<?xml version="1.0"?>
<!--  ================================================================================  -->
<!--  NOTES TO READERS OF THIS SCHEMA:                                                  -->
<!--  The default value for both minOccurs and maxOccurs is "1".                        -->
<!--  The XQueryX schema has been designed to provide the ability to extend definitions -->
<!--    of top-level elements in extensions such as Full-Text and the Update Facility.  -->
<!--    The nature of the modification is to define named complex types and redefine    -->
<!--    those top-level elements in terms of the named complex types.                   -->
<!--  ================================================================================  -->
<!--  Changes from Recommendation (edition 1):                                          -->
<!--  * Element defs using anon complex types changed to use named types (bug #4924)    -->
<!--  * In Example 4, replaced xqx:parentheziedExpr with xqx:sequenceExpr (bug #4963)   -->
<!--  * In XSLT stylesheet, deleted template for xqx:parenthesizedExpr (bug #4963)      -->
<!--  * Replaced link to grammar applet with correct link (bug #5323)                   -->
<!--  * In XSLT stylesheet, corrected template for xqx:namespaceDeclaration (bug #5343) -->
<!--  Changes from Recommendation (edition 2):                                          -->
<!--  * Added support for new Windowing clause in FLWOR expression                      -->
<!--  * Added support for new Group By Clause in FLWOR expression                       -->
<!--  * Added support for new Count Clause in FLWOR expression                          -->
<!--  * Added support for keyword "outer" on for expression                             -->
<!--  * Modified structure of FLWOR clause per "simplified FLWOR expressions"           -->
<!--  * Modified validation syntax per Bugzilla Bug 5472                                -->
<!--  * Modified function declaration so that external functions can be nondeterminstic -->
<!--  * Modified variable declaration so external variables can have an initial value   -->
<!--  * Added support for new try-catch expression                                      -->
<!--  * Added support for new decimal formatting declaration                            -->
<!--  * Added support for encoding in the version declaration                           -->
<!--  * Added support for new context item declaration                                  -->
<!--  * Added support for computed namespace constructor                                -->
<!--  *                                                                                 -->
<!--  *                                                                                 -->
<!--  ================================================================================  -->
<!--  Errata applied:                                                                   -->
<!--    XQX.E1 - Editorial (Bugzilla Bug 4924)                                          -->
<!--  ================================================================================  -->
<!--  Modifications:                                                                    -->
<!--    2008-07-30 - Add XQuery 1.1 grouping and windowing support                      -->
<!--    2008-09-18 - Add XQuery 1.1 count and outer-for support, simplified FLWOR       -->
<!--    2008-09-27 - Add validation type, nondeterministic function declarations,       -->
<!--                 initial values for external variables, try-catch expression        -->
<!--  ================================================================================  -->

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns="http://www.w3.org/2005/XQueryX"
            targetNamespace="http://www.w3.org/2005/XQueryX"
            elementFormDefault="qualified" attributeFormDefault="qualified">


<!-- A few helper declarations                                                          -->
  <xsd:complexType name="emptyContent"/>

  <xsd:element name="NCName" type="xsd:NCName"/>

  <xsd:complexType name="QName">
    <xsd:simpleContent>
      <xsd:extension base="xsd:NCName">
        <xsd:attribute name="prefix" type="xsd:NCName" use="optional"/>
      </xsd:extension>
    </xsd:simpleContent>
  </xsd:complexType>


<!-- The base expression class                                                          -->
  <xsd:complexType name="expr"/>

  <xsd:element name="expr" type="expr" abstract="true"/>


<!-- A list of expressions                                                              -->
  <xsd:complexType name="exprList">
    <xsd:sequence>
      <xsd:element ref="expr" minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

<!-- A type to be used by elements that comprise an optional expr                       -->
  <xsd:complexType name="exprWrapperOptional">
    <xsd:sequence>
      <xsd:element ref="expr" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

<!-- Simple wrapper class                                                               -->
  <xsd:complexType name="exprWrapper">
    <xsd:sequence>
      <xsd:element ref="expr"/>
    </xsd:sequence>
  </xsd:complexType>

<!-- constant expressions. We have 4 different subclasses for this                      -->
  <xsd:complexType name="constantExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="value" type="xsd:anyType"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="constantExpr" type="constantExpr" abstract="true"
               substitutionGroup="expr"/>


  <xsd:complexType name="integerConstantExpr">
    <xsd:complexContent>
      <xsd:restriction base="constantExpr">
        <xsd:sequence>
          <xsd:element name="value" type="xsd:integer"/>
        </xsd:sequence>
      </xsd:restriction>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="integerConstantExpr" type="integerConstantExpr"
               substitutionGroup="constantExpr"/>


  <xsd:complexType name="decimalConstantExpr">
    <xsd:complexContent>
      <xsd:restriction base="constantExpr">
        <xsd:sequence>
          <xsd:element name="value" type="xsd:decimal"/>
        </xsd:sequence>
      </xsd:restriction>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="decimalConstantExpr" type="decimalConstantExpr"
               substitutionGroup="constantExpr"/>


  <xsd:complexType name="doubleConstantExpr">
    <xsd:complexContent>
      <xsd:restriction base="constantExpr">
        <xsd:sequence>
          <xsd:element name="value" type="xsd:double"/>
        </xsd:sequence>
      </xsd:restriction>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="doubleConstantExpr" type="doubleConstantExpr"
               substitutionGroup="constantExpr"/>


  <xsd:complexType name="stringConstantExpr">
    <xsd:complexContent>
      <xsd:restriction base="constantExpr">
        <xsd:sequence>
          <xsd:element name="value" type="xsd:string"/>
        </xsd:sequence>
      </xsd:restriction>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="stringConstantExpr" type="stringConstantExpr"
               substitutionGroup="constantExpr"/>


<!-- Variables                                                                          -->
  <xsd:complexType name="varRef">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="name" type="QName"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="varRef" type="varRef" substitutionGroup="expr"/>


<!-- root and context-item expressions                                                  -->
<!-- rootExpr deleted per Bugzilla Bug #2523                                            -->
  <xsd:complexType name="contextItemExpr">
    <xsd:complexContent>
      <xsd:extension base="expr"/>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="contextItemExpr" type="contextItemExpr"
               substitutionGroup="expr"/>


