XLANG: Web Services for Business Process Design
From:  http://www.gotdotnet.com/team/xml_wsspecs/xlang-c/default.htm
See: http://xml.coverpages.org/xlang.html

--------------------------------------------

Appendix A - XSD Schema


                  <schema xmlns="http://www.w3.org/2000/10/XMLSchema"
                    xmlns:xlang="urn:schemas-microsoft-com:xlang"
                    targetNamespace="urn:schemas-microsoft-com:xlang"
                    elementFormDefault="qualified">


                    <!-- ==================================================================== -->


                    <annotation>
                      <documentation>
                        Optional documentation element used as first child of xlang elements.
                      </documentation>
                    </annotation>

                    <element name="documentation">
                      <complexType mixed="true">
                        <choice minOccurs="0" maxOccurs="unbounded">
                          <any minOccurs="0" maxOccurs="unbounded"/>
                        </choice>
                        <anyAttribute/>
                      </complexType>
                    </element>
                    <complexType name="documented" abstract="true">
                      <sequence>
                        <element ref="xlang:documentation" minOccurs="0" maxOccurs="1"/>
                      </sequence>
                    </complexType>


                    <!-- ==================================================================== -->


                    <annotation>
                      <documentation>
                        behavior := BEHAVIOR body
                        body := BODY headerProcess
                      </documentation>
                    </annotation>

                    <element name="behavior" type="xlang:behaviorType"/>
                    <complexType name="behaviorType">
                      <complexContent>
                        <extension base="xlang:documented">
                          <sequence>
                            <element name="body" type="xlang:headerProcessType" 
                              minOccurs="1" maxOccurs="1"/>
                          </sequence>
                        </extension>
                      </complexContent>
                    </complexType>

                    <annotation>
                      <documentation>
                        headerProcess := header? process
                      </documentation>
                    </annotation>
                    <complexType name="headerProcessType">
                      <complexContent>
                        <extension base="xlang:documented">
                          <sequence>
                            <element name="header" type="xlang:headerType" 
                              minOccurs="0" maxOccurs="1"/>
                            <group ref="xlang:processGroup" 
                              minOccurs="1" maxOccurs="1"/>
                          </sequence>
                        </extension>
                      </complexContent>
                    </complexType>

                    <annotation>
                      <documentation>
                        header := HEADER localDecls
                        localDecls := LOCAL decls
                        decls := portReferenceDecl* correlationSetDecl*
                      </documentation>
                    </annotation>

                    <complexType name="headerType">
                      <complexContent>
                        <extension base="xlang:documented">
                          <sequence>
                            <element name="local" type="xlang:decls" 
                              minOccurs="0" maxOccurs="1"/>
                          </sequence>
                        </extension>
                      </complexContent>
                    </complexType>

                    <complexType name="decls">
                      <complexContent>
                        <extension base="xlang:documented">
                          <sequence>
                            <element name="portReferenceDecl" type="xlang:portInformation" 
                              minOccurs="0" maxOccurs="unbounded"/>
                            <element name="correlationSetDecl" 
                              type="xlang:correlationSetDeclType" 
                              minOccurs="0" maxOccurs="unbounded"/>
                          </sequence>
                        </extension>
                      </complexContent>
                    </complexType>


                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        portReferenceDecl := portReference URI
                      </documentation>
                    </annotation>
                    <complexType name="portInformation">
                      <attribute name="portReference" type="anyUri" use="required"/>
                    </complexType>

                    <element name="propertyRef">
                      <complexType>
                        <attribute name="name" type="QName" use="required"/>
                      </complexType>
                    </element>


                    <annotation>
                      <documentation>
                        correlationSetDecl := correlationSetDecl name propertyRef+
                        name := NCName
                        propertyRef := propertyRef QName
                      </documentation>
                    </annotation>
                    <complexType name="correlationSetDeclType">
                      <sequence>
                        <element ref="xlang:propertyRef" minOccurs="1" maxOccurs="unbounded"/>
                      </sequence>
                      <attribute name="name" type="NCName" use="required"/>
                    </complexType>


