Hi, Andreas,

just one answer at your first question:
VW allow parcel to modify a method already on the image. Interesting behavior is the fact that, if and when you remove the parcel (thing you can do on a running application) the modification goes away, and the old behavior get restored.
This seems to me more on the Smalltalk stile of thinking: I can do what I want, obviously also shut at my foot.
But this is just my way of thinking. 

ciao

Giorgio Ferraris


>----- ------- Message Originale ------- -----
>From: squeak-dev at lists.squeakfoundation.org
>To: squeak-dev at lists.squeakfoundation.org
>Sent: Thu, 01 Mar 2007 01:22:18
>
>stephane ducasse wrote:
>>> In short: What impresses me about the Java
>solution is not that it's 
>>> flawless - what impresses me is that it works,
>that people actually 
>>> use it to deploy code and this code actually
>works in the way intended.
>> 
>> But do you think that VW, VA code does not work
>once deployed? I would 
>> like to understand why Jar are better than
>parcels for example.
>
>Here are some "simple" issues: 
o base classes? Say, one that says
>"Object>>isCommon 
>^true" and one that says "Object>>isCommon ^false"?
>(Java simply doesn't 
>allow modifications to base classes which, really,
>isn't such a bad 
>thing from the point of view of modularity)
>
>Another one: Which assurances do parcels give in
>terms of security? As 
>far as I know there is no bytecode verifier, parcel
>have full access to 
>the entire Smalltalk namespace (covered by
>ClassLoaders in Java), there 
>are no limitations in terms of what operations a
>parcel can perform (nil 
>become: true; Java had a good set of fixes in this
>area to get it right 
>and not to leak ambient authority) and I don't
>think VW even knows what 
>a sandbox is.
>
>A third one: Which namespace are parcels loaded
>into? Can two different 
>versions of parcels be loaded side-by-side? How (if
>at all) do they 
>affect each other? Etc.
>
>> May be I should post to VW to see what are the
>problem with deployed 
>> code in VW.
>> A parcel in VW has dev and depl prerequisites and
>it seems to work too.
>
>Well, sure. Sorta. Kinda. :-) We can do the same in
>Squeak with projects 
>and change sets and it seems to work, too. Sorta.
>Kinda. :-)
>
>Cheers,
>   - Andreas