--- a/MCDefinition.st	Thu Apr 23 15:08:45 2015 +0100
+++ b/MCDefinition.st	Thu Apr 23 15:12:09 2015 +0100
@@ -1,5 +1,7 @@
 "{ Package: 'stx:goodies/monticello' }"
 
+"{ NameSpace: Smalltalk }"
+
 Object subclass:#MCDefinition
 	instanceVariableNames:''
 	classVariableNames:'Instances'
@@ -150,6 +152,44 @@
 	self subclassResponsibility 
 ! !
 
+!MCDefinition methodsFor:'serializing'!
+
+storeDataOn: aDataStream
+    "Store myself on a DataStream.  
+     Answer self.  
+     This is a low-level DataStream/ReferenceStream method. 
+     See also objectToStoreOnDataStream.  
+     NOTE: This method must send 'aDataStream beginInstance:size:' and then (nextPut:/nextPutWeak:) its subobjects.  
+     readDataFrom:size: reads back what we write here."
+
+    | cntInstVars cntIndexedVars |
+
+    cntInstVars := self class instSize.
+    cntIndexedVars := self basicSize.
+    aDataStream
+        beginInstance: self class
+        size: cntInstVars + cntIndexedVars.
+    1 to: cntInstVars do:[:i | 
+        | value |
+
+        value := (self instVarAt: i).
+        "/ Special hack for ImmutableString / ImmutableArray which is not known by Squeak / Pharo,
+        "/ and therefore will fail to load properly there.
+        "/ In one of those is encountered, convert them to their mutable version.
+        (value class == ImmutableString or:[value class == ImmutableArray or:[value class == ImmutableByteArray]]) ifTrue:[ 
+            value := value asMutableCollection.
+        ].
+        aDataStream nextPut: value   
+    ].
+
+    "Write fields of a variable length object.  When writing to a dummy
+        stream, don't bother to write the bytes"
+    "1 to: cntInstVars do:
+        [:i | aDataStream nextPut: (self instVarAt: i)]."
+
+    "Created: / 23-04-2015 / 15:10:58 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+! !
+
 !MCDefinition methodsFor:'testing'!
 
 isClassDefinition
@@ -185,6 +225,12 @@
     ^ '$Header: /cvs/stx/stx/goodies/monticello/MCDefinition.st,v 1.5 2012-09-11 21:21:09 cg Exp $'
 !
 
+version_HG
+
+    ^ '$Changeset: <not expanded> $'
+!
+
 version_SVN
     ^ '§Id: MCDefinition.st 24 2010-11-09 14:00:17Z vranyj1 §'
 ! !
+