From: Robert Klemme <bob.news@...>
Date: 2005-04-30T00:04:28+09:00
Subject: Re: Deep copy?


"Trans" <transfire@gmail.com> schrieb im Newsbeitrag
news:1114716185.239134.214060@o13g2000cwo.googlegroups.com...
> ruby-talk:64146 is from over 2 years ago. I wonder if any progress on
> this idea has been made. Ruby 2.0?

Hm, why wait?  You can cook one on your own:

Regards

    robert


require 'set'

class Traversal
  include Enumerable

  def self.traverse(obj,&b)
    v = self.new obj
    v.each &b
    v
  end

  def self.next_objects(obj)
    case obj
      when Hash
        obj.keys + obj.values
      when String
        []
      when Enumerable
        obj
      else
        obj.instance_variables.map{|v| obj.instance_variable_get v}
    end
  end

  def initialize(obj)
    @start = obj
  end

  def each
    visited = Set.new
    queue = [@start]

    until queue.empty?
      n = queue.shift
      visited << n.object_id
      tmp = yield n
      # pp tmp
      tmp.each {|ne| queue << ne unless visited.include? ne.object_id}
    end

    self
  end
end

require 'pp'

h = {1=>"one", 2=>"two", 3=>"three"}
h[4] = h[2]
h[5] = h

pp h
puts "---------------"

Traversal.traverse h do |obj|
  # pp obj.object_id, obj
  pp obj
  Traversal.next_objects obj
end