<!-- Pragmas and extension expressions                                                  -->
  <xsd:complexType name="pragma">
    <xsd:sequence>
      <xsd:element name="pragmaName" type="QName"/>
      <xsd:element name="pragmaContents" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="pragma" type="pragma"/>


  <xsd:complexType name="extensionExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element ref="pragma" maxOccurs="unbounded"/>
          <xsd:element name="argExpr" type="exprWrapper" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="extensionExpr" type="extensionExpr"
               substitutionGroup="expr"/>


<!-- Function call expressions                                                          -->
  <xsd:complexType name="functionCallExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="functionName" type="QName"/>
          <xsd:element name="arguments" type="exprList" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="functionCallExpr" type="functionCallExpr"
               substitutionGroup="expr"/>


<!-- Constructor functions                                                              -->
  <xsd:complexType name="constructorFunctionExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="typeName" type="QName"/>
          <xsd:element name="argExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="constructorFunctionExpr" type="constructorFunctionExpr"
               substitutionGroup="expr"/>


<!-- Sequence expressions                                                               -->
  <xsd:complexType name="sequenceExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element ref="expr" minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="sequenceExpr" type="sequenceExpr" substitutionGroup="expr"/>


  <xsd:complexType name="rangeSequenceExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="startExpr" type="exprWrapper"/>
          <xsd:element name="endExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="rangeSequenceExpr" type="rangeSequenceExpr"
               substitutionGroup="expr"/>


<!-- Builtin operator expressions                                                       -->
  <xsd:complexType name="operatorExpr">
    <xsd:complexContent>
      <xsd:extension base="expr"/>
    </xsd:complexContent>
  </xsd:complexType>


  <xsd:complexType name="unaryOperatorExpr">
    <xsd:complexContent>
      <xsd:extension base="operatorExpr">
        <xsd:sequence>
          <xsd:element name="operand" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>


  <xsd:complexType name="binaryOperatorExpr">
    <xsd:complexContent>
      <xsd:extension base="operatorExpr">
        <xsd:sequence>
          <xsd:element name="firstOperand" type="exprWrapper"/>
          <xsd:element name="secondOperand" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>


  <xsd:element name="operatorExpr" type="operatorExpr"
               abstract="true" substitutionGroup="expr"/>

  <xsd:element name="arithmeticOp" type="operatorExpr"
               abstract="true" substitutionGroup="operatorExpr"/>

  <xsd:element name="addOp" type="binaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="subtractOp" type="binaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="multiplyOp" type="binaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="divOp" type="binaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="idivOp" type="binaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="modOp" type="binaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="unaryMinusOp" type="unaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="unaryPlusOp" type="unaryOperatorExpr"
               substitutionGroup="arithmeticOp"/>

  <xsd:element name="comparisonOp" type="binaryOperatorExpr" abstract="true"
               substitutionGroup="operatorExpr"/>

  <xsd:element name="valueComparisonOp" type="binaryOperatorExpr" abstract="true"
               substitutionGroup="operatorExpr"/>

  <xsd:element name="eqOp" type="binaryOperatorExpr"
               substitutionGroup="valueComparisonOp"/>

  <xsd:element name="neOp" type="binaryOperatorExpr"
               substitutionGroup="valueComparisonOp"/>

  <xsd:element name="gtOp" type="binaryOperatorExpr"
               substitutionGroup="valueComparisonOp"/>

  <xsd:element name="geOp" type="binaryOperatorExpr"
               substitutionGroup="valueComparisonOp"/>

  <xsd:element name="ltOp" type="binaryOperatorExpr"
               substitutionGroup="valueComparisonOp"/>

  <xsd:element name="leOp" type="binaryOperatorExpr"
               substitutionGroup="valueComparisonOp"/>

  <xsd:element name="generalComparisonOp" type="binaryOperatorExpr" abstract="true"
               substitutionGroup="operatorExpr"/>

  <xsd:element name="equalOp" type="binaryOperatorExpr"
               substitutionGroup="generalComparisonOp"/>

  <xsd:element name="notEqualOp" type="binaryOperatorExpr"
               substitutionGroup="generalComparisonOp"/>

  <xsd:element name="lessThanOp" type="binaryOperatorExpr"
               substitutionGroup="generalComparisonOp"/>

  <xsd:element name="lessThanOrEqualOp" type="binaryOperatorExpr"
               substitutionGroup="generalComparisonOp"/>

  <xsd:element name="greaterThanOp" type="binaryOperatorExpr"
               substitutionGroup="generalComparisonOp"/>

  <xsd:element name="greaterThanOrEqualOp" type="binaryOperatorExpr"
               substitutionGroup="generalComparisonOp"/>

  <xsd:element name="nodeComparisonOp" type="binaryOperatorExpr" abstract="true"
               substitutionGroup="operatorExpr"/>

  <xsd:element name="isOp" type="binaryOperatorExpr"
               substitutionGroup="nodeComparisonOp"/>

  <xsd:element name="orderComparisonOp" type="binaryOperatorExpr" abstract="true"
               substitutionGroup="operatorExpr"/>

  <xsd:element name="nodeBeforeOp" type="binaryOperatorExpr"
               substitutionGroup="orderComparisonOp"/>

  <xsd:element name="nodeAfterOp" type="binaryOperatorExpr"
               substitutionGroup="orderComparisonOp"/>

  <xsd:element name="logicalOp" type="binaryOperatorExpr" abstract="true"
               substitutionGroup="operatorExpr"/>

  <xsd:element name="andOp" type="binaryOperatorExpr"
               substitutionGroup="logicalOp"/>

  <xsd:element name="orOp" type="binaryOperatorExpr"
               substitutionGroup="logicalOp"/>

  <xsd:element name="setOp" type="binaryOperatorExpr"
               abstract="true" substitutionGroup="operatorExpr"/>

  <xsd:element name="unionOp" type="binaryOperatorExpr"
               substitutionGroup="setOp"/>

  <xsd:element name="intersectOp" type="binaryOperatorExpr"
               substitutionGroup="setOp"/>

  <xsd:element name="exceptOp" type="binaryOperatorExpr"
               substitutionGroup="setOp"/>


<!-- Basic typenames                                                                    -->
  <xsd:element name="atomicType" type="QName" substitutionGroup="itemType"/>


