From: kjana@...4lab.to (YANAGAWA Kazuhisa)
Date: 2002-06-28T21:19:58+09:00
Subject: Re: Transparent asynchronous execution

In message <002b01c21e92$40cb77d0$0e01a8c0@fightclub>
corion@informatik.uni-frankfurt.de writes:

> For the implementation, almost everything seems to go smoothly except for
> the delegation part. Before the result becomes available, I want the Promise
> class to block the calling thread on every message sent to it (this could
> maybe done by overriding Object#send), and after the result becomes
> available, I want the Promise to send all messages to the result (i.e., I
> want the Promise to be as transparent to the caller as possible). I've
> looked at the Delegator class, but this class wants to know which object it
> delegates to - the Promise dosen't know which object it will delegate to
> until the result becomes available - how can I approach this problem ?

You can use method_missing hack for this.  May be you interested in my
toy script which implements almost same functionary.
<http://www.dm4lab.to/~kjana/ruby/udelegator.rb>

In my script, Promise is a name for `delay'ed expressions whereas
Future for expressions evaluated concurrently and caller wait on them.

# The terms `promise' and `delay' were borrowed from Scheme, while
# `future' is from Multilisp or ABCL/1.


-- 
kjana@dm4lab.to                                  June 28, 2002
What is done can't be undone.