Eli, in different bug report, namely 27526, I recently wrote the following remark:
> the line-wrapping bug is still a major annoyance, at best, and until it is fixed, Emacs cannot claim to be Unicode compliant.
to which you replied:
> I disagree, as I already said many times.
Note that, because reordering is implemented below the level in
xdisp.c that breaks glyphs into screen lines, we are violating
paragraph 3.4 of UAX#9. which mandates that line breaking shall be
done before reordering each screen line separately.
So the only thing you disagree with me is that non-conformance to the Unicode Bidirectional Algorithm is tantamount to non-conformance to the Unicode Standard. Well, this disagreement is easily settled by reading article C12 'Bidirectional Text' of section 3.2 'Conformance Requirements' of the Unicode Standard:
A process that displays text containing supported right-to-left characters or embedding codes shall display all visible representations of characters (excluding format characters) in the same order as if the Bidirectional Algorithm had been applied to the text, unless tailored by a higher-level protocol as permitted by the specification.
* The Bidirectional Algorithm is specified in Unicode Standard Annex #9, “Uni- code Bidirectional Algorithm.”