From: Michael Witrant <mike@...>
Date: 2002-03-01T21:02:01+09:00
Subject: Re: RCR?: parallel to until: as_soon_as

On Wed, 27 Feb 2002 18:16:27 +0900
Tobias Reif <tobiasreif@pinkjuice.com> wrote:

> Perhaps some shorter(and perhaps slower) construct might be a nice 
> alternative.

I wrote for myself a Signal class to handle events. I think ruby 1.7 includes a Signal class I don't know anything about, so my class name might change.

Basically, you define a new signal like this:
  button_pressed = Signal.new

In a thread, you "emit" the signal using
  button_pressed.emit("foo", 1, 2)

And wait for the signal in another thread like this:
  name, a, b = button_pressed.wait
or like this:
  button_pressed.wait_each { |name, a, b|
    ... this block is executed each time the signal is emited ...
  }

The wait_each call can be placed in a thread created only to handle this signal.

It uses Queues to manage the waiting threads.

The code is quite small (about 60 lines). Would it be usefull to anyone if I released it?

Mike.