1/*=============================================================================
2 Copyright (c) 2016 Lee Clagett
3 Copyright (c) 2018 Kohei Takahashi
4
5 Distributed under the Boost Software License, Version 1.0. (See accompanying
6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7==============================================================================*/
8#ifndef FUSION_AND_07152016_1625
9#define FUSION_AND_07152016_1625
10
11#include <boost/config.hpp>
12#include <boost/config/workaround.hpp>
13#include <boost/type_traits/integral_constant.hpp>
14
15#if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
16#error fusion::detail::and_ requires variadic templates
17#endif
18
19namespace boost { namespace fusion { namespace detail {
20#if defined(BOOST_NO_CXX17_FOLD_EXPRESSIONS) \
21 || BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1913))
22 template<typename ...Cond>
23 struct and_impl : false_type {};
24
25 template<typename ...T>
26 struct and_impl<integral_constant<T, true>...> : true_type {};
27
28 // This specialization is necessary to avoid MSVC-12 variadics bug.
29 template<bool ...Cond>
30 struct and_impl1 : and_impl<integral_constant<bool, Cond>...> {};
31
32 /* fusion::detail::and_ differs from mpl::and_ in the following ways:
33 - The empty set is valid and returns true
34 - A single element set is valid and returns the identity
35 - There is no upper bound on the set size
36 - The conditions are evaluated at once, and are not short-circuited. This
37 reduces instantations when returning true; the implementation is not
38 recursive. */
39 template<typename ...Cond>
40 struct and_ : and_impl1<Cond::value...> {};
41#else
42 template <typename ...Cond>
43 struct and_ : integral_constant<bool, ((bool)Cond::value && ...)> {};
44#endif
45}}}
46
47#endif // FUSION_AND_07152016_1625
48