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- /*=============================================================================
- Copyright (c) 2016 Lee Clagett
- Copyright (c) 2018 Kohei Takahashi
- Distributed under the Boost Software License, Version 1.0. (See accompanying
- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- ==============================================================================*/
- #ifndef FUSION_AND_07152016_1625
- #define FUSION_AND_07152016_1625
- #include <boost/config.hpp>
- #include <boost/config/workaround.hpp>
- #include <boost/type_traits/integral_constant.hpp>
- #if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
- #error fusion::detail::and_ requires variadic templates
- #endif
- namespace boost { namespace fusion { namespace detail {
- #if defined(BOOST_NO_CXX17_FOLD_EXPRESSIONS) \
- || BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1913))
- template<typename ...Cond>
- struct and_impl : false_type {};
- template<typename ...T>
- struct and_impl<integral_constant<T, true>...> : true_type {};
- // This specialization is necessary to avoid MSVC-12 variadics bug.
- template<bool ...Cond>
- struct and_impl1 : and_impl<integral_constant<bool, Cond>...> {};
- /* fusion::detail::and_ differs from mpl::and_ in the following ways:
- - The empty set is valid and returns true
- - A single element set is valid and returns the identity
- - There is no upper bound on the set size
- - The conditions are evaluated at once, and are not short-circuited. This
- reduces instantations when returning true; the implementation is not
- recursive. */
- template<typename ...Cond>
- struct and_ : and_impl1<Cond::value...> {};
- #else
- template <typename ...Cond>
- struct and_ : integral_constant<bool, ((bool)Cond::value && ...)> {};
- #endif
- }}}
- #endif // FUSION_AND_07152016_1625
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