From: ptkwt@...1.aracnet.com (Phil Tomson)
Date: 2001-12-06T18:52:45+09:00
Subject: [ruby-talk:27664] Re: Sending a Proc to a remote dRuby object

In article <Pine.GSO.4.21.0112061022210.14067-100000@godzilla.ce.chalmers.se>,
Robert Feldt  <feldt@ce.chalmers.se> wrote:
>On Thu, 6 Dec 2001, Phil Tomson wrote:
>
>> Is it even possible to pass a Proc to a remote dRuby object like this?
>> 
>This is a "classic" q so if its not in the FAQ we should probably move it
>there. Procs and Threads (and some other type of objects) cannot be
>marshaled so dRuby will have problems... ;-) Maybe we should list which
>classes are affected in the FAQ?

This is what I thought, but why does this example work:

#----remote object ------------
require "drb/drb"
primary = DRb::DRbServer.new("druby://localhost:5555", [1,2,3,4,5])
primary.thread.join

#----local--------
require "drb/drb"
primary = DRb::DRbServer.new
ts = DRb::DRbObject.new(nil, ARGV.shift)
#try sending a proc:
ts.each { |i| puts i }

#prints, on local machine:
1
2
3
4
5

(I suppose the answer has soemthing to do with the proc executing on the 
local machine.)

>
>It has been discussed a lot and I think Matju (and someone more,
>Chad?) proposed the nicest solution: add a source_code attribute to Proc
>(or subclass) and redefine proc/lambda so that it sets the attribute if
>given a string. Then add marshaling and the proper init and you're
>set. Of course, it would be nice if future Ruby's could marshal all
>objects but there are real problems with doing this for Procs and Threads
>so maybe not. 

Yes, I would imagine it's a big problem

>The nice thing about the solution above is that when using
>this feature all you have to do is add a '%':
>
>proc %{|x| x*x}
>

That would be nice...


Phil