[libc++][format] Mark range formaters as complete.

[Mordante]

Summary

The __cpp_lib_format_ranges feature-test macro only depends on P2286R8
and P2585R0. Note since LWG3750 only affects these two C++23 papers
there is nothing to do for older language versions.

(The __cpp_lib_format feature-test macro depends on the incomplete
formatting for chrono. So this part can't be marked as complete yet.)

This completes

• P2286R8 Formatting ranges
• P2585R0 Improving default container formatting

This partly implements

• LWG3750 Too many papers bump __cpp_lib_format

[ldionne]

LGTM w/ changes!

libcxx/utils/generate_feature_test_macro_components.py

334–335

If you rebase onto main, I think what you want here is just !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT).

340–341

These ones should also be updated to just !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT). I think you created the patch that added this before I changed __availability.

[Mordante]

libcxx/utils/generate_feature_test_macro_components.py

340–341

Yes and since there were no merge conflicts there was no notification of the issue. But at least good we spotted it during review!

libcxx/docs/FeatureTestMacroTable.rst

.. table:: Current Status
     ``__cpp_lib_constexpr_cmath``                     *unimplemented*
     ------------------------------------------------- -----------------
     ``__cpp_lib_constexpr_memory``                    ``202202L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_constexpr_typeinfo``                  ``202106L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_expected``                            ``202202L``
     ------------------------------------------------- -----------------
+    ``__cpp_lib_format_ranges``                       ``202207L``
+    ------------------------------------------------- -----------------
     ``__cpp_lib_formatters``                          *unimplemented*
     ------------------------------------------------- -----------------
     ``__cpp_lib_forward_like``                        ``202207L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_invoke_r``                            ``202106L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_is_scoped_enum``                      ``202011L``
     ------------------------------------------------- -----------------

libcxx/docs/Status/Cxx2b.rst

 
 .. csv-table::
    :file: Cxx2bIssues.csv
    :header-rows: 1
    :widths: auto
 
 .. note::
 
+   .. [#note-LWG3750] LWG3750 Only ``__cpp_lib_format_ranges`` is fully implemented.
    .. [#note-LWG3798] LWG3798: ``join_with_view``, ``zip_transform_view``, and ``adjacent_transform_view`` haven't been done yet since these types aren't implemented yet.

libcxx/docs/Status/Cxx2bIssues.csv

 "`3732 <https://wg21.link/LWG3732>`__","``prepend_range`` and ``append_range`` can't be amortized constant time", "November 2022","|Nothing to do|","","|ranges|"
 "`3736 <https://wg21.link/LWG3736>`__","``move_iterator`` missing ``disable_sized_sentinel_for`` specialization", "November 2022","","","|ranges|"
 "`3737 <https://wg21.link/LWG3737>`__","``take_view::sentinel`` should provide ``operator-``", "November 2022","","","|ranges|"
 "`3738 <https://wg21.link/LWG3738>`__","Missing preconditions for ``take_view`` constructor", "November 2022","|Complete|","16.0","|ranges|"
 "`3743 <https://wg21.link/LWG3743>`__","``ranges::to``'s reserve may be ill-formed", "November 2022","","","|ranges|"
 "`3745 <https://wg21.link/LWG3745>`__","``std::atomic_wait`` and its friends lack ``noexcept``", "November 2022","|Complete|","16.0",""
 "`3746 <https://wg21.link/LWG3746>`__","``optional``'s spaceship with ``U`` with a type derived from optional causes infinite constraint meta-recursion", "November 2022","","","|spaceship|"
 "`3747 <https://wg21.link/LWG3747>`__","``ranges::uninitialized_copy_n``, ``ranges::uninitialized_move_n``, and ``ranges::destroy_n`` should use ``std::move``", "November 2022","","","|ranges|"
-"`3750 <https://wg21.link/LWG3750>`__","Too many papers bump ``__cpp_lib_format``", "November 2022","","","|format|"
+"`3750 <https://wg21.link/LWG3750>`__","Too many papers bump ``__cpp_lib_format``", "November 2022","|Partial| [#note-LWG3750]_","","|format|"
 "`3751 <https://wg21.link/LWG3751>`__","Missing feature macro for ``flat_set``", "November 2022","","","|flat_containers|"
 "`3753 <https://wg21.link/LWG3753>`__","Clarify entity vs. freestanding entity", "November 2022","","",""
 "`3754 <https://wg21.link/LWG3754>`__","Class template expected synopsis contains declarations that do not match the detailed description", "November 2022","|Nothing to do|","",""
 "`3755 <https://wg21.link/LWG3755>`__","``tuple-for-each`` can call ``user-defined`` ``operator,``", "November 2022","|Complete|","17.0",""
 "`3757 <https://wg21.link/LWG3757>`__","What's the effect of ``std::forward_like<void>(x)``?", "November 2022","","",""
 "`3759 <https://wg21.link/LWG3759>`__","``ranges::rotate_copy`` should use ``std::move``", "November 2022","","","|ranges|"
 "`3760 <https://wg21.link/LWG3760>`__","``cartesian_product_view::iterator``'s ``parent_`` is never valid", "November 2022","","","|ranges|"
 "`3761 <https://wg21.link/LWG3761>`__","``cartesian_product_view::iterator::operator-`` should pass by reference", "November 2022","","","|ranges|"

