--- a/Smalltalk.st	Mon Dec 26 15:52:18 2011 +0100
+++ b/Smalltalk.st	Tue Dec 27 10:44:18 2011 +0100
@@ -918,8 +918,12 @@
      If there is nothing stored under this key, do nothing.
      Otherwise, evaluate aBlock, passing the retrieved value as argument."
 
+    |val|
+
     (self includesKey:aKey) ifTrue:[
-	^ aBlock value:(self at:aKey)
+        (val := self at:aKey) notNil ifTrue:[
+            ^ aBlock value:val
+        ]
     ].
     ^ nil
 
@@ -928,6 +932,7 @@
      Smalltalk at:#Object ifPresent:[:what | Transcript showCR:what].
     "
 
+    "Modified: / 27-12-2011 / 10:14:30 / cg"
 !
 
 at:aKey put:aValue
@@ -7696,11 +7701,11 @@
 !Smalltalk class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/Smalltalk.st,v 1.982 2011-12-06 12:28:53 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Smalltalk.st,v 1.983 2011-12-27 09:44:18 cg Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic/Smalltalk.st,v 1.982 2011-12-06 12:28:53 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Smalltalk.st,v 1.983 2011-12-27 09:44:18 cg Exp $'
 !
 
 version_SVN