<!-- Used in castable expression and cast expression                                    -->
  <xsd:complexType name="singleType">
    <xsd:sequence>
      <xsd:element ref="atomicType"/>
      <xsd:element name="optional" type="emptyContent" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="singleType" type="singleType"/>


<!-- Item type schema types and elements                                                -->
  <xsd:element name="itemType" abstract="true"/>


  <xsd:complexType name="emptyItemTypeContent"/>

  <xsd:element name="anyItemType" type="emptyItemTypeContent"
               substitutionGroup="itemType"/>


  <xsd:simpleType name="occurrenceIndicator">
    <xsd:restriction base="xsd:string">
      <xsd:enumeration value="?"/>
      <xsd:enumeration value="*"/>
      <xsd:enumeration value="+"/>
    </xsd:restriction>
  </xsd:simpleType>


<!-- Sequence type                                                                      -->
  <xsd:complexType name="sequenceType">
    <xsd:choice>
      <xsd:element name="voidSequenceType" type="emptyContent"/>
      <xsd:sequence>
        <xsd:element ref="itemType"/>
        <xsd:element name="occurrenceIndicator" type="occurrenceIndicator"
                     minOccurs="0"/>
      </xsd:sequence>
    </xsd:choice>
  </xsd:complexType>

  <xsd:element name="sequenceType" type="sequenceType"/>

  <xsd:element name="typeDeclaration" type="sequenceType"/>


<!-- Represents a "typed" variable (for clause, let clause etc)                         -->
  <xsd:complexType name="typedVariableBinding">
    <xsd:sequence>
      <xsd:element name="varName" type="QName"/>
      <xsd:element ref="typeDeclaration" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="typedVariableBinding" type="typedVariableBinding"/>


<!-- Represents an untyped variable for the "at" clause in a for clause                 -->
  <xsd:element name="positionalVariableBinding" type="QName"/>

  <xsd:element name="variableBinding" type="QName"/>


<!-- Represents all variable bindings in a for or let clause except typed and           -->
<!--   positional variable bindings                                                     -->
  <xsd:element name="forLetClauseItemExtensions" abstract="true"/>


<!-- Major syntax productions: FLWOR clause components                                  -->
<!-- for clause                                                                         -->
  <xsd:complexType name="forClauseItem">
    <xsd:sequence>
  	  <xsd:element ref="typedVariableBinding"/>
	    <xsd:element ref="positionalVariableBinding" minOccurs="0" maxOccurs="1"/>
      <xsd:element ref="forLetClauseItemExtensions" minOccurs="0"
                   maxOccurs="unbounded"/>
      <xsd:element name="forExpr" type="exprWrapper"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="forClauseItem" type="forClauseItem"/>


  <xsd:complexType name="forClause">
    <xsd:sequence>
      <xsd:element ref="forClauseItem" minOccurs="1" maxOccurs="unbounded"/>
    </xsd:sequence>
    <xsd:attribute name="outer" type="xsd:boolean" default="false"/>
  </xsd:complexType>

  <xsd:element name="forClause" type="forClause"/>


<!-- let clause                                                                         -->
  <xsd:complexType name="letClauseItem">
    <xsd:sequence>
      <xsd:choice>
        <xsd:sequence>
          <xsd:element ref="typedVariableBinding"/>
          <xsd:element ref="forLetClauseItemExtensions"
                       minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
        <xsd:element ref="forLetClauseItemExtensions"
                     minOccurs="0" maxOccurs="unbounded"/>
      </xsd:choice>
      <xsd:element name="letExpr" type="exprWrapper"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="letClauseItem" type="letClauseItem"/>


  <xsd:complexType name="letClause">
    <xsd:sequence>
      <xsd:element ref="letClauseItem" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="letClause" type="letClause"/>


<!-- This is the windowClause (part of FLWOR expression)                                -->
<!-- It corresponds to the following XQuery grammar                                     -->
<!--	WindowClause ::= "for" (TumblingWindowClause | SlidingWindowClause)               -->
  <xsd:complexType name="windowClause">
    <xsd:choice>
      <xsd:element ref="tumblingWindowClause"/>
      <xsd:element ref="slidingWindowClause"/>
    </xsd:choice>
  </xsd:complexType>

  <xsd:element name="windowClause" type="windowClause"/>


<!-- This is the tumblingWindowClause                                                   -->
<!-- It corresponds to the following XQuery grammar                                     -->
<!-- TumblingWindowClause ::= "tumbling" "window" "$" VarName TypeDeclaration?          -->
<!--                           "in" ExprSingle WindowStartCondition WindowEndCondition? -->
  <xsd:complexType name="tumblingWindowClause">
    <xsd:sequence>
      <xsd:element ref="typedVariableBinding"/>
      <xsd:element name="bindingSequence" type="exprWrapper"/>
      <xsd:element name="windowStartCondition" type="windowStartCondition"/>
      <xsd:element name="windowEndCondition" type="windowEndCondition" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="tumblingWindowClause" type="tumblingWindowClause"/>


<!-- This is the slidingWindowClause                                                    -->
<!-- It corresponds to the following XQuery grammar                                     -->
<!-- SlidingWindowClause ::= "sliding" "window" "$" VarName TypeDeclaration?            -->
<!--                         "in" ExprSingle WindowStartCondition WindowEndCondition    -->
  <xsd:complexType name="slidingWindowClause">
    <xsd:sequence>
      <xsd:element ref="typedVariableBinding"/>
      <xsd:element name="bindingSequence" type="exprWrapper"/>
      <xsd:element ref="windowStartCondition"/>
      <xsd:element ref="windowEndCondition"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="slidingWindowClause" type="slidingWindowClause"/>


<!-- windowStartCondition                                                               -->
<!-- Corresponds to the following XQuery grammar                                        -->
<!-- WindowStartCondition ::= "start" WindowVars "when" ExprSingle                      -->
  <xsd:complexType name="windowStartCondition">
    <xsd:sequence>
      <xsd:element ref="windowVars" minOccurs="0"/>
      <xsd:element name="winStartExpr" type="exprWrapper"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="windowStartCondition" type="windowStartCondition"/>


