Allow for custom URL handlers in browse-url.

* lisp/net/browse-url.el (browse-url-handlers): New defcustom.
(browse-url-default-handlers): New defvar.
(browse-url): Use them.  Adapt docstring.  Issue a warning pointing to
browse-url-handlers when browse-url-browser-function is an alist.
(browse-url--mailto, browse-url--man): New functions.
(browse-url--browser-defcustom-type): Add :doc that the alist usage is
deprecated.
(browse-url-browser-function): Remove documentation referring to the
alist usage and mention browse-url-handlers.
* doc/emacs/misc.texi: Document browse-url-handlers in Browse-URL
node.
* etc/NEWS: Mention browse-url-default-handlers and
browse-url-handlers.

1 files changed, 16 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 0f4b6244c62..ac93a76ff95 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -304,6 +304,22 @@ use ‘doxygen’ by default one might evaluate:
                     (c++-mode  . doxygen)))
 
 or use it in a custom ‘c-style’.
+
+** browse-url
+
+*** Added support for custom URL handlers
+
+There is a new defvar 'browse-url-default-handlers' and a defcustom
+'browse-url-handlers' being alists with (REGEXP . FUNCTION) entries
+allowing to define different browsing FUNCTIONs depending on the URL
+to be browsed.  The defvar is for default handlers provided by Emacs
+itself or external packages, the defcustom is for the user (and allows
+for overriding the default handlers).
+
+Formerly, one could do the same by setting
+'browse-url-browser-function' to such an alist.  This usage is still
+supported but deprecated.
+
 
 * New Modes and Packages in Emacs 28.1