libcxx/docs/Status/Cxx2bPapers.csv

 "`P2508R1 <https://wg21.link/P2508R1>`__","LWG","Exposing ``std::basic-format-string``","July 2022","|Complete|","15.0"
 "`P2513R4 <https://wg21.link/P2513R4>`__","LWG","``char8_t`` Compatibility and Portability Fixes","July 2022","",""
 "`P2517R1 <https://wg21.link/P2517R1>`__","LWG","Add a conditional ``noexcept`` specification to ``std::apply``","July 2022","",""
 "`P2520R0 <https://wg21.link/P2520R0>`__","LWG","``move_iterator`` should be a random access iterator","July 2022","|Complete| [#note-P2520R0]_","17.0","|ranges|"
 "`P2540R1 <https://wg21.link/P2540R1>`__","LWG","Empty Product for certain Views","July 2022","","","|ranges|"
 "`P2549R1 <https://wg21.link/P2549R1>`__","LWG","``std::unexpected`` should have ``error()`` as member accessor","July 2022","|Complete|","16.0"
 "`P2553R1 <https://wg21.link/P2553R1>`__","LWG","Make ``mdspan`` ``size_type`` controllable","July 2022","",""
 "`P2554R0 <https://wg21.link/P2554R0>`__","LWG","C-Array Interoperability of MDSpan","July 2022","",""
-"`P2585R0 <https://wg21.link/P2585R0>`__","LWG","Improving default container formatting","July 2022","|Partial|",""
+"`P2585R0 <https://wg21.link/P2585R0>`__","LWG","Improving default container formatting","July 2022","|Complete|","17.0"
 "`P2590R2 <https://wg21.link/P2590R2>`__","LWG","Explicit lifetime management","July 2022","",""
 "`P2599R2 <https://wg21.link/P2599R2>`__","LWG","``mdspan::size_type`` should be ``index_type``","July 2022","",""
 "`P2604R0 <https://wg21.link/P2604R0>`__","LWG","mdspan: rename pointer and contiguous","July 2022","",""
 "`P2613R1 <https://wg21.link/P2613R1>`__","LWG","Add the missing ``empty`` to ``mdspan``","July 2022","",""
 "","","","","","",""
 "`P1202R5 <https://wg21.link/P1202R5>`__","LWG", "Asymmetric Fences", "November 2022","","","|concurrency TS|"
 "`P1264R2 <https://wg21.link/P1264R2>`__","LWG", "Revising the wording of ``stream`` input operations", "November 2022","|Complete|","9.0",""
 "`P1478R8 <https://wg21.link/P1478R8>`__","LWG", "``Byte-wise`` ``atomic`` ``memcpy``", "November 2022","","","|concurrency TS|"

