todo-mode.el: Don't let-bind `buffer-read-only`

Prefer let-binding `inhibit-read-only` so the code can freely change
`buffer-read-only`.  While at it, prefer #' to quote function names.

* lisp/calendar/todo-mode.el (todo-rename-category)
(todo-delete-category, todo-delete-item)
(todo-edit-item--diary-inclusion, todo-edit-category-diary-inclusion)
(todo-edit-category-diary-nonmarking, todo-archive-done-item)
(todo-unarchive-items, todo-display-categories)
(todo-update-categories-display, todo-filter-items-1)
(todo-reset-nondiary-marker, todo-reset-done-separator-string)
(todo-reset-done-string, todo-reset-comment-string):
Bind `inhibit-read-only` instead of `buffer-read-only`.
(todo-mode, todo-archive-mode, todo-edit-mode, todo-categories-mode)
(todo-filtered-items-mode): Let `define-derived-mode` take care of
adding the keymap to the docstring.
(todo-mode, todo-archive-mode, todo-categories-mode)
(todo-filtered-items-mode): Let `define-derived-mode` set
`mode-class`.

1 files changed, 60 insertions, 77 deletions

diff --git a/lisp/calendar/todo-mode.el b/lisp/calendar/todo-mode.el
index dbd1388848e..4f6a964eb4d 100644
--- a/lisp/calendar/todo-mode.el
+++ b/lisp/calendar/todo-mode.el
@@ -139,8 +139,8 @@ automatically recalculated when the window width changes.  If the
 string consists of more (or less) than one character, it will be
 the value of `todo-done-separator'."
   :type 'string
-  :initialize 'custom-initialize-default
-  :set 'todo-reset-done-separator-string
+  :initialize #'custom-initialize-default
+  :set #'todo-reset-done-separator-string
   :group 'todo-display)
 
 (defun todo-done-separator ()
@@ -170,8 +170,8 @@ have its intended effect.  The second string is inserted after
 the diary date."
   :type '(list string string)
   :group 'todo-edit
-  :initialize 'custom-initialize-default
-  :set 'todo-reset-nondiary-marker)
+  :initialize #'custom-initialize-default
+  :set #'todo-reset-nondiary-marker)
 
 (defconst todo-nondiary-start (nth 0 todo-nondiary-marker)
   "String inserted before item date to block diary inclusion.")
@@ -248,8 +248,8 @@ the date header.")
 (defcustom todo-done-string "DONE "
   "Identifying string appended to the front of done todo items."
   :type 'string
-  :initialize 'custom-initialize-default
-  :set 'todo-reset-done-string
+  :initialize #'custom-initialize-default
+  :set #'todo-reset-done-string
   :group 'todo-edit)
 
 (defconst todo-done-string-start
@@ -275,16 +275,16 @@ the date header.")
                       (format-message
                        "Invalid value: must be distinct from `todo-item-mark'"))
                      widget)))
-  :initialize 'custom-initialize-default
-  :set 'todo-reset-prefix
+  :initialize #'custom-initialize-default
+  :set #'todo-reset-prefix
   :group 'todo-display)
 
 (defcustom todo-number-prefix t
   "Non-nil to prefix items with consecutively increasing integers.
 These reflect the priorities of the items in each category."
   :type 'boolean
-  :initialize 'custom-initialize-default
-  :set 'todo-reset-prefix
+  :initialize #'custom-initialize-default
+  :set #'todo-reset-prefix
   :group 'todo-display)
 
 (defun todo-mode-line-control (cat)
@@ -306,8 +306,8 @@ todo category.  The resulting control becomes the local value of
 (defcustom todo-highlight-item nil
   "Non-nil means highlight items at point."
   :type 'boolean
-  :initialize 'custom-initialize-default
-  :set 'todo-reset-highlight-item
+  :initialize #'custom-initialize-default
+  :set #'todo-reset-highlight-item
   :group 'todo-display)
 
 (defcustom todo-wrap-lines t
@@ -605,8 +605,8 @@ This lacks the extension and directory components."
   "Non-nil to make `todo-show' visit the current todo file.
 Otherwise, `todo-show' always visits `todo-default-todo-file'."
   :type 'boolean
-  :initialize 'custom-initialize-default
-  :set 'todo-set-show-current-file
+  :initialize #'custom-initialize-default
+  :set #'todo-set-show-current-file
   :group 'todo)
 