<!-- windowEndCondition                                                                 -->
<!-- Corresponds to the following XQuery grammar                                        -->
<!-- WindowEndCondition 	   ::=    	"only"? "end" WindowVars "when" ExprSingle        -->
  <xsd:complexType name="windowEndCondition">
    <xsd:sequence>
      <xsd:element ref="windowVars" minOccurs="0"/>
      <xsd:element name="winEndExpr" type="exprWrapper"/>
    </xsd:sequence>
    <xsd:attribute name="onlyEnd" type="xsd:boolean" default="false"/>
  </xsd:complexType>

  <xsd:element name="windowEndCondition" type="windowEndCondition"/>


<!-- windowVars                                                                         -->
<!-- Corresponds to the following XQuery grammar                                        -->
<!-- WindowVars ::= ("$" CurrentItem)? PositionalVar? ("previous" "$" PreviousItem)?    -->
<!--                ("next" "$" NextItem)?                                              -->
  <xsd:complexType name="windowVars">
    <xsd:sequence>
      <xsd:element name="currentItem" type="QName" minOccurs="0"/>
      <xsd:element ref="positionalVariableBinding"/>
      <xsd:element name="previousItem" type="QName" minOccurs="0"/>
      <xsd:element name="nextItem" type="QName" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="windowVars" type="windowVars"/>


<!-- countClause (part of FLWOR expression)                                             -->
  <xsd:complexType name="countClause">
    <xsd:sequence>
      <xsd:element ref="varRef"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="countClause" type="countClause"/>


<!-- whereClause (part of FLWOR expression)                                             -->
  <xsd:element name="whereClause" type="exprWrapper"/>


<!-- groupByClause (part of FLWOR expression)                                           -->
<!-- Corresponds to the following XQuery syntax                                         -->
<!-- GroupByClause ::= "group" "by" GroupingSpecList                                    -->
<!-- GroupingSpecList ::= GroupingSpec ("," GroupingSpec)*                              -->
  <xsd:complexType name="groupByClause">
    <xsd:sequence maxOccurs="unbounded">
      <xsd:element ref="groupingSpec"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="groupByClause" type="groupByClause"/>


<!-- Corresponds to the following XQuery syntax                                         -->
<!-- GroupingSpec ::= "$" VarName ("collation" URILiteral)?                             -->
  <xsd:complexType name="groupingSpec">
    <xsd:sequence>
      <xsd:element name="varName" type="QName"/>
      <xsd:element name="collation" type="xsd:string" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="groupingSpec" type="groupingSpec"/>


<!-- order by clause                                                                    -->
  <xsd:simpleType name="emptyOrderingMode">
    <xsd:restriction base="xsd:string">
      <xsd:enumeration value="empty greatest"/>
      <xsd:enumeration value="empty least"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:simpleType name="orderingKind">
    <xsd:restriction base="xsd:string">
      <xsd:enumeration value="ascending"/>
      <xsd:enumeration value="descending"/>
    </xsd:restriction>
  </xsd:simpleType>


  <xsd:complexType name="orderModifier">
    <xsd:sequence>
      <xsd:element name="orderingKind" type="orderingKind" minOccurs="0"/>
      <xsd:element name="emptyOrderingMode" type="emptyOrderingMode" minOccurs="0"/>
      <xsd:element name="collation" type="xsd:string" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="orderModifier" type="orderModifier"/>


  <xsd:complexType name="orderBySpec">
    <xsd:sequence>
      <xsd:element name="orderByExpr" type="exprWrapper"/>
      <xsd:element ref="orderModifier" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="orderBySpec" type="orderBySpec"/>


  <xsd:complexType name="orderByClause">
    <xsd:sequence>
      <xsd:element name="stable" type="emptyContent" minOccurs="0"/>
      <xsd:element ref="orderBySpec" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="orderByClause" type="orderByClause"/>


<!-- return clause                                                                      -->
  <xsd:element name="returnClause" type="exprWrapper"/>


<!-- This is the XQuery 1.1 flwor expression                                            -->
<!-- Corresponds to the following XQuery syntax:                                        -->
<!-- 1.1 FLWORExpr ::= (ForClause | LetClause | WindowClause)                           -->
<!--                   (ForClause | LetClause | WindowClause | CountClause |            -->
<!--                    WhereClause | GroupByClause | OrderByClause)*                   -->
<!--                   ReturnClause                                                     -->
  <xsd:complexType name="flworExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:choice>
            <xsd:element ref="forClause"/>
            <xsd:element ref="letClause"/>
            <xsd:element ref="windowClause"/>
          </xsd:choice>
          <xsd:sequence>
            <xsd:choice minOccurs="0" maxOccurs="unbounded">
              <xsd:element ref="forClause"/>
              <xsd:element ref="letClause"/>
              <xsd:element ref="windowClause"/>
              <xsd:element ref="countClause"/>
              <xsd:element ref="whereClause"/>
              <xsd:element ref="groupByClause"/>
              <xsd:element ref="orderByClause"/>
            </xsd:choice>
          <xsd:element ref="returnClause"/>
        </xsd:sequence>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="flworExpr" type="flworExpr" substitutionGroup="expr"/>


<!-- conditional expressions                                                            -->
  <xsd:complexType name="ifThenElseExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="ifClause" type="exprWrapper"/>
          <xsd:element name="thenClause" type="exprWrapper"/>
          <xsd:element name="elseClause" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="ifThenElseExpr" type="ifThenElseExpr" 
               substitutionGroup="expr"/>


<!-- The following clauses describe quantified expressions                              -->
  <xsd:simpleType name="quantifier">
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="some"/>
      <xsd:enumeration value="every"/>
    </xsd:restriction>
  </xsd:simpleType>


  <xsd:complexType name="quantifiedExprInClause">
    <xsd:sequence>
      <xsd:element ref="typedVariableBinding"/>
      <xsd:element name="sourceExpr" type="exprWrapper"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="quantifiedExprInClause" type="quantifiedExprInClause"/>


  <xsd:complexType name="quantifiedExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="quantifier" type="quantifier"/>
          <xsd:element ref="quantifiedExprInClause" maxOccurs="unbounded"/>
          <xsd:element name="predicateExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="quantifiedExpr" type="quantifiedExpr"
               substitutionGroup="expr"/>


