On Wed, 4 Jul 2012, Frank Shearar wrote:

snip

> I'd like to run an experiment with Environments, actually: on binding
> access, lazily create a subclass of the thing accessed. Initially,
> that would mean that in an Environment called 'Foo' when you say
> "Object new" the Environment makes a FooObject in the global space and
> exposes it as Object to the contained code. When you load a package
> that contains extensions to Object, they actually appear in FooObject,
> meaning that code outside the Environment doesn't see the extensions.

This wouldn't work, because if you add an extension method to Object, then 
you have to create a copy of all classes of the global environment which 
are accessed from your environment (plus their superclasses up to Object). 
But in practice this doesn't work, because the VM has some expectations 
about some objects/classes (true, false, nil, LargePositiveInteger, etc). 
Also you'd have to convert objects which are passed from one environment 
to another, otherwise code like

 	foo class == bar class

would break.


Levente

>
> This doesn't solve the problem of clashing extensions when you import
> two environments with a common extension, but it does mean that loaded
> code goes into a sandbox. The code being loaded could still "true
> become: false" but "Smalltalk at: #Object put: nil" would only affect
> the loaded code.
>
> Is there a place where we can get our hands on Monticello packages? Or
> does Environments require some bootstrapping?
>
> frank
>
>