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saxon-manual-9.4.0.9-2.mga7.noarch.rpm

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Instruction
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net.sf.saxon.expr.instruct</FONT>
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Class Instruction</H2>
<PRE>
<A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">java.lang.Object</A>
  <IMG SRC="../../../../../resources/inherit.gif" ALT="extended by "><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">net.sf.saxon.expr.Expression</A>
      <IMG SRC="../../../../../resources/inherit.gif" ALT="extended by "><B>net.sf.saxon.expr.instruct.Instruction</B>
</PRE>
<DL>
<DT><B>All Implemented Interfaces:</B> <DD><A HREF="http://download.oracle.com/javase/6/docs/api/java/io/Serializable.html?is-external=true" title="class or interface in java.io">Serializable</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A>, <A HREF="../../../../../net/sf/saxon/event/LocationProvider.html" title="interface in net.sf.saxon.event">LocationProvider</A>, <A HREF="../../../../../net/sf/saxon/event/SaxonLocator.html" title="interface in net.sf.saxon.event">SaxonLocator</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/TailCallReturner.html" title="interface in net.sf.saxon.expr.instruct">TailCallReturner</A>, <A HREF="../../../../../net/sf/saxon/trace/InstructionInfo.html" title="interface in net.sf.saxon.trace">InstructionInfo</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/org/xml/sax/Locator.html?is-external=true" title="class or interface in org.xml.sax">Locator</A></DD>
</DL>
<DL>
<DT><B>Direct Known Subclasses:</B> <DD><A HREF="../../../../../net/sf/saxon/expr/instruct/AnalyzeString.html" title="class in net.sf.saxon.expr.instruct">AnalyzeString</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/ApplyImports.html" title="class in net.sf.saxon.expr.instruct">ApplyImports</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/ApplyTemplates.html" title="class in net.sf.saxon.expr.instruct">ApplyTemplates</A>, <A HREF="../../../../../com/saxonica/expr/Assign.html" title="class in com.saxonica.expr">Assign</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/Block.html" title="class in net.sf.saxon.expr.instruct">Block</A>, <A HREF="../../../../../com/saxonica/expr/BreakInstr.html" title="class in com.saxonica.expr">BreakInstr</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/CallTemplate.html" title="class in net.sf.saxon.expr.instruct">CallTemplate</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/Choose.html" title="class in net.sf.saxon.expr.instruct">Choose</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/CopyOf.html" title="class in net.sf.saxon.expr.instruct">CopyOf</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/Doctype.html" title="class in net.sf.saxon.expr.instruct">Doctype</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/ForEach.html" title="class in net.sf.saxon.expr.instruct">ForEach</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/ForEachGroup.html" title="class in net.sf.saxon.expr.instruct">ForEachGroup</A>, <A HREF="../../../../../com/saxonica/expr/IterateInstr.html" title="class in com.saxonica.expr">IterateInstr</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/LocalParamBlock.html" title="class in net.sf.saxon.expr.instruct">LocalParamBlock</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/LocalParamSetter.html" title="class in net.sf.saxon.expr.instruct">LocalParamSetter</A>, <A HREF="../../../../../com/saxonica/xsltextn/MergeInstr.html" title="class in com.saxonica.xsltextn">MergeInstr</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/Message.html" title="class in net.sf.saxon.expr.instruct">Message</A>, <A HREF="../../../../../com/saxonica/expr/NextIteration.html" title="class in com.saxonica.expr">NextIteration</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/ParentNodeConstructor.html" title="class in net.sf.saxon.expr.instruct">ParentNodeConstructor</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/ProcessRegexMatchInstruction.html" title="class in net.sf.saxon.expr.instruct">ProcessRegexMatchInstruction</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/ResultDocument.html" title="class in net.sf.saxon.expr.instruct">ResultDocument</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/SimpleNodeConstructor.html" title="class in net.sf.saxon.expr.instruct">SimpleNodeConstructor</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/TraceExpression.html" title="class in net.sf.saxon.expr.instruct">TraceExpression</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/UseAttributeSets.html" title="class in net.sf.saxon.expr.instruct">UseAttributeSets</A>, <A HREF="../../../../../com/saxonica/expr/While.html" title="class in com.saxonica.expr">While</A></DD>
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<DL>
<DT><PRE>public abstract class <B>Instruction</B><DT>extends <A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A><DT>implements <A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A>, <A HREF="../../../../../net/sf/saxon/expr/instruct/TailCallReturner.html" title="interface in net.sf.saxon.expr.instruct">TailCallReturner</A></DL>
</PRE>

<P>
Abstract superclass for all instructions in the compiled stylesheet.
 This represents a compiled instruction, and as such, the minimum information is
 retained from the original stylesheet. <br>
 Note: this class implements SourceLocator: that is, it can identify where in the stylesheet
 the source instruction was located.
<P>

