Hash.class_eval do
  # TODO: unit test this

  def find_and_replace( x, y )
    self.dup.find_and_replace! x, y
  end

  def find_and_replace!( x, y )
    self.each_pair do |k,v|
      if v.is_a?(Hash)
        v.find_and_replace! x, y
      else
        if x.is_a?(Regexp) && v.is_a?(String)
          v.gsub!( x, y )
        else
          v = y if v == x
        end
        self[k] = v
      end
    end
  end

end