Unicode "no-op" Character?

[Philippe Verdy via Unicode]

Le mer. 3 juil. 2019 à 06:09, Sławomir Osipiuk <sosipiuk at gmail.com> a
écrit :

> I don’t think you understood me at all. I can packetize a string with any
> character that is guaranteed not to appear in the text.
>

Your goal is **impossible** to reach with Unicode. Assume sich character is
"added" to the UCS, then it can appear in the text. Your goal being that it
should be "warrantied" not to be used in any text, means that your
"character" cannot be encoded at all. Unicode and ISO **require** that the
any proposed character can be used in text without limitation. Logivally it
would be rejected becauyse your character would not be usable at all from
the start.

So you have no choice: you must use some transport format for your
"packeting", jsut like what is used in MIME for emails, in HTTP(S) for
streaming, or in internationalized domain names.

For your escaping mechanism you have a very large choice already of
characters considered special only for your chosen transport syntax.

Your goal shows a chicken and egg problem. It is not solvable without
creating self-contradictions immediately (and if you attempt to add some
restriction to avoid the contradiction, then you'll fall on cases where you
can no longer transport your message and your protocol will become unusable.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://unicode.org/pipermail/unicode/attachments/20190703/63567167/attachment.html>