<instructional-design level="course">	
	<uol-structure>
		<learning-object element-id="INTRODUCTION"> <!-- introduction first -->
			<selection-rule>
				<include att-name="type" att-value="explanation-content"/>
				<include att-name="label" att-value="introduction"/>
			</selection-rule>
		</learning-object>
		
		<sequence level = "lesson" element-id="LESSON_SEQUENCE">						
			<learning-object element-id="PRE-TEST"> <!-- pre-test -->
				<selection-rule>
					<include att-name="label" att-value="pre-test"/>
				</selection-rule>			
				<grading>
					<type>boolean</type>
				</grading>
			</learning-object>
		
			<sequence level = "topic" element-id="TOPIC_SEQUENCE"> 
				<learning-object>
					<selection-rule>
						<include att-name="type" att-value="explanation-content" priority="1"/>  
						<include att-name="type" att-value="examples" priority="2"/>  
						<include att-name="type" att-value="*" priority="3"/>  
						<exclude att-name="type" att-value="exercise"/>
					</selection-rule>					
				</learning-object>
			</sequence>
			
			<learning-object element-id = "POST_TEST"> <!-- post-test -->
				<selection-rule>
					<include att-name="label" att-value="post-test"/>
				</selection-rule>						
				<grading>
					<type>boolean</type>
				</grading>											
			</learning-object>
		</sequence>
	</uol-structure>
	
	<element-relationships>	
		<element-relationship>
			<element element-ref="INTRODUCTION" alias="i"/> <!-- before lesson_sequence  we have to finish introduction -->
			<element element-ref="LESSON_SEQUENCE" alias="ls"/>	
			<conditions>
				<if> 
					<completed element="i"/>
				</if>
				<then>
					<show element="ls"/>
				</then>
				<else>
					<hide element="ls"/>
				</else>
			</conditions>
		</element-relationship>
		<element-relationship>
			<element element-ref="TOPIC_SEQUENCE" alias="ts"/> <!-- post-test is available after finishing lesson (all topics in the lesson) -->
			<element element-ref="POST_TEST" alias="pt"/>
			<join> 
				<equals>
					<parent-name element="ts"/>
					<parent-name element="pt"/> <!-- relation is created only between a post-test and a topic that belongs to the same lesson -->
				</equals>						
			</join>			
			<conditions>
				<if> 
					<completed element="ts"/>
				</if>
				<then>
					<show element="pt"/>
				</then>
				<else>
					<hide element="pt"/>
				</else>
			</conditions>
		</element-relationship>
		<element-relationship> <!-- relation between post-test and pre-test -->
			<element element-ref="PRE_TEST" alias="pre"/>
			<element element-ref="POST_TEST" alias="post"/>	
			<join> 
				<equals>
					<parent-name element="pre"/>
					<parent-name element="post"/>
				</equals>						
			</join>				
			<conditions>
				<if> 
					<or> <!-- if a student complete pre-test or post-test, we should disable both post-test and pre-test -->
						<completed element="pre"/>
						<completed element="post"/>
					</or>		
				</if>
				<then>
					<hide element="pre"/>
					<hide element="post"/>
				</then>
				<else>
					<show element="pre"/>
					<show element="post"/>
				</else>					
			</conditions>
		</element-relationship>		
	</element-relationships>	
</instructional-design>

