Parallel-safe lambdas

[Mark Thornton]

Olivier Allouch wrote:
> Ouch !
>
> I, like Stephen Colebourne, am surprised. I thought the goal was to add 
> closures to the language, not to a single library.
>   
I'm not sure why you are surprised given that the closures exercise was 
restarted with this:
http://blogs.sun.com/mr/entry/closures
The motivation is clearly to aid use of parallelism. Now this doesn't 
mean that many ordinary programmers will be writing parallel code, but 
that more API may use parallel implementations. So if someone uses 
Collections.sort or Arrays.sort, the implementation may be parallel if 
the size warrants it.

For API taking lambda parameters it would be desireable to be able to 
mark such parameters as 'restricted' in some way. Or perhaps have 
lambdas that satisfy appropriate concurrency rules implement some marker 
interface. The API could then use a parallel implementation for such 
marked lambdas. The user can then be largely oblivious to the 
concurrency issues, while leaving the likes of Doug Lea to provide high 
performance implementations.

Mark Thornton