Bidi paragraph direction in terminal emulators (was: Proposal for BiDi in terminal emulators)

Egmont Koblinger via Unicode unicode at
Mon Feb 18 03:47:28 CST 2019

On Sun, Feb 17, 2019 at 1:59 PM Philippe Verdy <verdy_p at> wrote:

> Resist this idea, I've not been impolite.

I didn't say a word about you being impolite. I said I might be
impolite for not wishing to continue this discussion in that

> I just want to show you that terminals are legacy environments

You might have missed the thread's opening mail where I mentioned that
I've been developing a terminal emulator for five years. So I'm not
sure what you exactly want to show me about what a legacy environment
it is; I think I perfectly know it.

> that are far behind what is needed for proper internationalization

For many languages (or should I say scripts) internationalization is
pretty well solved in terminals. For others, requiring LTR complex
rendering, so-so. For RTL scripts it's a straight disaster, an
application can't even count on the letters of a word showing up in
the expected order, no matter what it does.

My work fixes the latter only, within(!) the limitations of this
legacy environment. I don't find it feasible to get rid of this legacy
(the concept of strict grid), and I find it a waste of time to ponder
about it.

Not sure why after about 200 mails on the topic, I still have a hard
time getting this message through. Seems to me that folks here on the
Unicode list want everything to be perfect for all the scripts at once
and not compromise to the slightest bit; and don't really appreciate
work that only offers partial improvement due to a special context's
constraints. This is something I didn't expect when I posted to this

At this point I think I've gathered all the actionable positive
feedback I could (two issues: one is that shaping needs to be done
differently, and the other one is that the paragraph direction should
be detected on larger chunks of data (at least optionally) – thanks
again for them, I'll rework my spec accordingly). For all the rest,
irrelevant and hopeless stuff, like switching to proportional fonts,
IMO it's high time we let this thread end here.


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