From: Sylvain Joyeux <sylvain.joyeux@...>
Date: 2008-09-22T22:42:37+09:00
Subject: Re: for or each?

On Mon, Sep 22, 2008 at 07:52:47PM +0900, Brian Candler wrote:
> Sylvain Joyeux wrote:
> > Nope. each { } needs one new scope for each iteration while "for ... in"
> > explicitely uses the parent scope... In the end, you create with #each
> > as many objects as there are in your collection
> 
> P.S. Here's a simple experiment, and I can't see any of these 
> dark-matter objects that you talk about.
> 
>   def countobj
>     count = 0
>     ObjectSpace.each_object(Object) { count += 1 }
>     count
>   end
> 
>   def foo
>     :dummy
>   end
> 
>   puts "#{countobj} objects"
>   GC.disable
>   (1..1_000_000).each { foo }
>   puts "#{countobj} objects"
Thanks but nope...

each_object *specifically* filters out objects that are internal to the
interpreter, therefore you don't see those here. For that, you actually
need a better object-counting setup. See Ruby patches for one that I
submitted. I hope that the "new Ruby GC profiler" that have been
included in 1.9 will provide the same amount of information.

Sylvain