Re: Mixed L2R and R2L paragraphs and horizontal scroll

>  >>  >       +---------+---------+-------------------+
>  >>  >       |$ijk     |abcdefgh$|abcdefghijk        |
>  >>  >       |     KJI$|$HGFEDCBA|        KJIHGFEDCBA|
>  >>  >       |         |         |                   |
>  >>  >       +---------+---------+-------------------+
>  >>  >
>  >>  > Is this what you are suggesting?
>  >>
>  >> This would be needlessly inconvenient.
>  >
>  > Why inconvenient?
> 
> Inconvenient for the user.  Why scroll something out of view if there's
> no urgent need to do so.  (Although a similar argument could be made for
> pure LR text as well

Exactly!  So perhaps we should adopt this design, as it doesn't make
things worse and does not require additional interfaces (such as
`window-RL-hscroll').

>  > That's what would happen if the second line was
>  > displayed at the left margin, like this:
>  >
>  >       +---------+---------+-------------------+
>  >       |$ijk     |abcdefgh$|abcdefghijk        |
>  >       |$IJK     |$HGFEDCBA|        KJIHGFEDCBA|
>           ^^^^^^^^^
>  >       |         |         |                   |
>  >       +---------+---------+-------------------+
> 
> I fail to understand the marked text in your example.

In the current unidirectional display, where text is always displayed
in its logical (i.e. reading) order, the second line would have been
displayed as "ABCDEFGHIJK", flushed to the left margin.  Then when the
line above it is scrolled to show just "$ijk", so would be the second
line, and it would display as "$IJK".

My point was that the bidirectional display conceptually does the
same, except it reverses the characters and flushes them to the right.