From: matt@... (matt neuburg)
Date: 2008-10-14T07:02:59+09:00
Subject: Re: status of cache in Memoizable

James Gray <james@grayproductions.net> wrote:

> On Oct 13, 2008, at 2:17 PM, matt neuburg wrote:
> 
> > There's one thing happening here I don't understand. Let's say you don't
> > supply a value for the "cache" parameter. So the cache is simply Hash.new.
> > But where does this Hash.new live? It isn't assigned to a variable name so
> > what keeps it alive? It works, but how?
> 
> That variable is kept alive thanks to the magic of closures.  The block
> passed to define_method() references the variable, so it will exist as
> long as that closure does.  Think of it as private storage that only
> that block uses.

Great answer, thanks! m.

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