<!-- handle the typeswitch construct                                                    -->
<!-- Note: no substitutionGroup as we cannot use this anywhere                          -->
  <xsd:complexType name="typeswitchExprCaseClause">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element ref="variableBinding" minOccurs="0"/>
          <xsd:element ref="sequenceType"/>
          <xsd:element name="resultExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="typeswitchExprCaseClause"
               type="typeswitchExprCaseClause"/>


<!-- Note: no substitutionGroup as we cannot use this anywhere                          -->
  <xsd:complexType name="typeswitchExprDefaultClause">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element ref="variableBinding" minOccurs="0"/>
          <xsd:element name="resultExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="typeswitchExprDefaultClause"
               type="typeswitchExprDefaultClause"/>


  <xsd:complexType name="typeswitchExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
          <xsd:element ref="typeswitchExprCaseClause" maxOccurs="unbounded"/>
          <xsd:element ref="typeswitchExprDefaultClause"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="typeswitchExpr" type="typeswitchExpr"
               substitutionGroup="expr"/>


<!-- TryCatchExpression                                                                 -->
<!-- Corresponds to the following XQuery syntax                                         -->
<!-- TryCatchExpression ::= TryClause CatchClause+                                      -->
<!-- TryClause ::= "{" TryTargetExpr "}"                                                -->
<!-- TryTargetExpr ::= Expr                                                             -->
  <xsd:complexType name="tryCatchExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="tryClause" type="exprWrapper"/>
          <xsd:element ref="catchClause" maxOccurs="unbounded"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="tryCatchExpr" type="tryCatchExpr"
               substitutionGroup="expr"/>


<!-- CatchClause (part of the TryCatchExpression)                                       -->
<!-- Corresponds to the following XQuery syntax                                         -->
<!-- CatchClause ::= "catch" CatchErrorList CatchVars* "{" Expr "}"                     -->
  <xsd:complexType name="catchClause">
    <xsd:sequence>
      <xsd:element ref="catchErrorList"/>
      <xsd:element ref="catchVars" minOccurs="0"/>
      <xsd:element name="catchExpr" type="exprWrapper"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="catchClause" type="catchClause"/>


<!-- CatchErrorList (part of the TryCatchExpression)                                    -->
<!-- Corresponds to the following XQuery syntax                                         -->
<!-- CatchErrorList ::= NameTest ( "|" NameTest )*                                      -->
  <xsd:complexType name="catchErrorList">
    <xsd:sequence>
      <xsd:element ref="nameTest" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="catchErrorList" type="catchErrorList"/>


<!-- CatchVars (part of the TryCatchExpression)                                         -->
<!-- Corresponds to the following XQuery syntax                                         -->
<!-- CatchVars ::= "(" CatchErrorCode ( "," CatchErrorDesc ( "," CatchErrorVal )? )? ")"-->
<!-- CatchErrorCode ::= "$" VarName                                                     -->
<!-- CatchErrorDesc ::= "$" VarName                                                     -->
<!-- CatchErrorVal ::= "$" VarName                                                      -->
  <xsd:complexType name="catchVars">
    <xsd:sequence>
      <xsd:element name="catchErrorCode">
        <xsd:complexType>
          <xsd:sequence>
            <xsd:element ref="varRef"/>
          </xsd:sequence>
        </xsd:complexType>
      </xsd:element>
      <xsd:sequence minOccurs="0">
        <xsd:element name="catchErrorDesc">
          <xsd:complexType>
            <xsd:sequence>
              <xsd:element ref="varRef"/>
            </xsd:sequence>
          </xsd:complexType>
        </xsd:element>
        <xsd:sequence minOccurs="0">
          <xsd:element name="catchErrorVal">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element ref="varRef"/>
              </xsd:sequence>
            </xsd:complexType>
          </xsd:element>
        </xsd:sequence>
      </xsd:sequence>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="catchVars" type="catchVars"/>


<!-- instance-of expressions                                                            -->
  <xsd:complexType name="instanceOfExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
          <xsd:element ref="sequenceType"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="instanceOfExpr" type="instanceOfExpr"
               substitutionGroup="expr"/>


<!-- treat-as expressions                                                               -->
  <xsd:complexType name="treatExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
          <xsd:element ref="sequenceType"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="treatExpr" type="treatExpr"
               substitutionGroup="expr"/>


<!-- castable and cast expressions                                                      -->
  <xsd:complexType name="castableExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
          <xsd:element ref="singleType"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="castableExpr" type="castableExpr"
               substitutionGroup="expr"/>


  <xsd:complexType name="castExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
          <xsd:element ref="singleType"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="castExpr" type="castExpr"
               substitutionGroup="expr"/>


<!-- Validate expressions                                                               -->
  <xsd:simpleType name="validationMode">
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="lax"/>
      <xsd:enumeration value="strict"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:complexType name="validateExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:choice>
            <xsd:element name="validationMode" type="validationMode" minOccurs="0"/>
            <xsd:element ref="sequenceType" minOccurs="0"/>
          </xsd:choice>
          <xsd:element name="argExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="validateExpr" type="validateExpr"
               substitutionGroup="expr"/>


<!-- Direct constructors. Only elementConstructor for now                               -->
<!-- Note the absence of constructors corresponding to                                  -->
<!-- the directCommentConstructor and the directPIConstructor                           -->
<!-- productions in the XQuery grammar. This is because they are                        -->
<!-- trivially identical to the computed variants                                       -->

<!-- attributeConstructor is no longer a subclass of expr                               -->
  <xsd:complexType name="attributeConstructor">
    <xsd:sequence>
      <xsd:element name="attributeName" type="QName"/>
      <xsd:choice>
        <xsd:element name="attributeValueExpr" type="exprList"/>
        <xsd:element name="attributeValue" type="xsd:string"/>
      </xsd:choice>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="namespaceDeclaration">
    <xsd:sequence>
      <xsd:element name="prefix" type="xsd:NCName" minOccurs="0"/>
      <xsd:element name="uri" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>


<!-- element constructors                                                               -->
  <xsd:complexType name="attributeList">
    <xsd:sequence>
      <xsd:choice maxOccurs="unbounded">
        <xsd:element name="attributeConstructor" type="attributeConstructor"/>
        <xsd:element name="namespaceDeclaration" type="namespaceDeclaration"/>
      </xsd:choice>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="attributeList" type="attributeList"/>


