<xs:schema targetNamespace="http://www.imsglobal.org/xsd/imsld_v1p0" xmlns="http://www.imsglobal.org/xsd/imsld_v1p0" xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified" version="IMS LD Level B version 1.0 Final Draft">
	<xs:annotation>
		<xs:documentation>This module contains the elements that constitute the expression schema that is used in IMS LD. 
		The module must be included in level B of the IMS LD specifications.
		This module can not be used independently, because it makes use of several IMS LD elements and attributes.
		Changed the namespace.
		</xs:documentation>
	</xs:annotation>
	
	<!-- ******************** -->
	<!-- ** Change History ** -->
	<!-- ******************** -->
	<xs:annotation>
		<xs:documentation>4 November 2002
		Created module.
		</xs:documentation>
	</xs:annotation>
	
	<!-- ***************************** -->
	<!-- **Re-usable content models ** -->
	<!-- ***************************** -->
	<xs:group name="grp.operand">
		<xs:annotation>
			<xs:documentation xml:lang="en">This model consists of the operands used in the expression.</xs:documentation>
		</xs:annotation>
		<xs:choice>
			<xs:element ref="property-ref"/>
			<xs:element ref="property-value"/>
			<xs:group ref="grp.expression"/>
		</xs:choice>
	</xs:group>
	<xs:group name="grp.calculate">
		<xs:annotation>
			<xs:documentation xml:lang="en">This model consists of the operands and expressions used in the expression. This model is used in several elements.</xs:documentation>
		</xs:annotation>
		<xs:sequence>
			<xs:group ref="grp.operand" minOccurs="2" maxOccurs="2"/>
		</xs:sequence>
	</xs:group>
	<xs:group name="grp.expression">
		<xs:annotation>
			<xs:documentation xml:lang="en">This model consists of operator elements that can be used to build expressions. This model is used in several elements.</xs:documentation>
		</xs:annotation>
		<xs:choice>
			<xs:element ref="is-member-of-role"/>
			<xs:element ref="is"/>
			<xs:element ref="is-not"/>
			<xs:element ref="and"/>
			<xs:element ref="or"/>
			<xs:element ref="sum"/>
			<xs:element ref="subtract"/>
			<xs:element ref="multiply"/>
			<xs:element ref="divide"/>
			<xs:element ref="greater-than"/>
			<xs:element ref="less-than"/>
			<xs:element ref="users-in-role"/>
			<xs:element ref="no-value"/>
			<xs:element ref="time-unit-of-learning-started"/>
			<xs:element ref="datetime-activity-started"/>
			<xs:element ref="current-datetime"/>
			<xs:element ref="complete"/>
			<xs:element ref="not"/>
		</xs:choice>
	</xs:group>
	
	<!-- ************************** -->
	<!-- ** Element declarations ** -->
	<!-- ************************** -->
	<xs:element name="is" type="calculateType"/>
	<xs:element name="is-not" type="calculateType"/>
	<xs:element name="and" type="operatorType"/>
	<xs:element name="or" type="operatorType"/>
	<xs:element name="sum" type="sumType"/>
	<xs:element name="subtract" type="calculateType"/>
	<xs:element name="multiply" type="calculateType"/>
	<xs:element name="divide" type="calculateType"/>
	<xs:element name="greater-than" type="calculateType"/>
	<xs:element name="less-than" type="calculateType"/>
	<xs:element name="users-in-role" type="users-in-roleType"/>
	<xs:element name="no-value" type="no-valueType"/>
	<xs:element name="complete" type="completeType"/>
	<xs:element name="not" type="expressionType"/>

	<!-- *********** -->
	<!-- ** Empty ** -->
	<!-- *********** -->
	<xs:element name="current-datetime">
		<xs:annotation>
			<xs:documentation xml:lang="en">This refers to a system variable when implementing IMS LD. The system should return a variable of type dateTime, holding the current date and time.</xs:documentation>
			<xs:appinfo>Return a variable of type dateTime.</xs:appinfo>
		</xs:annotation>
		<xs:complexType/>
	</xs:element>
	
	<!-- *************************** -->
	<!-- ** Empty with attributes ** -->
	<!-- *************************** -->
	<xs:element name="is-member-of-role">
		<xs:complexType>
			<xs:attributeGroup ref="attr.ref.req"/>
		</xs:complexType>
	</xs:element>
	<xs:element name="time-unit-of-learning-started">
		<xs:annotation>
			<xs:documentation xml:lang="en">This refers to a system variable when implementing IMS LD. The system should return a variable of type dateTime.</xs:documentation>
			<xs:appinfo>Return a variable of type dateTime</xs:appinfo>
		</xs:annotation>
		<xs:complexType>
			<xs:attribute name="unit-of-learning-uri" type="xs:anyURI" use="required"/>
		</xs:complexType>
	</xs:element>
	<xs:element name="datetime-activity-started">
		<xs:annotation>
			<xs:documentation xml:lang="en">This refers to a system variable when implementing IMS LD. The system should return a variable of type dateTime.</xs:documentation>
			<xs:appinfo>Return a variable of type dateTime</xs:appinfo>
		</xs:annotation>
		<xs:complexType>
			<xs:attributeGroup ref="attr.ref.req"/>
		</xs:complexType>
	</xs:element>
	<xs:element name="role-part-ref">
		<xs:complexType>
			<xs:attributeGroup ref="attr.ref.req"/>
		</xs:complexType>
	</xs:element>
	<xs:element name="act-ref">
		<xs:complexType>
			<xs:attributeGroup ref="attr.ref.req"/>
		</xs:complexType>
	</xs:element>
	
	<!-- ******************* -->
	<!-- ** Complex types ** -->
	<!-- ******************* -->
	<xs:complexType name="calculateType">
		<xs:group ref="grp.calculate"/>
	</xs:complexType>
	<xs:complexType name="expressionType">
		<xs:group ref="grp.expression"/>
	</xs:complexType>
	<xs:complexType name="operatorType">
		<xs:annotation>
			<xs:documentation xml:lang="en">This model is used in the elements 'and' and 'or'.</xs:documentation>
		</xs:annotation>
		<xs:sequence>
			<xs:group ref="grp.expression" minOccurs="2" maxOccurs="unbounded"/>
		</xs:sequence>
	</xs:complexType>
	<xs:complexType name="sumType">
		<xs:group ref="grp.calculate" maxOccurs="unbounded"/>
	</xs:complexType>
	<xs:complexType name="users-in-roleType">
		<xs:sequence>
			<xs:element ref="role-ref"/>
			<xs:element ref="expression"/>
		</xs:sequence>
	</xs:complexType>
	<xs:complexType name="no-valueType">
		<xs:sequence>
			<xs:element ref="property-ref"/>
		</xs:sequence>
	</xs:complexType>
	<xs:complexType name="completeType">
		<xs:choice>
			<xs:element ref="learning-activity-ref"/>
			<xs:element ref="support-activity-ref"/>
			<xs:element ref="unit-of-learning-href"/>
			<xs:element ref="activity-structure-ref"/>
			<xs:element ref="role-part-ref"/>
			<xs:element ref="act-ref"/>
			<xs:element ref="play-ref"/>
		</xs:choice>
	</xs:complexType>
</xs:schema>