From 60362f5419335b6198fc049fee05f7beeba312ae Mon Sep 17 00:00:00 2001
From: bolero-MURAKAMI <bolero.murakami@gmail.com>
Date: Sun, 21 Feb 2016 16:49:14 +0900
Subject: [PATCH] add conversion to atd classes

---
 sprout/array/array.hpp            |  8 ++++++--
 sprout/tuple/tuple/tuple_decl.hpp | 16 ++++++++++++++++
 sprout/utility/pair/pair_decl.hpp |  7 +++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/sprout/array/array.hpp b/sprout/array/array.hpp
index 04063fc9..25e2f2c8 100644
--- a/sprout/array/array.hpp
+++ b/sprout/array/array.hpp
@@ -70,7 +70,9 @@ namespace sprout {
 	private:
 		template<sprout::index_t... Indexes>
 		SPROUT_CONSTEXPR std::array<T, N>
-		to_std_array(sprout::index_tuple<Indexes...>) const {
+		to_std_array(sprout::index_tuple<Indexes...>) const
+		SPROUT_NOEXCEPT_IF(sprout::is_nothrow_copy_constructible<typename std::remove_cv<T>::type>::value)
+		{
 			return std::array<T, N>{{elems[Indexes]...}};
 		}
 	public:
@@ -265,7 +267,9 @@ namespace sprout {
 		}
 #endif
 
-		SPROUT_CONSTEXPR operator std::array<T, N>() const {
+		SPROUT_CONSTEXPR operator std::array<T, N>() const
+		SPROUT_NOEXCEPT_IF(sprout::is_nothrow_copy_constructible<typename std::remove_cv<T>::type>::value)
+		{
 			return to_std_array(sprout::make_index_tuple<N>::make());
 		}
 	};
diff --git a/sprout/tuple/tuple/tuple_decl.hpp b/sprout/tuple/tuple/tuple_decl.hpp
index 851a4012..66151dae 100644
--- a/sprout/tuple/tuple/tuple_decl.hpp
+++ b/sprout/tuple/tuple/tuple_decl.hpp
@@ -22,6 +22,7 @@
 #include <sprout/utility/pack.hpp>
 #include <sprout/utility/pair/pair_fwd.hpp>
 #include <sprout/type_traits/integral_constant.hpp>
+#include <sprout/type_traits/is_nothrow_copy_constructible.hpp>
 #include <sprout/type_traits/is_convert_constructible.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
 #include <sprout/tpp/algorithm/all_of.hpp>
@@ -298,6 +299,11 @@ namespace sprout {
 				typedef typename std::decay<Tuple>::type type;
 				sprout::eat((sprout::eat(base_type::template get<Indexes>(*this) = sprout::move(type::template get<Indexes>(SPROUT_FORWARD(Tuple, t)))), 0)...);
 			}
+			template<sprout::index_t... Indexes>
+			SPROUT_CONSTEXPR std::tuple<Types...>
+			to_std_tuple(sprout::index_tuple<Indexes...>) {
+				return std::tuple<Types...>(base_type::template get<Indexes>(*this)...);
+			}
 		public:
 			// tuple construction
 			SPROUT_CONSTEXPR tuple()
@@ -462,6 +468,12 @@ namespace sprout {
 			{
 				swap_impl(other, index_tuple_type());
 			}
+
+			SPROUT_EXPLICIT_CONVERSION SPROUT_CONSTEXPR operator std::tuple<Types...>() const
+			SPROUT_NOEXCEPT_IF(sprout::tpp::all_of<sprout::is_nothrow_copy_constructible<Types>...>::value)
+			{
+				return to_std_tuple(index_tuple_type());;
+			}
 		};
 		template<>
 		class tuple<> {
@@ -489,6 +501,10 @@ namespace sprout {
 			SPROUT_CONSTEXPR tuple(sprout::tuples::flexibly_construct_t, sprout::pair<UType1, UType2>&&) SPROUT_NOEXCEPT {}
 			// tuple swap
 			SPROUT_CXX14_CONSTEXPR void swap(tuple&) SPROUT_NOEXCEPT {}
+
+			SPROUT_CONSTEXPR operator std::tuple<>() const SPROUT_NOEXCEPT {
+				return std::tuple<>();;
+			}
 		};
 
 		//
diff --git a/sprout/utility/pair/pair_decl.hpp b/sprout/utility/pair/pair_decl.hpp
index b7fa3374..8949337c 100644
--- a/sprout/utility/pair/pair_decl.hpp
+++ b/sprout/utility/pair/pair_decl.hpp
@@ -12,6 +12,7 @@
 #include <type_traits>
 #include <sprout/config.hpp>
 #include <sprout/index_tuple/metafunction.hpp>
+#include <sprout/type_traits/is_nothrow_copy_constructible.hpp>
 #include <sprout/utility/forward.hpp>
 #include <sprout/utility/swap.hpp>
 #include <sprout/utility/pair/pair_fwd.hpp>
@@ -162,6 +163,12 @@ namespace sprout {
 			sprout::swap(first, other.first);
 			sprout::swap(second, other.second);
 		}
+
+		SPROUT_EXPLICIT_CONVERSION SPROUT_CONSTEXPR operator std::pair<T1, T2>() const
+		SPROUT_NOEXCEPT_IF(sprout::is_nothrow_copy_constructible<T1>::value && sprout::is_nothrow_copy_constructible<T2>::value)
+		{
+			return std::pair<T1, T2>(first, second);
+		}
 	};
 
 	//