 (defcustom todo-show-first 'first
@@ -1367,7 +1367,7 @@ category there as well."
                               (list archive)))))
       (dolist (buf buffers)
         (with-current-buffer (find-file-noselect buf)
-          (let (buffer-read-only)
+          (let ((inhibit-read-only t))
             (setq todo-categories (todo-set-categories))
             (save-excursion
               (save-restriction
@@ -1415,7 +1415,7 @@ todo or done items."
                                      "\"" (and arg " and all its entries")
                                      "? "))))
         (widen)
-        (let ((buffer-read-only)
+        (let ((inhibit-read-only t)
               (beg (re-search-backward
                     (concat "^" (regexp-quote (concat todo-category-beg cat))
                             "\n")
@@ -1795,8 +1795,8 @@ only when no items are marked."
 (defcustom todo-comment-string "COMMENT"
   "String inserted before optional comment appended to done item."
   :type 'string
-  :initialize 'custom-initialize-default
-  :set 'todo-reset-comment-string
+  :initialize #'custom-initialize-default
+  :set #'todo-reset-comment-string
   :group 'todo-edit)
 
 (defcustom todo-undo-item-omit-comment 'ask
@@ -2077,7 +2077,7 @@ their associated keys and their effects."
         (todo-date-from-calendar
          (let (calendar-view-diary-initially-flag)
            (calendar))                  ; *Calendar* is now current buffer.
-         (define-key calendar-mode-map [remap newline] 'exit-recursive-edit)
+         (define-key calendar-mode-map [remap newline] #'exit-recursive-edit)
          ;; If user exits Calendar before choosing a date, clean up properly.
          (define-key calendar-mode-map
            [remap calendar-exit] (lambda ()
@@ -2112,7 +2112,7 @@ prompt for a todo file and then for a category in it."
   (calendar-exit)
   (todo-insert-item--basic arg nil todo-date-from-calendar))
 
-(define-key calendar-mode-map "it" 'todo-insert-item-from-calendar)
+(define-key calendar-mode-map "it" #'todo-insert-item-from-calendar)
 
 (defun todo-delete-item ()
   "Delete at least one item in this category.
@@ -2133,7 +2133,7 @@ the item at point."
                                      (save-excursion (todo-item-end))))
                            (overlay-put ov 'face 'todo-search)
                            (todo-y-or-n-p "Permanently delete this item? "))))
-               buffer-read-only)
+               (inhibit-read-only t))
           (when answer
             (and marked (goto-char (point-min)))
             (catch 'done
@@ -2566,7 +2566,7 @@ made in the number or names of categories."
 
