(help-xref-mule-regexp): New variable

(help-make-xrefs): Handle help-xref-mule-regexp.

2 files changed, 41 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 3a8794f3b78..56f46e7bd27 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,6 +1,6 @@
 2000-08-29  Kenichi Handa  <handa@etl.go.jp>
 
-        * help.el (help-xref-mule-regexp): New variable
+        * help.el (help-xref-mule-regexp): New variable.
         (help-make-xrefs): Handle help-xref-mule-regexp.
 
         * international/mule-cmds.el (help-xref-mule-regexp-template): New
diff --git a/lisp/help.el b/lisp/help.el
index abb59fc0b16..4c8fa346eaa 100644
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -1056,6 +1056,14 @@ Must be previously-defined."
 The words preceding the quoted symbol can be used in doc strings to
 distinguish references to variables, functions and symbols.")
 
+(defconst help-xref-mule-regexp nil
+  "Regexp matching doc string references to multilingualization related keywords.
+
+It is usually nil, and temporarily bound to a proper regexp while
+executing multilingualiation related help commands
+(e.g. describe-coding-system).")
+
+
 (defconst help-xref-info-regexp
   (purecopy "\\<[Ii]nfo[ \t\n]+node[ \t\n]+`\\([^']+\\)'")
   "Regexp matching doc string references to an Info node.")
@@ -1084,6 +1092,11 @@ with `help-follow'.  Cross-references have the canonical form `...'
 and the type of reference may be disambiguated by the preceding
 word(s) used in `help-xref-symbol-regexp'.
 
+If the variable `help-xref-mule-regexp' is non-nil, find also
+cross-reference information related to multiligualization issues
+\(e.g. coding-system).  This variable is also used to disambiguate the
+type of reference as the same way as `help-xref-symbol-regexp'.
+
 A special reference `back' is made to return back through a stack of
 help buffers.  Variable `help-back-label' specifies the text for
 that."
@@ -1111,6 +1124,33 @@ that."
                         (setq data (concat "(emacs)" data))))
                     (help-xref-button 1 #'info data
                                       "mouse-2, RET: read this Info node"))))
+              ;; Mule related keywords.  Do this before trying
+              ;; `help-xref-symbol-regexp' because some of Mule
+              ;; keywords have variable or function definitions.
+              (if help-xref-mule-regexp
+                  (save-excursion
+                    (while (re-search-forward help-xref-mule-regexp nil t)
+                      (let* ((data (match-string 5))
+                             (sym (intern-soft data)))
+                        (cond
+                         ((match-string 3) ; coding system
+                          (and (coding-system-p sym)
+                               (help-xref-button
+                                5 #'describe-coding-system sym
+                                "mouse-2, RET: describe this coding system")))
+                         ((match-string 4) ; input method
+                          (and (assoc data input-method-alist)
+                               (help-xref-button
+                                5 #'describe-input-method data
+                                "mouse-2, RET: describe this input method")))
+                         ((coding-system-p sym)
+                          (help-xref-button
+                           5 #'describe-coding-system sym
+                           "mouse-2, RET: describe this coding system"))
+                         ((assoc data input-method-alist)
+                          (help-xref-button
+                           5 #'describe-input-method data
+                           "mouse-2, RET: describe this input method")))))))
               ;; Quoted symbols
               (save-excursion
                 (while (re-search-forward help-xref-symbol-regexp nil t)