From: Caleb Clausen <vikkous@...>
Date: 2010-04-04T09:12:56+09:00
Subject: Re: combined ranges...

On 4/3/10, Intransition <transfire@gmail.com> wrote:
> The more OOP approach would be:
>
>   class Object
>     def visits
>       yield(self)
>     end
>   end
>
>   module Enumerable
>     def visits(&block)
>       each{ |item| item.visits(&block) }
>     end
>   end

This won't behave well if passed a true graph (not just tree or dag)
of ruby objects. For instance:

  a=[]
  a<<a
  a.visits{|x| p x }

At one time, I got interested enough in this problem to write a fairly
complete solution to this problem (at least I think so). If
interested, please have a look at:
  http://github.com/coatl/ron/blob/master/lib/ron/graphedge.rb