Re: align a column

[Benjamin Rutt]

Zimmen Gnauh <yah00204052@yahoo.com> writes:

> Suppose I have the following text
>
> first     test
> second      line
> third       line
> fourth       line
> fifth         line
> ...
>
> How can I quickly align the second column to the first word (test)?

I found the following function 'align-cols' in a file called align.el
(not the one by John Wiegley included with emacs).  It should do most
of what you want.

(defun align-cols (start end max-cols)
"Align text between point and mark as columns.
Columns are separated by whitespace characters.
Prefix arg means align that many columns. (default is all)"
  (interactive "r\nP")
  (save-excursion
    (let ((p start)
          pos
          end-of-line
          word
          count
          (max-cols (if (numberp max-cols) (max 0 (1- max-cols)) nil))
          (pos-list nil)
          (ref-list nil))
      ;; find the positions
      (goto-char start)
      (while (< p end)
        (beginning-of-line)
        (setq count 0)
        (setq end-of-line (save-excursion (end-of-line) (point)))
        (re-search-forward "^\\s-*" end-of-line t)
        (setq pos (current-column))     ;start of first word
        (if (null (car ref-list))
            (setq pos-list (list pos))
          (setq pos-list (list (max pos (car ref-list))))
          (setq ref-list (cdr ref-list)))
        (while (and (if max-cols (< count max-cols) t)
                    (re-search-forward "\\s-+" end-of-line t))
          (setq count (1+ count))
          (setq word (- (current-column) pos))
          ;; length of next word including following whitespaces
          (setq pos (current-column))
          (if (null (car ref-list))
              (setq pos-list (cons word pos-list))
            (setq pos-list (cons (max word (car ref-list)) pos-list))
            (setq ref-list (cdr ref-list))))
        (while ref-list
          (setq pos-list (cons (car ref-list) pos-list))
          (setq ref-list (cdr ref-list)))
        (setq ref-list (nreverse pos-list))
        (forward-line)
        (setq p (point)))
      ;; aling the cols starting with last row
      (setq pos-list (copy-sequence ref-list))
      (setq start 
            (save-excursion (goto-char start) (beginning-of-line) (point)))
      (goto-char end)
      (beginning-of-line)
      (while (>= p start)
        (beginning-of-line)
        (setq count 0)
        (setq end-of-line (save-excursion (end-of-line) (point)))
        (re-search-forward "^\\s-*" end-of-line t)
        (goto-char (match-end 0))
        (setq pos (nth count pos-list))
        (while (< (current-column) pos)
          (insert-char ?\040 1))
        (setq end-of-line (save-excursion (end-of-line) (point)))
        (while (and (if max-cols (< count max-cols) t)
                    (re-search-forward "\\s-+" end-of-line t))
          (setq count (1+ count))
          (setq pos   (+  pos (nth count pos-list)))
          (goto-char (match-end 0))
          (while (< (current-column) pos)
            (insert-char ?\040 1))
          (setq end-of-line (save-excursion (end-of-line) (point))))
        (forward-line -1)
        (if (= p (point-min)) (setq p (1- p))
          (setq p (point)))))))

-- 
Benjamin