Re: Emacs Lisp Programming Questions

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

David Combs wrote:
> In article <mailman.8228.1254921577.2239.help-gnu-emacs@gnu.org>,
> Kevin Rodgers  <kevin.d.rodgers@gmail.com> wrote:
>> clint.laskowski wrote:
>>> Hello, gnu.emacs.help. I have a few questions about programming in
>>> Emacs Lisp. I hope you can help. Here they are:
>>>
>>> 1. Is this a good place to ask questions about programming in Emacs
>>> Lisp, especially with regards to text processing? If there's a better
>>> place, I'd appreciate knowing.
>>>
>>> 2. I want to write an interactive Elisp program to remove sequential
>>> duplicate lines from a buffer. This buffer is not sorted, and it
>>> should not be sorted. The program should simply look for two
>>> sequential lines that are identical, delete one, and then move on to
>>> the next line and do it over until it reaches the end of the buffer.
>>>
...

In use here

(defun just-one-empty-line (&optional beg end)
  "Delete consecutive empty lines, retain just one. "
  (interactive "*")
  (let ((beg (cond (beg beg)
		   ((region-active-p)
		    (region-beginning))
		   (t (point-min))))
	(end (cond (end (copy-marker end))
		   ((region-active-p)
		    (copy-marker (region-end)))
		   (t (copy-marker (point-max))))))
    (save-excursion
      (save-restriction
        (narrow-to-region beg end)
        (goto-char beg)
        (while (not (eobp))
          (while (looking-at "^\\([ \t]*\n\\)[ \t]*$")
            (delete-region (match-beginning 1) (match-end 1)))
          (forward-line 1)))
      (widen))))


Andreas

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