libcxx/docs/Status/FormatIssues.csv

 Number,Name,Standard,Assignee,Status,First released version
 `P0645 <https://wg21.link/P0645>`_,"Text Formatting","C++20",Mark de Wever,|Complete|,Clang 14
 `P1652 <https://wg21.link/P1652>`_,"Printf corner cases in std::format","C++20",Mark de Wever,|Complete|,Clang 14
 `P1892 <https://wg21.link/P1892>`_,"Extended locale-specific presentation specifiers for std::format","C++20",Mark de Wever,|Complete|,Clang 14
 `P1868 <https://wg21.link/P1868>`_,"width: clarifying units of width and precision in std::format (Implements the unicode support.)","C++20",Mark de Wever,|Complete|,Clang 14
 `P2216 <https://wg21.link/P2216>`_,"std::format improvements","C++20",Mark de Wever,|Complete|,Clang 15
 `P2418 <https://wg21.link/P2418>`__,"Add support for ``std::generator``-like types to ``std::format``","C++20",Mark de Wever,|Complete|, Clang 15
 "`P2093R14 <https://wg21.link/P2093R14>`__","Formatted output","C++23"
 "`P2286R8 <https://wg21.link/P2286R8>`__","Formatting Ranges","C++23","Mark de Wever","|Complete|",Clang 16
 "`P2508R1 <https://wg21.link/P2508R1>`__","Exposing ``std::basic-format-string``","C++23","Mark de Wever","|Complete|", Clang 15
-"`P2585R0 <https://wg21.link/P2585R0>`__","Improving default container formatting","C++23","Mark de Wever","|In progress|"
+"`P2585R0 <https://wg21.link/P2585R0>`__","Improving default container formatting","C++23","Mark de Wever","|Complete|", Clang 17
 "`P2539R4 <https://wg21.link/P2539R4>`__","Should the output of ``std::print`` to a terminal be synchronized with the underlying stream?","C++23"
 "`P2713R1 <https://wg21.link/P2713R1>`__","Escaping improvements in ``std::format``","C++23","Mark de Wever",""
 "`P2675R1 <https://wg21.link/P2675R1>`__","``format``'s width estimation is too approximate and not forward compatible","C++23","Mark de Wever",""
 "`P2572R1 <https://wg21.link/P2572R1>`__","``std::format`` fill character allowances","C++23","Mark de Wever","|In progress|"
 "`P2693R1 <https://wg21.link/P2693R1>`__","Formatting ``thread::id`` and ``stacktrace``","C++23","Mark de Wever","|In progress|"
 `P1361 <https://wg21.link/P1361>`_,"Integration of chrono with text formatting","C++20",Mark de Wever,|In Progress|,
 `P2372 <https://wg21.link/P2372>`__,"Fixing locale handling in chrono formatters","C++20",Mark de Wever,|In Progress|,
 "`P2419R2 <https://wg21.link/P2419R2>`__","Clarify handling of encodings in localized formatting of chrono types","C++23",
 

libcxx/include/version

__cpp_lib_erase_if                                      202002L <deque> <forward_list> <list>
                                                                 <map> <set> <string>
                                                                 <unordered_map> <unordered_set> <vector>
 __cpp_lib_exchange_function                             201304L <utility>
 __cpp_lib_execution                                     201902L <execution>
                                                         201603L // C++17
 __cpp_lib_expected                                      202202L <expected>
 __cpp_lib_filesystem                                    201703L <filesystem>
 __cpp_lib_format                                        202106L <format>
+__cpp_lib_format_ranges                                 202207L <format>
 __cpp_lib_formatters                                    202302L <stacktrace> <thread>
 __cpp_lib_forward_like                                  202207L <utility>
 __cpp_lib_gcd_lcm                                       201606L <numeric>
 __cpp_lib_generic_associative_lookup                    201304L <map> <set>
 __cpp_lib_generic_unordered_lookup                      201811L <unordered_map> <unordered_set>
 __cpp_lib_hardware_interference_size                    201703L <new>
 __cpp_lib_has_unique_object_representations             201606L <type_traits>
 __cpp_lib_hypot                                         201603L <cmath>

