From: Jacob Fugal <lukfugl@...>
Date: 2006-01-10T13:19:51+09:00
Subject: Re: Futures in Ruby

On 1/9/06, Trejkaz <trejkaz@gmail.com> wrote:
> I think the semantics in this case are just semantics.  The difference
> between a "future" being executed on request and being executed in the
> background is merely the difference between two implementations of the
> executor service the task was run under (another implementation might
> even calculate the future up-front.)

Not really. As I said, there may be side-effects that shouldn't occur
until the value is actually processed. As far as delayed effects, true
this wouldn't matter as much. But say the future wraps a
mathematically intensive operation that may or may not be used in the
program. I certainly want to put off that operation until I know I
need it. To be clear, I'm not arguing that this interpretation is more
correct -- an implementation that calculates the future  as soon as
possible or even in advance can be just as useful. My claim is only
that the difference *is* significant.

Jacob Fugal