(contains_impl<S>,
28 hana::Searchable<S>::value
29 );
30
31 #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
32 static_assert(hana::Searchable<S>::value,
33 "hana::contains(xs, key) requires 'xs' to be a Searchable");
34 #endif
35
36 return Contains::apply(static_cast<Xs&&>(xs),
37 static_cast<Key&&>(key));
38 }
39 //! @endcond
40
41 template <typename S, bool condition>
42 struct contains_impl<S, when<condition>> : default_ {
43 template <typename Xs, typename X>
44 static constexpr auto apply(Xs&& xs, X&& x) {
45 return hana::any_of(static_cast<Xs&&>(xs),
46 hana::equal.to(static_cast<X&&>(x)));
47 }
48 };
49}} // end namespace boost::hana
50
51#endif // !BOOST_HANA_CONTAINS_HPP
52

source code of boost/libs/hana/include/boost/hana/contains.hpp