1 /*!
2 @file
3 Defines `boost::hana::and_`.
4 
5 @copyright Louis Dionne 2013-2017
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_AND_HPP
11 #define BOOST_HANA_AND_HPP
12 
13 #include <boost/hana/fwd/and.hpp>
14 
15 #include <boost/hana/concept/logical.hpp>
16 #include <boost/hana/config.hpp>
17 #include <boost/hana/core/dispatch.hpp>
18 #include <boost/hana/detail/variadic/foldl1.hpp>
19 #include <boost/hana/if.hpp>
20 
21 
22 BOOST_HANA_NAMESPACE_BEGIN
23     //! @cond
24     template <typename X, typename Y>
operator ()(X && x,Y && y) const25     constexpr decltype(auto) and_t::operator()(X&& x, Y&& y) const {
26         using Bool = typename hana::tag_of<X>::type;
27         using And = BOOST_HANA_DISPATCH_IF(and_impl<Bool>,
28             hana::Logical<Bool>::value
29         );
30 
31     #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
32         static_assert(hana::Logical<Bool>::value,
33         "hana::and_(x, y) requires 'x' to be a Logical");
34     #endif
35 
36         return And::apply(static_cast<X&&>(x), static_cast<Y&&>(y));
37     }
38 
39     template <typename X, typename ...Y>
operator ()(X && x,Y &&...y) const40     constexpr decltype(auto) and_t::operator()(X&& x, Y&& ...y) const {
41         return detail::variadic::foldl1(
42             *this,
43             static_cast<X&&>(x),
44             static_cast<Y&&>(y)...
45         );
46     }
47     //! @endcond
48 
49     template <typename L, bool condition>
50     struct and_impl<L, when<condition>> : default_ {
51         template <typename X, typename Y>
applyand_impl52         static constexpr decltype(auto) apply(X&& x, Y&& y) {
53             return hana::if_(x, static_cast<Y&&>(y), x);
54         }
55     };
56 BOOST_HANA_NAMESPACE_END
57 
58 #endif // !BOOST_HANA_AND_HPP
59