UAX #9: applicability of higher-level protocols to bidi plaintext

[Shai Berger via Unicode]

On Sat, 14 Jul 2018 12:14:35 -0700
Asmus Freytag via Unicode <unicode at unicode.org> wrote:

> I would say the problem lies in the attempt to exchange arbitrary raw
> data and expect perfectly compatible rendering [...] Editors for
> plain text will wrap or not wrap lines on presentation [...] The bidi
> case is just another such case 

This is not about "perfectly compatible rendering", it is about
legible rendering. As specified in the Unicode standard. Another
example below.

On Sat, 14 Jul 2018 14:15:37 +0100
Richard Wordingham via Unicode <unicode at unicode.org> wrote:

> If the display concept is to treat lines as being of unbounded length,
> one needs a left margin, a right margin, or perhaps one centres each
> line.  Centred text does not strike me as 'plain'.

You seem to be confounding directionality with alignment. While, for
plaintext, I would find it preferable if the two always matched, this
is not what I'm asking for, and not what I see as a requirement for
making plain text usable.

To be clear: If I write a file containing a single line (this is all
English, no special use of capitals), the iconic:

Hello, World!

then, when I open this file in a standard-compliant editor, I'm ok with
seeing (centered)

                              Hello, World!

or (right aligned)

                                                          Hello, World!

or even (wrapped at a surprisingly short line length)

Hello, 
World!

Indeed, these are presentation issues, where fidelity is not expected,
almost on a level with font and color.

What I'm not OK with is:

!Hello, World

Which is what you'll see if your editor decides to use RTL
directionality for this file, as the FAQ says it may. What I'm asking
is that we stop calling this behavior "standard compliant"; and I refer
you back to my first message in this thread[1] for an example of the
mess that this creates with true BiDi text.

Thanks,
	Shai.

[1] http://unicode.org/pipermail/unicode/2018-July/006702.html