require 'rexml/parsers/baseparser'
require 'rexml/parsers/streamparser'
require 'rexml/streamlistener'
xml = <<EOS
<!DOCTYPE root [
  <!ENTITY % YN '"Yes"'>
  <!ENTITY % YN 'Yes'>
  <!ENTITY WhatHeSaid "He said %YN;">
  <!ENTITY open-hatch SYSTEM "http://www.textuality.com/boilerplate/OpenHatch.xml">
  <!ENTITY open-hatch PUBLIC "-//Textuality//TEXT Standard open-hatch boilerplate//EN" "http://www.textuality.com/boilerplate/OpenHatch.xml">
  <!ENTITY hatch-pic SYSTEM "../grafix/OpenHatch.gif" NDATA gif>
]>
<root />
EOS
  
class Listener 
  include REXML::StreamListener
  def entitydecl(content); p content; end
end
REXML::Parsers::StreamParser.new(xml, Listener.new).parse