 # define __cpp_lib_constexpr_bitset                     202207L
 # define __cpp_lib_constexpr_charconv                   202207L
 // # define __cpp_lib_constexpr_cmath                      202202L
 # undef  __cpp_lib_constexpr_memory
 # define __cpp_lib_constexpr_memory                     202202L
 # define __cpp_lib_constexpr_typeinfo                   202106L
 # define __cpp_lib_expected                             202202L
 # if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+#   define __cpp_lib_format_ranges                      202207L
+# endif
+# if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
 // #   define __cpp_lib_formatters                         202302L
 # endif
 # define __cpp_lib_forward_like                         202207L
 # define __cpp_lib_invoke_r                             202106L
 # define __cpp_lib_is_scoped_enum                       202011L
 // # define __cpp_lib_move_only_function                   202110L
 # undef  __cpp_lib_optional
 # define __cpp_lib_optional                             202110L

libcxx/test/std/language.support/support.limits/support.limits.general/format.version.compile.pass.cpp

 // clang-format off
 
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
 // <format>
 
 // Test the feature test macros defined by <format>
 
-/*  Constant            Value
-    __cpp_lib_format    202106L [C++20]
+/*  Constant                   Value
+    __cpp_lib_format           202106L [C++20]
+    __cpp_lib_format_ranges    202207L [C++2b]
 */
 
 #include <format>
 #include "test_macros.h"
 
 #if TEST_STD_VER < 14
 
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 #elif TEST_STD_VER == 14
 
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 #elif TEST_STD_VER == 17
 
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 #elif TEST_STD_VER == 20
 
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_format
 #     error "__cpp_lib_format should be defined in c++20"
 #   endif
 #   if __cpp_lib_format != 202106L
 #     error "__cpp_lib_format should have the value 202106L in c++20"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_format
 #     error "__cpp_lib_format should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 #elif TEST_STD_VER > 20
 
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_format
 #     error "__cpp_lib_format should be defined in c++2b"
 #   endif
 #   if __cpp_lib_format != 202106L
 #     error "__cpp_lib_format should have the value 202106L in c++2b"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_format
 #     error "__cpp_lib_format should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+#   ifndef __cpp_lib_format_ranges
+#     error "__cpp_lib_format_ranges should be defined in c++2b"
+#   endif
+#   if __cpp_lib_format_ranges != 202207L
+#     error "__cpp_lib_format_ranges should have the value 202207L in c++2b"
+#   endif
+# else
+#   ifdef __cpp_lib_format_ranges
+#     error "__cpp_lib_format_ranges should not be defined when the requirement '!defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)' is not met!"
+#   endif
+# endif
+
 #endif // TEST_STD_VER > 20
 

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp

/*  Constant                                       Value
     __cpp_lib_endian                               201907L [C++20]
     __cpp_lib_erase_if                             202002L [C++20]
     __cpp_lib_exchange_function                    201304L [C++14]
     __cpp_lib_execution                            201603L [C++17]
                                                    201902L [C++20]
     __cpp_lib_expected                             202202L [C++2b]
     __cpp_lib_filesystem                           201703L [C++17]
     __cpp_lib_format                               202106L [C++20]
+    __cpp_lib_format_ranges                        202207L [C++2b]
     __cpp_lib_formatters                           202302L [C++2b]
     __cpp_lib_forward_like                         202207L [C++2b]
     __cpp_lib_gcd_lcm                              201606L [C++17]
     __cpp_lib_generic_associative_lookup           201304L [C++14]
     __cpp_lib_generic_unordered_lookup             201811L [C++20]
     __cpp_lib_hardware_interference_size           201703L [C++17]
     __cpp_lib_has_unique_object_representations    201606L [C++17]
     __cpp_lib_hypot                                201603L [C++17]

