How to jump on a position specified by line and column?

Question

When opening a file one can use

$ emacs +2:9 practice.b

Which will open file ‘practice.b’ on line 2 and character 9 on that line. How do I jump like this in an already running Emacs? I know about M-x goto-line but it doesn’t recognize semicolon.

Answer 1

M-x goto-line (M-g g or M-g M-g) gets you to the beginning of the target line. Then you can use C-u 8 right to move to the target column. Note that this puts you in column 8, because Emacs numbers columns from 0, except that the command line option +LINE:COLUMN numbers columns from 1.

If you want an Emacs command where you can type 2:9, here's some code you can paste in your .emacs that allows you to write it as an argument to goto-line. Note that the code is only minimally tested in Emacs 23.

(defadvice goto-line (around goto-column activate)
  "Allow a specification of LINE:COLUMN instead of just COLUMN.
Just :COLUMN moves to the specified column on the current line.
Just LINE: moves to the current column on the specified line.
LINE alone still moves to the beginning of the specified line (like LINE:0)."
  (if (symbolp line) (setq line (symbol-name line)))
  (let ((column (save-match-data
                  (if (and (stringp line)
                           (string-match "\\`\\([0-9]*\\):\\([0-9]*\\)\\'" line))
                      (prog1
                        (match-string 2 line)
                        (setq line (match-string 1 line)))
                    nil))))
    (if (stringp column)
        (setq column (if (= (length column) 0)
                         (current-column)
                       (string-to-int column))))
    (if (stringp line)
        (setq line (if (= (length line) 0)
                       (if buffer
                         (save-excursion
                           (set-buffer buffer)
                           (line-number-at-pos))
                         nil)
                     (string-to-int line))))
    (if line
        ad-do-it)
    (if column
        (let ((limit (- (save-excursion (forward-line 1) (point))
                        (point))))
          (when (< column limit)
            (beginning-of-line)
            (forward-char column))))))