  <xsd:element name="elementContent" type="exprList"/>


  <xsd:complexType name="elementConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="tagName" type="QName"/>
          <xsd:element ref="attributeList" minOccurs="0"/>
          <xsd:element ref="elementContent" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="elementConstructor" type="elementConstructor"
               substitutionGroup="expr"/>


<!-- computed constructors                                                              -->
<!-- computed element constructor                                                       -->
  <xsd:complexType name="computedElementConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:choice>
            <xsd:element name="tagName" type="QName"/>
            <xsd:element name="tagNameExpr" type="exprWrapper"/>
          </xsd:choice>
          <xsd:element name="contentExpr" type="exprWrapper" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="computedElementConstructor" type="computedElementConstructor"
               substitutionGroup="expr"/>


<!-- computed attribute constructor                                                     -->
  <xsd:complexType name="computedAttributeConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:choice>
            <xsd:element name="tagName" type="QName"/>
            <xsd:element name="tagNameExpr" type="exprWrapper"/>
          </xsd:choice>
          <xsd:element name="valueExpr" type="exprWrapper" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="computedAttributeConstructor" type="computedAttributeConstructor"
               substitutionGroup="expr"/>


<!-- computed document constructor                                                      -->
  <xsd:complexType name="computedDocumentConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="computedDocumentConstructor" type="computedDocumentConstructor"
               substitutionGroup="expr"/>


<!-- computed text constructor                                                          -->
  <xsd:complexType name="computedTextConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="computedTextConstructor" type="computedTextConstructor"
               substitutionGroup="expr"/>


<!-- computed comment constructor                                                       -->
  <xsd:complexType name="computedCommentConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="computedCommentConstructor" type="computedCommentConstructor"
               substitutionGroup="expr"/>


<!-- computed namespace constructor                                                     -->
  <xsd:complexType name="computedNamespaceConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:choice>
            <xsd:element name="prefix" type="xsd:NCName"/>
            <xsd:element name="prefixExpr" type="exprWrapper"/>
          </xsd:choice>
          <xsd:element name="URIExpr" type="exprWrapper" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="computedNamespaceConstructor" type="computedNamespaceConstructor"
               substitutionGroup="expr"/>


<!-- computed processing instruction constructor                                        -->
  <xsd:complexType name="computedPIConstructor">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:choice>
            <xsd:element name="piTarget" type="xsd:NCName"/>
            <xsd:element name="piTargetExpr" type="exprWrapper"/>
          </xsd:choice>
          <xsd:element name="piValueExpr" type="exprWrapper" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="computedPIConstructor" type="computedPIConstructor"
               substitutionGroup="expr"/>


<!-- ordered and unordered expressions                                                  -->
  <xsd:complexType name="unorderedExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="unorderedExpr" type="unorderedExpr" substitutionGroup="expr"/>


  <xsd:complexType name="orderedExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:sequence>
          <xsd:element name="argExpr" type="exprWrapper"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="orderedExpr" type="orderedExpr" substitutionGroup="expr"/>


<!-- wildcards                                                                          -->
  <xsd:complexType name="simpleWildcard">
    <xsd:choice>
      <xsd:element name="QName" type="QName"/>
      <xsd:element name="star" type="emptyContent"/>
    </xsd:choice>
  </xsd:complexType>


  <xsd:complexType name="Wildcard">
    <xsd:all>
      <xsd:element name="star" type="emptyContent" minOccurs="0"/>
      <xsd:element ref="NCName" minOccurs="0"/>
    </xsd:all>
  </xsd:complexType>

  <xsd:element name="Wildcard" type="Wildcard"/>


<!-- tests (name and/or type)                                                           -->
  <xsd:element name="schemaAttributeTest" type="QName"
               substitutionGroup="kindTest"/>


  <xsd:complexType name="attributeTest">
    <xsd:complexContent>
      <xsd:extension base="emptyItemTypeContent">
        <xsd:sequence minOccurs="0">
          <xsd:element name="attributeName" type="simpleWildcard"/>
          <xsd:element name="typeName" type="QName" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="attributeTest" type="attributeTest"
               substitutionGroup="kindTest"/>


  <xsd:element name="anyElementTest" abstract="true"
               substitutionGroup="kindTest"/>


  <xsd:element name="schemaElementTest" type="QName"
               substitutionGroup="anyElementTest"/>


  <xsd:complexType name="elementTest">
    <xsd:complexContent>
      <xsd:extension base="emptyItemTypeContent">
        <xsd:sequence minOccurs="0">
          <xsd:element name="elementName" type="simpleWildcard"/>
          <xsd:sequence minOccurs="0">
            <xsd:element name="typeName" type="QName"/>
            <xsd:element name="nillable" type="emptyContent" minOccurs="0"/>
          </xsd:sequence>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="elementTest" type="elementTest"
               substitutionGroup="anyElementTest"/>


  <xsd:complexType name="documentTest">
    <xsd:complexContent>
      <xsd:extension base="emptyItemTypeContent">
        <xsd:sequence>
           <xsd:element ref="anyElementTest" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="documentTest" type="documentTest"
               substitutionGroup="kindTest"/>


  <xsd:complexType name="piTest">
    <xsd:complexContent>
      <xsd:extension base="emptyItemTypeContent">
        <xsd:sequence>
          <xsd:element name="piTarget" type="xsd:NCName" minOccurs="0"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="piTest" type="piTest" substitutionGroup="kindTest"/>


  <xsd:element name="nameTest" type="QName"/>

  <xsd:element name="kindTest" substitutionGroup="itemType"/>

  <xsd:element name="textTest" type="emptyItemTypeContent"
               substitutionGroup="kindTest"/>

  <xsd:element name="commentTest" type="emptyItemTypeContent"
               substitutionGroup="kindTest"/>

  <xsd:element name="namespaceTest" type="emptyItemTypeContent"
               substitutionGroup="kindTest"/>

  <xsd:element name="anyKindTest" type="emptyItemTypeContent"
               substitutionGroup="kindTest"/>


