Thanks.

As for fixing the problem...this seems like it will be an error for 
anyone trying to save a book morph to a file so I'm confident it will 
be fixed by the masters.

mlm

>On Thu, 19 Aug 1999 17:09:41 -0500 "Mark Mayfield" 
><mmayfield at nuforia.com> wrote:
>>When I inspect the objects within the debugger, each is a
>>PasteUpMorph object, BUT aUniClass is a MorphObjectOut. When a
>>MorphObjectOut is sent the message isSystemDefine, I get the error.
>>Why wouldn't the assignment aUniClass := each class not assign
>>aUniClass the class of the object referenced by each?
>
>Mark,
>
>Here's the short answer which may not do a lot to solve the problem, 
>but which may keep you from going nuts looking at this.
>
>MorphObjectOut is a proxy class, i.e. instances of it are used to 
>represent instances of other Classes which may not be available 
>(like they are on disk and not yet read in). To do this, it 
>implements #doesNotUnderstand: and uses that as a cue to get the 
>real object and become: that object. The problem is that #class is 
>one of those few messages which are dispatched directly from 
>bytecodes and not through normal method lookup routines (try 
>overidding #class in some Class and see if it ever gets hit). So, 
>while 99.999% of messages to an instance of MorphObjectOut get 
>forwarded to, and answered by, the real object, #class gets answered 
>by the VM on behalf of MorphObjectOut with unfortunate effects. I 
>haven't looked into the intent of the code at work here, so I cannot 
>give you a guaranteed solution at this time, but here is what I 
>would try:
>
>1. Implement in Object
>
>realObjectClass
>
>	^self class
>
>2. Change the line in the method you referenced to read:
>
>		(aUniClass := each realObjectClass) isSystemDefined ifFalse: [
>
>and see if that works.
>
>Cheers,
>Bob