X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/2238127283d703f38765f9b3f6a64f799d18e9e5..6ae948d87e16588cd1c2a08d41331923e9786109:/lisp/info-look.el

diff --git a/lisp/info-look.el b/lisp/info-look.el
index 13edc0269d..b800fc885f 100644
--- a/lisp/info-look.el
+++ b/lisp/info-look.el
@@ -1,7 +1,7 @@
 ;;; info-look.el --- major-mode-sensitive Info index lookup facility -*- lexical-binding: t -*-
 ;; An older version of this was known as libc.el.
 
-;; Copyright (C) 1995-1999, 2001-2011 Free Software Foundation, Inc.
+;; Copyright (C) 1995-1999, 2001-2014 Free Software Foundation, Inc.
 
 ;; Author: Ralph Schleicher <rs@nunatak.allgaeu.org>
 ;;         (did not show signs of life (Nov 2001)  -stef)
@@ -27,6 +27,14 @@
 ;; Really cool code to lookup info indexes.
 ;; Try especially info-lookup-symbol (aka C-h S).
 
+;; Some additional sources of (Tex)info files for non-GNU packages:
+;;
+;; Scheme: <URL:http://groups.csail.mit.edu/mac/ftpdir/scm/r5rs.info.tar.gz>
+;; LaTeX:
+;;  <URL:ftp://ctan.tug.org/tex-archive/info/latex2e-help-texinfo/latex2e.texi>
+;;  (or CTAN mirrors)
+;; Perl: <URL:ftp://ftp.cpan.org/pub/CPAN/doc/manual/texinfo/> (or CPAN mirrors)
+
 ;;; Code:
 
 (require 'info)
@@ -298,6 +306,21 @@ If optional argument QUERY is non-nil, query for the help mode."
 	(when (string-match (caar file-name-alist) file-name)
 	  (setq info-lookup-mode (cdar file-name-alist)))
 	(setq file-name-alist (cdr file-name-alist)))))
+
+  ;; If major-mode has no setups in info-lookup-alist, under any topic, then
+  ;; search up through derived-mode-parent to find a parent mode which does
+  ;; have some setups.  This means that a `define-derived-mode' with no
+  ;; setups of its own will select its parent mode for lookups, if one of
+  ;; its parents has some setups.  Good for example on `makefile-gmake-mode'
+  ;; and similar derivatives of `makefile-mode'.
+  ;;
+  (let ((mode major-mode)) ;; Look for `mode' with some setups.
+    (while (and mode (not info-lookup-mode))
+      (dolist (topic-cell info-lookup-alist) ;; Usually only two topics here.
+        (if (info-lookup->mode-value (car topic-cell) mode)
+            (setq info-lookup-mode mode)))
+      (setq mode (get mode 'derived-mode-parent))))
+
   (or info-lookup-mode (setq info-lookup-mode major-mode)))
 
 (defun info-lookup-change-mode (topic)
@@ -732,7 +755,7 @@ Return nil if there is nothing appropriate in the buffer near point."
  :parse-rule "\\$[^({]\\|\\.[_A-Z]*\\|[_a-zA-Z0-9-]+\\|##\\|\\+="
  :doc-spec   '(
                ;; "(automake)Macro Index" is autoconf macros used in
-               ;; configure.in, not Makefile.am, so don't have that here.
+               ;; configure.ac, not Makefile.am, so don't have that here.
                ("(automake)Variable Index" nil "^[ \t]*`" "'")
                ;; In automake 1.4 macros and variables were a combined node.
                ("(automake)Macro and Variable Index" nil "^[ \t]*`" "'")
@@ -858,8 +881,11 @@ Return nil if there is nothing appropriate in the buffer near point."
 (info-lookup-maybe-add-help
  :mode 'latex-mode
  :regexp "\\\\\\([a-zA-Z]+\\|[^a-zA-Z]\\)"
- :doc-spec '(("(latex)Command Index" nil
-	      "`" "\\({[^}]*}\\)?'")))
+ :doc-spec `((,(if (Info-find-file "latex2e" t)
+		   ;; From http://home.gna.org/latexrefman
+		   "(latex2e)Command Index"
+		 "(latex)Command Index")
+	      nil "`" "\\({[^}]*}\\)?'")))
 
 (info-lookup-maybe-add-help
  :mode 'emacs-lisp-mode