Re: [PATCH] New command to invert lines in region

[Kaushal Modi <kaushal.modi@gmail.com>]

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I believe there is reverse-lines

On Mon, Oct 3, 2016, 6:43 AM Tino Calancha <tino.calancha@gmail.com> wrote:

>
> Hello Emacs,
>
> i cannot find a command to invert the lines within a region.
> Does such thing already exists? Where?
> IMO, it might be good to have a command doing such thing.
> For instance, let's suppose the region contains following lines:
>
> foo 2 3
> bar 8 9
> baz 10 14
> qux 22 28
>
> The proposed command would change the region to:
>
> qux 22 28
> baz 10 14
> bar 8 9
> foo 2 3
>
> What do you think about this idea? Does it have sense?
> Feel free to make comments.
> Regards,
> Tino
>
>
> I have prepared following patch:
>
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> From 763e69bd0f22ae91be23cb384ec33cca0220f937 Mon Sep 17 00:00:00 2001
> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Mon, 3 Oct 2016 19:25:18 +0900
> Subject: [PATCH] invert-lines: New comman to invert lines in region
>
> * lisp/simple.el (invert-lines): New command.
> Bind to 'C-x I'.
> * etc/NEWS: Add entry for this new feature.
> ---
>   etc/NEWS       |  4 ++++
>   lisp/simple.el | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 56 insertions(+)
>
> diff --git a/etc/NEWS b/etc/NEWS
> index bd94c94..d3dffc0 100644
> --- a/etc/NEWS
> +++ b/etc/NEWS
> @@ -61,6 +61,10 @@ affected by this, as SGI stopped supporting IRIX in
> December 2013.
>
>   * Changes in Emacs 26.1
>
> +
> +** The new command 'invert-lines' invert the lines in region.  Bound
> +to 'C-x I'.
> +
>   +++
>   ** The new function 'call-shell-region' executes a command in an
>   inferior shell with the buffer region as input.
> diff --git a/lisp/simple.el b/lisp/simple.el
> index 70bd759..9233bf6 100644
> --- a/lisp/simple.el
> +++ b/lisp/simple.el
> @@ -6761,6 +6761,58 @@ global-visual-line-mode
>     visual-line-mode turn-on-visual-line-mode)
>
>
> +(defun invert-lines (&optional buffer start end)
> +  "Invert order of lines in region.
> +Optional arg BUFFER (or buffer name) is the output buffer.
> + Default to current one.
> +Optional arguments, START and END, define the region.
> + If START is nil, then default to minimum permissible value of point
> + in the current buffer.
> + If END is nil, then default to maximum permissible value of point
> + in the current buffer.
> +With prefix argument prompt for BUFFER."
> +  (interactive
> +   (let ((buf (if current-prefix-arg
> +                  (read-buffer "Invert lines to buffer: "
> +                               (current-buffer)
> +                               'must-match)
> +                (current-buffer)))
> +         (beg (region-beginning))
> +         (end (region-end)))
> +     (list buf beg end)))
> +  (let ((tmp-buf (get-buffer-create
> +                  (generate-new-buffer " *invert-lines*")))
> +        (buf (or buffer (current-buffer)))
> +        (beg-pos (or start (point-min)))
> +        (end-pos (or end (point-max)))
> +        (init-pos (point))
> +        line)
> +    (unwind-protect
> +        (progn
> +          (goto-char beg-pos)
> +          (while (and (not (eobp))
> +                      (not (>= (point) end-pos))
> +                      (re-search-forward "^.*$"))
> +            (setq line (match-string 0))
> +            (with-current-buffer tmp-buf
> +              (save-excursion
> +                (insert line "\n")))
> +            (forward-line 1))
> +          (if (eq (get-buffer buf) (current-buffer))
> +              (progn
> +                (delete-region beg-pos end-pos)
> +                (goto-char beg-pos)
> +                (insert-buffer-substring tmp-buf))
> +            (with-current-buffer tmp-buf
> +              (copy-to-buffer buf (point-min) (point-max)))))
> +      (kill-buffer tmp-buf)
> +      (goto-char init-pos)
> +      (when (region-active-p)
> +        (deactivate-mark 'force)))))
> +
> +(define-key ctl-x-map "I" 'invert-lines)
> +
> +
>   (defun transpose-chars (arg)
>     "Interchange characters around point, moving forward one character.
>   With prefix arg ARG, effect is to take character before point
> --
> 2.9.3
>
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> In GNU Emacs 26.0.50.4 (x86_64-pc-linux-gnu, GTK+ Version 3.22.0)
>   of 2016-10-03 built on calancha-pc
> Repository revision: 8cd975cebd588d5435fa2b333dba6c526e602933
>
> --

Kaushal Modi

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