Proposal for BiDi in terminal emulators

[Egmont Koblinger via Unicode]

Hi Adam,

One more note, to hopefully clarify:

> ╒═══════════╤══════╕
> │ filename1 │  123 │
> │ FILENAME2 │   17 │
> └───────────┴──────┘
>
> I'm afraid there's no good way to do BiDi without support from individual
> programs.

In this particular example, when the output consists of RTL text in
logical order (the emitter does not reorder the characters to their
visual order, nor emit any BiDi controls), combined with line drawing
and such, there is hardly anything we could do purely on the terminal
emulator's side.

I did not consider the possibility of certain characters (e.g. line
drawing ones) being "stop characters", and BiDi to get applied only in
runs of other characters. Any such magic would be arbitrary, fix a
subset of the cases while cause other unforeseen breakages elsewhere.
E.g. what if someone intentionally uses these characters as
letter-like ones in a BiDi text, like """here I'm talking about the
'└' shaped corner"""... or what if poor man's ASCII pipe and other
symbols are used... it's way too risky to go into any kind of
heuristics.

In this particular case the terminal cannot magically fix the output
for you, you'll need to get the application fixed.

cheers,
egmont