Skip to content

R
riscv-gcc-1
Commit a577f786 by Ville Voutilainen Committed by Ville Voutilainen
Options

Implement the latest proposed resolution of LWG 2756. 

	* include/std/optional (Optional_base(const _Tp&))
	(Optional_base(_Tp&&), using _Base::_Base): Remove.
	(optional(nullopt_t)): New.
	(optional(_Up&&)): Invoke base directly with in_place
	rather than creating a temporary, add default template
	argument, change constraints.
	(optional(const optional<_Up>&)): Invoke base directly
	with in_place, remove unnecessary constraints.
	(optional(optional<_Up>&& __t)): Likewise.
	(optional(in_place_t, _Args&&...)): New.
	(optional(in_place_t, initializer_list<_Up>, _Args&&...)): Likewise.
	(operator=(_Up&&)): Add default template argument, change constraints.
	(operator=(const optional<_Up>&)): Put is_same first in the
	constraints.
	(operator=(optional<_Up>&&)): Likewise.
	* testsuite/20_util/optional/assignment/5.cc: Add a test to
	verify assignment from something that can't be perfect-forwarded.
	* testsuite/20_util/optional/cons/value.cc: Add tests to verify
	that a nested optional is disengaged when constructed
	from a disengaged element type,	and to verify that assignments
	from an engaged element type engage the optional.

