Re: [emacs-bidi] Mixed L2R and R2L paragraphs and horizontal scroll

[Eli Zaretskii]

> Date: Mon, 1 Feb 2010 16:00:45 +0200
> From: "Ehud Karni" <address@hidden>
> Cc: address@hidden, address@hidden
> 
> [sniped]  Eli's final conclusion for scrolled text is:
> 
> >       +---------+---------+-------------------+
> >       |$ijk     |abcdefgh$|abcdefghijk        |
> >       |     KJI$|$HGFEDCBA|        KJIHGFEDCBA|
> >       |         |         |                   |
> >       +---------+---------+-------------------+
> 
> I agree with Eli's decision, but it applies only to non-technical text.

What is a ``non-technical text'', and how is it different from the
other kind?  Also, to what kind belong your examples in this message?

> Consider Example1: a list of items, each line has: name, quantity,
> catalog-id and description. Most of the names are in Latin but some
> are in Hebrew.

Where is Example1?  I don't see it in the message you posted?  Did you
talk in general about itemized lists with mixed L2R and R2L text?

> In this case there must be an external dictation of paragraph direction.

There is already a variable to force certain paragraph direction on
all the paragraphs in a buffer.  Finer (per-paragraph) control can be
exercised by starting a paragraph with a suitable mark (RLM or LRM)
character.

But what does this have to do with the issue at hand?

> scrolled (23) in a smaller window:
>        +-------------------------------+
>        |$ong-description               |
>        |$NOITPIRCSED-GNO               |
>        +--------------------------------

Why like above and not like below:

       +-------------------------------+
       |$ong-description               |
       |$RCSED-GNOL-YREV               |
       +--------------------------------

?

> Example 3: text, mostly in Hebrew but some lines have no Hebrew,
> like arithmetic formulas (Latin + digits + neutrals only) or
> ls output (real recent email I got).
> 
> Here we could use either external dictation of RTL direction or
> automatic paragraph direction. In RTL direction the formula may be
> displayed wrongly (if neutral characters are on the sides). When
> automatic paragraph direction is used, short lines may be too far
> apart.

A real example will help here.

> In this case, something like `right-margin-goal-column' as suggested
> by RMS is a good solution.

The problem with such a ``rigid scrolling'' is that it must affect L2R
lines as well, for consistency.  In the current display engine, we
don't allow scrolling to the right (e.g., with C-x >) once column zero
is visible.  With rigid scrolling, we will need to allow it.

Anyway, thanks for the feedback.