                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        action := operation | delay | raise
                        delay := delayFor | delayUntil
                      </documentation>
                    </annotation>
                    <group name="actionGroup">
                      <choice>
                        <element ref="xlang:operation"/>
                        <element ref="xlang:raise"/>
                        <element ref="xlang:delayFor"/>
                        <element ref="xlang:delayUntil"/>
                      </choice>
                    </group>


                    <complexType name="agentBaseType" abstract="true">
                      <!-- stuff common to all agents -->
                      <complexContent>
                        <extension base="xlang:documented">
                          <attribute name="comment" type="string" use="optional"/>
                        </extension>
                      </complexContent>
                    </complexType>

                    <complexType name="actionBaseType" abstract="true">
                      <!-- stuff common to all actions -->
                      <complexContent>
                        <extension base="xlang:agentBaseType">
                        </extension>
                      </complexContent>
                    </complexType>


                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        operation := action operationRef portRef activation? correlationBegin? correlationSetRef* portDescription*
                        correlationSetRef := CORRELATION setNames
                        correlationBegin := CORRELATIONBEGIN setNames 
                        operationRef := OPERATION NCName
                        setNames := NCNameList
                      </documentation>
                    </annotation>

                    <complexType name="correlationBeginType">
                      <attribute name="correlationBegin" type="NCName" use="required"/>
                      <sequence>
                        <element ref="xlang:correlationSetRef" minOccurs="1" maxOccurs="unbounded"/>
                      </sequence>
                    </complexType>

                    <complexType name="operationRef">
                      <attribute name="operation" type="NCName" use="required"/>
                    </complexType>

                    <element name="action">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:actionBaseType">
                            <sequence>
                              <element ref="xlang:operationRef" minOccurs="1" maxOccurs="1"/>
                              <element ref="xlang:portRef" minOccurs="1" maxOccurs="1"/>
                              <element ref="xlang:correlationBeginType" 
                                minOccurs="0" maxOccurs="1"/>
                              <element ref="xlang:portDescription" 
                                minOccurs="1" maxOccurs="unbounded"/>
                            </sequence>
                            <attribute name="activation" type="boolean"/>
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>



                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        delayFor := DELAYFOR QName
                        delayUntil := DELAYUNTIL QName
                      </documentation>
                    </annotation>
                    <element name="delayFor">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:actionBaseType">
                            <attribute name="period" type="QName" />
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>

                    <element name="delayUntil">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:actionBaseType">
                            <attribute name="clock" type="QName" />
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>


                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        raise := raise QName? 
                      </documentation>
                    </annotation>
                    <element name="raise">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:actionBaseType">
                            <attribute name="signal" type="QName" use="required"/>
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>

                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        process := empty | sequence | switch | pick | all | while 
                        | context | compensate
                      </documentation>
                    </annotation>
                    <group name="processGroup">
                      <choice>
                        <element ref="xlang:empty"/>
                        <element ref="xlang:sequence"/>
                        <element ref="xlang:switch"/>
                        <element ref="xlang:pick"/>
                        <element ref="xlang:all"/>
                        <element ref="xlang:while"/>
                        <element ref="xlang:context"/>
                        <element ref="xlang:compensate"/>
                      </choice>
                    </group>

                    <complexType name="processBaseType" abstract="true">
                      <!-- stuff common to all processes go here -->
                      <complexContent>
                        <extension base="xlang:agentBaseType">
                          <attribute name="expanded" type="boolean" use="optional" default="true"/>
                        </extension>
                      </complexContent>
                    </complexType>

                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        empty := EMPTY
                      </documentation>
                    </annotation>
                    <element name="empty">
                      <complexType>
                        <complexContent>
                          <restriction base="xlang:processBaseType"/>
                        </complexContent>
                      </complexType>
                    </element>

                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        sequence := SEQUENCE [action | process ]* 
                      </documentation>
                    </annotation>
                    <element name="sequence">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <choice minOccurs="0" maxOccurs="unbounded">
                              <group ref="xlang:actionGroup" />
                              <element ref="xlang:empty"/>
                              <element ref="xlang:sequence"/>
                              <element ref="xlang:switch"/>
                              <element ref="xlang:pick"/>
                              <element ref="xlang:all"/>
                              <element ref="xlang:while"/>
                              <element ref="xlang:context"/>
                              <element ref="xlang:compensate"/>
                            </choice>
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>