<!-- XPath axes                                                                         -->
  <xsd:simpleType name="xpathAxis">
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="child"/>
      <xsd:enumeration value="attribute"/>
      <xsd:enumeration value="self"/>
      <xsd:enumeration value="parent"/>
      <xsd:enumeration value="descendant-or-self"/>
      <xsd:enumeration value="descendant"/>
      <xsd:enumeration value="following"/>
      <xsd:enumeration value="following-sibling"/>
      <xsd:enumeration value="ancestor"/>
      <xsd:enumeration value="ancestor-or-self"/>
      <xsd:enumeration value="preceding"/>
      <xsd:enumeration value="preceding-sibling"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:element name="xpathAxis" type="xpathAxis"/>


<!-- filter expressions                                                                 -->
  <xsd:group name="filterExpr">
    <xsd:choice>
      <xsd:element ref="constantExpr"/>
      <xsd:element ref="varRef"/>
      <xsd:element ref="contextItemExpr"/>
      <xsd:element ref="functionCallExpr"/>
      <xsd:element ref="sequenceExpr"/>
      <xsd:element ref="elementConstructor"/>
      <xsd:element ref="computedElementConstructor"/>
      <xsd:element ref="computedAttributeConstructor"/>
      <xsd:element ref="computedDocumentConstructor"/>
      <xsd:element ref="computedTextConstructor"/>
      <xsd:element ref="computedCommentConstructor"/>
      <xsd:element ref="computedNamespaceConstructor"/>
      <xsd:element ref="computedPIConstructor"/>
      <xsd:element ref="orderedExpr"/>
      <xsd:element ref="unorderedExpr"/>
    </xsd:choice>
  </xsd:group>


<!-- step expression                                                                    -->
<!-- removed nameTest and Wildcard outer choices per Bugzilla Bug #2523                 -->
  <xsd:complexType name="stepExpr">
    <xsd:sequence>
      <xsd:choice>
        <xsd:sequence>
          <xsd:element ref="xpathAxis"/>
          <xsd:choice>
            <xsd:element ref="kindTest"/>
            <xsd:element ref="nameTest"/>
            <xsd:element ref="Wildcard"/>
          </xsd:choice>
        </xsd:sequence>
        <xsd:element name="filterExpr">
          <xsd:complexType>
            <xsd:sequence>
              <xsd:group ref="filterExpr"/>
            </xsd:sequence>
          </xsd:complexType>
        </xsd:element>
      </xsd:choice>
      <xsd:element name="predicates" type="exprList" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="stepExpr" type="stepExpr"/>


<!-- path expression                                                                    -->
<!-- rewrote pathExpr definition per Bugzilla Bug #2523                                 -->
  <xsd:complexType name="pathExpr">
    <xsd:complexContent>
      <xsd:extension base="expr">
        <xsd:choice>
          <xsd:sequence>
            <xsd:element name="rootExpr" type="emptyContent"/>
            <xsd:element ref="stepExpr" minOccurs="0" maxOccurs="unbounded"/>
          </xsd:sequence>
          <xsd:element ref="stepExpr" maxOccurs="unbounded"/>
        </xsd:choice>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:element name="pathExpr" type="pathExpr" substitutionGroup="expr"/>


<!-- The following constructs deal with the query prolog                                -->
  <xsd:complexType name="module">
    <xsd:sequence>
      <xsd:element ref="versionDecl" minOccurs="0"/>
      <xsd:choice>
        <xsd:element ref="mainModule"/>
        <xsd:element ref="libraryModule"/>
      </xsd:choice>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="module" type="module"/>


  <xsd:complexType name="mainModule">
    <xsd:sequence>
      <xsd:element ref="prolog" minOccurs="0"/>
      <xsd:element name="queryBody" type="exprWrapper"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="mainModule" type="mainModule"/>


  <xsd:complexType name="libraryModule">
    <xsd:sequence>
      <xsd:element ref="moduleDecl"/>
      <xsd:element ref="prolog" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="libraryModule" type="libraryModule"/>


  <xsd:complexType name="versionDecl">
    <xsd:sequence>
      <xsd:element name="version" type="xsd:string" minOccurs="0"/>
      <xsd:element name="encoding" type="xsd:string" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="versionDecl" type="versionDecl"/>


  <xsd:complexType name="prolog">
    <xsd:sequence>
	    <xsd:element ref="prologPartOneItem" minOccurs="0" maxOccurs="unbounded"/>
	    <xsd:element ref="prologPartTwoItem" minOccurs="0" maxOccurs="unbounded"/>
	  </xsd:sequence>
	</xsd:complexType>

  <xsd:element name="prolog" type="prolog"/>


  <xsd:element name="prologPartOneItem" abstract="true"/>


  <xsd:element name="prologPartTwoItem" abstract="true"/>


  <xsd:simpleType name="boundarySpaceDecl">
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="strip"/>
      <xsd:enumeration value="preserve"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:element name="boundarySpaceDecl" type="boundarySpaceDecl"
               substitutionGroup="prologPartOneItem"/>


  <xsd:element name="defaultCollationDecl" type="xsd:string"
               substitutionGroup="prologPartOneItem"/>


  <xsd:element name="baseUriDecl" type="xsd:string"
               substitutionGroup="prologPartOneItem"/>


  <xsd:simpleType name="constructionDecl">
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="strip"/>
      <xsd:enumeration value="preserve"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:element name="constructionDecl" type="constructionDecl"
               substitutionGroup="prologPartOneItem"/>


  <xsd:simpleType name="orderingModeDecl">
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="ordered"/>
      <xsd:enumeration value="unordered"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:element name="orderingModeDecl" type="orderingModeDecl"
               substitutionGroup="prologPartOneItem"/>


  <xsd:element name="emptyOrderingDecl" type="emptyOrderingMode"
               substitutionGroup="prologPartOneItem"/>


  <xsd:complexType name="copyNamespacesDecl">
    <xsd:sequence>
      <xsd:element name="preserveMode">
        <xsd:simpleType>
          <xsd:restriction base="xsd:NMTOKEN">
            <xsd:enumeration value="preserve"/>
            <xsd:enumeration value="no-preserve"/>
          </xsd:restriction>
        </xsd:simpleType>
      </xsd:element>
      <xsd:element name="inheritMode">
        <xsd:simpleType>
          <xsd:restriction base="xsd:NMTOKEN">
            <xsd:enumeration value="inherit"/>
            <xsd:enumeration value="no-inherit"/>
          </xsd:restriction>
        </xsd:simpleType>
      </xsd:element>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="copyNamespacesDecl" type="copyNamespacesDecl"
               substitutionGroup="prologPartOneItem"/>


