chapter.rb

class Chapter
  include Mongoid::Document
  field :position, :type => Integer
  field :title, :type => String
  field :identifier, :type => String
  
  embedded_in :book
  embeds_many :elements
  
  def self.process!(git, file)
    chapter = new
    # Parsing of XML goes here, generating parsed_doc
    elements = parsed_doc.css("div.chapter > *")
    elements.each { |element| element.process! }
  end

element.rb

class Element
  include Mongoid::Document
  include Processor
  field :tag, :type => String
  field :identifier, :type => String
  field :title, :type => String
  
  embedded_in :chapter
end

processor.rb

module Processor
  
  def process!(markup)
    #######################
    # How do I gain access to the chapter object these elements are being created from here?
    #######################
    send("process_#{markup.name}!")
  end

end