[Help-smalltalk] ObjectSpaces for GST and VM ideas

[Gwenael Casaccio]

Hi Paolo,

I rewrite the implementation of the ObjectSpaces for GST, you can look
on my GST fork inside the branch object-space. This clean up is really
better :
  - I use macros instead of _object_space[_current_space].myField
  - no more inside the oop.h
  - new files : 
       system-dict which contains the structure with all the class name 
       object-space : object-space it self

 At this time I've not merged the security work on the branch and the
multi image support ;) I'll try to do to soon as possible.

ObjectSpaces are a kind of software process isolation in Smalltalk the
interest is :

This is really nice we can prevent big allocation : 
   OrderedCollection new: 10.....0.
We can disable some primitives useful : 
   ObjectMemory quit :)
Of course writing on external ObjectSpace can be impossible : 
   Array := 1 :D.
   myExternalRef instVarAt: 1 put: ...
An other nice property is :
   Array allInstances will only returns instances inside the
ObjectSpace 

I've also an idea : thread each spaces with a vm thread and use a
message queue when you send a message to an external ObjectSpaces.

Also I've  made a copy on write for strings with a VM support ( not
finished patch ) and a largeOOP prototype with a BTree support : I
should extend the GC to support BTree.

For a 3.3 version of GST ;)

Gwen