diff options
Diffstat (limited to 'lisp/so-long.el')
| -rw-r--r-- | lisp/so-long.el | 99 |
1 files changed, 98 insertions, 1 deletions
diff --git a/lisp/so-long.el b/lisp/so-long.el index dafcfaa18cb..a74a9200dec 100644 --- a/lisp/so-long.el +++ b/lisp/so-long.el @@ -214,6 +214,24 @@ ;; performance or otherwise avoid undesirable behaviours. If `so-long-revert' ;; is called, then the original values are restored. +;; * Retaining minor modes and settings when switching to `so-long-mode' +;; --------------------------------------------------------------------- +;; A consequence of switching to a new major mode is that many buffer-local +;; minor modes and variables from the original major mode will be disabled. +;; For performance purposes this is a desirable trait of `so-long-mode', but +;; specified modes and variables can also be preserved across the major mode +;; transition by customizing the `so-long-mode-preserved-minor-modes' and +;; `so-long-mode-preserved-variables' user options. +;; +;; When `so-long-mode' is called, the states of any modes and variables +;; configured by these options are remembered in the original major mode, and +;; reinstated after switching to `so-long-mode'. Likewise, if `so-long-revert' +;; is used to switch back to the original major mode, these modes and variables +;; are again set to the same states. +;; +;; The default values for these options ensure that if `view-mode' was active +;; in the original mode, then it will also be active in `so-long-mode'. + ;; * Hooks ;; ------- ;; `so-long-hook' runs at the end of the `so-long' command, after the configured @@ -394,6 +412,8 @@ ;; 1.1 - Increase `so-long-threshold' from 250 to 10,000. ;; - Increase `so-long-max-lines' from 5 to 500. ;; - Include `fundamental-mode' in `so-long-target-modes'. +;; - New user option `so-long-mode-preserved-minor-modes'. +;; - New user option `so-long-mode-preserved-variables'. ;; 1.0 - Included in Emacs 27.1, and in GNU ELPA for prior versions of Emacs. ;; - New global mode `global-so-long-mode' to enable/disable the library. ;; - New user option `so-long-action'. @@ -859,6 +879,44 @@ intended to be edited manually." (which-func-mode boolean)) :package-version '(so-long . "1.0")) +(defcustom so-long-mode-preserved-minor-modes + '(view-mode) + "List of buffer-local minor modes to preserve in `so-long-mode'. + +These will be enabled or disabled after switching to `so-long-mode' (by calling +them with the numeric argument 1 or 0) in accordance with their state in the +buffer's original major mode. Unknown modes, and modes which are already in the +desired state, are ignored. + +This happens before `so-long-variable-overrides' and `so-long-minor-modes' +have been processed. + +By default this happens only if `so-long-action' is set to `so-long-mode'. +If `so-long-revert' is subsequently invoked, then the modes are again set +to their original state after the original major mode has been called. + +See also `so-long-mode-preserved-variables' (processed after this)." + :type '(repeat symbol) ;; not function, as may be unknown => mismatch. + :package-version '(so-long . "1.1")) + +(defcustom so-long-mode-preserved-variables + '(view-old-buffer-read-only) + "List of buffer-local variables to preserve in `so-long-mode'. + +The original value of each variable will be maintained after switching to +`so-long-mode'. Unknown variables are ignored. + +This happens before `so-long-variable-overrides' and `so-long-minor-modes' +have been processed. + +By default this happens only if `so-long-action' is set to `so-long-mode'. +If `so-long-revert' is subsequently invoked, then the variables are again +set to their original values after the original major mode has been called. + +See also `so-long-mode-preserved-minor-modes' (processed before this)." + :type '(repeat variable) + :package-version '(so-long . "1.1")) + (defcustom so-long-hook nil "List of functions to call after `so-long' is called. @@ -945,10 +1003,17 @@ If RESET is non-nil, remove any existing values before storing the new ones." (setq so-long-original-values nil)) (so-long-remember 'so-long-variable-overrides) (so-long-remember 'so-long-minor-modes) + (so-long-remember 'so-long-mode-preserved-variables) + (so-long-remember 'so-long-mode-preserved-minor-modes) (dolist (ovar so-long-variable-overrides) (so-long-remember (car ovar))) (dolist (mode so-long-minor-modes) (when (and (boundp mode) mode) + (so-long-remember mode))) + (dolist (var so-long-mode-preserved-variables) + (so-long-remember var)) + (dolist (mode so-long-mode-preserved-minor-modes) + (when (and (boundp mode) mode) (so-long-remember mode)))) (defun so-long-menu () @@ -1333,6 +1398,16 @@ This advice acts before `so-long-mode', with the previous mode still active." "Run by `so-long-mode' in `after-change-major-mode-hook'. Calls `so-long-disable-minor-modes' and `so-long-override-variables'." + ;; Check/set the state of 'preserved' variables and minor modes. + ;; (See also `so-long-mode-revert'.) + ;; The "modes before variables" sequence is important for the default + ;; preserved mode `view-mode' which remembers the `buffer-read-only' state + ;; (which is also permanent-local). That causes problems unless we restore + ;; the original value of `view-old-buffer-read-only' after; otherwise the + ;; sequence `view-mode' -> `so-long' -> `so-long-revert' -> `view-mode' + ;; results in `view-mode' being disabled but the buffer still read-only. + (so-long-mode-maintain-preserved-minor-modes) + (so-long-mode-maintain-preserved-variables) ;; Disable minor modes. (so-long-disable-minor-modes) ;; Override variables (again). We already did this in `so-long-mode' in @@ -1377,7 +1452,7 @@ The variables are set in accordance with what was remembered in `so-long'." ;; In the instance where `so-long-mode-revert' has just reverted the major ;; mode, note that `kill-all-local-variables' was already called by the ;; original mode function, and so these 'overridden' variables may now have - ;; global rather than buffer-local values. + ;; global rather than buffer-local values (if they are not permanent-local). (let* ((remembered (so-long-original variable :exists)) (originally-local (nth 2 remembered))) (if originally-local @@ -1393,6 +1468,24 @@ The variables are set in accordance with what was remembered in `so-long'." ;; the old value as a buffer-local value, so we keep it simple. (kill-local-variable variable)))) +(defun so-long-mode-maintain-preserved-variables () + "Set any 'preserved' variables. + +The variables are set in accordance with what was remembered in `so-long'." + (dolist (var (so-long-original 'so-long-mode-preserved-variables)) + (so-long-restore-variable var))) + +(defun so-long-mode-maintain-preserved-minor-modes () + "Enable or disable 'preserved' minor modes. + +The modes are set in accordance with what was remembered in `so-long'." + (dolist (mode (so-long-original 'so-long-mode-preserved-minor-modes)) + (when (boundp mode) + (let ((original (so-long-original mode)) + (current (symbol-value mode))) + (unless (equal current original) + (funcall mode (if original 1 0))))))) + (defun so-long-mode-revert () "Call the `major-mode' which was selected before `so-long-mode' replaced it. @@ -1420,6 +1513,10 @@ This is the `so-long-revert-function' for `so-long-mode'." ;; `kill-all-local-variables' was already called by the original mode ;; function, so we may be seeing global values. (so-long-restore-variables) + ;; Check/set the state of 'preserved' variables and minor modes. + ;; (Refer to `so-long-after-change-major-mode' regarding the sequence.) + (so-long-mode-maintain-preserved-minor-modes) + (so-long-mode-maintain-preserved-variables) ;; Restore the mode line construct. (unless (derived-mode-p 'so-long-mode) (setq so-long-mode-line-info (so-long-mode-line-info))))) |