X-Git-Url: https://code.delx.au/gnu-emacs-elpa/blobdiff_plain/bd339239fb5e2e097f45444c476964bb11080608..af5a17495f80e22dae84f22f2b8b4b1105ca102b:/packages/quarter-plane/quarter-plane.el

diff --git a/packages/quarter-plane/quarter-plane.el b/packages/quarter-plane/quarter-plane.el
index dbde4238a..f73fd4e4e 100644
--- a/packages/quarter-plane/quarter-plane.el
+++ b/packages/quarter-plane/quarter-plane.el
@@ -1,4 +1,4 @@
-;;; 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.
 
@@ -21,10 +21,17 @@
 
 ;;; 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:
 
@@ -53,15 +60,8 @@
     (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
@@ -75,29 +75,30 @@ infinitely down and to the right, inserting spaces as necessary.
 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 ()