;; Generate key binding summary for Emacs
;; Copyright (C) 1985 Richard M. Stallman.

;; This file is part of GNU Emacs.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY.  No author or distributor
;; accepts responsibility to anyone for the consequences of using it
;; or for whether it serves any particular purpose or works at all,
;; unless he says so in writing.  Refer to the GNU Emacs General Public
;; License for full details.

;; Everyone is granted permission to copy, modify and redistribute
;; GNU Emacs, but only under the conditions described in the
;; GNU Emacs General Public License.   A copy of this license is
;; supposed to have been given to you along with GNU Emacs so you
;; can know your rights and responsibilities.  It should be in a
;; file named COPYING.  Among other things, the copyright notice
;; and this notice must be preserved on all copies.


(defun make-command-summary ()
  "Make a summary of current key bindings in the buffer *Summary*.
Previous contents of that buffer are killed first."
  (interactive)
  (message "Making command summary...")
  ;; This puts a description of bindings in a buffer called *Help*.
  (save-window-excursion
   (describe-bindings))
  (with-output-to-temp-buffer "*Summary*"
    (save-excursion
     (let ((cur-mode mode-name))
       (set-buffer standard-output)
       (erase-buffer)
       (insert-buffer-substring "*Help*")
       (goto-char (point-min))
       (delete-region (point) (progn (forward-line 1) (point)))
       (while (search-forward "         " nil t)
	 (replace-match "  "))
       (goto-char (point-min))
       (while (search-forward "-@ " nil t)
	 (replace-match "-SP"))
       (goto-char (point-min))
       (while (search-forward "  .. ~ " nil t)
	 (replace-match "SP .. ~"))
       (goto-char (point-min))
       (while (search-forward "C-?" nil t)
	 (replace-match "DEL"))
       (goto-char (point-min))
       (while (search-forward "C-i" nil t)
	 (replace-match "TAB"))
       (goto-char (point-min))
       (if (re-search-forward "^Local Bindings:" nil t)
	   (progn
	    (forward-char -1)
	    (insert " for " cur-mode " Mode")
	    (while (search-forward "??\n" nil t)
	      (delete-region (point)
			     (progn
			      (forward-line -1)
			      (point))))))
       (goto-char (point-min))
       (insert "Emacs command summary, " (substring (current-time-string) 0 10)
	       ".\n")
       ;; Delete "key    binding" and underlining of dashes.
       (delete-region (point) (progn (forward-line 2) (point)))
       (forward-line 1)			;Skip blank line
       (while (not (eobp))
	 (let ((beg (point)))
	   (or (re-search-forward "^$" nil t)
	       (goto-char (point-max)))
	   (double-column beg (point))
	   (forward-line 1)))
       (goto-char (point-min)))))
  (message "Making command summary...done"))

(defun double-column (start end)
  (interactive "r")
  (let (half cnt
        line lines nlines
	(from-end (- (point-max) end)))
    (setq nlines (count-lines start end))
    (if (<= nlines 1)
	nil
      (setq half (/ (1+ nlines) 2))
      (goto-char start)
      (save-excursion
       (forward-line half)
       (while (< half nlines)
	 (setq half (1+ half))
	 (setq line (buffer-substring (point) (save-excursion (end-of-line) (point))))
	 (setq lines (cons line lines))
	 (delete-region (point) (progn (forward-line 1) (point)))))
      (setq lines (nreverse lines))
      (while lines
	(end-of-line)
	(indent-to 41)
	(insert (car lines))
	(forward-line 1)
	(setq lines (cdr lines))))
    (goto-char (- (point-max) from-end))))