Re: Keep-only-column

[weber]

On 9 fev, 07:58, Marc Tfardy <m-t-o___CUT__IT...@web.de> wrote:
> Marc Tfardy schrieb:
>
>
>
> > weber wrote:
> >  >> Quite frequently I paste stuff which is space-separated.
> >  >> I would really like a function that would let me select a region and
> >  >> keep only a column, deleting all the rest.
> >  >> Anyone knows how I could implement something like this?
> >  >> I can do it with regexps, but then I have to come up with a new one
> >  >> every time...
> >  >> TIA
> >  >> HS
>
> >  > I think the format of "stuff" can't be understood from above :) Here
> >  > it is:
>
> >  > variable BLABLA  =     438438
> >  > variable LABLAC  =     312
> >  > variable DAUSH  =     43538
>
> >  > Apply to that region: keep-only-column 2 makes it:
> >  > BLABLA
> >  > LABLAC
> >  > DAUSHD
>
> > Here my draft. Probalby inefficient, but it does the job.
>
> > (defun trim-rectangle (start end)
> >   "Trims region to rectangle."
> >   (interactive "r")
> >   (save-excursion
> >     (let ((offset 0)
> >           (width 0)
> >           (lines (count-lines start end))
> >           (i 0))
> >       (goto-char start)
> >       (beginning-of-line)
> >       (setq offset (- start (point)))
> >       (goto-char end)
> >       (beginning-of-line)
> >       (forward-char offset)
> >       (setq width (- end (point)))
> >       (goto-char start)
> >       (while (< i lines)
> >         (beginning-of-line)
> >         (delete-region (point) (+ (point) offset))
> >         (forward-char width)
> >         (delete-region (point) (line-end-position))
> >         (end-of-line)
> >         (forward-char)
> >         (setq i (+ i 1))))))
>
> And now slightly tuned version with extra feature - deleting
> trailing whitespaces in the region:
>
> (defun trim-rectangle (start end &optional delete-whitespace)
>    "Trims region to rectangle. With \\[universal-argument] deletes
> trailing whitespaces."
>    (interactive "*r\nP")
>    (save-match-data
>      (save-excursion
>        (let ((offset 0)
>              (width 0)
>              (lines (count-lines start end))
>              (curren-point 0)
>              (i 0))
>          (goto-char start)
>          (setq offset (current-column))
>          (goto-char end)
>          (setq width (- (current-column) offset))
>          (goto-char start)
>          (while (< i lines)
>            (beginning-of-line)
>            (setq current-point (point))
>            (delete-region current-point (+ current-point offset))
>            (forward-char width)
>            (delete-region (point) (line-end-position))
>            (if delete-whitespace
>                (progn
>                  (beginning-of-line)
>                  (if (re-search-forward "[ \t]*$" (line-end-position) t)
>                      (delete-region(match-beginning 0) (match-end 0)))
>                  (end-of-line)))
>            (forward-char)
>            (setq i (+ i 1)))))))
>
> regards
>
> Marc

Hello.
Here's a version to apply the function to a region.
If there is a easier way plese tell me!

(defun keep-column-on-region (beg end &optional arg)
  "Apply keep-column over region."
  (interactive "r\np")
  (save-excursion
        (if mark-active
                (let ((beg (region-beginning))
                          (end (copy-marker (region-end))))
                  (goto-char beg)
                  (while (< (point) end)
                        (beginning-of-line)
                        (keep-column arg)
                        (next-line 1))))))

Also, is there a way to make the ARG 0 (instead of 1) when it's not
supplied ?
Thanks
weber