Proposal for BiDi in terminal emulators

[Egmont Koblinger via Unicode]

Hi,

> To me, 'visual order' means in the dominant order of the script.

This is not a definition I've come across anywhere else, nor matches
my intuition of "visual order" : the exact visual order (recursive
definition, yay!) of how you see the glyphs being displayed in the
row.

> So,
> if one takes it as natural that a decimal number starts with the most
> significant digits, the decimal numbers used with Arabic are *not*
> stored in visual order if considered as part of that script.

The visual order is: You get the string rendered properly. You scan
with your eyes in one strict direction, and take note of what you see
in that order.

For example, let's say: "Hello Shalom" (the latter word in Hebrew):

HELLO שָׁלוֹם

The logical order:
H
E
L
L
O
space
שָׁ
ל
וֹ
ם

The visual order, from left to right is:
H
E
L
L
O
space
ם
וֹ
ל
שָׁ

Similarly, the visual order from right to left (a much more rarely
seen concept, the exact reverse of the visual LTR order) is:
שָׁ
ל
וֹ
ם
space
O
L
L
E
H

"Visual order" most of the time means "visual left to right order",
although strictly speaking, "visual right to left order" is just as
much a visual order. This is all independent from the script's
dominant order.

> "In combination with the following rule, this means that trailing
> whitespace will appear at the visual end of the line (in the paragraph
> direction)."
>
> The 'visual end' is clearly not always the right-hand end!

Yes, that's right. (And it doesn't contradict the definition of
"visual order". For RTL paragraphs, those trailing whitespaces appear
at the beginning of the "visual LTR order").


e.