 (defun todo-edit-item--diary-inclusion (&optional nonmarking)
   "Function providing diary marking facilities of `todo-edit-item'."
-  (let ((buffer-read-only)
+  (let ((inhibit-read-only t)
         (marked (assoc (todo-current-category) todo-categories-with-marks)))
     (when marked (todo--user-error-if-marked-done-item))
     (catch 'stop
@@ -2616,7 +2616,7 @@ items."
     (goto-char (point-min))
     (let ((todo-count (todo-get-count 'todo))
           (diary-count (todo-get-count 'diary))
-          (buffer-read-only))
+          (inhibit-read-only t))
       (catch 'stop
         (while (not (eobp))
           (if (todo-done-item-p)        ; We've gone too far.
@@ -2652,7 +2652,7 @@ items in this category."
   (interactive "P")
   (save-excursion
     (goto-char (point-min))
-    (let (buffer-read-only)
+    (let ((inhibit-read-only t))
       (catch 'stop
         (while (not (eobp))
           (if (todo-done-item-p)                ; We've gone too far.
@@ -3322,13 +3322,14 @@ this category does not exist in the archive, it is created."
             (with-current-buffer archive
               (unless (derived-mode-p 'todo-archive-mode) (todo-archive-mode))
               (let ((headers-hidden todo--item-headers-hidden)
-                    buffer-read-only)
+                    (inhibit-read-only t))
                 (if headers-hidden (todo-toggle-item-header))
                 (widen)
                 (goto-char (point-min))
                 (if (and (re-search-forward
                           (concat "^" (regexp-quote
-                                       (concat todo-category-beg cat)) "$")
+                                       (concat todo-category-beg cat))
+                                  "$")
                           nil t)
                          (re-search-forward (regexp-quote todo-category-done)
                                             nil t))
@@ -3420,7 +3421,7 @@ the only category in the archive, the archive file is deleted."
            (item (concat (todo-item-string) "\n"))
            (marked-count 0)
            marked-items
-           buffer-read-only)
+           (inhibit-read-only t))
       (when marked
         (save-excursion
           (goto-char (point-min))
@@ -3432,7 +3433,7 @@ the only category in the archive, the archive file is deleted."
       ;; Restore items to top of category's done section and update counts.
       (with-current-buffer tbuf
         (let ((headers-hidden todo--item-headers-hidden)
-              buffer-read-only newcat)
+              (inhibit-read-only t) newcat)
           (if headers-hidden (todo-toggle-item-header))
           (widen)
           (goto-char (point-min))
@@ -3922,7 +3923,7 @@ which is the value of the user option
     (kill-all-local-variables)
     (todo-categories-mode)
     (let ((archive (member todo-current-todo-file todo-archives))
-          buffer-read-only)
+          (inhibit-read-only t))
       (erase-buffer)
       (insert (format (concat "Category counts for todo "
                               (if archive "archive" "file")
@@ -3961,7 +3962,7 @@ which is the value of the user option
                    (forward-line -2)
                    (goto-char (next-single-char-property-change
                                (point) 'face nil (line-end-position))))))
-         (buffer-read-only))
+         (inhibit-read-only t))
     (forward-line 2)
     (delete-region (point) (point-max))
     ;; Fill in the table with buttonized lines, each showing a category and
@@ -4533,7 +4534,7 @@ the values of FILTER and FILE-LIST."
                   (widen)))
                 (setq bufstr (buffer-string))
                 (with-current-buffer buf
-                  (let (buffer-read-only)
+                  (let ((inhibit-read-only t))
                     (insert bufstr)))))))
       (set-window-buffer (selected-window) (set-buffer buf))
       (todo-prefix-overlays)
@@ -5900,7 +5901,7 @@ Also return t if answer is \"Y\", but unlike `y-or-n-p', allow
 SPC to affirm the question only if option `todo-y-with-space' is
 non-nil."
   (unless todo-y-with-space
-    (define-key query-replace-map " " 'ignore))
+    (define-key query-replace-map " " #'ignore))
   (prog1
    (y-or-n-p prompt)
    (define-key query-replace-map " " 'act)))
@@ -6333,7 +6334,7 @@ the empty string (i.e., no time string)."
       (dolist (f files)
         (let ((buf (find-buffer-visiting f)))
           (with-current-buffer (find-file-noselect f)
-            (let (buffer-read-only)
+            (let ((inhibit-read-only t))
               (widen)
               (goto-char (point-min))
               (while (not (eobp))
@@ -6363,7 +6364,7 @@ the empty string (i.e., no time string)."
     (when (not (equal value oldvalue))
       (dolist (f files)
         (with-current-buffer (find-file-noselect f)
-          (let (buffer-read-only)
+          (let ((inhibit-read-only t))
             (setq todo-done-separator (todo-done-separator))
             (when (= 1 (length value))
               (todo-reset-done-separator sep)))
@@ -6382,7 +6383,7 @@ the empty string (i.e., no time string)."
       (dolist (f files)
         (let ((buf (find-buffer-visiting f)))
           (with-current-buffer (find-file-noselect f)
-            (let (buffer-read-only)
+            (let ((inhibit-read-only t))
               (widen)
               (goto-char (point-min))
               (while (not (eobp))
@@ -6408,7 +6409,7 @@ the empty string (i.e., no time string)."
       (dolist (f files)
         (let ((buf (find-buffer-visiting f)))
           (with-current-buffer (find-file-noselect f)
-            (let (buffer-read-only)
+            (let ((inhibit-read-only t))
               (widen)
               (goto-char (point-min))
               (while (not (eobp))
@@ -6643,32 +6644,32 @@ Filtered Items mode following todo (not done) items."
       (define-key map (nth 0 kb) (nth 1 kb)))
     (dolist (kb todo-key-bindings-t+a)
       (define-key map (nth 0 kb) (nth 1 kb)))
-    (define-key map "a" 'todo-jump-to-archive-category)
-    (define-key map "u" 'todo-unarchive-items)
+    (define-key map "a" #'todo-jump-to-archive-category)
+    (define-key map "u" #'todo-unarchive-items)
     map)
   "Todo Archive mode keymap.")
 
 (defvar todo-edit-mode-map
   (let ((map (make-sparse-keymap)))
-    (define-key map "\C-x\C-q" 'todo-edit-quit)
+    (define-key map "\C-x\C-q" #'todo-edit-quit)
     map)
   "Todo Edit mode keymap.")
 
