On Wed, Sep 14, 2022 at 7:11 PM Steve Downey via SG16 <sg16_at_[hidden]>
wrote:

> The new Unicode 15.0 version of UAX 31 clarifies
> https://unicode.org/reports/tr31/#Pattern_Syntax that the definitions of
> whitespace and characters used for syntax are intended to apply to
> programming languages. C++ does not use them, of course, nor am I
> suggesting we should make this change now.
>
> For purposes of the conformance annex, E,
> http://eel.is/c++draft/uaxid#pattern, I am thinking of extracting the
> profile we do use from our lexer defs, and refer back to those sections as
> being normative. Does that seem reasonable?
>

UAX-R3 claims:
When meeting this requirement, all characters except those that have the
Pattern_White_Space or Pattern_Syntax properties are available for use as
identifiers or literals.

Can you explain how that is true (especially for C++ identifiers) with a
profile?

Also, is it clear that our identifier grammar confers syntactic relevance
to, for example, XID_Start characters for this profile?


>
> They've also clarified in a few places where the intent has always been to
> choose from one of the alternatives, where for example Restricted Format
> Characters R1a is ruled out if you're following R1,
> https://unicode.org/reports/tr31/#R1 and
> https://unicode.org/reports/tr31/#R1a , because the characters are
> excluded from XID_Continue.
>
> My plan is to have a draft early next week, and it's currently on our NB
> comment list, with a note to have changes to refer to.
>
> I'll also add the updates from 14 to 15 as comments. Comments are due for
> us to INCITS on the 28th, so internal discussion is leaning towards getting
> in anything we think should be considered, and better two comments than
> none.
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