71 lines
2.1 KiB
C++
71 lines
2.1 KiB
C++
// Copyright Louis Dionne 2013-2017
|
|
// Distributed under the Boost Software License, Version 1.0.
|
|
// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
|
|
|
|
#include <boost/hana/assert.hpp>
|
|
#include <boost/hana/config.hpp>
|
|
#include <boost/hana/first.hpp>
|
|
#include <boost/hana/pair.hpp>
|
|
#include <boost/hana/second.hpp>
|
|
|
|
#include <utility>
|
|
namespace hana = boost::hana;
|
|
|
|
|
|
struct MoveOnly {
|
|
int data_;
|
|
MoveOnly(MoveOnly const&) = delete;
|
|
MoveOnly& operator=(MoveOnly const&) = delete;
|
|
MoveOnly(int data = 1) : data_(data) { }
|
|
MoveOnly(MoveOnly&& x) : data_(x.data_) { x.data_ = 0; }
|
|
|
|
MoveOnly& operator=(MoveOnly&& x)
|
|
{ data_ = x.data_; x.data_ = 0; return *this; }
|
|
|
|
bool operator==(const MoveOnly& x) const { return data_ == x.data_; }
|
|
};
|
|
|
|
struct MoveOnlyDerived : MoveOnly {
|
|
MoveOnlyDerived(MoveOnlyDerived&&) = default;
|
|
MoveOnlyDerived(int data = 1) : MoveOnly(data) { }
|
|
};
|
|
|
|
constexpr auto in_constexpr_context(int a, short b) {
|
|
hana::pair<int, short> p1(a, b);
|
|
hana::pair<int, short> p2;
|
|
hana::pair<double, long> p3;
|
|
p2 = std::move(p1);
|
|
p3 = std::move(p2);
|
|
return p3;
|
|
}
|
|
|
|
int main() {
|
|
// from pair<T, U> to pair<T, U>
|
|
{
|
|
hana::pair<MoveOnly, short> p1(MoveOnly{3}, 4);
|
|
hana::pair<MoveOnly, short> p2;
|
|
p2 = std::move(p1);
|
|
BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3});
|
|
BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
|
|
}
|
|
|
|
// from pair<T, U> to pair<V, W>
|
|
{
|
|
hana::pair<MoveOnlyDerived, short> p1(MoveOnlyDerived{3}, 4);
|
|
hana::pair<MoveOnly, long> p2;
|
|
p2 = std::move(p1);
|
|
BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3});
|
|
BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
|
|
}
|
|
|
|
// make sure that also works in a constexpr context
|
|
// (test fails under GCC <= 6 due to buggy constexpr)
|
|
#if BOOST_HANA_CONFIG_GCC >= BOOST_HANA_CONFIG_VERSION(7, 0, 0)
|
|
{
|
|
constexpr auto p = in_constexpr_context(3, 4);
|
|
static_assert(hana::first(p) == 3, "");
|
|
static_assert(hana::second(p) == 4, "");
|
|
}
|
|
#endif
|
|
}
|