Add new command 'toggle-theme'

* doc/emacs/custom.texi (Custom Themes): Mention it.
* etc/themes/leuven-dark-theme.el (leuven-dark): Add dual theme.
* etc/themes/leuven-theme.el (leuven): Add dual theme.
* etc/themes/tango-dark-theme.el (tango-dark): Add dual theme.
* etc/themes/tango-theme.el (tango): Add dual theme.
* etc/themes/tsdh-dark-theme.el (tsdh-dark): Add dual theme.
* etc/themes/tsdh-light-theme.el (tsdh-light): Add dual theme.
* lisp/cus-theme.el (describe-theme-1): Say if a theme has a dual.
* lisp/custom.el (toggle-theme): Add new command.

6 files changed, 14 insertions, 2 deletions

diff --git a/etc/themes/leuven-dark-theme.el b/etc/themes/leuven-dark-theme.el
index 0e162c8bab9..cef40782c1b 100644
--- a/etc/themes/leuven-dark-theme.el
+++ b/etc/themes/leuven-dark-theme.el
@@ -5,7 +5,7 @@
 ;; Author: Fabrice Niessen <(concat "fniessen" at-sign "pirilampo.org")>
 ;; Contributor: Thibault Polge <(concat "thibault" at-sign "thb.lt")>
 ;; URL: https://github.com/fniessen/emacs-leuven-dark-theme
-;; Version: 20220202.1126
+;; Version: 20220906.2016
 ;; Keywords: color theme
 
 ;; This file is part of GNU Emacs.
@@ -1083,6 +1083,8 @@ more...")
   (add-to-list 'custom-theme-load-path
                (file-name-as-directory (file-name-directory load-file-name))))
 
+(put 'leuven-dark 'dual-theme 'leuven) ;see `toggle-theme'
+
 (provide-theme 'leuven-dark)
 
 ;; This is for the sake of Emacs.
diff --git a/etc/themes/leuven-theme.el b/etc/themes/leuven-theme.el
index d9a8d5391ae..73ac96d28d9 100644
--- a/etc/themes/leuven-theme.el
+++ b/etc/themes/leuven-theme.el
@@ -4,7 +4,7 @@
 
 ;; Author: Fabrice Niessen <(concat "fniessen" at-sign "pirilampo.org")>
 ;; URL: https://github.com/fniessen/emacs-leuven-theme
-;; Version: 20200513.1928
+;; Version: 20220906.2016
 ;; Keywords: color theme
 
 ;; This file is part of GNU Emacs.
@@ -1065,6 +1065,8 @@ more...")
   (add-to-list 'custom-theme-load-path
                (file-name-as-directory (file-name-directory load-file-name))))
 
+(put 'leuven 'dual-theme 'leuven-dark) ;see `toggle-theme'
+
 (provide-theme 'leuven)
 
 ;; This is for the sake of Emacs.
diff --git a/etc/themes/tango-dark-theme.el b/etc/themes/tango-dark-theme.el
index ef00d2ac49f..f9f2692ac59 100644
--- a/etc/themes/tango-dark-theme.el
+++ b/etc/themes/tango-dark-theme.el
@@ -190,6 +190,8 @@ Semantic, and Ansi-Color faces are included.")
    `(ansi-color-bright-white ((,class (:background ,alum-1
 				       :foreground ,alum-1))))))
 
+(put 'tango-dark 'dual-theme 'tango) ;see `toggle-theme'
+
 (provide-theme 'tango-dark)
 
 ;;; tango-dark-theme.el ends here
diff --git a/etc/themes/tango-theme.el b/etc/themes/tango-theme.el
index ecbbf037536..8d1686f05e1 100644
--- a/etc/themes/tango-theme.el
+++ b/etc/themes/tango-theme.el
@@ -173,6 +173,8 @@ Semantic, and Ansi-Color faces are included.")
    `(ansi-color-bright-white ((,class (:background ,alum-1
 				       :foreground ,alum-1))))))
 
+(put 'tango 'dual-theme 'tango-dark) ;see `toggle-theme'
+
 (provide-theme 'tango)
 
 ;;; tango-theme.el ends here
diff --git a/etc/themes/tsdh-dark-theme.el b/etc/themes/tsdh-dark-theme.el
index a88ad75520b..ad54eb3df01 100644
--- a/etc/themes/tsdh-dark-theme.el
+++ b/etc/themes/tsdh-dark-theme.el
@@ -142,6 +142,8 @@
  '(widget-field ((t (:box (:line-width 2 :color "grey75" :style pressed-button)))))
  '(window-number-face ((t (:foreground "red" :weight bold)))))
 
+(put 'tsdh-dark 'dual-theme 'tsdh-light) ;see `toggle-theme'
+
 (provide-theme 'tsdh-dark)
 
 ;;; tsdh-dark-theme.el ends here
diff --git a/etc/themes/tsdh-light-theme.el b/etc/themes/tsdh-light-theme.el
index d9d09b702b7..64c048f7e5e 100644
--- a/etc/themes/tsdh-light-theme.el
+++ b/etc/themes/tsdh-light-theme.el
@@ -104,6 +104,8 @@ Used and created by Tassilo Horn.")
  '(show-paren-mismatch ((t (:background "deep pink" :weight bold))))
  '(window-number-face ((t (:foreground "red" :weight bold)))))
 
+(put 'tsdh-light 'dual-theme 'tsdh-dark) ;see `toggle-theme'
+
 (provide-theme 'tsdh-light)
 
 ;;; tsdh-light-theme.el ends here