Re: Zap-to-char behaviour

[Ehud Karni]

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On Wed, 21 May 2003 12:37:14 -0500 (CDT), Luc Teirlinck <address@hidden> wrote:
> 
> No, as John Paul Wallington already pointed out, all you need to do is
> uncomment a comment in the function definition.  If you are planning
> on using both functions, I would also suggest differentiating between
> the two echo area messages.  Result:
> 
> (defun zap-up-to-char (arg char)
>   "Kill up to, but not including ARG'th occurrence of CHAR.
> Case is ignored if `case-fold-search' is non-nil in the current buffer.
> Goes backward if ARG is negative; error if CHAR not found."
>   (interactive "p\ncZap up to char: ")
>   (kill-region (point) (progn
>                        (search-forward (char-to-string char) nil nil arg)
>                        (goto-char (if (> arg 0) (1- (point)) (1+ (point))))
>                        (point))))
> 
> The problem now is that if you want to keep the regular M-z binding to
> zap-to-char, then you probably will need to bind the new command to a
> longer key sequence and it takes only one keystroke to retype the
> character anyway.

No, that is not enough, because, as RMS pointed out, running this a
second time (when arg = 1, the default) will do nothing. This will
make it inconsistent (2 times M-3 `zap-up-to-char' will be different
from 3 * M-2 `zap-up-to-char'). If you want a consistent function I
propose the following:


(defun zap-up-to-char (arg char)
  "Kill up to, but not including ARG'th occurrence of CHAR.
Case is ignored if `case-fold-search' is non-nil in the current buffer.
Goes backward if ARG is negative; error if CHAR not found.
If ARG is 0, do nothing. If character at (point) is CHAR skip it."
  (interactive "p\ncZap up to char: ")
  (or (zerop arg)
      (let ((direction (if (> arg 0) 1 -1)))
           (kill-region (point)
                        (progn
                           (forward-char direction)
                           (search-forward (char-to-string char) nil nil arg)
                           (- (point) direction)))
           (backward-char direction))))

This was was tested lightly and it seems consistent. The kill ring
is also seems OK when repeating the operation several times.

My personal opinion is that `zap-to-char' is good enough for me and
I don't need this one, but if you want it, it better be good.

Ehud.


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