Paolo Bonzini wrote:
>> VW solved the problem too, they use a message (collection growTo: 
>> newSize) or something like that instead of (collection class new: 
>> newSize).
> 
> I've wondered though if it's necessary.  The adapter solution is better 
> in my humble opinion, because it is stupid that the stream imposes a 
> growing policy to a growing collection, and because an "adding stream" 
> would not need a final copy when calling #contents.

True, however, the adapter solution makes it very difficult to create 
streams that work on both sequenceable and arrayed collection. For 
example, is GZipWriteStream a subclass of WriteStream or 
AddingWriteStream? Do we need two classes, one for sequenceable and one 
for arrayed collections? Does any new stream require an extra method in 
sequenceable/arrayed collection (so that clients don't have to know 
about what exactly they are dealing with)? All in all, I find the VW 
solution of having a single polymorphic way that streams can use to 
access both arrayed and sequenceable collections vastly preferable.

Cheers,
   - Andreas