From-SVN: r239593
parent 197c757c
Showing with 101 additions and 59 deletions
libstdc++-v3/ChangeLog
2016-08-18 Ville Voutilainen <ville.voutilainen@gmail.com>
Implement the latest proposed resolution of LWG 2756.
* include/std/optional (Optional_base(const _Tp&))
(Optional_base(_Tp&&), using _Base::_Base): Remove.
(optional(nullopt_t)): New.
(optional(_Up&&)): Invoke base directly with in_place
rather than creating a temporary, add default template
argument, change constraints.
(optional(const optional<_Up>&)): Invoke base directly
with in_place, remove unnecessary constraints.
(optional(optional<_Up>&& __t)): Likewise.
(optional(in_place_t, _Args&&...)): New.
(optional(in_place_t, initializer_list<_Up>, _Args&&...)): Likewise.
(operator=(_Up&&)): Add default template argument, change constraints.
(operator=(const optional<_Up>&)): Put is_same first in the
constraints.
(operator=(optional<_Up>&&)): Likewise.
* testsuite/20_util/optional/assignment/5.cc: Add a test to
verify assignment from something that can't be perfect-forwarded.
* testsuite/20_util/optional/cons/value.cc: Add tests to verify
that a nested optional is disengaged when constructed
from a disengaged element type, and to verify that assignments
from an engaged element type engage the optional.
2016-08-18 Tim Shen <timshen@google.com>
Implement <variant>
......
libstdc++-v3/include/std/optional
......@@ -175,12 +175,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _Optional_base{} { }
// Constructors for engaged optionals.
constexpr _Optional_base(const _Tp& __t)
: _M_payload(__t), _M_engaged(true) { }
constexpr _Optional_base(_Tp&& __t)
: _M_payload(std::move(__t)), _M_engaged(true) { }
template<typename... _Args>
constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { }
......@@ -317,12 +311,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
constexpr _Optional_base(nullopt_t) noexcept
: _Optional_base{} { }
constexpr _Optional_base(const _Tp& __t)
: _M_payload(__t), _M_engaged(true) { }
constexpr _Optional_base(_Tp&& __t)
: _M_payload(std::move(__t)), _M_engaged(true) { }
template<typename... _Args>
constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { }
......@@ -478,80 +466,79 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
public:
using value_type = _Tp;
// _Optional_base has the responsibility for construction.
using _Base::_Base;
constexpr optional() = default;
constexpr optional(nullopt_t) noexcept
: _Base(nullopt) { }
// Converting constructors for engaged optionals.
template <typename _Up,
template <typename _Up = _Tp,
enable_if_t<__and_<
__not_<is_same<_Tp, _Up>>,
__not_<__is_optional<decay_t<_Up>>>,
is_constructible<_Tp, _Up&&>,
is_convertible<_Up&&, _Tp>
>::value, bool> = true>
constexpr optional(_Up&& __t)
: _Base(_Tp(std::forward<_Up>(__t))) { }
: _Base(std::in_place, std::forward<_Up>(__t)) { }
template <typename _Up,
template <typename _Up = _Tp,
enable_if_t<__and_<
__not_<is_same<_Tp, _Up>>,
is_constructible<_Tp, _Up&&>,
__not_<is_convertible<_Up&&, _Tp>>
>::value, bool> = false>
__not_<__is_optional<decay_t<_Up>>>,
is_constructible<_Tp, _Up&&>,
__not_<is_convertible<_Up&&, _Tp>>
>::value, bool> = false>
explicit constexpr optional(_Up&& __t)
: _Base(_Tp(std::forward<_Up>(__t))) { }
: _Base(std::in_place, std::forward<_Up>(__t)) { }
template <typename _Up,
enable_if_t<__and_<
__not_<is_same<_Tp, _Up>>,
__not_<is_constructible<
_Tp, const optional<_Up>&>>,
__not_<is_convertible<
const optional<_Up>&, _Tp>>,
is_constructible<_Tp, const _Up&>,
is_convertible<const _Up&, _Tp>
>::value, bool> = true>
constexpr optional(const optional<_Up>& __t)
: _Base(__t ? optional<_Tp>(*__t) : optional<_Tp>()) { }
: _Base(__t ? _Base(std::in_place, *__t) : _Base()) { }
template <typename _Up,
enable_if_t<__and_<
__not_<is_same<_Tp, _Up>>,
__not_<is_constructible<
_Tp, const optional<_Up>&>>,
__not_<is_convertible<
const optional<_Up>&, _Tp>>,
is_constructible<_Tp, const _Up&>,
__not_<is_convertible<const _Up&, _Tp>>
>::value, bool> = false>
explicit constexpr optional(const optional<_Up>& __t)
: _Base(__t ? optional<_Tp>(*__t) : optional<_Tp>()) { }
: _Base(__t ? _Base(std::in_place, *__t) : _Base()) { }
template <typename _Up,
enable_if_t<__and_<
__not_<is_same<_Tp, _Up>>,
__not_<is_constructible<
_Tp, optional<_Up>&&>>,
__not_<is_convertible<
optional<_Up>&&, _Tp>>,
is_constructible<_Tp, _Up&&>,
is_convertible<_Up&&, _Tp>
>::value, bool> = true>
constexpr optional(optional<_Up>&& __t)
: _Base(__t ? optional<_Tp>(std::move(*__t)) : optional<_Tp>()) { }
: _Base(__t ? _Base(std::in_place, std::move(*__t)) : _Base()) { }
template <typename _Up,
enable_if_t<__and_<
__not_<is_same<_Tp, _Up>>,
__not_<is_constructible<
_Tp, optional<_Up>&&>>,
__not_<is_convertible<
optional<_Up>&&, _Tp>>,
is_constructible<_Tp, _Up&&>,
__not_<is_convertible<_Up&&, _Tp>>
>::value, bool> = false>
explicit constexpr optional(optional<_Up>&& __t)
: _Base(__t ? optional<_Tp>(std::move(*__t)) : optional<_Tp>()) { }
: _Base(__t ? _Base(std::in_place, std::move(*__t)) : _Base()) { }
template<typename... _Args>
explicit constexpr optional(in_place_t, _Args&&... __args)
: _Base(std::in_place, std::forward<_Args>(__args)...) { }
template<typename _Up, typename... _Args,
enable_if_t<is_constructible<_Tp,
initializer_list<_Up>&,
_Args&&...>::value,
int>...>
explicit constexpr optional(in_place_t,
initializer_list<_Up> __il,
_Args&&... __args)
: _Base(std::in_place, __il, std::forward<_Args>(__args)...) { }
// Assignment operators.
optional&
......@@ -561,13 +548,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return *this;
}
template<typename _Up,
template<typename _Up = _Tp,
enable_if_t<__and_<
is_constructible<_Tp, _Up>,
is_assignable<_Tp&, _Up>,
__not_<is_same<_Up, nullopt_t>>,
__not_<__is_optional<_Up>>>::value,
bool> = true>
__not_<__is_optional<decay_t<_Up>>>,
is_constructible<_Tp, _Up>,
is_assignable<_Tp&, _Up>>::value,
bool> = true>
optional&
operator=(_Up&& __u)
{
......@@ -581,10 +567,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Up,
enable_if_t<__and_<
is_constructible<_Tp, _Up>,
is_assignable<_Tp&, _Up>,
__not_<is_same<_Tp, _Up>>>::value,
bool> = true>
__not_<is_same<_Tp, _Up>>,
is_constructible<_Tp, _Up>,
is_assignable<_Tp&, _Up>>::value,
bool> = true>
optional&
operator=(const optional<_Up>& __u)
{
......@@ -604,10 +590,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Up,
enable_if_t<__and_<
is_constructible<_Tp, _Up>,
is_assignable<_Tp&, _Up>,
__not_<is_same<_Tp, _Up>>>::value,
bool> = true>
__not_<is_same<_Tp, _Up>>,
is_constructible<_Tp, _Up>,
is_assignable<_Tp&, _Up>>::value,
bool> = true>
optional&
operator=(optional<_Up>&& __u)
{
......
libstdc++-v3/testsuite/20_util/optional/assignment/5.cc
......@@ -19,6 +19,7 @@
// <http://www.gnu.org/licenses/>.
#include <optional>
#include <vector>
#include <testsuite_hooks.h>
int counter = 0;
......@@ -61,6 +62,14 @@ int main()
o = {};
VERIFY( !o );
}
{
std::optional<std::vector<int>> ovi{{1, 2, 3}};
VERIFY(ovi->size() == 3);
VERIFY((*ovi)[0] == 1 && (*ovi)[1] == 2 && (*ovi)[2] == 3);
ovi = {4, 5, 6, 7};
VERIFY(ovi->size() == 4);
VERIFY((*ovi)[0] == 4 && (*ovi)[1] == 5 &&
(*ovi)[2] == 6 && (*ovi)[3] == 7);
}
VERIFY( counter == 0 );
}
libstdc++-v3/testsuite/20_util/optional/cons/value.cc
......@@ -255,4 +255,26 @@ int main()
std::optional<X> ox4;
ox4 = oi;
}
{
std::optional<std::optional<int>> ooi = std::optional<int>();
VERIFY(!bool(ooi));
ooi = std::optional<int>();
VERIFY(!bool(ooi));
ooi = std::optional<int>(42);
VERIFY(bool(ooi));
VERIFY(bool(*ooi));
std::optional<std::optional<int>> ooi2 = std::optional<short>();
VERIFY(!bool(ooi2));
ooi2 = std::optional<short>();
VERIFY(!bool(ooi2));
ooi2 = std::optional<short>(6);
VERIFY(bool(ooi2));
VERIFY(bool(*ooi2));
std::optional<std::optional<int>> ooi3 = std::optional<int>(42);
VERIFY(bool(ooi3));
VERIFY(bool(*ooi3));
std::optional<std::optional<int>> ooi4 = std::optional<short>(6);
VERIFY(bool(ooi4));
VERIFY(bool(*ooi4));
}
}
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment