Enable browse-url to buttonize buffers

This patch also moves the internal/external browser logic from
shr to browse-url, where it belongs more naturally.

* doc/misc/eww.texi (Basics): Adjust to browse-url-external-browser.

* doc/misc/gnus.texi (Article Commands): Ditto.

* lisp/gnus/gnus-art.el (gnus-button-url-regexp): Default to
`browse-url-button-regexp', which has taken over the definition
previously enjoyed by this variable.

* lisp/gnus/gnus-sum.el (gnus-summary-browse-url): Adjust usage.

* lisp/net/browse-url.el (browse-url--browser-defcustom-type): New
internal variable...
(browse-url-browser-function, browse-url-external-browser): Used
by these two; the latter of which is a new variable.
(browse-url-botton-regexp): New variable.
(browse-url-button-map): New keymap.
(browse-url-button): New face.
(browse-url-add-buttons): New function to add clickable browse-url
buttons to almost any buffer.
(browse-url-button-open): New command.
(browse-url-button-copy): New command.

* lisp/net/eww.el (eww-browse-with-external-browser)
(eww-follow-link): Adjust usage.

* lisp/net/shr.el (shr-external-browser): Make an obsolete alias
of `browse-url-external-browser'.
(shr-browse-url): Adjust usage.

2 files changed, 4 insertions, 22 deletions

diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index 65e1c8106d5..89f57712c56 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -7343,27 +7343,9 @@ groups."
 
 ;; Written by Per Abrahamsen <abraham@iesd.auc.dk>.
 
-;;; Internal Variables:
-
-(defcustom gnus-button-url-regexp
-  (concat
-   "\\b\\(\\(www\\.\\|\\(s?https?\\|ftp\\|file\\|gopher\\|"
-   "nntp\\|news\\|telnet\\|wais\\|mailto\\|info\\):\\)"
-   "\\(//[-a-z0-9_.]+:[0-9]*\\)?"
-   (let ((chars "-a-z0-9_=#$@~%&*+\\/[:word:]")
-         (punct "!?:;.,"))
-     (concat
-      "\\(?:"
-      ;; Match paired parentheses, e.g. in Wikipedia URLs:
-      ;; http://thread.gmane.org/47B4E3B2.3050402@gmail.com
-      "[" chars punct "]+" "(" "[" chars punct "]+" "[" chars "]*)"
-      "\\(?:" "[" chars punct "]+" "[" chars "]" "\\)?"
-      "\\|"
-      "[" chars punct "]+" "[" chars "]"
-      "\\)"))
-   "\\)")
+(defcustom gnus-button-url-regexp browse-url-button-regexp
   "Regular expression that matches URLs."
-  :version "24.4"
+  :version "27.1"
   :group 'gnus-article-buttons
   :type 'regexp)
 
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index b239890c884..d3103bd4b20 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -9478,7 +9478,7 @@ The 1st element is the widget named by `gnus-collect-urls-primary-text'."
   "Scan the current article body for links, and offer to browse them.
 
 Links are opened using `browse-url' unless a prefix argument is
-given: Then `shr-external-browser' is used instead.
+given: Then `browse-url-external-browser' is used instead.
 
 If only one link is found, browse that directly, otherwise use
 completion to select a link.  The first link marked in the
@@ -9502,7 +9502,7 @@ default."
                                     (car urls)))))
       (if target
           (if external
-              (funcall shr-external-browser target)
+              (funcall browse-url-external-browser target)
             (browse-url target))
         (message "No URLs found.")))))