--- a/Smalltalk.st	Mon Mar 20 09:43:20 2006 +0100
+++ b/Smalltalk.st	Mon Mar 20 09:55:17 2006 +0100
@@ -1642,6 +1642,20 @@
     "
 !
 
+allClassesForWhich:filter do:aBlock
+    "evaluate the argument, aBlock for all classes in the system, for which filter evaluates to true."
+
+    self allClassesDo:[:cls |
+        (filter value:cls) ifTrue:[ aBlock value:cls ].
+    ].
+
+    "
+     Smalltalk 
+        allClassesForWhich:[:cls | cls name startsWith:'Po'] 
+        do:[:aClass | Transcript showCR:aClass name]
+    "
+!
+
 allClassesInCategory:aCategory
     "return a collection of for all classes in aCategory;
      The order of the classes is not defined."
@@ -6752,5 +6766,5 @@
 !Smalltalk class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/Smalltalk.st,v 1.724 2006-03-16 22:31:56 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Smalltalk.st,v 1.725 2006-03-20 08:55:17 cg Exp $'
 ! !