concurrency

[downs]

Joel C. Salomon wrote:
> downs wrote:
>> Jason House wrote:
>>> I've never heard of that.  Does anyone have a good link for extra detail on futures?
>>>
>> Basically, it comes down to a function that takes a delegate dg, and runs it on a threadpool, returning a wrapper object.
>> The wrapper object can be evaluated, in which case it blocks until the original dg has returned a value. This value is then returned by the wrapper, as well as cached.
>> The idea is that you create a future for a value that you know you'll need soon, then do some other task and query it later. :)
> 
> & while Sean Kelly wrote:
>> Futures are basically Herb Sutter's rehashing of Hoare's CSP model.
> 
> More specifically, this sounds like a special case of a CSP-like channel
> where only one datum is ever transmitted.  (Generally, channels are
> comparable to UNIX pipes and can transmit many data.)
> 

Heh.
Funny coincidence.
Let's take a look at the implementation of Future(T):

  class Future(T) {
    T res; bool done;
    MessageChannel!(T) channel;
    this() { New(channel); }
    T eval() { if (!done) { res=channel.get(); done=true; } return res; }
    alias eval opCall;
    bool finished() { return channel.canGet; }
  }


:)

 --downs