diff --git a/source/clog-presentations.lisp b/source/clog-presentations.lisp
index cb7d147..fb205dc 100644
--- a/source/clog-presentations.lisp
+++ b/source/clog-presentations.lisp
@@ -34,21 +34,25 @@
 ;; link-slot-to-form-element ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(defmacro link-slot-to-form-element (object accessor clog-obj)
+(defmacro link-slot-to-form-element (object accessor clog-obj &key transform)
   "Link changes to lisp (ACCESSOR OBJECT) to (value CLOG-OBJ). Only one
 element can be bound at a time to a list object."
   `(defmethod (setf ,accessor) :after (new-value (obj (eql ,object)))
-     (setf (value ,clog-obj) new-value)))
+     (setf (value ,clog-obj) (if ,transform
+				 (funcall ,transform new-value)
+				 new-value))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; link-slot-to-element ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(defmacro link-slot-to-element (object accessor clog-obj)
+(defmacro link-slot-to-element (object accessor clog-obj &key transform)
   "Link changes to lisp (ACCESSOR OBJECT) to (text CLOG-OBJ). Only one
 element can be bound at a time to a list object."
   `(defmethod (setf ,accessor) :after (new-value (obj (eql ,object)))
-     (setf (text ,clog-obj) new-value)))
+     (setf (text ,clog-obj) (if ,transform
+				(funcall ,transform new-value)
+				new-value))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; link-form-element-to-object ;;
diff --git a/tutorial/29-tutorial.lisp b/tutorial/29-tutorial.lisp
index 04395d6..b5cc3d0 100644
--- a/tutorial/29-tutorial.lisp
+++ b/tutorial/29-tutorial.lisp
@@ -24,11 +24,18 @@
 	 (i3 (create-form-element body :text
 				  :label (create-label body :content "Change my-count:"))))
     ;; We set up direct relationships between lisp obj and clog objects
-    (link-form-element-to-slot i1 lisp-obj my-slot)  ;; any change to i1 will change my-slot
-    (link-slot-to-form-element lisp-obj my-slot i1)  ;; any change to my-slot will change i1
-    (link-slot-to-element lisp-obj my-count t1)      ;; any change to my-count will change h1
+    ;; any change to i1 will change my-slot
+    (link-form-element-to-slot i1 lisp-obj my-slot)
+    ;; any change to my-slot will change i1 after transforming
+    ;; my-slot to upercase
+    (link-slot-to-form-element lisp-obj my-slot i1
+			       :transform #'string-upcase)
+    ;; any change to my-count will change t1
+    (link-slot-to-element lisp-obj my-count t1)
+    ;; any change to i3 will change my-count
+    ;; and i3's value will be transformed to an integer
     (link-form-element-to-object
-     i3 (my-count lisp-obj) :transform #'parse-integer) ;; any change to i3 will change my-count
+     i3 (my-count lisp-obj) :transform #'parse-integer)
     ;; This change of my-slot will immediately change in the web page
     (setf (my-slot lisp-obj) "First Value")
     (set-on-click b1