[libc++][nfc] Move incrementable_traits and indirectly_readable_traits into separate headers.

[ldionne]

LGTM with fixes applied and CI passing. Thanks!

libcxx/include/__iterator/incrementable_traits.h

2

This needs a license. What I generally do is copy-paste an existing header and replace the contents. That makes sure I get the right boilerplate (not that we shouldn't work on reducing that boilerplate if possible, especially the pragma stuff).

libcxx/include/__iterator/readable_traits.h

17

It would make sense to hoist that out of this file and into <iterator>. Same for incrementable traits.

[zoecarver]

libcxx/include/__iterator/readable_traits.h

17

Eh, I don't know. I'd be OK doing that and adding an #error here if it's not defined. I'd kind of like all our headers to always be includable, though.

[zoecarver]

• Add licence comment.

[ldionne]

libcxx/include/__iterator/readable_traits.h

17

Ok, this is non-blocking anyway, feel free to leave as-is. Actually when we only support compilers that support concepts, this will become #if C++ >= 20, which we should leave in this header. So it makes sense to keep.

[zoecarver]

libcxx/include/__iterator/readable_traits.h

17

SGTM.

[cjdb]

LGTM with changes applied.

libcxx/include/__iterator/incrementable_traits.h

60

Please delete this now that we have the design doc.

libcxx/include/concepts

443–454

Please put these in __iterator/concepts.h. They shouldn't be in <concepts>.

[zoecarver]

• Apply cjdb's comments.

[zoecarver]

• Rebase

[zoecarver]

I accidently updated this patch instead of D100686. So, I'm just putting back the correct patch here.

[cjdb]

libcxx/include/__iterator/concepts.h

1

I made a mistake: putting them in this header will create circular dependencies, since iterator_traits needs these exposition-only concepts and __iterator_traits/concepts.h will depends on iterator_traits. They, along with the cpp17-*-iterator concepts should either be in __iterator/iterator_traits.h.

libcxx/include/CMakeLists.txt

 set(files
   __availability
   __bit_reference
   __bits
   __bsd_locale_defaults.h
   __bsd_locale_fallbacks.h
   __config
   __debug
   __errc
   __functional_03
   __functional_base
   __functional_base_03
   __hash_table
+  __iterator/concepts.h
+  __iterator/incrementable_traits.h
+  __iterator/readable_traits.h
   __libcpp_version
   __locale
   __memory/addressof.h
   __memory/allocation_guard.h
   __memory/allocator.h
   __memory/allocator_traits.h
   __memory/auto_ptr.h
   __memory/compressed_pair.h

libcxx/include/__iterator/concepts.h

+// -*- 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_CONCEPTS_TRAITS_H
+#define _LIBCPP___ITERATOR_CONCEPTS_TRAITS_H
+
+#include <__config>
+#include <concepts>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+template<class _Tp>
+using __with_reference = _Tp&;
+
+template<class _Tp>
+concept __referenceable = requires {
+  typename __with_reference<_Tp>;
+};
+
+template<class _Tp>
+concept __dereferenceable = requires(_Tp& __t) {
+  { *__t } -> __referenceable; // not required to be equality-preserving
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ITERATOR_CONCEPTS_TRAITS_H

libcxx/include/__iterator/incrementable_traits.h

+// -*- 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_INCREMENTABLE_TRAITS_H
+#define _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// [incrementable.traits]
+template<class> struct incrementable_traits {};
+
+template<class _Tp>
+requires is_object_v<_Tp>
+struct incrementable_traits<_Tp*> {
+  using difference_type = ptrdiff_t;
+};
+
+template<class _Ip>
+struct incrementable_traits<const _Ip> : incrementable_traits<_Ip> {};
+
+template<class _Tp>
+concept __has_member_difference_type = requires { typename _Tp::difference_type; };
+
+template<__has_member_difference_type _Tp>
+struct incrementable_traits<_Tp> {
+  using difference_type = typename _Tp::difference_type;
+};
+
+template<class _Tp>
+concept __has_integral_minus =
+  requires(const _Tp& __x, const _Tp& __y) {
+    { __x - __y } -> integral;
+  };
+
+template<__has_integral_minus _Tp>
+requires (!__has_member_difference_type<_Tp>)
+struct incrementable_traits<_Tp> {
+  using difference_type = make_signed_t<decltype(declval<_Tp>() - declval<_Tp>())>;
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H

libcxx/include/__iterator/readable_traits.h

+// -*- 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_READABLE_TRAITS_H
+#define _LIBCPP___ITERATOR_READABLE_TRAITS_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// [readable.traits]
+template<class> struct __cond_value_type {};
+
+template<class _Tp>
+requires is_object_v<_Tp>
+struct __cond_value_type<_Tp> { using value_type = remove_cv_t<_Tp>; };
+
+template<class _Tp>
+concept __has_member_value_type = requires { typename _Tp::value_type; };
+
+template<class _Tp>
+concept __has_member_element_type = requires { typename _Tp::element_type; };
+
+template<class> struct indirectly_readable_traits {};
+
+template<class _Ip>
+requires is_array_v<_Ip>
+struct indirectly_readable_traits<_Ip> {
+  using value_type = remove_cv_t<remove_extent_t<_Ip>>;
+};
+
+template<class _Ip>
+struct indirectly_readable_traits<const _Ip> : indirectly_readable_traits<_Ip> {};
+
+template<class _Tp>
+struct indirectly_readable_traits<_Tp*> : __cond_value_type<_Tp> {};
+
+template<__has_member_value_type _Tp>
+struct indirectly_readable_traits<_Tp>
+  : __cond_value_type<typename _Tp::value_type> {};
+
+template<__has_member_element_type _Tp>
+struct indirectly_readable_traits<_Tp>
+  : __cond_value_type<typename _Tp::element_type> {};
+
+// Pre-emptively applies LWG3541
+template<__has_member_value_type _Tp>
+requires __has_member_element_type<_Tp>
+struct indirectly_readable_traits<_Tp> {};
+template<__has_member_value_type _Tp>
+requires __has_member_element_type<_Tp> &&
+         same_as<remove_cv_t<typename _Tp::element_type>,
+                 remove_cv_t<typename _Tp::value_type>>
+struct indirectly_readable_traits<_Tp>
+  : __cond_value_type<typename _Tp::value_type> {};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ITERATOR_READABLE_TRAITS_H

