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Re: `C-b' is backward-char, `left' is left-char - why?
From: |
Eli Zaretskii |
Subject: |
Re: `C-b' is backward-char, `left' is left-char - why? |
Date: |
Thu, 02 Jun 2011 07:12:54 -0400 |
> From: Andy Moreton <address@hidden>
> Date: Thu, 02 Jun 2011 11:38:12 +0100
>
> On Thu 02 Jun 2011, Eli Zaretskii wrote:
>
> >> From: Andy Moreton <address@hidden>
> >> Date: Thu, 02 Jun 2011 00:26:59 +0100
> >
> >> - forward-char moves forward one character in the buffer, which in
> >> right-to-left text moves backward one position on the screen.
> >
> > Not "backward", but to the left. "Forward" and "backward" are not
> > well-defined on the screen in bidirectional context. For someone who
> > reads the bidirectional text, C-f always moves forward, i.e. in the
> > reading direction, the direction in which we scan characters while
> > reading the text.
>
> Explaining motion in terms of buffer position (forward and backward),
> reading direction (l2r/r2l) and screen position (left and right) may
> help to disambiguate things as long as those terms are used consistently
> and explained broefly in the doc string.
Yes. We are in agreement.
> So for forward-char, movement of point is always N characters forward in
> the buffer. The effect on the screen position must be considered as a
> sequence of single character movements in the buffer, each of which may
> move the screen position left or right (depending on the bidirectional
> context).
>
> Is that more accurate ?
Yes, this is accurate, though vague (because "bidirectional context"
is something left undefined).
Maybe the following variant of the 2nd sentence sounds better:
The effect on the screen is to place the cursor on the character N
buffer positions forward, which could be to the left or to the
right, depending on the bidirectional context.
That's because Emacs doesn't really move point one character at a
time (when N is more than 1).
- Re: `C-b' is backward-char, `left' is left-char - why?, Andy Moreton, 2011/06/01
- Re: `C-b' is backward-char, `left' is left-char - why?, Eli Zaretskii, 2011/06/01
- Re: `C-b' is backward-char, `left' is left-char - why?, Andy Moreton, 2011/06/01
- Re: `C-b' is backward-char, `left' is left-char - why?, Eli Zaretskii, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, Andy Moreton, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?,
Eli Zaretskii <=
- Re: `C-b' is backward-char, `left' is left-char - why?, Andy Moreton, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, Eli Zaretskii, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, Andy Moreton, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, Eli Zaretskii, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, Andy Moreton, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, Eli Zaretskii, 2011/06/03
- Re: `C-b' is backward-char, `left' is left-char - why?, David Kastrup, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, Eli Zaretskii, 2011/06/02
- Re: `C-b' is backward-char, `left' is left-char - why?, David Kastrup, 2011/06/03
- Re: `C-b' is backward-char, `left' is left-char - why?, Eli Zaretskii, 2011/06/03