DFS in nested Hashes

dfs-convert.rb

#! ruby19

require 'pp'

Converter = Struct.new :root, :converted do

  def convert
    @stack = []
    self.converted = {}
    dfs(root)
    self.converted
  end

private
  def dfs(n)
    case n
    when Hash
      n.each do |k,v|
        @stack.push k
        dfs(v)
        @stack.pop
      end
    else
      converted[@stack.join(' ')] = n
    end
  end
end

conv = Converter.new("a"=>{"b"=>{"c"=>1}, "b2"=>{"c2"=> {"d2" => 2}}})
conv.convert
pp conv.converted