026210e80d
This patch implements https://wg21.link/p2609r3. The test code was originally authored by JMazurkiewicz. Notes: - P2609R3 is not officially a Defect Report, but MSVC STL implements it in C++20 mode. Moreover, P2609R3 and P2997R1 touch exactly the same set of concepts, and MSVC STL and libc++ have already treated P2997R1 as a DR. - This patch also adjusted feature-test macros. + In C++20 mode, the value of __cpp_lib_ranges should be `202110L` because - `202202L` covers `range_adaptor_closure` (P2387R3), and - `202207L` covers move-only types in range adaptors (P2494R2). And all of these changes are only available since C++23 mode. + In C++23 mode, the value should be `202406L` because - `202211L` covers removing poison overloads (P2602R2), - `202302L` covers relaxing projected value types (P2609R3), and - `202406L` covers removing requirements on `iter_common_reference_t` (P2997R1). And all of these changes are already or being implemented. Fixes #105253. Co-authored-by: Jakub Mazurkiewicz <mazkuba3@gmail.com>
62 lines
2.0 KiB
C++
62 lines
2.0 KiB
C++
// -*- C++ -*-
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef _LIBCPP___ITERATOR_PROJECTED_H
|
|
#define _LIBCPP___ITERATOR_PROJECTED_H
|
|
|
|
#include <__config>
|
|
#include <__iterator/concepts.h>
|
|
#include <__iterator/incrementable_traits.h> // iter_difference_t
|
|
#include <__type_traits/remove_cvref.h>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
# pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
#if _LIBCPP_STD_VER >= 20
|
|
|
|
template <class _It, class _Proj>
|
|
struct __projected_impl {
|
|
struct __type {
|
|
using __primary_template = __type;
|
|
using __projected_iterator = _It;
|
|
using __projected_projection = _Proj;
|
|
|
|
using value_type = remove_cvref_t<indirect_result_t<_Proj&, _It>>;
|
|
indirect_result_t<_Proj&, _It> operator*() const; // not defined
|
|
};
|
|
};
|
|
|
|
template <weakly_incrementable _It, class _Proj>
|
|
struct __projected_impl<_It, _Proj> {
|
|
struct __type {
|
|
using __primary_template = __type;
|
|
using __projected_iterator = _It;
|
|
using __projected_projection = _Proj;
|
|
|
|
using value_type = remove_cvref_t<indirect_result_t<_Proj&, _It>>;
|
|
using difference_type = iter_difference_t<_It>;
|
|
indirect_result_t<_Proj&, _It> operator*() const; // not defined
|
|
};
|
|
};
|
|
|
|
// Note that we implement std::projected in a way that satisfies P2538R1 even in standard
|
|
// modes before C++26 to avoid breaking the ABI between standard modes (even though ABI
|
|
// breaks with std::projected are expected to have essentially no impact).
|
|
template <indirectly_readable _It, indirectly_regular_unary_invocable<_It> _Proj>
|
|
using projected = typename __projected_impl<_It, _Proj>::__type;
|
|
|
|
#endif // _LIBCPP_STD_VER >= 20
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
#endif // _LIBCPP___ITERATOR_PROJECTED_H
|