=== modified file 'lisp/replace.el'
--- lisp/replace.el	2013-03-08 04:18:16 +0000
+++ lisp/replace.el	2013-03-09 08:23:57 +0000
@@ -580,6 +580,39 @@ of `history-length', which see.")
 (defvar occur-collect-regexp-history '("\\1")
   "History of regexp for occur's collect operation")
 
+(defcustom read-regexp-user-defaults nil
+  ""
+  :type '(choice
+	  (const :tag "Use system defaults" nil)
+	  (repeat :tag "Per-command defaults"
+		  (list (radio :tag "Command"
+			       (function-item highlight-regexp)
+			       (function-item highlight-phrase)
+			       (function-item highlight-lines-matching-regexp)
+			       (function :tag "Command"))
+			(choice :tag "Function to retrieve the regexp"
+				(const :tag "Use no defaults" nil)
+				(const :tag "Use system defaults" t)
+				(radio
+				 (function-item find-tag-default-as-regexp)
+				 (function-item find-tag-default)
+				 (function-item :tag "Regexp history"
+						(lambda nil
+						  "Use regexp history."
+						  (car regexp-history)))
+				 function)))))
+  :group 'matching
+  :version "24.4")
+
+(defun read-regexp-defaults ()
+  (if (not read-regexp-user-defaults) t
+    (let ((user-default (assoc this-command read-regexp-user-defaults)))
+      (pcase user-default
+	(`(,cmd ,(and (pred functionp) getter))
+	 (funcall getter))
+	(`nil nil)
+	(_ t)))))
+
 (defun read-regexp (prompt &optional defaults history)
   "Read and return a regular expression as a string.
 When PROMPT doesn't end with a colon and space, it adds a final \": \".
@@ -597,6 +630,11 @@ and the last replacement regexp.
 
 Optional arg HISTORY is a symbol to use for the history list.
 If HISTORY is nil, `regexp-history' is used."
+  (let ((user-defaults (read-regexp-defaults)))
+    (unless (eq user-defaults t)
+      (setq defaults user-defaults)
+      (message "cmd: %s defaults: %S" this-command defaults)))
+
   (let* ((default     (if (consp defaults) (car defaults) defaults))
 	 (suggestions (if (listp defaults) defaults (list defaults)))
 	 (suggestions