hekate:xtt2_structured_rulre_representation_the_sublanguages_can_be_used_according_to_the_following_scenarios:attml_--_only_attribute_definition_the_minimalistic_case_-_attml_ardml_--_attributes_and_ard_dependencies_-_attml_ardml_xttml_--_attributes_dependencies_and_xtt2_rules_-_attml_xttml_--_attributes_and_rules_without_the_ard_prototype_a_hml_application_using_all_sublanguages_is_as_follows:code_xml_hml_--_attml_starts_here_--_types_..._types_attributes_..._attributes_--_attml_ends_here_--_--_ardml_starts_here_--_properties_..._properties_tph_..._tph_ard_..._ard_--_ardml_ends_here_--_--_xttml_starts_here_--_xtt_..._xtt_--_xttml_ends_here_--_--_extra_system_state_specification_--_states_states_hml_code_the_current_version_is_referred_to_as_hml2_._hekate_markup_history_the_markup_for_the_various_knowledge_representations_now_present_in_hekate_has_been_evolving._2004_-_first_markup_for_xtt_in_gjn_phd_-_xttml0_2007_-_first_markup_for_ard_in_varda_2007_-_second_version_of_markup_for_xtt_in_early_versions_of_hqed_-_xttml_2007_-_third_version_of_markup_for_xtt_in_hqed_m5_-_xttml2_2008_-_first_version_markup_proposal_for_hekate_ard_xtt_-_hml1:attml1_ardml1_xttml3_proposal_for_xtt_not_supported_by_design_tools_2009_-_second_version_of_hml_ard_xtt2_-_hml2:attml2_ardml2_xttml4_supported_by_hqed_m6_from_05.2009_hml_syntax_hekate_markup_language_dtd:hml.dtd_for_hml2_._for_syntax_test_purposes_there_is_example_xml_file:hml-test.xml_a_minimalistic_file_is:hml-test-min.xml_important_elements_are_indexed_with_an_attribute_id_._id_value_has_to_be_unique_enforced_by_dtd_and_should_start_with_depending_on_particular_element:types:id_tpe_..._attributes:id_att_..._properties:id_prp_..._type_groups:id_tgr_..._attribute_groups:id_agr_..._dependencies:id_dep_..._ard_history_tph:id_hst_..._an_additional_attribute_id_is_introduced_to_guarantee_that_types_attributes_properties_and_groups_can_be_uniquely_referenced._it_can_be_forced_using_dtd_that_an_attribute_has_a_unique_value_within_an_xml_document_it_becomes_a_unique_identifier._similarly_it_can_be_forced_that_an_attribute_references_an_element_by_its_unique_identifier._making_attribute_names_unique_identifiers_prevents_naming_a_group_or_type_with_the_same_name_as_the_attribute_since_unique_identifiers_are_unique_within_entire_document_regardless_of_the_element_they_regard_to._it_is_possible_to_validate_a_hml_file_using_a_validator_i.e._xmlstarlet:xmlstarlet_val_-e_-d_hml.dtd_hml-test.xml_attml_for_information_on_attributes