How to right align region and/or line?

Question

We can center text with M-x center-region and M-o M-s. Is there something similar for right-alignment?

Example before:

Item 0: value                                                       |
Item 100: value                                                     |
Item 30: value                                                      |

after:

                                                       Item 0: value|
                                                     Item 100: value|
                                                      Item 30: value|
                                                       fill-column  ^

What's easiest way to right-align text?

Answer 1

According to the manual node on Filling, several of the fill functions take an optional JUSTIFY argument that you can use. So, for example, to fill a paragraph with right justification, you can use (fill-paragraph 'right).

You can also use (justify-current-line 'right) for a single line.

If you plan to use these options a lot, you could wrap them in functions, such as the following, and then bind these functions to the keys of your choice:

(defun right-justify-current-line ()
  "Right-justify this line."
  (interactive)
  (justify-current-line 'right))

(defun right-fill-paragraph ()
  "Fill paragraph with right justification."
  (interactive)
  (fill-paragraph 'right))

Here's a function you might drop in as a replacement for fill-paragraph. With various prefixes, it allows you to decide what kind of justification to use on the paragraph you're filling:

(defun fill-paragraph-dwim (&optional arg)
  "Fills the paragraph as normal with no prefix. With C-u,
right-justify.  With C-u C-u, center-justify.  With C-u C-u C-u,
full-justify."
  (interactive "p")
  (fill-paragraph (cond ((= arg 4)  'right)
                        ((= arg 16) 'center)
                        ((= arg 64) 'full))))

If you don't want to fill when you're right-aligning, you can use the following function, which is cribbed directly from the center-region function with a single-line change to make it align right instead:

(defun right-region (from to)
  "Right-justify each nonblank line starting in the region."
  (interactive "r")
  (if (> from to)
      (let ((tem to))
    (setq to from from tem)))
  (save-excursion
    (save-restriction
      (narrow-to-region from to)
      (goto-char from)
      (while (not (eobp))
    (or (save-excursion (skip-chars-forward " \t") (eolp))
        ;; (center-line))              ; this was the original code
        (justify-current-line 'right)) ; this is the new code
    (forward-line 1)))))