The future of concurrent programming

[Brad Roberts]

David B. Held wrote:
> Mike Capp wrote:
>> == Quote from Sean Kelly (sean at f4.ca)'s article
>>
>>> Transactions are another idea, though the common
>>> implementation of software transactional memory
>>> (cloning objects and such) isn't really ideal.
>>
>> Would genuine compiler guarantees regarding const (or invariant, or 
>> final, or
>> whatever it's called today) reduce the need for cloning?
> 
> Word-based STM doesn't require cloning except when necessary to preserve 
> logical consistency, and then it doesn't require whole-object cloning. 
> On the other hand, it may not always be as efficient because it only 
> knows about words and not objects.  It's all a trade-off.
> 
> Dave

Objects (or memory locations) that aren't changing don't get cloned. 
Constants are a stronger case of something not changing (because it 
can't by language rules).  So, const (or invariant, or final) really 
doesn't assist in STM in any way.