diff --git a/lisp/emacs-lisp/lucid.el b/lisp/emacs-lisp/lucid.el
index 36600f540b6..6412b0bc8f4 100644
--- a/lisp/emacs-lisp/lucid.el
+++ b/lisp/emacs-lisp/lucid.el
@@ -44,3 +44,20 @@
       (if (eq (nth 2 plist) prop)
 	  (setcdr (cdr plist) (nthcdr 4 plist)))
       (setq plist (cdr (cdr plist))))))
+
+(defun map-keymap (function keymap)
+  "Call FUNCTION for every binding in KEYMAP.
+This includes bindings inherited from a parent keymap.
+FUNCTION receives two arguments each time it is called:
+the character (more generally, the event type) that is bound,
+and the binding it has."
+  (while (consp keymap)
+    (if (consp (car keymap))
+	(funcall function (car (car keymap)) (cdr (car keymap)))
+      (if (vectorp (car keymap))
+	  (let ((i (length (car keymap)))
+		(vector (car keymap)))
+	    (while (>= i 0)
+	      (funcall function i (aref vector i))
+	      (setq i (1- i))))))
+    (setq keymap (cdr keymap))))