Make `C-h S' work on symbols from most of the manuals in Emacs

* lisp/info-look.el (lambda): Add `C-h S' lookup for all the
"misc" manuals in Emacs (bug#42753).

1 files changed, 73 insertions, 1 deletions

diff --git a/lisp/info-look.el b/lisp/info-look.el
index 309f2e8d631..881f63c140c 100644
--- a/lisp/info-look.el
+++ b/lisp/info-look.el
@@ -358,9 +358,19 @@ If optional argument QUERY is non-nil, query for the help mode."
         (error "No %s help available for `%s'" topic mode))
     (setq info-lookup-mode mode)))
 
+(defun info-lookup--item-to-mode (item mode)
+  (let ((spec (cons mode (car (split-string (if (stringp item)
+                                                item
+                                              (symbol-name item))
+                                            "-")))))
+    (if (assoc spec (cdr (assq 'symbol info-lookup-alist)))
+        spec
+      mode)))
+
 (defun info-lookup (topic item mode)
   "Display the documentation of a help item."
   (or mode (setq mode (info-lookup-select-mode)))
+  (setq mode (info-lookup--item-to-mode item mode))
   (if-let ((info (info-lookup->mode-value topic mode)))
       (info-lookup--expand-info info)
     (error "No %s help available for `%s'" topic mode))
@@ -969,7 +979,69 @@ Return nil if there is nothing appropriate in the buffer near point."
              ;; sort of fallback match scheme existed.
              ("(elisp)Index"          nil "^ -+ .*: " "\\( \\|$\\)")
              ("(cl)Function Index"    nil "^ -+ .*: " "\\( \\|$\\)")
-             ("(cl)Variable Index"    nil "^ -+ .*: " "\\( \\|$\\)")))
+             ("(cl)Variable Index"    nil "^ -+ .*: " "\\( \\|$\\)")
+             ("(dired-x)Index"          nil "^ -+ .*: " "\\( \\|$\\)")))
+
+(mapc
+ (lambda (elem)
+   (let* ((prefix (car elem)))
+     (info-lookup-add-help
+      :mode (cons 'emacs-lisp-mode prefix)
+      :regexp (concat "\\b" prefix "-[^][()`'‘’,\" \t\n]+")
+      :doc-spec (cl-loop for node in (cdr elem)
+                         collect
+                         (list (if (string-match-p "^(" node)
+                                   node
+                                 (format "(%s)%s" prefix node))
+                               nil "^ -+ .*: " "\\( \\|$\\)")))))
+ ;; Below we have a list of prefixes (used to match on symbols in
+ ;; `emacs-lisp-mode') and the nodes where the function/variable
+ ;; indices live.  If the prefix is different than the name of the
+ ;; manual, then the full "(manual)Node" name has to be used.
+ '(("auth" "Function Index" "Variable Index")
+   ("autotype" "Command Index" "Variable Index")
+   ("calc" "Lisp Function Index" "Variable Index")
+   ;;("cc-mode" "Variable Index" "Command and Function Index")
+   ("dbus" "Index")
+   ("ediff" "Index")
+   ("eieio" "Function Index")
+   ("gnutls" "(emacs-gnutls)Variable Index" "(emacs-gnutls)Function Index")
+   ("mm" "(emacs-mime)Index")
+   ("epa" "Variable Index" "Function Index")
+   ("ert" "Index")
+   ("eshell" "Function and Variable Index")
+   ("eudc" "Index")
+   ("eww" "Variable Index" "Lisp Function Index")
+   ("flymake" "Index")
+   ("forms" "Index")
+   ("gnus" "Index")
+   ("htmlfontify" "Functions" "Variables & Customization")
+   ("idlwave" "Index")
+   ("ido" "Variable Index" "Function Index")
+   ("info" "Index")
+   ("mairix" "(mairix-el)Variable Index" "(mairix-el)Function Index")
+   ("message" "Index")
+   ("mh" "(mh-e)Option Index" "(mh-e)Command Index")
+   ("newsticker" "Index")
+   ("octave" "(octave-mode)Variable Index" "(octave-mode)Lisp Function Index")
+   ("org" "Variable Index" "Command and Function Index")
+   ("pgg" "Variable Index" "Function Index")
+   ("rcirc" "Variable Index" "Index")
+   ("reftex" "Index")
+   ("sasl" "Variable Index" "Function Index")
+   ("sc" "Variable Index")
+   ("semantic" "Index")
+   ("ses" "Index")
+   ("sieve" "Index")
+   ("smtpmail" "Function and Variable Index")
+   ("srecode" "Index")
+   ("tramp" "Variable Index" "Function Index")
+   ("url" "Variable Index" "Function Index")
+   ("vhdl" "(vhdl-mode)Variable Index" "(vhdl-mode)Command Index")
+   ("viper" "Variable Index" "Function Index")
+   ("widget" "Index")
+   ("wisent" "Index")
+   ("woman" "Variable Index" "Command Index")))
 
 ;; docstrings talk about elisp, so have apropos-mode follow emacs-lisp-mode
 (info-lookup-maybe-add-help