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[libc++][format] Finish P0645 Text Formatting.
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This adjust the version macro and sets it as completed. All parts of the paper
have been implemented, except for the parts replaced by later papers and
LWG-issues.

Adjusted the synopsis to match the synopsis in the Standard. Not yet
implemented parts of P2216 and P2418 still use the P0645 wording.

Completes:
- P0645 Text Formatting

Depends on D115991

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D115999
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@mordante
mordante committed Jan 24, 2022
1 parent eadf726 commit 4684857
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Showing 5 changed files with 18 additions and 156 deletions.
11 changes: 7 additions & 4 deletions libcxx/docs/ReleaseNotes.rst
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Expand Up @@ -38,10 +38,13 @@ What's New in Libc++ 14.0.0?
New Features
------------

- There's initial support for the C++20 header ``<format>``. The implementation
is incomplete. Some functions are known to be inefficient; both in memory
usage and performance. The implementation is considered experimental and isn't
considered ABI stable.
- There's support for the C++20 header ``<format>``. Some parts are still
missing, most notably the compile-time format string validation. Some
functions are known to be inefficient, both in memory usage and performance.
The implementation isn't API- or ABI-stable and therefore considered
experimental. (Some not-yet-implemented papers require an API-break.)
Vendors can still disable this header by turning the CMake option
`LIBCXX_ENABLE_INCOMPLETE_FEATURES` off.

- There's a new CMake option ``LIBCXX_ENABLE_UNICODE`` to disable Unicode
support in the ``<format>`` header. This only affects the estimation of the
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1 change: 1 addition & 0 deletions libcxx/docs/Status/Cxx20.rst
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Expand Up @@ -41,6 +41,7 @@ Paper Status
.. note::

