# File lib/maruku/input/parse_doc.rb, line 101
        def expand_attribute_list(al, result)
                al.each do |k, v|
                        case k
                        when :class
                                if not result[:class]
                                        result[:class] = v
                                else
                                        result[:class] += " " + v
                                end
                        when :id; result[:id] = v
                        when :ref; 
                                if self.ald[v]
                                        already = (result[:expanded_references] ||= [])
                                        if not already.include?(v)
                                                already.push v
                                                expand_attribute_list(self.ald[v], result)
                                        else
                                                already.push  v
                                                maruku_error "Circular reference between labels.\n\n"+
                                                "Label #{v.inspect} calls itself via recursion.\nThe recursion is "+
                                                        (already.map{|x| x.inspect}.join(' => ')) 
                                        end
                                else
                                        if not result[:unresolved_references]
                                                result[:unresolved_references] = v
                                        else
                                                result[:unresolved_references] << " #{v}"
                                        end
                                        
                                #   $stderr.puts "Unresolved reference #{v.inspect} (avail: #{self.ald.keys.inspect})"
                                        result[v.to_sym] = true
                                end
                        else
                                result[k.to_sym]=v
                        end
                end
        end