Hi anthony

Sorry for the confusion, I didn't mean the current VI4 would be changed,
> I just meant subjectivity could be added on top of VI4, call it VI5.
> Also, I do plan on fixing the rest of the decompiler.

Please ask to people like andreas, tim and other VM guys that they think
is missing or could be problem for integration so that we are sure that
there will be a smooth integration.
>
>> Still I think that all these subject-oriented programming papers that
>> were at OOPSLA few years ago before AOP were cool but I would not
>> like to program with that because it was complex.
>
> You should read the Us paper.  Its at the site I gave, just click on 
> PDF
> in the upper right corner
> (http://citeseer.nj.nec.com/smith96simple.html).

Thanks I was looking for this paper, I will read it.

> I agree AOP is
> complex, but layers is implemented as just another lookup dimension.
> And from the programmer's/user's point of view it is just projects.  
> You
> work in one project then maybe switch to another, any if there is
> anything in common you want to share between the projects put
> them in an inherited project.  The concept is the same as behavior
> inheritance, but this is at a larger scale, call it image inheritance.
>
>>> I really think layers will improve our package model in the
>>> image, particularly with respect to dependencies, versions, and
>>> unloading capabilities.
>>
>> I think that we do not need that for that. Basic software engineering
>> principle and namespaces are enough for that. May be Layers could
>> solve that but may be they are introducing another layer of complexity
>> just at the cognitive level.
>
> Layers (environments as I have described them on my website) are
> dynamically bound namespaces and nothing more.  This allows you
> to override them to change the behavior in different layers.  Thus
> giving you multiple packages/projects that can be run and analyzed in
> the same image.  Being able to work on different packages/projects in
> the same image is important, and without something like layers it can't
> be achieved.

so you have a different method lookup that is layer aware?


>> but may be they are introducing another layer of complexity just at 
>> the
>> cognitive level.
>> (This what was worrying me the most with traits, the model is simple 
>> still
>> you have one extra concept)
>
> That's what also bothers me about traits.  I wish you would just use
> straight multiple inheritance and eliminate the extra concept of traits
> when there really isn't an extra concept.  Layers is different.  Its an
> extra concept that adds another dimension of functionality, which is
> needed in a multi view/version world.

Traits add a extra smaller abstraction for reuse.

>
>> Sorry to be a little rude but I really appreciate your effort to add
>> block-closure to squeak don't mess it up. But still have fun so build
>> your stuff on a separate VM.
>
> Your not rude, and I hope you don't think I'm rude.  I really think
> these discussions are valuable for advancing our understanding and
> knowledge.  And don't worry, I put so much time into VI4, I am very 
> keen
> on getting it into the base image.  I'm just waiting for Ian to look at
> it so we can decide how to merge it with a Jitter.

Good.

> "Stephen Pair" <spair at acm.org> wrote:
>> But even the stack optimizations that are in VI4
>> concern me a bit.  It seems like that goes too far into the research
>> realm and jeopardizes the acceptance of the work done on block 
>> closures.
>> Everyone knows what block closures are and why they are needed; there 
>> is
>> a much greater chance of them getting into the base VM if they don't
>> come with extra stuff that's less well understood and proven.
>
> The stack issue will be worked out when considering a Jitter.  But if 
> we
> keep on resisting changes because they are not proven, we'll never make
> progress.  Squeak is primarily a research project.  We don't have any
> customers funding or donating to us.  So lets take advantage of this
> freedom and really advance Squeak.

But this is why we need a small core and multiple research boats ;)
>
> Cheers,
> Anthony
>
>
Dr. Stéphane DUCASSE (ducasse at iam.unibe.ch) 
http://www.iam.unibe.ch/~ducasse/
  "if you knew today was your last day on earth, what would you do
  different? ... especially if, by doing something different, today
  might not be your last day on earth" Calvin&Hobbes