[libc++] Implement views::join_with

* Implement "P2441R2 `views::join_with`" (https://wg21.link/P2441R2)
* Complete implementation of "P2711R1 Making multi-param constructors of views explicit" (https://wg21.link/P2711R1)
* Complete implementation of "P2770R0 Stashing stashing iterators for proper flattening" (https://wg21.link/P2770R0)

Author: JMazurkiewicz

libcxx/docs/FeatureTestMacroTable.rst

@@ -362,7 +362,7 @@ Status
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_ranges_iota``                                  *unimplemented*
     ---------------------------------------------------------- -----------------
-    ``__cpp_lib_ranges_join_with``                             *unimplemented*
+    ``__cpp_lib_ranges_join_with``                             ``202202L``
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_ranges_repeat``                                ``202207L``
     ---------------------------------------------------------- -----------------

libcxx/docs/ReleaseNotes/19.rst

@@ -53,6 +53,9 @@ Implemented Papers
 - P2387R3 - Pipe support for user-defined range adaptors
 - P2713R1 - Escaping improvements in ``std::format``
 - P2231R1 - Missing ``constexpr`` in ``std::optional`` and ``std::variant``
+- P2441R2 - ``views::join_with``
+- P2711R1 - Making multi-param constructors of ``views`` ``explicit``
+- P2770R0 - Stashing stashing ``iterators`` for proper flattening
 
 Improvements and New Features
 -----------------------------

libcxx/docs/Status/Cxx23.rst

@@ -44,8 +44,6 @@ Paper Status
    .. [#note-P1413R3] P1413R3: ``std::aligned_storage_t`` and ``std::aligned_union_t`` are marked deprecated, but
       clang doesn't issue a diagnostic for deprecated using template declarations.
    .. [#note-P2520R0] P2520R0: Libc++ implemented this paper as a DR in C++20 as well.
-   .. [#note-P2711R1] P2711R1: ``join_with_view`` hasn't been done yet since this type isn't implemented yet.
-   .. [#note-P2770R0] P2770R0: ``join_with_view`` hasn't been done yet since this type isn't implemented yet.
    .. [#note-P2693R1] P2693R1: The formatter for ``std::thread::id`` is implemented.
       The formatter for ``stacktrace`` is not implemented, since ``stacktrace`` is
       not implemented yet.
@@ -63,5 +61,5 @@ Library Working Group Issues Status
 .. 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.
+   .. [#note-LWG3798] LWG3798: ``zip_transform_view`` and ``adjacent_transform_view`` haven't been done yet since these types aren't implemented yet.
    .. [#note-LWG3036] LWG3036: This issue was reverted by P2875R4

