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Add initializer list support

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This commit is contained in:
Peter Dimov
2017-05-31 04:19:40 +03:00
parent 8301228e22
commit 755bc60c2b
5 changed files with 67 additions and 7 deletions
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22
include/boost/variant2/variant.hpp
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@@ -749,8 +749,10 @@ public:
{
}
template<class U, class V, class... A>
constexpr explicit variant( in_place_type_t<U>, std::initializer_list<V>, A&&... a );
template<class U, class V, class... A, class I = mp_find<variant<T...>, U>>
constexpr explicit variant( in_place_type_t<U>, std::initializer_list<V> il, A&&... a ): variant_base( I(), il, std::forward<A>(a)... )
{
}
template<std::size_t I, class... A>
constexpr explicit variant( in_place_index_t<I>, A&&... a ): variant_base( mp_size_t<I>(), std::forward<A>(a)... )
@@ -758,7 +760,9 @@ public:
}
template<std::size_t I, class V, class... A>
constexpr explicit variant( in_place_index_t<I>, std::initializer_list<V>, A&&... );
constexpr explicit variant( in_place_index_t<I>, std::initializer_list<V> il, A&&... a ): variant_base( mp_size_t<I>(), il, std::forward<A>(a)... )
{
}
// assignment
variant& operator=( variant const & r )
@@ -836,7 +840,11 @@ public:
return _get_impl( I() );
}
template<class U, class V, class... A> U& emplace( std::initializer_list<V> il, A&&... a );
template<class U, class V, class... A, class I = mp_find<variant<T...>, U>> U& emplace( std::initializer_list<V> il, A&&... a )
{
variant_base::template emplace<I::value>( il, std::forward<A>(a)... );
return _get_impl( I() );
}
template<std::size_t I, class... A> variant_alternative_t<I, variant<T...>>& emplace( A&&... a )
{
@@ -844,7 +852,11 @@ public:
return _get_impl( mp_size_t<I>() );
}
template<std::size_t I, class V, class... A> variant_alternative_t<I, variant<T...>>& emplace( std::initializer_list<V> il, A&&... a );
template<std::size_t I, class V, class... A> variant_alternative_t<I, variant<T...>>& emplace( std::initializer_list<V> il, A&&... a )
{
variant_base::template emplace<I>( il, std::forward<A>(a)... );
return _get_impl( mp_size_t<I>() );
}
// value status

8
test/variant_emplace_index.cpp
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@@ -128,6 +128,14 @@ int main()
v.emplace<3>();
BOOST_TEST_EQ( v.index(), 3 );
BOOST_TEST_EQ( get<3>(v), std::string() );
v.emplace<3>( { 'a', 'b' } );
BOOST_TEST_EQ( v.index(), 3 );
BOOST_TEST_EQ( get<3>(v), (std::string{ 'a', 'b'}) );
v.emplace<3>( { 'c', 'd' }, std::allocator<char>() );
BOOST_TEST_EQ( v.index(), 3 );
BOOST_TEST_EQ( get<3>(v), (std::string{ 'c', 'd'}) );
}
{

8
test/variant_emplace_type.cpp
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@@ -116,6 +116,14 @@ int main()
v.emplace<std::string>();
BOOST_TEST_EQ( v.index(), 3 );
BOOST_TEST_EQ( get<3>(v), std::string() );
v.emplace<std::string>( { 'a', 'b' } );
BOOST_TEST_EQ( v.index(), 3 );
BOOST_TEST_EQ( get<3>(v), (std::string{ 'a', 'b' }) );
v.emplace<std::string>( { 'c', 'd' }, std::allocator<char>() );
BOOST_TEST_EQ( v.index(), 3 );
BOOST_TEST_EQ( get<3>(v), (std::string{ 'c', 'd' }) );
}
{

18
test/variant_in_place_index_construct.cpp
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@@ -17,8 +17,8 @@ using namespace boost::variant2;
struct X
{
X() = default;
X( in_place_index_t<0> ) = delete;
X() = default;
X( in_place_index_t<0> ) = delete;
};
int main()
@@ -120,5 +120,19 @@ int main()
BOOST_TEST_EQ( get<5>(v), std::string( 4, 'a' ) );
}
{
variant<int, int, float, float, std::string, std::string> v( in_place_index<4>, { 'a', 'b', 'c' } );
BOOST_TEST_EQ( v.index(), 4 );
BOOST_TEST_EQ( get<4>(v), (std::string{ 'a', 'b', 'c' }) );
}
{
variant<int, int, float, float, std::string, std::string> v( in_place_index<5>, { 'a', 'b', 'c' }, std::allocator<char>() );
BOOST_TEST_EQ( v.index(), 5 );
BOOST_TEST_EQ( get<5>(v), (std::string{ 'a', 'b', 'c' }) );
}
return boost::report_errors();
}

18
test/variant_in_place_type_construct.cpp
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@@ -112,5 +112,23 @@ int main()
BOOST_TEST( holds_alternative<std::string>(v) );
}
{
variant<int, int, float, float, std::string> v( in_place_type<std::string>, { 'a', 'b', 'c' } );
BOOST_TEST_EQ( v.index(), 4 );
BOOST_TEST_EQ( get<4>(v), (std::string{ 'a', 'b', 'c' }) );
BOOST_TEST( holds_alternative<std::string>(v) );
}
{
variant<int, int, float, float, std::string> v( in_place_type<std::string>, { 'a', 'b', 'c' }, std::allocator<char>() );
BOOST_TEST_EQ( v.index(), 4 );
BOOST_TEST_EQ( get<4>(v), (std::string{ 'a', 'b', 'c' }) );
BOOST_TEST( holds_alternative<std::string>(v) );
}
return boost::report_errors();
}