picture.el

早期freebsd实现

;; "Picture mode" -- editing using quarter-plane screen model.
;; Copyright (C) 1985 Free Software Foundation, Inc.
;; Principal author K. Shane Hartman

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 1, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.


(provide 'picture)

(defun move-to-column-force (column)
  "Move to column COLUMN in current line.
Differs from move-to-column in that it creates or modifies whitespace
if necessary to attain exactly the specified column."
  (move-to-column column)
  (let ((col (current-column)))
    (if (< col column)
	(indent-to column)
      (if (and (/= col column)
	       (= (preceding-char) ?\t))
	  (let (indent-tabs-mode)
	    (delete-char -1)
            (indent-to col)
            (move-to-column column))))))


;; Picture Movement Commands

(defun picture-end-of-line (&optional arg)
  "Position point after last non-blank character on current line.
With ARG not nil, move forward ARG - 1 lines first.
If scan reaches end of buffer, stop there without error."
  (interactive "P")
  (if arg (forward-line (1- (prefix-numeric-value arg))))
  (beginning-of-line)
  (skip-chars-backward " \t" (prog1 (point) (end-of-line))))

(defun picture-forward-column (arg)
  "Move cursor right, making whitespace if necessary.
With argument, move that many columns."
  (interactive "p")
  (move-to-column-force (+ (current-column) arg)))

(defun picture-backward-column (arg)
  "Move cursor left, making whitespace if necessary.
With argument, move that many columns."
  (interactive "p")
  (move-to-column-force (- (current-column) arg)))

(defun picture-move-down (arg)
  "Move vertically down, making whitespace if necessary.
With argument, move that many lines."
  (interactive "p")
  (let ((col (current-column)))
    (picture-newline arg)
    (move-to-column-force col)))

(defconst picture-vertical-step 0
  "Amount to move vertically after text character in Picture mode.")

(defconst picture-horizontal-step 1
  "Amount to move horizontally after text character in Picture mode.")

(defun picture-move-up (arg)
  "Move vertically up, making whitespace if necessary.
With argument, move that many lines."
  (interactive "p")
  (picture-move-down (- arg)))

(defun picture-movement-right ()
  "Move right after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion 0 1))

(defun picture-movement-left ()
  "Move left after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion 0 -1))

(defun picture-movement-up ()
  "Move up after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion -1 0))

(defun picture-movement-down ()
  "Move down after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion 1 0))

(defun picture-movement-nw ()
  "Move up and left after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion -1 -1))

(defun picture-movement-ne ()
  "Move up and right after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion -1 1))

(defun picture-movement-sw ()
  "Move down and left after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion 1 -1))

(defun picture-movement-se ()
  "Move down and right after self-inserting character in Picture mode."
  (interactive)
  (picture-set-motion 1 1))

(defun picture-set-motion (vert horiz)
  "Set VERTICAL and HORIZONTAL increments for movement in Picture mode.
The mode line is updated to reflect the current direction."
  (setq picture-vertical-step vert
	picture-horizontal-step horiz)
  (setq mode-name
	(format "Picture:%s"
		(car (nthcdr (+ 1 (% horiz 2) (* 3 (1+ (% vert 2))))
			     '(nw up ne left none right sw down se)))))
  ;; Kludge - force the mode line to be updated.  Is there a better
  ;; way to this?
  (set-buffer-modified-p (buffer-modified-p))
  (message ""))

(defun picture-move ()
  "Move in direction of  picture-vertical-step  and  picture-horizontal-step."
  (picture-move-down picture-vertical-step)
  (picture-forward-column picture-horizontal-step))

(defun picture-motion (arg)
  "Move point in direction of current picture motion in Picture mode.
With ARG do it that many times.  Useful for delineating rectangles in
conjunction with diagonal picture motion.
Do \\[command-apropos]  picture-movement  to see commands which control motion."
  (interactive "p")
  (picture-move-down (* arg picture-vertical-step))
  (picture-forward-column (* arg picture-horizontal-step)))

(defun picture-motion-reverse (arg)
  "Move point in direction opposite of current picture motion in Picture mode.
With ARG do it that many times.  Useful for delineating rectangles in
conjunction with diagonal picture motion.
Do \\[command-apropos]  picture-movement  to see commands which control motion."
  (interactive "p")
  (picture-motion (- arg)))


;; Picture insertion and deletion.