libcxx/include/concepts

 
 // [concept.equiv]
 template<class _Rp, class _Tp, class _Up>
 concept equivalence_relation = relation<_Rp, _Tp, _Up>;
 
 // [concept.strictweakorder]
 template<class _Rp, class _Tp, class _Up>
 concept strict_weak_order = relation<_Rp, _Tp, _Up>;
+
 #endif //_LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP_CONCEPTS

libcxx/include/iterator

 #include <__config>
 #include <iosfwd> // for forward declarations of vector and string.
 #include <__functional_base>
 #include <type_traits>
 #include <compare>
 #include <concepts>
 #include <cstddef>
 #include <initializer_list>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/readable_traits.h>
 #include <__memory/addressof.h>
 #include <__memory/pointer_traits.h>
 #include <version>
 
 #include <__debug>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if !defined(_LIBCPP_HAS_NO_RANGES)
 
-template<class _Tp>
-using __with_reference = _Tp&;
-
-template<class _Tp>
-concept __referenceable = requires {
-  typename __with_reference<_Tp>;
-};
-
-template<class _Tp>
-concept __dereferenceable = requires(_Tp& __t) {
-  { *__t } -> __referenceable; // not required to be equality-preserving
-};
-
-// [incrementable.traits]
-template<class> struct incrementable_traits {};
-
-template<class _Tp>
-requires is_object_v<_Tp>
-struct incrementable_traits<_Tp*> {
-  using difference_type = ptrdiff_t;
-};
-
-template<class _Ip>
-struct incrementable_traits<const _Ip> : incrementable_traits<_Ip> {};
-
-template<class _Tp>
-concept __has_member_difference_type = requires { typename _Tp::difference_type; };
-
-template<__has_member_difference_type _Tp>
-struct incrementable_traits<_Tp> {
-  using difference_type = typename _Tp::difference_type;
-};
-
-template<class _Tp>
-concept __has_integral_minus =
-  requires(const _Tp& __x, const _Tp& __y) {
-    { __x - __y } -> integral;
-  };
-
-template<__has_integral_minus _Tp>
-requires (!__has_member_difference_type<_Tp>)
-struct incrementable_traits<_Tp> {
-  using difference_type = make_signed_t<decltype(declval<_Tp>() - declval<_Tp>())>;
-};
-
-// TODO(cjdb): add iter_difference_t once iterator_traits is cleaned up.
-
-// [readable.traits]
-template<class> struct __cond_value_type {};
-
-template<class _Tp>
-requires is_object_v<_Tp>
-struct __cond_value_type<_Tp> { using value_type = remove_cv_t<_Tp>; };
-
-template<class _Tp>
-concept __has_member_value_type = requires { typename _Tp::value_type; };
-
-template<class _Tp>
-concept __has_member_element_type = requires { typename _Tp::element_type; };
-
-template<class> struct indirectly_readable_traits {};
-
-template<class _Ip>
-requires is_array_v<_Ip>
-struct indirectly_readable_traits<_Ip> {
-  using value_type = remove_cv_t<remove_extent_t<_Ip>>;
-};
-
-template<class _Ip>
-struct indirectly_readable_traits<const _Ip> : indirectly_readable_traits<_Ip> {};
-
-template<class _Tp>
-struct indirectly_readable_traits<_Tp*> : __cond_value_type<_Tp> {};
-
-template<__has_member_value_type _Tp>
-struct indirectly_readable_traits<_Tp>
-  : __cond_value_type<typename _Tp::value_type> {};
-
-template<__has_member_element_type _Tp>
-struct indirectly_readable_traits<_Tp>
-  : __cond_value_type<typename _Tp::element_type> {};
-
-// Pre-emptively applies LWG3541
-template<__has_member_value_type _Tp>
-requires __has_member_element_type<_Tp>
-struct indirectly_readable_traits<_Tp> {};
-template<__has_member_value_type _Tp>
-requires __has_member_element_type<_Tp> &&
-         same_as<remove_cv_t<typename _Tp::element_type>,
-                 remove_cv_t<typename _Tp::value_type>>
-struct indirectly_readable_traits<_Tp>
-  : __cond_value_type<typename _Tp::value_type> {};
-
 // [iterator.traits]
 template<__dereferenceable _Tp>
 using iter_reference_t = decltype(*declval<_Tp&>());
 #endif // !defined(_LIBCPP_HAS_NO_RANGES)
 
 template <class _Iter>
 struct _LIBCPP_TEMPLATE_VIS iterator_traits;