class Lutaml::Model::Schema::XmlCompiler::Sequence

def <<(instance)
  return if instance.nil?
  @instances << instance
end

def initialize
  @instances = []
end

def required_files
  @instances.map(&:required_files)
end

def to_attributes(indent)
  instances.filter_map { |instance| instance.to_attributes(indent) }.join
end

def to_xml_mapping(indent)
  content = xml_block_content(indent)
  return "" if content.empty?
  XML_MAPPING_TEMPLATE.result(binding)
end

def xml_block_content(indent)
  instances.filter_map { |instance| instance.to_xml_mapping(indent * 2) }.join
end