Re: bidi reordering in program source buffers

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 25 Aug 2011 23:01:38 +0300
> From: "Ehud Karni" <ehud@unix.mvs.co.il>
> Cc: cyd@stupidchicken.com, schwab@linux-m68k.org, monnier@iro.umontreal.ca,
>         emacs-devel@gnu.org
> 
> On Thu, 25 Aug 2011 20:28:30 Eli Zaretskii wrote:
> >
> > So in your opinion, buffers that display source code should not be
> > reordered, not even the strings and comments they display?  IOW, we
> > should give up showing human-readable portions of those buffers in a
> > legible display form?  That's a bit harsh, no?
> 
> Yes, not even in comments or strings, see more below.
> 
> > > I think a (global) function that toggles the bidi reordering
> > > ONLY for the local buffer should ease the work of Emacs users.
> >
> > Can you elaborate why this is needed?
> >
> > In any case, the function should simply toggle the value of
> > bidi-display-reordering, as it's per-buffer variable.  But I rather
> > think Emacs should set this variable correctly without user
> > intervention.
> 
> I meant a command like `toggle-truncate-lines' or `toggle-word-wrap'.
> Then the user can assign it to a key, so she can easily change from
> logical to bidi ordered. In this way she can easily edit the R2L text
> when she needs, but with one keystroke see the logic of the program
> even if the R2L text is harder to read.

But without any reasonable way of displaying strings in printf-like
function calls, what good will it do to the user to turn on
reordering?  She will just see jumbled text, with no real way of
knowing the reading order except moving the cursor with C-f.

OTOH, if we do have a reasonable way of showing the reordered text,
then why not have it on at all times?

> On second thought, may be the command should change the input method
> too ?

Strings are not necessarily made of only R2L characters.  Only the
user knows which parts she wants to edit.