                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        pick := PICK eventHandler+
                        eventHandler := EVENTHANDLER event process
                        event := delayFor | delayUntil | operation | catch
                        catch := catch QName
                      </documentation>
                    </annotation>
                    <element name="catch">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <attribute name="catch" type="QName" use="required"/>
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>

                    <complexType name="eventHandlerType">
                      <complexContent>
                        <extension base="xlang:documented">
                          <sequence>
                            <choice minOccurs="1" maxOccurs="1">
                              <element ref="xlang:delayFor"/>
                              <element ref="xlang:delayUntil"/>
                              <element ref="xlang:operation"/>
                              <element ref="xlang:catch"/>
                            </choice>
                            <choice minOccurs="1" maxOccurs="1">
                              <element ref="xlang:empty"/>
                              <element ref="xlang:sequence"/>
                              <element ref="xlang:switch"/>
                              <element ref="xlang:pick"/>
                              <element ref="xlang:all"/>
                              <element ref="xlang:while"/>
                              <element ref="xlang:context"/>
                              <element ref="xlang:compensate"/>
                            </choice>
                          </sequence>
                        </extension>
                      </complexContent>
                    </complexType>

                    <element name="pick">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <sequence>
                              <element name="eventHandler" type="xlang:eventHandlerType" 
                                minOccurs="1" maxOccurs="unbounded"/>
                            </sequence>
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>


                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        all := ALL (process)*
                      </documentation>
                    </annotation>
                    <element name="all">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <choice minOccurs="0" maxOccurs="unbounded">
                              <element ref="xlang:empty"/>
                              <element ref="xlang:sequence"/>
                              <element ref="xlang:switch"/>
                              <element ref="xlang:pick"/>
                              <element ref="xlang:all"/>
                              <element ref="xlang:while"/>
                              <element ref="xlang:context"/>
                              <element ref="xlang:compensate"/>
                            </choice>
                          </extension>
                        </complexContent>
                      </complexType>
                    </element>

                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        switch := SWITCH branch* default? 
                      </documentation>
                    </annotation>
                    <element name="switch">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <sequence>
                              <element name="branch" type="xlang:branchType" 
                                minOccurs="0" maxOccurs="unbounded"/>
                              <element name="default" type="xlang:defaultType" 
                                minOccurs="0" maxOccurs="1"/>
                            </sequence>
                          </extension>
                        </complexContent>
                      </complexType> 
                    </element>

                    <annotation>
                      <documentation>
                        branch := BRANCH case process 
                      </documentation>
                    </annotation>
                    <complexType name="branchType">
                      <complexContent>
                        <extension base="xlang:documented">
                          <sequence>
                            <element name="case" type="xlang:caseType" 
                              minOccurs="1" maxOccurs="1"/>
                            <choice minOccurs="1" maxOccurs="1">
                              <element ref="xlang:empty"/>
                              <element ref="xlang:sequence"/>
                              <element ref="xlang:switch"/>
                              <element ref="xlang:pick"/>
                              <element ref="xlang:all"/>
                              <element ref="xlang:while"/>
                              <element ref="xlang:context"/>
                              <element ref="xlang:compensate"/>
                            </choice>
                          </sequence>
                        </extension>
                      </complexContent>
                    </complexType>

                    <annotation>
                      <documentation>
                        case := CASE QName
                      </documentation>
                    </annotation>
                    <complexType name="caseType">
                      <complexContent>
                        <extension base="xlang:documented">
                          <attribute name="case" type="QName" use="required"/>
                        </extension>
                      </complexContent>
                    </complexType>

                    <annotation>
                      <documentation>
                        default := DEFAULT process
                      </documentation>
                    </annotation>
                    <complexType name="defaultType">
                      <complexContent>
                        <extension base="xlang:documented">
                          <choice minOccurs="1" maxOccurs="1">
                            <element ref="xlang:empty"/>
                            <element ref="xlang:sequence"/>
                            <element ref="xlang:switch"/>
                            <element ref="xlang:pick"/>
                            <element ref="xlang:all"/>
                            <element ref="xlang:while"/>
                            <element ref="xlang:context"/>
                            <element ref="xlang:compensate"/>
                          </choice>
                        </extension>
                      </complexContent>
                    </complexType>

