Add new hooks when enabling and disabling themes

* lisp/custom.el (enable-theme-hook, disable-theme-hook): New
hooks (bug#37802).
(enable-theme, disable-theme): Call them.

1 files changed, 28 insertions, 4 deletions

diff --git a/lisp/custom.el b/lisp/custom.el
index 76c14831cac..181711967db 100644
--- a/lisp/custom.el
+++ b/lisp/custom.el
@@ -1422,6 +1422,22 @@ are not directories are omitted from the expansion."
 
 ;;; Enabling and disabling loaded themes.
 
+(defcustom enable-theme-hook nil
+  "Atypical hook run after a theme has been enabled.
+The functions in the hook are called with one parameter -- the
+ name of the theme that's been enabled (as a symbol)."
+  :type 'hook
+  :group 'customize
+  :version "29.1")
+
+(defcustom disable-theme-hook nil
+  "Atypical hook run after a theme has been disabled.
+The functions in the hook are called with one parameter -- the
+ name of the theme that's been disabled (as a symbol)."
+  :type 'hook
+  :group 'customize
+  :version "29.1")
+
 (defun enable-theme (theme)
   "Reenable all variable and face settings defined by THEME.
 THEME should be either `user', or a theme loaded via `load-theme'.
@@ -1430,7 +1446,9 @@ After this function completes, THEME will have the highest
 precedence (after `user') among enabled themes.
 
 Note that any already-enabled themes remain enabled after this
-function runs.  To disable other themes, use `disable-theme'."
+function runs.  To disable other themes, use `disable-theme'.
+
+After THEME has been enabled, `enable-theme-hook' is run."
   (interactive (list (intern
 		      (completing-read
 		       "Enable custom theme: "
@@ -1478,7 +1496,9 @@ function runs.  To disable other themes, use `disable-theme'."
     (setq custom-enabled-themes
 	  (cons theme (remq theme custom-enabled-themes)))
     ;; Give the `user' theme the highest priority.
-    (enable-theme 'user)))
+    (enable-theme 'user))
+  ;; Allow callers to react to the enabling.
+  (run-hook-with-args 'enable-theme-hook theme))
 
 (defcustom custom-enabled-themes nil
   "List of enabled Custom Themes, highest precedence first.
@@ -1523,7 +1543,9 @@ Setting this variable through Customize calls `enable-theme' or
 
 (defun disable-theme (theme)
   "Disable all variable and face settings defined by THEME.
-See `custom-enabled-themes' for a list of enabled themes."
+See `custom-enabled-themes' for a list of enabled themes.
+
+After THEME has been disabled, `disable-theme-hook' is run."
   (interactive (list (intern
 		      (completing-read
 		       "Disable custom theme: "
@@ -1567,7 +1589,9 @@ See `custom-enabled-themes' for a list of enabled themes."
                             "unspecified-fg" "black"))
       (face-set-after-frame-default frame))
     (setq custom-enabled-themes
-          (delq theme custom-enabled-themes))))
+          (delq theme custom-enabled-themes))
+    ;; Allow callers to react to the disabling.
+    (run-hook-with-args 'disable-theme-hook theme)))
 
 ;; Only used if window-system not null.
 (declare-function x-get-resource "frame.c"