See https://corp.unicode.org/pipermail/unicode/2021-March/009400.html

There was no intent for Pattern_White_Space to ever apply to C++-like
languages.

Just saying: "C++ does not claim conformance with this requirement." would
be sufficient and more correct. Otherwise, something along the lines of
"C++ is not a pattern language so this requirement is not applicable". Or
saying nothing, that would work too.

On Thu, May 26, 2022 at 8:09 AM Jens Maurer via SG16 <sg16_at_[hidden]>
wrote:

> On 26/05/2022 02.19, Hubert Tong via SG16 wrote:
> > Suggestion:
> > UAX #31 describes what characters formal languages, such as computer
> > languages, should choose for use as whitespace and syntactically
> > significant characters during the process of lexical analysis. C++
> > does not claim conformance with this requirement.
>
> Sounds good to me.
>
> Jens
>
>
>
> > In particular, the "should describe and implement" wording implies
> > more comprehensive and broader advice than is given by UAX #31. Also,
> > lexing produces tokens from characters; past that, we are dealing with
> > tokens (not characters). Commas also added as an editorial change.
> >
> > On Wed, May 25, 2022 at 6:05 PM Steve Downey via SG16
> > <sg16_at_[hidden]> wrote:
> >>
> >> E.4 R3 Pattern_White_Space and Pattern_Syntax characters[uaxid.pattern]
> >>
> >> 1
> >> #
> >> UAX #31 describes how languages that use or interpret patterns of
> characters, such as regular expressions or number formats, may describe
> that syntax with Unicode properties.
> >> 2
> >> #
> >> 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++.
> >>
> >> 1 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.
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>
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