From: Dave Thomas <dave@...>
Date: 2008-04-11T07:33:26+09:00
Subject: Re: How can I demonstrate that weakref works in 1.9?


On Apr 10, 2008, at 5:21 PM, David A. Black wrote:
>> So, assuming Weakref works in 1.9, is there a clever way of  
>> demonstrating it?
>
> I wanted to try this out and investigate but I can't seem to get the
> exception out of 1.8:
>
> $ ruby -v weakref.rb ruby 1.8.6 (2007-09-24 patchlevel 111)  
> [universal-darwin9.0]
> Initial object is fol de rol
> Weak reference is fol de rol
> But then it is fol de rol

Yeah, I'm seeing that too. I believe the exception was reliable on  
1.8.4, so GC may have changed in 1.8.

I tried putting the variable in a function:

require 'weakref'
def gen_reference
   ref = "fol de rol"
   puts "Initial object is #{ref}"
   WeakRef.new(ref)
end

ref = gen_reference
puts "Weak reference is #{ref}"
ObjectSpace.garbage_collect
puts "But then it is #{ref}"

Still no IllegalReference exception on either 1.8.6 or 1.9.

So... any ideas?  I don;t want to publish code without a working  
example.

Thanks


Dave