From: Lyle Johnson <lyle@...>
Date: 2003-03-28T23:19:52+09:00
Subject: [Q] How far does a closure reach?

I was trying to understand how Ruby's finalizers work, or, in this case, 
why they weren't working as I expected. I found a solution, short and 
sweet, at this Wiki page:

	http://www.rubygarden.org/ruby?ObjectsNotGetFinalized

I want to make sure I understand *why* the finalizer in the first 
example doesn't work:

     class Test
       def initialize
         ObjectSpace.define_finalizer(self,
                                      Proc.new{ puts "finalizing" })
       end
     end

The Proc doesn't have any explicit reference to self, and that's what 
threw me at first. But am I correct that because the Proc acts as a 
closure, it has a "hidden" reference to self from the enclosing scope?

If the answer to that question was "yes", then the follow-up question is 
"How far does the scope of a closure reach?". Does it more-or-less 
follow the same kinds of block-scoping rules as, say, C/C++?