 (defvar todo-categories-mode-map
   (let ((map (make-sparse-keymap)))
-    (define-key map "c" 'todo-sort-categories-alphabetically-or-numerically)
-    (define-key map "t" 'todo-sort-categories-by-todo)
-    (define-key map "y" 'todo-sort-categories-by-diary)
-    (define-key map "d" 'todo-sort-categories-by-done)
-    (define-key map "a" 'todo-sort-categories-by-archived)
-    (define-key map "#" 'todo-set-category-number)
-    (define-key map "l" 'todo-lower-category)
-    (define-key map "r" 'todo-raise-category)
-    (define-key map "n" 'todo-next-button)
-    (define-key map "p" 'todo-previous-button)
-    (define-key map [tab] 'todo-next-button)
-    (define-key map [backtab] 'todo-previous-button)
-    (define-key map "q" 'todo-quit)
+    (define-key map "c" #'todo-sort-categories-alphabetically-or-numerically)
+    (define-key map "t" #'todo-sort-categories-by-todo)
+    (define-key map "y" #'todo-sort-categories-by-diary)
+    (define-key map "d" #'todo-sort-categories-by-done)
+    (define-key map "a" #'todo-sort-categories-by-archived)
+    (define-key map "#" #'todo-set-category-number)
+    (define-key map "l" #'todo-lower-category)
+    (define-key map "r" #'todo-raise-category)
+    (define-key map "n" #'todo-next-button)
+    (define-key map "p" #'todo-previous-button)
+    (define-key map [tab] #'todo-next-button)
+    (define-key map [backtab] #'todo-previous-button)
+    (define-key map "q" #'todo-quit)
     map)
   "Todo Categories mode keymap.")
 
@@ -6678,8 +6679,8 @@ Filtered Items mode following todo (not done) items."
       (define-key map (nth 0 kb) (nth 1 kb)))
     (dolist (kb todo-key-bindings-t+f)
       (define-key map (nth 0 kb) (nth 1 kb)))
-    (define-key map "g" 'todo-go-to-source-item)
-    (define-key map [remap newline] 'todo-go-to-source-item)
+    (define-key map "g" #'todo-go-to-source-item)
+    (define-key map [remap newline] #'todo-go-to-source-item)
     map)
   "Todo Filtered Items mode keymap.")
 
@@ -6835,13 +6836,9 @@ Added to `window-configuration-change-hook' in Todo mode."
   ;; (add-hook 'find-file-hook #'todo-display-as-todo-file nil t)
   )
 
-(put 'todo-mode 'mode-class 'special)
-
 ;;;###autoload
 (define-derived-mode todo-mode special-mode "Todo"
-  "Major mode for displaying, navigating and editing todo lists.
-
-\\{todo-mode-map}"
+  "Major mode for displaying, navigating and editing todo lists."
   (if (called-interactively-p 'any)
       (message "%s"
                (substitute-command-keys
@@ -6863,15 +6860,11 @@ Added to `window-configuration-change-hook' in Todo mode."
               #'todo-reset-and-enable-done-separator nil t)
     (add-hook 'kill-buffer-hook #'todo-reset-global-current-todo-file nil t)))
 
-(put 'todo-archive-mode 'mode-class 'special)
-
 ;; If todo-mode is parent, all todo-mode key bindings appear to be
 ;; available in todo-archive-mode (e.g. shown by C-h m).
 ;;;###autoload
 (define-derived-mode todo-archive-mode special-mode "Todo-Arch"
-  "Major mode for archived todo categories.
-
-\\{todo-archive-mode-map}"
+  "Major mode for archived todo categories."
   (todo-modes-set-1)
   (todo-modes-set-2)
   (todo-modes-set-3)
@@ -6879,9 +6872,7 @@ Added to `window-configuration-change-hook' in Todo mode."
   (setq-local todo-show-done-only t))
 
 (define-derived-mode todo-edit-mode text-mode "Todo-Ed"
-  "Major mode for editing multiline todo items.
-
-\\{todo-edit-mode-map}"
+  "Major mode for editing multiline todo items."
   (todo-modes-set-1)
   (setq-local indent-line-function #'todo-indent)
   (if (> (buffer-size) (- (point-max) (point-min)))
@@ -6894,12 +6885,8 @@ Added to `window-configuration-change-hook' in Todo mode."
     (setq-local todo-categories (todo-set-categories)))
   (setq buffer-read-only nil))
 
-(put 'todo-categories-mode 'mode-class 'special)
-
 (define-derived-mode todo-categories-mode special-mode "Todo-Cats"
-  "Major mode for displaying and editing todo categories.
-
-\\{todo-categories-mode-map}"
+  "Major mode for displaying and editing todo categories."
   (setq-local todo-current-todo-file todo-global-current-todo-file)
   (setq-local todo-categories
               ;; Can't use find-buffer-visiting when
@@ -6910,13 +6897,9 @@ Added to `window-configuration-change-hook' in Todo mode."
                                     todo-current-todo-file 'nowarn)
                 todo-categories)))
 
-(put 'todo-filtered-items-mode 'mode-class 'special)
-
 ;;;###autoload
 (define-derived-mode todo-filtered-items-mode special-mode "Todo-Fltr"
-  "Mode for displaying and reprioritizing top priority Todo.
-
-\\{todo-filtered-items-mode-map}"
+  "Mode for displaying and reprioritizing top priority Todo."
   (todo-modes-set-1)
   (todo-modes-set-2))