                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        while := WHILE case process 
                      </documentation>
                    </annotation>
                    <element name="while">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <sequence>
                              <element name="case" type="xlang:caseType" 
                                minOccurs="1" maxOccurs="1"/>
                              <choice minOccurs="1" maxOccurs="1">
                                <element ref="xlang:empty"/>
                                <element ref="xlang:sequence"/>
                                <element ref="xlang:switch"/>
                                <element ref="xlang:pick"/>
                                <element ref="xlang:all"/>
                                <element ref="xlang:while"/>
                                <element ref="xlang:context"/>
                                <element ref="xlang:compensate"/>
                              </choice>
                            </sequence>
                          </extension>
                        </complexContent>
                      </complexType> 
                    </element>

                    <!-- ==================================================================== -->

                    <annotation>
                      <documentation>
                        context := CONTEXT localDecls? process transaction? exception? 
                        transaction := TRANSACTION txnid compensation? 
                        tnxid := name NCName
                        compensation := COMPENSATION process
                        exception := EXCEPTION pick finally?
                        finally := FINALLY process
                      </documentation>
                    </annotation>
                    <element name="finally">
                      <complexType>
                        <extension base="xlang:documented">
                          <choice minOccurs="1" maxOccurs="1">
                            <element ref="xlang:empty"/>
                            <element ref="xlang:sequence"/>
                            <element ref="xlang:switch"/>
                            <element ref="xlang:pick"/>
                            <element ref="xlang:all"/>
                            <element ref="xlang:while"/>
                            <element ref="xlang:context"/>
                            <element ref="xlang:compensate"/>
                          </choice>
                        </extension>
                      </complexType>
                    </element>

                    <element name="exception">
                      <complexType>
                        <sequence>
                          <element ref="xlang:pick" minOccurs="1" maxOccurs="1"/>
                          <element ref="xlang:finally" minOccurs="0" maxOccurs="1"/>
                        </sequence>
                      </complexType> 
                    </element>


                    <element name="compensation">
                      <complexContent>
                        <extension base="xlang:documented">
                          <choice minOccurs="1" maxOccurs="1">
                            <element ref="xlang:empty"/>
                            <element ref="xlang:sequence"/>
                            <element ref="xlang:switch"/>
                            <element ref="xlang:pick"/>
                            <element ref="xlang:all"/>
                            <element ref="xlang:while"/>
                            <element ref="xlang:context"/>
                            <element ref="xlang:compensate"/>
                          </choice>
                        </extension>
                      </complexContent>
                    </element>

                    <element name="transaction">
                      <sequence>
                        <element name="compensation" type="xlang:compensationType" minOccurs="0" maxOccurs="1"/>
                      </sequence>
                      <attribute name="name" type="NCName" use="required"/>
                    </element>

                    <element name="context">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <sequence>
                              <element name="local" type="xlang:localDeclsType" 
                                minOccurs="0" maxOccurs="1"/>
                              <choice minOccurs="1" maxOccurs="1">
                                <element ref="xlang:empty"/>
                                <element ref="xlang:sequence"/>
                                <element ref="xlang:switch"/>
                                <element ref="xlang:pick"/>
                                <element ref="xlang:all"/>
                                <element ref="xlang:while"/>
                                <element ref="xlang:context"/>
                                <element ref="xlang:compensate"/>
                              </choice>
                              <element ref="xlang:transaction" minOccurs="0" maxOccurs="1"/>
                              <element ref="xlang:exception" minOccurs="0" maxOccurs="1"/>
                            </sequence>
                          </extension>
                        </complexContent>
                      </complexType> 
                    </element>

                    <annotation>
                      <documentation>
                        compensate := COMPENSATE txn-id
                      </documentation>
                    </annotation>
                    <element name="compensate">
                      <complexType>
                        <complexContent>
                          <extension base="xlang:processBaseType">
                            <attribute name="name" type="NCName" use="required"/>
                          </extension>
                        </complexContent>
                      </complexType> 
                    </element>


                  </schema>