Sprout/sprout/container/has_sprout_begin.hpp

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/*=============================================================================
Copyright (c) 2011-2019 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
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 SPROUT_CONTAINER_HAS_SPROUT_BEGIN_HPP
#define SPROUT_CONTAINER_HAS_SPROUT_BEGIN_HPP
#include <utility>
#include <sprout/config.hpp>
#include <sprout/type_traits/integral_constant.hpp>
#include <sprout/type_traits/identity.hpp>
#include <sprout/container/begin.hpp>
namespace sprout {
//
// has_sprout_begin
//
namespace detail {
template<typename T>
struct has_sprout_begin_test {
public:
template<
typename U = T,
typename = typename sprout::identity<decltype(sprout::begin(std::declval<U>()))>::type
>
static sprout::true_type test(int);
static sprout::false_type test(...);
};
#if defined(_MSC_VER) && (_MSC_VER > 1900)
template<typename T, typename Base_ = typename sprout::identity<decltype(sprout::detail::has_sprout_begin_test<T>::test(0))>::type>
struct has_sprout_begin
: public Base_
{};
#else
template<typename T>
struct has_sprout_begin
: public sprout::identity<decltype(sprout::detail::has_sprout_begin_test<T>::test(0))>::type
{};
#endif
} // namespace detail
template<typename T>
struct has_sprout_begin
: public sprout::detail::has_sprout_begin<T>
{};
#if SPROUT_USE_VARIABLE_TEMPLATES
template<typename T>
SPROUT_STATIC_CONSTEXPR bool has_sprout_begin_v = sprout::has_sprout_begin<T>::value;
#endif // #if SPROUT_USE_VARIABLE_TEMPLATES
} // namespace sprout
#endif // #ifndef SPROUT_CONTAINER_HAS_SPROUT_BEGIN_HPP