.. [#note-P0600] P0600: The missing bits in P0600 are in |sect|\ [mem.res.class] and |sect|\ [mem.poly.allocator.class].
.. [#note-P0645] P0645: The paper is implemented but still marked as an incomplete feature. Not yet implemented LWG-issues will cause API and ABI breakage.
.. [#note-P0966] P0966: It was previously erroneously marked as complete in version 8.0. See `bug 45368 <https://llvm.org/PR45368>`__.
.. [#note-P0619] P0619: Only sections D.8, D.9, D.10 and D.13 are implemented. Sections D.4, D.7, D.11, D.12, and D.14 remain undone.
.. [#note-P0883] P0883: shared_ptr and floating-point changes weren't applied as they themselves aren't implemented yet.
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2 changes: 1 addition & 1 deletion libcxx/docs/Status/Cxx20Papers.csv
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Expand Up @@ -103,7 +103,7 @@
"`P0466R5 <https://wg21.link/P0466R5>`__","LWG","Layout-compatibility and Pointer-interconvertibility Traits","Cologne","",""
"`P0553R4 <https://wg21.link/P0553R4>`__","LWG","Bit operations","Cologne","|Complete|","9.0"
"`P0631R8 <https://wg21.link/P0631R8>`__","LWG","Math Constants","Cologne","|Complete|","11.0"
"`P0645R10 <https://wg21.link/P0645R10>`__","LWG","Text Formatting","Cologne","|In Progress|",""
"`P0645R10 <https://wg21.link/P0645R10>`__","LWG","Text Formatting","Cologne","|Complete| [#note-P0645]_","14.0"
"`P0660R10 <https://wg21.link/P0660R10>`__","LWG","Stop Token and Joining Thread, Rev 10","Cologne","",""
"`P0784R7 <https://wg21.link/P0784R7>`__","CWG","More constexpr containers","Cologne","|Complete|","12.0"
"`P0980R1 <https://wg21.link/P0980R1>`__","LWG","Making std::string constexpr","Cologne","",""
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2 changes: 1 addition & 1 deletion libcxx/docs/Status/FormatIssues.csv
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@@ -1,5 +1,5 @@
Number,Name,Assignee,Patch,Status,First released version
`P0645 <https://wg21.link/P0645>`_,"Text Formatting",Mark de Wever,,|Partial|,
`P0645 <https://wg21.link/P0645>`_,"Text Formatting",Mark de Wever,,|Complete|,Clang 14
`P1652 <https://wg21.link/P1652>`_,"Printf corner cases in std::format",Mark de Wever,"`D103433 <https://reviews.llvm.org/D103433>`__, `D114001 <https://reviews.llvm.org/D114001>`__",|Review|,
`P1892 <https://wg21.link/P1892>`_,"Extended locale-specific presentation specifiers for std::format",Mark de Wever,`D103368 <https://reviews.llvm.org/D103368>`__,|Complete|,Clang 14
`P1868 <https://wg21.link/P1868>`_,"width: clarifying units of width and precision in std::format (Implements the unicode support.)",Mark de Wever,"`D103413 <https://reviews.llvm.org/D103413>`__ `D103425 <https://reviews.llvm.org/D103425>`__ `D103670 <https://reviews.llvm.org/D103670>`__",|Complete|,Clang 14
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158 changes: 8 additions & 150 deletions libcxx/include/format
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Expand Up @@ -14,43 +14,15 @@
namespace std {
// [format.context], class template basic_format_context
template<class Out, class charT>
class basic_format_context {
basic_format_args<basic_format_context> args_; // exposition only
Out out_; // exposition only
public:
using iterator = Out;
using char_type = charT;
template<class T> using formatter_type = formatter<T, charT>;
basic_format_arg<basic_format_context> arg(size_t id) const;
std::locale locale();
iterator out();
void advance_to(iterator it);
};
template<class Out, class charT> class basic_format_context;
using format_context = basic_format_context<unspecified, char>;
using wformat_context = basic_format_context<unspecified, wchar_t>;
// [format.args], class template basic_format_args
template<class Context>
class basic_format_args {
size_t size_; // exposition only
const basic_format_arg<Context>* data_; // exposition only
public:
basic_format_args() noexcept;
template<class... Args>
basic_format_args(const format-arg-store<Context, Args...>& store) noexcept;
basic_format_arg<Context> get(size_t i) const noexcept;
};
template<class Context> class basic_format_args;
using format_args = basic_format_args<format_context>;
using wformat_args = basic_format_args<wformat_context>;
// [format.functions], formatting functions
template<class... Args>
string format(string_view fmt, const Args&... args);
Expand Down Expand Up @@ -90,8 +62,7 @@ namespace std {
Out out;
iter_difference_t<Out> size;
};
template<class Out, class... Args>
template<class Out, class... Args>
format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
string_view fmt, const Args&... args);
template<class Out, class... Args>
Expand All @@ -116,99 +87,22 @@ namespace std {
size_t formatted_size(const locale& loc, wstring_view fmt, const Args&... args);
// [format.formatter], formatter
template<> struct formatter<char, char>;
template<> struct formatter<char, wchar_t>;
template<> struct formatter<wchar_t, wchar_t>;
template<> struct formatter<charT*, charT>;
template<> struct formatter<const charT*, charT>;
template<size_t N> struct formatter<const charT[N], charT>;
template<class traits, class Allocator>
struct formatter<basic_string<charT, traits, Allocator>, charT>;
template<class traits>
struct formatter<basic_string_view<charT, traits>, charT>;
template<class T, class charT = char> struct formatter;
// [format.parse.ctx], class template basic_format_parse_context
template<class charT>
class basic_format_parse_context {
public:
using char_type = charT;
using const_iterator = typename basic_string_view<charT>::const_iterator;
using iterator = const_iterator;
private:
iterator begin_; // exposition only
iterator end_; // exposition only
enum indexing { unknown, manual, automatic }; // exposition only
indexing indexing_; // exposition only
size_t next_arg_id_; // exposition only
size_t num_args_; // exposition only
public:
constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
size_t num_args = 0) noexcept;
basic_format_parse_context(const basic_format_parse_context&) = delete;
basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
constexpr const_iterator begin() const noexcept;
constexpr const_iterator end() const noexcept;
constexpr void advance_to(const_iterator it);
constexpr size_t next_arg_id();
constexpr void check_arg_id(size_t id);
};
template<class charT> class basic_format_parse_context;
using format_parse_context = basic_format_parse_context<char>;
using wformat_parse_context = basic_format_parse_context<wchar_t>;
// [format.arguments], arguments
// [format.arg], class template basic_format_arg
template<class Context>
class basic_format_arg {
public:
class handle;
private:
using char_type = typename Context::char_type; // exposition only
variant<monostate, bool, char_type,
int, unsigned int, long long int, unsigned long long int,
float, double, long double,
const char_type*, basic_string_view<char_type>,
const void*, handle> value; // exposition only
template<class T> explicit basic_format_arg(const T& v) noexcept; // exposition only
explicit basic_format_arg(float n) noexcept; // exposition only
explicit basic_format_arg(double n) noexcept; // exposition only
explicit basic_format_arg(long double n) noexcept; // exposition only
explicit basic_format_arg(const char_type* s); // exposition only
template<class traits>
explicit basic_format_arg(
basic_string_view<char_type, traits> s) noexcept; // exposition only
template<class traits, class Allocator>
explicit basic_format_arg(
const basic_string<char_type, traits, Allocator>& s) noexcept; // exposition only
explicit basic_format_arg(nullptr_t) noexcept; // exposition only
template<class T>
explicit basic_format_arg(const T* p) noexcept; // exposition only
public:
basic_format_arg() noexcept;
explicit operator bool() const noexcept;
};
template<class Context> class basic_format_arg;
template<class Visitor, class Context>
see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
// [format.arg.store], class template format-arg-store
template<class Context, class... Args>
struct format-arg-store { // exposition only
array<basic_format_arg<Context>, sizeof...(Args)> args;
};
template<class Context, class... Args> struct format-arg-store; // exposition only
template<class Context = format_context, class... Args>
format-arg-store<Context, Args...>
Expand All @@ -218,43 +112,7 @@ namespace std {
make_wformat_args(const Args&... args);
// [format.error], class format_error
class format_error : public runtime_error {
public:
explicit format_error(const string& what_arg);
explicit format_error(const char* what_arg);
};
// [format.parse.ctx], class template basic_format_parse_context
template<class charT>
class basic_format_parse_context {
public:
using char_type = charT;
using const_iterator = typename basic_string_view<charT>::const_iterator;
using iterator = const_iterator;
private:
iterator begin_; // exposition only
iterator end_; // exposition only
enum indexing { unknown, manual, automatic }; // exposition only
indexing indexing_; // exposition only
size_t next_arg_id_; // exposition only
size_t num_args_; // exposition only
public:
constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
size_t num_args = 0) noexcept;
basic_format_parse_context(const basic_format_parse_context&) = delete;
basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
constexpr const_iterator begin() const noexcept;
constexpr const_iterator end() const noexcept;
constexpr void advance_to(const_iterator it);
constexpr size_t next_arg_id();
constexpr void check_arg_id(size_t id);
};
using format_parse_context = basic_format_parse_context<char>;
using wformat_parse_context = basic_format_parse_context<wchar_t>;
class format_error;
}
*/
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