  <xsd:simpleType name="defaultNamespaceCategory">
    <xsd:restriction base="xsd:NMTOKEN">
      <xsd:enumeration value="function"/>
      <xsd:enumeration value="element"/>
    </xsd:restriction>
  </xsd:simpleType>

  <xsd:complexType name="defaultNamespaceDecl">
    <xsd:sequence>
      <xsd:element name="defaultNamespaceCategory" type="defaultNamespaceCategory"/>
      <xsd:element name="uri" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="defaultNamespaceDecl" type="defaultNamespaceDecl"
               substitutionGroup="prologPartOneItem"/>


  <xsd:complexType name="namespaceDeclType">
    <xsd:sequence>
      <xsd:element name="prefix" type="xsd:NCName"/>
      <xsd:element name="uri" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="namespaceDecl" type="namespaceDeclType"
               substitutionGroup="prologPartOneItem"/>


  <xsd:element name="moduleDecl" type="namespaceDeclType"/>


  <xsd:complexType name="decimalFormatDeclType">
        <xsd:sequence>
          <xsd:element name="decimalFormatName" type="xsd:QName" minOccurs="0"/>
          <xsd:element name="decimalFormatParam" minOccurs="0" maxOccurs="unbounded">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="decimalFormatParamName">
                  <xsd:simpleType>
                    <xsd:restriction base="xsd:NMTOKEN">
                      <xsd:enumeration value="decimal-separator"/>
                      <xsd:enumeration value="grouping-separator"/>
                      <xsd:enumeration value="infinity"/>
                      <xsd:enumeration value="minus-sign"/>
                      <xsd:enumeration value="NaN"/>
                      <xsd:enumeration value="percent"/>
                      <xsd:enumeration value="per-mille"/>
                      <xsd:enumeration value="zero-digit"/>
                      <xsd:enumeration value="digit"/>
                      <xsd:enumeration value="pattern-separator"/>
                    </xsd:restriction>
                  </xsd:simpleType>
                </xsd:element>
                <xsd:element name="decimalFormatParamValue" type="xsd:string"/>
              </xsd:sequence>
            </xsd:complexType>
          </xsd:element>
        </xsd:sequence>
        <xsd:attribute name="default" default="false">
          <xsd:simpleType>
            <xsd:restriction base="xsd:NMTOKEN">
              <xsd:enumeration value="true"/>
              <xsd:enumeration value="false"/>
            </xsd:restriction>
          </xsd:simpleType>
        </xsd:attribute>
  </xsd:complexType>

  <xsd:element name="decimalFormatDecl" type="decimalFormatDeclType"
               substitutionGroup="prologPartOneItem"/>


  <xsd:complexType name="schemaImport">
    <xsd:sequence>
      <xsd:choice minOccurs="0">
        <xsd:element name="namespacePrefix" type="xsd:NCName"/>
        <xsd:element name="defaultElementNamespace" type="emptyContent"/>
      </xsd:choice>
      <xsd:element name="targetNamespace" type="xsd:string"/>
      <xsd:element name="targetLocation" type="xsd:string"
                   minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="schemaImport" type="schemaImport"
               substitutionGroup="prologPartOneItem"/>


  <xsd:complexType name="moduleImport">
    <xsd:sequence>
      <xsd:element name="namespacePrefix" type="xsd:NCName" minOccurs="0"/>
      <xsd:element name="targetNamespace" type="xsd:string"/>
      <xsd:element name="targetLocation" type="xsd:string"
                   minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="moduleImport" type="moduleImport"
               substitutionGroup="prologPartOneItem"/>


  <xsd:complexType name="contextItemDecl">
    <xsd:sequence>
      <xsd:element ref="typeDeclaration" minOccurs="0"/>
      <xsd:choice>
        <xsd:element name="varValue" type="exprWrapper"/>
        <xsd:sequence>
          <xsd:element name="external">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="varValue" type="exprWrapper" minOccurs="0"/>
              </xsd:sequence>
            </xsd:complexType>
          </xsd:element>
        </xsd:sequence>
      </xsd:choice>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="contextItemDecl" type="contextItemDecl"
               substitutionGroup="prologPartTwoItem"/>


  <xsd:complexType name="varDecl">
    <xsd:sequence>
      <xsd:element name="varName" type="QName"/>
      <xsd:element ref="typeDeclaration" minOccurs="0"/>
      <xsd:choice>
        <xsd:element name="varValue" type="exprWrapper"/>
        <xsd:sequence>
          <xsd:element name="external">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="varValue" type="exprWrapper" minOccurs="0"/>
              </xsd:sequence>
            </xsd:complexType>
          </xsd:element>
        </xsd:sequence>
      </xsd:choice>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="varDecl" type="varDecl"
               substitutionGroup="prologPartTwoItem"/>


  <xsd:complexType name="optionDecl">
    <xsd:sequence>
      <xsd:element name="optionName" type="QName"/>
      <xsd:element name="optionContents" type="xsd:string"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="optionDecl" type="optionDecl"
               substitutionGroup="prologPartTwoItem"/>


  <xsd:complexType name="functionDecl">
    <xsd:sequence>
      <xsd:element name="functionName" type="QName"/>
      <xsd:element ref="paramList"/>
      <xsd:element ref="typeDeclaration" minOccurs="0"/>
      <xsd:choice>
        <xsd:element name="functionBody" type="exprWrapper"/>
        <xsd:element name="externalDefinition">
          <xsd:complexType>
            <xsd:attribute name="nondeterministic" use="optional"
                           type="xsd:boolean" default="false"/>
          </xsd:complexType>
        </xsd:element>
      </xsd:choice>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="functionDecl" type="functionDecl"
               substitutionGroup="prologPartTwoItem"/>


  <xsd:complexType name="param">
    <xsd:sequence>
      <xsd:element name="varName" type="QName"/>
      <xsd:element ref="typeDeclaration" minOccurs="0"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="param" type="param"/>


  <xsd:complexType name="paramList">
    <xsd:sequence>
      <xsd:element ref="param" minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>

  <xsd:element name="paramList" type="paramList"/>


</xsd:schema>