 # ifdef __cpp_lib_filesystem
 #   error "__cpp_lib_filesystem should not be defined before c++17"
 # endif
 
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 # ifdef __cpp_lib_formatters
 #   error "__cpp_lib_formatters should not be defined before c++2b"
 # endif
 
 # ifdef __cpp_lib_forward_like
 #   error "__cpp_lib_forward_like should not be defined before c++2b"
 # endif
 

 # ifdef __cpp_lib_filesystem
 #   error "__cpp_lib_filesystem should not be defined before c++17"
 # endif
 
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 # ifdef __cpp_lib_formatters
 #   error "__cpp_lib_formatters should not be defined before c++2b"
 # endif
 
 # ifdef __cpp_lib_forward_like
 #   error "__cpp_lib_forward_like should not be defined before c++2b"
 # endif
 

 #     error "__cpp_lib_filesystem should not be defined when the requirement '!defined(_LIBCPP_AVAILABILITY_HAS_NO_FILESYSTEM)' is not met!"
 #   endif
 # endif
 
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 # ifdef __cpp_lib_formatters
 #   error "__cpp_lib_formatters should not be defined before c++2b"
 # endif
 
 # ifdef __cpp_lib_forward_like
 #   error "__cpp_lib_forward_like should not be defined before c++2b"
 # endif
 

 #     error "__cpp_lib_format should have the value 202106L in c++20"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_format
 #     error "__cpp_lib_format should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# ifdef __cpp_lib_format_ranges
+#   error "__cpp_lib_format_ranges should not be defined before c++2b"
+# endif
+
 # ifdef __cpp_lib_formatters
 #   error "__cpp_lib_formatters should not be defined before c++2b"
 # endif
 
 # ifdef __cpp_lib_forward_like
 #   error "__cpp_lib_forward_like should not be defined before c++2b"
 # endif
 

 #     error "__cpp_lib_format should have the value 202106L in c++2b"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_format
 #     error "__cpp_lib_format should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+#   ifndef __cpp_lib_format_ranges
+#     error "__cpp_lib_format_ranges should be defined in c++2b"
+#   endif
+#   if __cpp_lib_format_ranges != 202207L
+#     error "__cpp_lib_format_ranges should have the value 202207L in c++2b"
+#   endif
+# else
+#   ifdef __cpp_lib_format_ranges
+#     error "__cpp_lib_format_ranges should not be defined when the requirement '!defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)' is not met!"
+#   endif
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_formatters
 #     error "__cpp_lib_formatters should be defined in c++2b"
 #   endif
 #   if __cpp_lib_formatters != 202302L
 #     error "__cpp_lib_formatters should have the value 202302L in c++2b"
 #   endif
 # else // _LIBCPP_VERSION

libcxx/utils/generate_feature_test_macro_components.py

"values": {
         "c++20": 202106,
         # "c++23": 202207, Not implemented P2419R2 Clarify handling of encodings in localized formatting of chrono types
         },
     "headers": ["format"],
     "test_suite_guard": "!defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)",
     "libcxx_guard": "!defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)",
     "unimplemented": True,
   }, {
+    "name": "__cpp_lib_format_ranges",
+    "values": { "c++2b": 202207 },
+    "headers": ["format"],
+    "test_suite_guard": "!defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)",
+    "libcxx_guard": "!defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)",
+  }, {
     "name": "__cpp_lib_formatters",
     "values": { "c++2b": 202302 },
     "headers": ["stacktrace", "thread"],
     "test_suite_guard": "!defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)",
     "libcxx_guard": "!defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)",
     "unimplemented": True,
   }, {
     "name": "__cpp_lib_forward_like",
     "values": { "c++2b": 202207 },
     "headers": ["utility"],
   }, {
     "name": "__cpp_lib_gcd_lcm",
     "values": { "c++17": 201606 },