On 9/9/26 21:52, Steve Downey via SG16 wrote:
> https://github.com/cplusplus/draft/issues/9228 <https://github.com/cplusplus/draft/issues/9228>
>>>>>>
> In the current standard, we have four references to
>
> Unicode Standard, Chapter 3.9 \ucode{fffd} Substitution in Conversion
> Something is wrong here.
>
> There is a Chapter 5.22 since Unicode 11 which is titled U+FFFD Substitution in Conversion, but it's not Chapter 3.9. This chapter number and title remain unchanged up to and including the latest Unicode 18 draft.
> That Chapter 5.22 used to be called "Best Practice for U+FFFD Substitution" for several standards before Unicode 11, so it's not just that it's been moved from 3.9 to 5.22.
> Chapter 5.22 makes several references to Chapter 3.9 Unicode Encoding Forms (which also includes the definition of "maximal subpart"), but Chapter 3.9 has never been called "U+FFFD Substitution in Conversion".
> Basically, we need to decide for the existing references whether they are intended to refer to §3.9 or to §5.22 and how to phrase that.

We definitely want to refer to the "U+FFFD Substitution of Maximal Subparts"
algorithm in 3.9. Whether we do so indirectly by referring to 5.22 or directly doesn't
really matter. Except that 5.22 is phrased in a rather colloquial style, so I'd prefer
to refer to 3.9 directly.

>>>>>>
>
> Where should this point to? The Unicode standard does not have "stable names" so we need to pick a version to pin to for reference.

We have a "normative references" section that resolves that part of the issue.

Jens