ad2fbea797
This has the benefit of consistent placement for these macros (outside the namespace, not inside it). This, in turn, makes it more obvious that the condition applies to the entire namespace scope. Compile times are also reduced a bit, since the compiler doesn't have to open a namespace just to close it again. This is enforced with a clang-tidy check. As a drive-by this also fixes a few macro comments.
50 lines
1.4 KiB
C++
50 lines
1.4 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___RANGES_ENABLE_VIEW_H
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#define _LIBCPP___RANGES_ENABLE_VIEW_H
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#include <__concepts/derived_from.h>
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#include <__concepts/same_as.h>
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#include <__config>
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#include <__type_traits/is_class.h>
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#include <__type_traits/remove_cv.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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#if _LIBCPP_STD_VER >= 20
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_LIBCPP_BEGIN_NAMESPACE_STD
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namespace ranges {
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struct view_base {};
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template <class _Derived>
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requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
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class view_interface;
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template <class _Op, class _Yp>
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requires(!same_as<_Op, view_interface<_Yp>>)
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void __is_derived_from_view_interface(view_interface<_Yp>*);
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template <class _Tp>
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inline constexpr bool enable_view = derived_from<_Tp, view_base> || requires {
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ranges::__is_derived_from_view_interface<remove_cv_t<_Tp>>((remove_cv_t<_Tp>*)nullptr);
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};
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} // namespace ranges
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER >= 20
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#endif // _LIBCPP___RANGES_ENABLE_VIEW_H
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