Index: find-func.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/emacs-lisp/find-func.el,v
retrieving revision 1.82
diff -p -u -w -r1.82 find-func.el
--- find-func.el	17 Oct 2007 23:49:00 -0000	1.82
+++ find-func.el	23 Oct 2007 06:17:37 -0000
@@ -192,11 +192,21 @@ TYPE should be nil to find a function, o
 (defun find-library (library)
   "Find the elisp source of LIBRARY."
   (interactive
+   (let* ((path (cons (or find-function-source-path load-path)
+                      (find-library-suffixes)))
+          (def (if (eq (function-called-at-point) 'require)
+                   (save-excursion
+                     (backward-up-list)
+                     (forward-char)
+                     (backward-sexp -2)
+                     (thing-at-point 'symbol))
+                 (thing-at-point 'symbol))))
+     (when def
+       (setq def (and (locate-file-completion def path 'test) def)))
    (list
-    (completing-read "Library name: "
-		     'locate-file-completion
-		     (cons (or find-function-source-path load-path)
-			   (find-library-suffixes)))))
+      (completing-read (if def (format "Library name (default %s): " def)
+                         "Library name: ")
+		     'locate-file-completion path nil nil nil def))))
   (let ((buf (find-file-noselect (find-library-name library))))
     (condition-case nil (switch-to-buffer buf) (error (pop-to-buffer buf)))))