P0009R18 mdspan

[jensmaurer]

• Rephrase "may" in notes

Fixes #5589
Fixes cplusplus/papers#96
Fixes cplusplus/papers#1213
Fixes cplusplus/papers#1214

[JohelEGP]

Why do index-cast and the mapping's operator() not use std::move, like the operator[] that uses index-cast?

[JohelEGP]

Why not use \range? Same everywhere for all text that beings with $[ and ends with )$.

[jensmaurer]

\range is for iterator ranges, and puts its start and end into \tcode. The ranges discussed here are not iterator ranges.

[JohelEGP]

There's examples of non-iterator ranges and the use of math fonts for its arguments.

algorithms.tex:where \tcode{n} is the smallest integer in \range{0}{$N$} such that $E$ holds,
algorithms.tex:$E(i)$, where $i$ is the smallest integer in \range{0}{$N$}
algorithms.tex:For each integer \tcode{K} in \range{0}{last - first}
algorithms.tex:For each integer \tcode{K} in \range{0}{last - first}
algorithms.tex:For each integer \tcode{K} in \range{0}{last - first}
algorithms.tex:For each integer \tcode{K} in \range{0}{last - first}
iterators.tex:If \tcode{n > 0}, \range{i}{bound} denotes a range.
iterators.tex:If \tcode{n == 0}, \range{i}{bound} or \range{bound}{i} denotes a range.
iterators.tex:If \tcode{n < 0}, \range{bound}{i} denotes a range,
threads.tex:For all \tcode{i} in \range{0}{sizeof...(MutexTypes)},
utilities.tex:for all \tcode{i} in the range \range{0}{N}.
utilities.tex:\range{0}{sizeof...(Types)} in order, $\tcode{T}_i$
utilities.tex:In the function descriptions that follow, let $i$ be in the range \range{0}{sizeof...\brk{}(Types)}
utilities.tex:In the descriptions that follow, let $i$ be in the range \range{0}{sizeof...(Types)},

expressions.tex:\crange{-32768}{+32767}, the implementation cannot rewrite this
strings.tex:\tcode{i} in \crange{0}{size()}.
strings.tex:\tcode{i} in \crange{0}{size()}.
time.tex:The value held is unspecified if \tcode{d} is not in the range \crange{0}{255}.
time.tex:The value held is unspecified if \tcode{m} is not in the range \crange{0}{255}.
time.tex:always produces a remainder in the range of \crange{0}{11}.
time.tex:this operation results in a \tcode{month} holding a value in the range \crange{1}{12} even if \tcode{!x.ok()}.
time.tex:in the range \crange{months\{0\}}{months\{11\}}
time.tex:It can represent values in the range \crange{min()}{max()}.
time.tex:The value held is unspecified if \tcode{y} is not in the range \crange{-32767}{32767}.
time.tex:The value held is unspecified if \tcode{wd} is not in the range \crange{0}{255}.
time.tex:always produces a remainder in the range of \crange{0}{6}.
time.tex:this operation results in a \tcode{weekday} holding a value in the range \crange{0}{6} even if \tcode{!x.ok()}.
time.tex:in the range \crange{days\{0\}}{days\{6\}}
time.tex:The values held are unspecified if \tcode{!wd.ok()} or \tcode{index} is not in the range \crange{0}{7}.
time.tex:A \tcode{sys_days} in the range \crange{days\{-12687428\}}{days\{11248737\}}
time.tex:and \tcode{d_} is in the range \crange{1d}{(y_/m_/last).day()},
time.tex:If \tcode{ymd.day()} is in the range \crange{1d}{28d},
time.tex:and \tcode{ymd.day()} is not in the range \crange{1d}{28d},
time.tex:of the smallest possible integer in the range \crange{0}{18} such that
time.tex:The 12-hour equivalent of \tcode{h} in the range \crange{1h}{12h}.
time.tex:If \tcode{h} is not in the range \crange{0h}{23h},
time.tex:in the range \crange{0h}{11h},
time.tex:in the range \crange{12h}{23h},
time.tex:If \tcode{h} is not in the range \crange{1h}{12h},
time.tex:values in the range \crange{69}{99}
time.tex:and values in the range \crange{00}{68}

[tkoeppe]

I was wondering the same. I thought our range macros were for all kinds of ranges, not just iterators. By contrast, there's nothing "code" about [a, b], and for a half-open range [a, b) would look outright weird, supposing that you associate "code font" with "balanced parentheses".

We can leave this as an open issue though, if this is controversial.

[JohelEGP]

See also: #5647 (comment).

[tkoeppe]

Thanks!

[tkoeppe]

Sorry, I misread, there's no code font involved here -- rather, it's whether we should manually spell out ranges in maths, or use a macro. That distinction seems to be largely unobservable in the output, so we can think about that later and consider the arguments for and against.

[jensmaurer]

I have applied the obvious formatting suggestions and will go through the rest of the comments separately.

[JohelEGP]

See #5635 (comment).

Suggested change

	$[0, n)$ is an accessible range for
	an object \tcode{p} of type \tcode{pointer} and
	an object of type \tcode{default_accessor}
	if and only if \range{p}{p + $n$} is a valid range.
	$[0, \tcode{n})$ is an accessible range for
	an object \tcode{p} of type \tcode{pointer} and
	an object of type \tcode{default_accessor}
	if and only if \range{p}{p + n} is a valid range.

[jensmaurer]

Ok, agreed.

[tkoeppe]

Just some minor whitespace tweaking, then we're off. And I'll send a follow-up PR to propose using "rank index" more instead of spelling out intervals.

[Mick235711]

This fixes cplusplus/papers#1213 and cplusplus/papers#1214 too (those two papers are merged into P0009R17)