(describe-key-briefly): Handle mode line strings

with local-map properties.
(describe-key): Ditto.
(mode-line-key-binding): New.

diff --git a/lisp/help.el b/lisp/help.el
index d2da9a55b5ab1208a219ebb8cef5b727476479cf..b9b71903e002f1ed3f8ccf84d87065bfd7d71a42 100644 (file)
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -216,6 +216,19 @@ With arg, you are asked to choose which language."
       (goto-char (point-min))
       (set-buffer-modified-p nil))))
 
+(defun mode-line-key-binding (key)
+  "Value is the binding of KEY in the mode line or nil if none."
+  (let (string-info defn)
+    (when (and (eq 'mode-line (aref key 0))
+              (consp (setq string-info (nth 4 (event-start (aref key 1))))))
+    (let* ((string (car string-info))
+          (pos (cdr string-info))
+          (local-map (and (> pos 0)
+                          (< pos (length string))
+                          (get-text-property pos 'local-map string))))
+      (setq defn (and local-map (lookup-key local-map key)))))
+    defn))
+
 (defun describe-key-briefly (key &optional insert)
   "Print the name of the function KEY invokes.  KEY is a string.
 If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
@@ -236,7 +249,8 @@ If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
            (set-buffer (window-buffer window))
            (goto-char position)))
       ;; Ok, now look up the key and name the command.
-      (let ((defn (key-binding key))
+      (let ((defn (or (mode-line-key-binding key)
+                     (key-binding key)))
            (key-desc (key-description key)))
        (if (or (null defn) (integerp defn))
            (princ (format "%s is undefined" key-desc))
@@ -317,7 +331,7 @@ If FUNCTION is nil, applies `message' to it, thus printing it."
          (progn
            (set-buffer (window-buffer window))
            (goto-char position)))
-      (let ((defn (key-binding key)))
+      (let ((defn (or (mode-line-key-binding key) (key-binding key))))
        (if (or (null defn) (integerp defn))
            (message "%s is undefined" (key-description key))
          (with-output-to-temp-buffer "*Help*"