From 9c14983767905260fb5a57543adc4c446e26cb92 Mon Sep 17 00:00:00 2001
From: Stefan Kangas <stefankangas@gmail.com>
Date: Tue, 20 Dec 2022 02:49:54 +0100
Subject: [PATCH 1/2] Make Info-url-for-node support more manuals

* lisp/info.el (info--url-for-node-manuals-built-in)
(info-url-for-node-manuals): New variables.
(Info-url-for-node): Support all built-in manuals, and add support
for external manuals.
---
 lisp/info.el | 44 +++++++++++++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 9 deletions(-)

diff --git a/lisp/info.el b/lisp/info.el
index 05ad27e180..f939c42874 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -1793,16 +1793,43 @@ Info-goto-node-web
                                          Info-current-file))
                               node))))
 
+(defvar info--url-for-node-manuals-built-in
+  ;; All manuals are at https://www.gnu.org/software/emacs/manual/
+  '("auth" "autotype" "bovine" "calc" "ccmode" "cl" "dbus" "dired-x"
+    "ebrowse" "ede" "ediff" "edt" "efaq" "efaq-w32" "eglot" "eieio"
+    "eintr" "elisp" "emacs" "emacs-gnutls" "emacs-mime" "epa" "erc"
+    "ert" "eshell" "eudc" "eww" "faq" "flymake" "forms" "gnus"
+    "htmlfontify" "idlwave" "ido" "info" "mairix-el" "message" "mh-e"
+    "modus-themes" "newsticker" "nxml-mode" "octave-mode" "org"
+    "pcl-cvs" "pgg" "rcirc" "reftex" "remember" "sasl" "sc" "semantic"
+    "ses" "sieve" "smtpmail" "speedbar" "srecode" "todo-mode" "tramp"
+    "transient" "url" "use-package" "vhdl-mode" "vip" "viper" "widget"
+    "wisent" "woman")
+  "List of built-in manual names (strings) supported by `Info-url-for-node'.")
+
+(defvar info-url-for-node-manuals ()
+  "Alist of manuals for `Info-url-for-node'.
+Each entry has the form (NAME . URL) where NAME is the Info
+manual name, and URL is the canonical URL of the manual.
+The URL should not end in \"/\".")
+
 (defun Info-url-for-node (node)
-  "Return a URL for NODE, a node in the GNU Emacs or Elisp manual.
-NODE should be a string on the form \"(manual)Node\".  Only emacs
-and elisp manuals are supported."
+  "Return a URL for NODE, a node in the current manual.
+NODE should be a string on the form \"(manual)Node\".
+
+All built-in manuals are supported by default, but additional
+manuals can be added to the variable `info-url-for-node-manuals'."
   (unless (string-match "\\`(\\(.+\\))\\(.+\\)\\'" node)
     (error "Invalid node name %s" node))
-  (let ((manual (match-string 1 node))
-        (node (match-string 2 node)))
-    (unless (member manual '("emacs" "elisp"))
-      (error "Only emacs/elisp manuals are supported"))
+  (let* ((manual (match-string 1 node))
+         (node (match-string 2 node))
+         (base-url
+          (or (assoc manual info-url-for-node-manuals)
+              (and (member manual info--url-for-node-manuals-built-in)
+                   "https://www.gnu.org/software/emacs/manual/html_node")
+              (error "Manual not supported: %s" manual))))
+    (when (equal node "Top")
+      (setq node "index"))
     ;; Encode a bunch of characters the way that makeinfo does.
     (setq node
           (mapconcat (lambda (ch)
@@ -1815,8 +1842,7 @@ Info-url-for-node
                          (char-to-string ch)))
                      node
                      ""))
-    (concat "https://www.gnu.org/software/emacs/manual/html_node/"
-            manual "/"
+    (concat base-url "/" manual "/"
             (url-hexify-string (string-replace " " "-" node))
             ".html")))
 
-- 
2.35.1