From: Chuck Remes <cremes.devlist@...>
Date: 2008-10-14T04:33:37+09:00
Subject: Re: status of cache in Memoizable


On Oct 13, 2008, at 2:17 PM, matt neuburg wrote:

> [snip]
>
> [The actual question:]
>
> 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?

This line here keeps the reference to cache alive:

define_method(name) { |*args| cache[args] ||= send(original, *args) }

This is defining a new method and knows to return the cached value or  
send the arguments to the original unmemoized method so it can compute  
your value.

cr