Require custom values of `boolean` type to be nil or t

This helps detecting mistakes in types and/or initial values.

* lisp/wid-edit.el (boolean): Add :match function.

diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index 60bd2baa6fb442e0f8b4720e3050d3667db3fc83..8b035224c9bdb972e2792504eb121895e746f39c 100644 (file)
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -4038,6 +4038,7 @@ is inline."
   :button-prefix 'widget-push-button-prefix
   :button-suffix 'widget-push-button-suffix
   :format "%{%t%}: %[Toggle%]  %v\n"
+  :match (lambda (_widget value) (booleanp value))
   :on "on (non-nil)"
   :off "off (nil)")