libcxx/docs/Status/Cxx23Papers.csv

@@ -47,7 +47,7 @@
 "`P2273R3 <https://wg21.link/P2273R3>`__","LWG","Making ``std::unique_ptr`` constexpr","February 2022","|Complete|","16.0"
 "`P2387R3 <https://wg21.link/P2387R3>`__","LWG","Pipe support for user-defined range adaptors","February 2022","|Complete|","19.0","|ranges|"
 "`P2440R1 <https://wg21.link/P2440R1>`__","LWG","``ranges::iota``, ``ranges::shift_left`` and ``ranges::shift_right``","February 2022","","","|ranges|"
-"`P2441R2 <https://wg21.link/P2441R2>`__","LWG","``views::join_with``","February 2022","|In Progress|","","|ranges|"
+"`P2441R2 <https://wg21.link/P2441R2>`__","LWG","``views::join_with``","February 2022","|Complete|","19.0","|ranges|"
 "`P2442R1 <https://wg21.link/P2442R1>`__","LWG","Windowing range adaptors: ``views::chunk`` and ``views::slide``","February 2022","","","|ranges|"
 "`P2443R1 <https://wg21.link/P2443R1>`__","LWG","``views::chunk_by``","February 2022","|Complete|","18.0","|ranges|"
 "","","","","","",""
@@ -104,9 +104,9 @@
 "`P2708R1 <https://wg21.link/P2708R1>`__","LWG", "No Further Fundamentals TSes", "November 2022","|Nothing to do|","",""
 "","","","","","",""
 "`P0290R4 <https://wg21.link/P0290R4>`__","LWG", "``apply()`` for ``synchronized_value<T>``","February 2023","","","|concurrency TS|"
-"`P2770R0 <https://wg21.link/P2770R0>`__","LWG", "Stashing stashing ``iterators`` for proper flattening","February 2023","|Partial| [#note-P2770R0]_","","|ranges|"
+"`P2770R0 <https://wg21.link/P2770R0>`__","LWG", "Stashing stashing ``iterators`` for proper flattening","February 2023","|Complete|","19.0","|ranges|"
 "`P2164R9 <https://wg21.link/P2164R9>`__","LWG", "``views::enumerate``","February 2023","","","|ranges|"
-"`P2711R1 <https://wg21.link/P2711R1>`__","LWG", "Making multi-param constructors of ``views`` ``explicit``","February 2023","|In Progress| [#note-P2711R1]_","","|ranges|"
+"`P2711R1 <https://wg21.link/P2711R1>`__","LWG", "Making multi-param constructors of ``views`` ``explicit``","February 2023","|Complete|","19.0","|ranges|"
 "`P2609R3 <https://wg21.link/P2609R3>`__","LWG", "Relaxing Ranges Just A Smidge","February 2023","","","|ranges|"
 "`P2713R1 <https://wg21.link/P2713R1>`__","LWG", "Escaping improvements in ``std::format``","February 2023","|Complete|","19.0","|format|"
 "`P2675R1 <https://wg21.link/P2675R1>`__","LWG", "``format``'s width estimation is too approximate and not forward compatible","February 2023","|Complete|","17.0","|format|"

libcxx/docs/Status/RangesMajorFeatures.csv

@@ -2,4 +2,4 @@ Standard,Name,Assignee,CL,Status
 C++23,`ranges::to <https://wg21.link/P1206R7>`_,Konstantin Varlamov,`D142335 <https://reviews.llvm.org/D142335>`_,Complete
 C++23,`Pipe support for user-defined range adaptors <https://wg21.link/P2387R3>`_,"Louis Dionne, Jakub Mazurkiewicz, and Xiaoyang Liu",Various,Complete
 C++23,`Formatting Ranges <https://wg21.link/P2286R8>`_,Mark de Wever,Various,Complete
-C++20,`Stashing stashing iterators for proper flattening <https://wg21.link/P2770R0>`_,Jakub Mazurkiewicz,Various,In progress
+C++20,`Stashing stashing iterators for proper flattening <https://wg21.link/P2770R0>`_,Jakub Mazurkiewicz,Various,Complete

libcxx/docs/Status/RangesViews.csv

@@ -28,7 +28,7 @@ C++23,`zip <https://wg21.link/P2321R2>`_,Hui Xie,`D122806 <https://llvm.org/D122
 C++23,`zip_transform <https://wg21.link/P2321R2>`_,Hui Xie,No patch yet,Not started
 C++23,`adjacent <https://wg21.link/P2321R2>`_,Hui Xie,No patch yet,Not started
 C++23,`adjacent_transform <https://wg21.link/P2321R2>`_,Hui Xie,No patch yet,Not started
-C++23,`join_with <https://wg21.link/P2441R2>`_,Jakub Mazurkiewicz,`65536 <https://github.com/llvm/llvm-project/pull/65536>`_,In progress
+C++23,`join_with <https://wg21.link/P2441R2>`_,Jakub Mazurkiewicz,`65536 <https://github.com/llvm/llvm-project/pull/65536>`_,✅
 C++23,`slide <https://wg21.link/P2442R1>`_,Will Hawkins,`67146 <https://github.com/llvm/llvm-project/pull/67146>`_,In Progress
 C++23,`chunk <https://wg21.link/P2442R1>`_,Unassigned,No patch yet,Not started
 C++23,`chunk_by <https://wg21.link/P2443R1>`_,Jakub Mazurkiewicz,`D144767 <https://llvm.org/D144767>`_,✅

libcxx/include/CMakeLists.txt

@@ -657,6 +657,7 @@ set(files
   __ranges/iota_view.h
   __ranges/istream_view.h
   __ranges/join_view.h
+  __ranges/join_with_view.h
   __ranges/lazy_split_view.h
   __ranges/movable_box.h
   __ranges/non_propagating_cache.h