Use of tag characters in a private encoding - is it valid please?

[Erik Carvalhal Miller]

UTS #51 (Unicode Emoji) tells us an emoji tag sequence begins with an emoji
tag base, continues with one or more tag characters from U+E0020‥U+E007E,
and terminates with U+E007F (CANCEL TAG).  The core specificationʼs chapter
23 (“Special Areas and Format Characters”), §23.5 (“Private‐Use
Characters”) asserts that a private agreement can override any of the
default properties of private‐use characters except for those related to
normalization.  Ergo, it appears that a private agreement that endows a
particular private‐use character with emoji properties would permit that
private‐use character to serve as the base of an emoji tag sequence, within
the scope of that same private agreement.

On Fri, Apr 26, 2024 at 8:24 PM William_J_G Overington via Unicode <
unicode at corp.unicode.org> wrote:

> May I ask please, Is it valid to use a sequence of tag characters ending
> in a cancel tag in a private use encoding of characters if the base
> character of the sequence is a Private Use Area character?
>
>
>
> William Overington
>
>
>
> Friday 26 April 2024
>
>
>
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://corp.unicode.org/pipermail/unicode/attachments/20240426/cdb73a71/attachment.htm>