From: "ara.t.howard" <ara.t.howard@...>
Date: 2008-07-30T02:13:53+09:00
Subject: Re: Concurrent Ruby?


On Jul 29, 2008, at 10:00 AM, David Masover wrote:

> I'm trying to figure out how to at least partly duplicate the semantic
> advantage in Ruby, but it's not easy -- I'm stuck either #freeze-ing
> everything, or wrapping every message in an actor of its own, and both
> approaches seem more obnoxious and error-prone than forcing the  
> developer to
> deal with it.

fan out multiple processes with a message queue each - easy to do with  
drb.  naive impl:


cfp:~> cat a.rb
b got "hello" (pid=94677)
a got "hello" (pid=94676)




cfp:~> cat a.rb

a =
   actor {
     recv_msg { |msg|
       puts "a got #{ msg.inspect } (pid=#{ Process.pid })"
     }
   }


b =
   actor {
     recv_msg { |msg|
       puts "b got #{ msg.inspect } (pid=#{ Process.pid })"
       a.send_msg msg
     }
   }


b.send_msg 'hello'

STDIN.gets



BEGIN {

   require 'rubygems'
   require 'thread'
   require 'drb'
   require 'slave'

   class Actor
     include ::DRb::DRbUndumped

     def initialize &block
       @q = Queue.new
       @block = block
       act!
     end

     def act!
       @thread = Thread.new do
         Thread.current.abort_on_exception = true
         instance_eval &@block
       end
     end

     def send_msg message
       @q.push message
     end

     def recv_msg
       while(( message = @q.pop ))
         yield message
       end
     end
   end

   def actor(*a, &b)
     Slave.new{ Actor.new(*a, &b) }.object
   end

   STDOUT.sync = true

}


a @ http://codeforpeople.com/
--
we can deny everything, except that we have the possibility of being  
better. simply reflect on that.
h.h. the 14th dalai lama