From: "Aryeh M. Frierdman" <aryeh@...>
Date: 2003-07-07T07:33:36+09:00
Subject: Re: Freezing an arbitary object

Joel VanderWerf wrote:

> Brian Candler wrote:
> 
>> - local variables: cannot be frozen, since they don't belong to an object
>>   and are not an object themselves. They can always be reassigned to
>>   point to another object. Sorry, that's a Ruby fact of life.
> 
> I wonder why this doesn't work? I didn't expect it to, but I'm curious.
> 
> irb(main):005:0> b = binding
> #<Binding:0x401d7e7c>
> irb(main):006:0> eval "y=1", b
> 1
> irb(main):007:0> eval "y", b
> 1
> irb(main):008:0> b.freeze
> #<Binding:0x401d7e7c>
> irb(main):009:0> eval "y=2", b
> 2
> 
> Would it be useful to be able to freeze the current binding? Disastrous?
> Inefficient?

Being new to ruby I would not know the exact reasons but I susbect that
at the interpreter level a local is implimented as a ptr into a stack frame
vs. a ptr to the free store thus it would be dangerous to freeze a tempurary
object.  On second thought this might not be true since how whould you
handle doing garbage collection on a long running method that "free's" a
local????