/*=============================================================================
    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
