Thanks for the quick reply, Marcus!

Marcus Denker wrote:
> 
> On 21.02.2006, at 22:48, Michael van der Gulik wrote:
> 
>> Hi.
>>
>> I see this class hierarchy:
>>
>> ...IdentityDictionary etc.
>>    SystemDictionary
>>       Environment
>>          SmalltalkEnvironment
>>
>> What are they? I understand that #Smalltalk of class  SystemDictionary 
>> is a singleton and a global variables holder, used  by the compiler to 
>> add Associations pointing to global variables in  method dictionaries 
>> for classes.
>>
>> But Environment? When was it made? What were the original  intentions? 
>> Does it work and is it stable and safe to use?
>>
> 
> It was a first experiment for namespaces in Squeak a long time ago.  
> Needs to be cleaned up.

...how did it get into the "production" image if it was an 
experiment!!?? Shouldn't experiments be done on experimental images, and 
when they are stable, only then add them to the "production" image?

>> I'm trying to create a secure, segregated Smalltalk environment in  my 
>> image where remotely loaded code has no references to objects  that I 
>> don't want it to have (aka "capabilities" ala the E language).
> 
> You should have a look at the Island work of Andreas for Croquet,  there 
> was a mail to squeak-dev some month ago describing a first  version.

Yes, I've read a bit about it and I should really look at his code.

I'm interested in how Andreas managed to lock down the image.

The following is only out of interest, and I'm not asking any 
questions... I can work out most of this by playing around.

I've just done the following little experiment using the following code 
on the class side of ProtoObject:

allReferences
	| literalCollection |
	" Return all references that I have to other objects. Used only for 
playing around with the image. "
	literalCollection := Dictionary new.
	methodDict valuesDo: [ :eachCompiledMethod |
		eachCompiledMethod literals do: [ :eachLiteral |
			(eachLiteral isKindOf: LookupKey) ifTrue: [
				literalCollection at: (eachLiteral key) put: (eachLiteral value).
			].
		].
	].
	^ literalCollection.

(yea, okay it could have been done with collect: or something...)

What is revealing is the following:

ProtoObject allReferences ----> a Dictionary(#Array->Array 
#ContextPart->ContextPart #Error->Error 
#MessageNotUnderstood->MessageNotUnderstood #Smalltalk->a 
SystemDictionary(lots of globals) )

For my purposes, all of these will need to be removed or replaced with 
distributable objects... somehow... hmm...

[Object allReferences] is too big to cut and paste here, but includes 
such wonderful things as #CardPlayer->CardPlayer and #ScriptingSystem->a 
StandardScriptingSystem.

Also, adding the same method to Metaclass also shows the list of 
class-side global references.

The big picture here is that I'm trying to move Classes (including 
MethodDictionary-s, CompiledMethod-s and all the Association-s to other 
objects they have) to remote systems over a network.

Regards,
Mikevdg.