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Re: arrow keys vs. C-f/b/n/p
From: |
Eli Zaretskii |
Subject: |
Re: arrow keys vs. C-f/b/n/p |
Date: |
Sat, 12 Jun 2010 21:49:21 +0300 |
> From: "Drew Adams" <address@hidden>
> Date: Sat, 12 Jun 2010 10:12:04 -0700
> Cc: address@hidden
>
> But I think you should also make it clear (clearer) that this "logical" order
> corresponds to buffer position
I did:
Emacs stores right-to-left and bidirectional text in the so-called
"logical" (or "reading") order: the buffer or string position of the
first character you read precedes that of the next character.
> In fact, you might drop "logical" altogether - the word itself doesn't really
> help here.
This term is widely used in literature about editing bidirectional
text.
> And changing "character position" to "buffer position" would help.
See above: the text does talk about buffer positions.
> What I got from your mail yesterday, which I think is clear there, is that (a)
> the buffer text stays put, regardless of how it might be displayed (I already
> supposed that), and (b) cursor movement always follows buffer order: forward
> means toward eob; backward means toward bob.
>
> It is (b) that is not so clear from the doc. That notion of "logical" movement
> (movement along the buffer-position gradient) is important to understand.
The manual does touch on that:
Because characters are reordered for display, Emacs commands that
operate in the logical order or on stretches of buffer positions may
produce unusual effects. For example, `C-f' and `C-b' commands move
point in the logical order, so the cursor will sometimes jump when
point traverses reordered bidirectional text. Similarly, a highlighted
region covering a contiguous range of character positions may look
discontinuous if the region spans reordered text. This is normal and
similar to behavior of other programs that support bidirectional text.
> Admittedly, it can be tricky to talk about these things. But I found your mail
> yesterday to be clearer than the current doc. In the doc you say things like
> "the buffer is reordered for display", which is correct but which could also
> be
> misunderstood. The chars are not reordered in the buffer - the buffer itself
> is
> not reordered. It is just that the displayed order differs from the buffer
> order
> (which does not change).
I see no "buffer is reordered" in the manual. I see these instead:
Reordering of bidirectional text into the "visual" order happens at
display time.
[...]
The buffer-local variable `bidi-display-reordering' controls whether
text in the buffer is reordered for display.
[...]
Because characters are reordered for display,
> BTW, maybe the node should be called Bidirectional Text (or Editing
> Bidirectional Text) instead of Bidirectional Editing. We've all been doing
> bidirectional (multidirectional) editing forever.
I will rename the section, thanks.
- RE: arrow keys vs. C-f/b/n/p, (continued)
- RE: arrow keys vs. C-f/b/n/p, Drew Adams, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/12
- RE: arrow keys vs. C-f/b/n/p, Drew Adams, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Lennart Borgman, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Lennart Borgman, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Lennart Borgman, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Uday S Reddy, 2010/06/12
- RE: arrow keys vs. C-f/b/n/p, Drew Adams, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p,
Eli Zaretskii <=
- RE: arrow keys vs. C-f/b/n/p, Drew Adams, 2010/06/12
- RE: arrow keys vs. C-f/b/n/p, Davis Herring, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Chong Yidong, 2010/06/11
- Re: arrow keys vs. C-f/b/n/p, Chong Yidong, 2010/06/11
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/13
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, David Kastrup, 2010/06/12
- Re: arrow keys vs. C-f/b/n/p, Eli Zaretskii, 2010/06/12