-;;; quarter-plane.el --- editing using quarter-plane screen model
+;;; quarter-plane.el --- Minor mode for quarter-plane style editing
;; Copyright (C) 2011 Free Software Foundation, Inc.
;;; Commentary:
-;; This code provides a minor mode to enable the some of picture-mode
-;; commands documented in the Emacs manual in order to treat the
-;; screen as a semi-infinite quarter-plane, without changing the
-;; buffer's major mode.
+;; This package provides Quarter Plane mode, a minor mode which
+;; provides Picture mode style editing (treating the screen as a
+;; semi-infinite quarter-plane). Unlike Picture mode, it is a minor
+;; modes (see the Emacs manual for the documentation of Picture mode).
+;; Type M-x quarter-plane-mode to enable Quarter Plane mode in the
+;; current buffer, and M-x global-quarter-plane-mode to enable it
+;; globally.
+
+;; In Quarter Plane mode, the commands `right-char', `forward-char',
+;; `previous-line', `next-line', and `mouse-set-point' are rebound to
+;; Quarter Plane commands.
;; Known issues:
(define-key map [remap mouse-set-point] 'picture-mouse-set-point)
map))
-(defconst quarter-plane-saved-symbols
- '(truncate-lines show-trailing-whitespace)
- "Buffer-local variables whose modified by `quarter-plane-mode`.
-Their values are saved when `quarter-plane-mode` is enabled and restored
-when it's disabled.")
-
-(defvar quarter-plane-saved-values)
+(defvar quarter-plane-saved-values nil)
(make-variable-buffer-local 'quarter-plane-saved-values)
-(put 'quarter-plane-saved-values 'permanent-local t)
;;;###autoload
(define-minor-mode quarter-plane-mode
Excess whitespace is trimmed when saving or exiting Quarter-Plane mode.
Because it works by inserting spaces, Quarter-Plane mode won't work in
-read-only buffers
+read-only buffers.
\\{quarter-plane-mode-map}"
:lighter " Plane"
:group 'picture
:keymap quarter-plane-mode-map
- (cond
- (quarter-plane-mode
+ (remove-hook 'before-save-hook 'quarter-plane-delete-whitespace t)
+ (dolist (symval (prog1 quarter-plane-saved-values
+ (setq quarter-plane-saved-values nil)))
+ (set (car symval) (cdr symval)))
+ (when quarter-plane-mode
(add-hook 'before-save-hook 'quarter-plane-delete-whitespace nil t)
- (setq quarter-plane-saved-values nil)
- (dolist (sym quarter-plane-saved-symbols)
- (push (symbol-value sym) quarter-plane-saved-values))
- (setq quarter-plane-saved-values (nreverse quarter-plane-saved-values))
- (setq truncate-lines t)
- (setq show-trailing-whitespace nil))
- (t
- (remove-hook 'before-save-hook 'quarter-plane-delete-whitespace t)
- (dolist (sym quarter-plane-saved-symbols)
- (set sym (pop quarter-plane-saved-values))))))
+ ;; Since quarter-plane-mode is not permanent-local, it should turn itself
+ ;; off cleanly.
+ (add-hook 'change-major-mode-hook (lambda () (quarter-plane-mode -1)) nil t)
+ (dolist (symval '((truncate-lines . t)
+ (show-trailing-whitespace . nil)))
+ (push (cons (car symval) (symbol-value (car symval)))
+ quarter-plane-saved-values)
+ (set (car symval) (cdr symval)))))
;;;###autoload
(define-global-minor-mode global-quarter-plane-mode quarter-plane-mode
- turn-on-quarter-plane-mode
+ quarter-plane-mode
:group 'picture)
(defun quarter-plane-delete-whitespace ()