(defun picture-self-insert (arg)
  "Insert this character in place of character previously at the cursor.
The cursor then moves in the direction you previously specified
with the commands picture-movement-right, picture-movement-up, etc.
Do \\[command-apropos]  picture-movement  to see those commands."
  (interactive "p")
  (while (> arg 0)
    (setq arg (1- arg))
    (move-to-column-force (1+ (current-column)))
    (delete-char -1)
    (insert last-input-char)
    (forward-char -1)
    (picture-move)))

(defun picture-clear-column (arg)
  "Clear out ARG columns after point without moving."
  (interactive "p")
  (let* ((opoint (point))
	 (original-col (current-column))
	 (target-col (+ original-col arg)))
    (move-to-column-force target-col)
    (delete-region opoint (point))
    (save-excursion
     (indent-to (max target-col original-col)))))

(defun picture-backward-clear-column (arg)
  "Clear out ARG columns before point, moving back over them."
  (interactive "p")
  (picture-clear-column (- arg)))

(defun picture-clear-line (arg)
  "Clear out rest of line; if at end of line, advance to next line.
Cleared-out line text goes into the kill ring, as do
newlines that are advanced over.
With argument, clear out (and save in kill ring) that many lines."
  (interactive "P")
  (if arg
      (progn
       (setq arg (prefix-numeric-value arg))
       (kill-line arg)
       (newline (if (> arg 0) arg (- arg))))
    (if (looking-at "[ \t]*$")
	(kill-ring-save (point) (progn (forward-line 1) (point)))
      (kill-region (point) (progn (end-of-line) (point))))))

(defun picture-newline (arg)
  "Move to the beginning of the following line.
With argument, moves that many lines (up, if negative argument);
always moves to the beginning of a line."
  (interactive "p")
  (if (< arg 0)
      (forward-line arg)
    (while (> arg 0)
      (end-of-line)
      (if (eobp) (newline) (forward-char 1))
      (setq arg (1- arg)))))

(defun picture-open-line (arg)
  "Insert an empty line after the current line.
With positive argument insert that many lines."
  (interactive "p")
  (save-excursion
   (end-of-line)
   (open-line arg)))

(defun picture-duplicate-line ()
  "Insert a duplicate of the current line, below it."
  (interactive)
  (save-excursion
   (let ((contents
	  (buffer-substring
	   (progn (beginning-of-line) (point))
	   (progn (picture-newline 1) (point)))))
     (forward-line -1)
     (insert contents))))


;; Picture Tabs

(defvar picture-tab-chars "!-~"
  "*A character set which controls behavior of commands
\\[picture-set-tab-stops] and \\[picture-tab-search].  It is NOT a
regular expression, any regexp special characters will be quoted.
It defines a set of \"interesting characters\" to look for when setting
\(or searching for) tab stops, initially \"!-~\" (all printing characters).
For example, suppose that you are editing a table which is formatted thus:
| foo		| bar + baz | 23  *
| bubbles	| and + etc | 97  *
and that picture-tab-chars is \"|+*\".  Then invoking
\\[picture-set-tab-stops] on either of the previous lines would result
in the following tab stops
		:     :     :     :
Another example - \"A-Za-z0-9\" would produce the tab stops
  :		  :	:     :

Note that if you want the character `-' to be in the set, it must be
included in a range or else appear in a context where it cannot be
taken for indicating a range (e.g. \"-A-Z\" declares the set to be the
letters `A' through `Z' and the character `-').  If you want the
character `\\' in the set it must be preceded by itself: \"\\\\\".

The command \\[picture-tab-search] is defined to move beneath (or to) a
character belonging to this set independent of the tab stops list.")

(defun picture-set-tab-stops (&optional arg)
  "Set value of  tab-stop-list  according to context of this line.
This controls the behavior of \\[picture-tab].  A tab stop
is set at every column occupied by an \"interesting character\" that is
preceded by whitespace.  Interesting characters are defined by the
variable  picture-tab-chars,  see its documentation for an example
of usage.  With ARG, just (re)set  tab-stop-list  to its default value.
The tab stops computed are displayed in the minibuffer with `:' at
each stop."
  (interactive "P")
  (save-excursion
    (let (tabs)
      (if arg
	  (setq tabs (default-value 'tab-stop-list))
	(let ((regexp (concat "[ \t]+[" (regexp-quote picture-tab-chars) "]")))
	  (beginning-of-line)
	  (let ((bol (point)))