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Re: Agenda for the 2022-10-12 SG16 telecon​

From: Steve Downey <sdowney_at_[hidden]>
Date: Fri, 7 Oct 2022 19:29:11 -0400
US-64 was supposed to have a matching paper, but it looks like it got
folded inline. In any case https://isocpp.org/files/papers/P2653R0.pdf

  UAX #31 describes how languages that use or interpret patterns of
characters such as regular expressions or number formatscomputer languages,
may describe that syntax with Unicode properties.
  C++ does not do this as part of the language, deferring to library
components for such usage of patterns. This requirement does not apply to
  C++ does not use the methods or properties in UAX #31 to do this. It
instead uses the whitespace and syntax characters defined in [lex] to
describe the white space characters and the basic source characters used to
define syntactic elements other than identifiers.

Wordsmithing more than welcome.

On Thu, Oct 6, 2022 at 6:19 PM Corentin Jabot via SG16 <
sg16_at_[hidden]> wrote:

> I would prefer to wait for all nb comments to be filled in. In particular,
> US-38 and US-64 may end up conflicting or overlapping with other NB
> comments.
> Thanks,
> Corentin
> On Thu, Oct 6, 2022 at 11:59 PM Tom Honermann via SG16 <
> sg16_at_[hidden]> wrote:
>> SG16 will hold a telecon on Wednesday, October 12th, at 19:30 UTC (timezone
>> conversion
>> <https://www.timeanddate.com/worldclock/converter.html?iso=20221012T193000&p1=1440&p2=tz_pdt&p3=tz_mdt&p4=tz_cdt&p5=tz_edt&p6=tz_cest>
>> ).
>> The agenda is:
>> - A presentation by Michael Kuperstein regarding i18n and l10n and
>> existing practice in the industry.
>> - NB comment processing.
>> INCITS has made US NB comments available to its members. I reviewed the
>> list and identified the following as ones that I believe SG16 should
>> establish a position on. There are other comments that are related to
>> papers SG16 has previously discussed, but in those cases, I believe the
>> concerns raised do not require SG16 input.
>> Due to duplicated comments in the list of US comments, it is possible
>> that the comment identifiers below will change.
>> US-2: [defns.multibyte] <http://eel.is/c++draft/defns.multibyte>
>> The notion of an "execution character set" is no longer given prominence
>> in the Draft standard, aside from some notes about its relationship to the
>> concept as defined by C, and clarifying that certain character encodings
>> are unrelated to this character set. This makes it a questionable choice
>> for use in the definition of "multibyte character".
>> *Proposed change:*
>> Change the definition of "multibyte character" to use a character
>> encoding with a more definite specification given by the Standard.
>> US-38: [format.string.escaped]
>> <https://eel.is/c++draft/format.string.escaped>
>> The subject subclause describes how characters or strings are "escaped"
>> to be formatted more suitably "for debugging or for logging".
>> The actual suitability for debugging or for logging depends on the needs
>> of the application, and there is a conflict between formatting for human
>> readability of the textual content and formatting for clarity and fidelity
>> of encoding nuances. Indeed, for the latter, there can still be (for
>> stateful encodings) a conflict between formatting for human visual
>> inspection versus formatting for machine consumption of the output sequence
>> as a C++ string/character literal.
>> The current design introduces extensions to the API and to the format
>> string syntax that assume that there is one specific default that should be
>> chosen "for debugging or for logging". The reasoning behind the chosen
>> default and the extensibility of the current design does not appear to be
>> sufficiently explored.
>> Note 1:
>> An example, for Unicode encodings, of a choice between prioritizing
>> between human readability of the textual content and visual clarity of
>> encoding nuances is in the treatment of characters having Unicode property
>> Grapheme_Extend=Yes. The current design favors visual clarity of encoding
>> nuances by outputing such characters as escape sequences.
>> Note 2:
>> For stateful encodings, the lack of return to the initial shift state at
>> the end of the sequence cannot be represented using a C++ string/character
>> literal unless if a prior shift sequence from the initial shift state is
>> rendered via escape sequence(s). It is not clear that scanning forward is
>> generally always an option (nor is it clear that doing so is desirable).
>> *Proposed change:*
>> Narrow the purported scope and affirm the design choices of the default
>> behavior:
>> Modify "logging" to "technical logging" and spell out the priorities in
>> order in the description (this has the benefit of clearly communicating
>> intention and providing guidance for implementation choices).
>> 1. The output is intended to be a C++ string/character literal that
>> reproduces the encoded sequence. (This seems to be taken for granted and
>> not made explicit in the current draft.)
>> 2. Prefer visually distinguishing between different methods of
>> encoding "equivalent" textual content.
>> Make any adjustments necessary to the API or the format string syntax
>> associated with "escaped" strings to allow for future additions for
>> alternative escaping.
>> US-64: [uaxid.pattern] <https://eel.is/c++draft/uaxid.pattern>
>> The Unicode org has clarified that the pattern whitespace and pattern
>> syntax rules apply to the lexing and parsing of computer languages.
>> *Proposed change:*
>> Replace with "UAX#31 describes how formal languages such as computer
>> languages should describe and implement their use of whitespace and
>> syntactically significant characters during the processes of lexing and
>> parsing. C++ does not claim conformance with this requirement."
>> Tom.
>> --
>> SG16 mailing list
>> SG16_at_[hidden]
>> https://lists.isocpp.org/mailman/listinfo.cgi/sg16
> --
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> SG16_at_[hidden]
> https://lists.isocpp.org/mailman/listinfo.cgi/sg16

Received on 2022-10-07 23:29:25