Proposal for BiDi in terminal emulators

[Eli Zaretskii via Unicode]

> From: Egmont Koblinger <egmont at gmail.com>
> Date: Fri, 1 Feb 2019 14:35:35 +0100
> Cc: Frédéric Grosshans <frederic.grosshans at gmail.com>, 
> 	unicode at unicode.org
> 
> > You could do that, but it will require a lot of non-trivial processing
> > from the applications.  Text-mode applications don't want any complex
> > tinkering, they want just to write their text and be done.  The more
> > overhead you add to that simple task, the less probable it is that
> > applications will support such a terminal.
> 
> I agree with your overall observation, but I'm not sure how much it
> applies to this context.
> 
> Text-mode applications have to run the BiDi algorithm. The one I
> picked can also do shaping (well, the pretty limited one, using
> presentation forms).

Reordering and shaping have different requirements.  Reordering can be
done based only on the codepoints, whereas shaping needs also intimate
knowledge of the fonts being used.  The former can be done by a
text-mode application, the latter cannot, not anywhere close to what
readers of the respective scripts would expect.