<P>
<DL>
<DT><B>See Also:</B><DD><A HREF="../../../../../serialized-form.html#net.sf.saxon.expr.instruct.Instruction">Serialized Form</A></DL>
<HR>

<P>
<!-- =========== FIELD SUMMARY =========== -->

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<TH ALIGN="left"><B>Fields inherited from class net.sf.saxon.expr.<A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></B></TH>
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<TD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#EFFECTIVE_BOOLEAN_VALUE">EFFECTIVE_BOOLEAN_VALUE</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#EVALUATE_METHOD">EVALUATE_METHOD</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#EVENT_FEED_METHOD">EVENT_FEED_METHOD</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#ITEM_FEED_METHOD">ITEM_FEED_METHOD</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#ITERATE_METHOD">ITERATE_METHOD</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#locationId">locationId</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#MAX_SEQUENCE_LENGTH">MAX_SEQUENCE_LENGTH</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#MAX_STRING_LENGTH">MAX_STRING_LENGTH</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#PROCESS_METHOD">PROCESS_METHOD</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#PUSH_SELECTION">PUSH_SELECTION</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#staticProperties">staticProperties</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#UNBOUNDED_LOWER">UNBOUNDED_LOWER</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#UNBOUNDED_UPPER">UNBOUNDED_UPPER</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#WATCH_METHOD">WATCH_METHOD</A></CODE></TD>
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<!-- ======== CONSTRUCTOR SUMMARY ======== -->

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<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#Instruction()">Instruction</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Constructor</TD>
</TR>
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&nbsp;
<!-- ========== METHOD SUMMARY =========== -->

<A NAME="method_summary"><!-- --></A>
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<B>Method Summary</B></FONT></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>static&nbsp;<A HREF="../../../../../net/sf/saxon/expr/instruct/ParameterSet.html" title="class in net.sf.saxon.expr.instruct">ParameterSet</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#assembleParams(net.sf.saxon.expr.XPathContext, net.sf.saxon.expr.instruct.WithParam[])">assembleParams</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context,
               <A HREF="../../../../../net/sf/saxon/expr/instruct/WithParam.html" title="class in net.sf.saxon.expr.instruct">WithParam</A>[]&nbsp;actualParams)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Assemble a ParameterSet.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>static&nbsp;<A HREF="../../../../../net/sf/saxon/expr/instruct/ParameterSet.html" title="class in net.sf.saxon.expr.instruct">ParameterSet</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#assembleTunnelParams(net.sf.saxon.expr.XPathContext, net.sf.saxon.expr.instruct.WithParam[])">assembleTunnelParams</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context,
                     <A HREF="../../../../../net/sf/saxon/expr/instruct/WithParam.html" title="class in net.sf.saxon.expr.instruct">WithParam</A>[]&nbsp;actualParams)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Assemble a ParameterSet.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#computeCardinality()">computeCardinality</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the cardinality of the sequence returned by evaluating this instruction</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#computeSpecialProperties()">computeSpecialProperties</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the static properties of this expression (other than its type).</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#createsNewNodes()">createsNewNodes</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Determine whether this instruction creates new nodes.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>protected static&nbsp;<A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#dynamicError(javax.xml.transform.SourceLocator, net.sf.saxon.trans.XPathException, net.sf.saxon.expr.XPathContext)">dynamicError</A></B>(<A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A>&nbsp;loc,
             <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A>&nbsp;error,
             <A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Construct an exception with diagnostic information.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/CharSequence.html?is-external=true" title="class or interface in java.lang">CharSequence</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#evaluateAsString(net.sf.saxon.expr.XPathContext)">evaluateAsString</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Evaluate an expression as a String.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#evaluateItem(net.sf.saxon.expr.XPathContext)">evaluateItem</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Evaluate an expression as a single item.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getConstructType()">getConstructType</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the type of this expression for use in tracing and diagnostics</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getExpressionName()">getExpressionName</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get a name identifying the kind of expression, in terms meaningful to a user.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getImplementationMethod()">getImplementationMethod</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getInstructionName()">getInstructionName</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get a name identifying the kind of instruction, in terms meaningful to a user.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getInstructionNameCode()">getInstructionNameCode</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the namecode of the instruction for use in diagnostics</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../../../../net/sf/saxon/type/ItemType.html" title="interface in net.sf.saxon.type">ItemType</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getItemType(net.sf.saxon.type.TypeHierarchy)">getItemType</A></B>(<A HREF="../../../../../net/sf/saxon/type/TypeHierarchy.html" title="class in net.sf.saxon.type">TypeHierarchy</A>&nbsp;th)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the item type of the items returned by evaluating this instruction</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>protected &nbsp;<A HREF="../../../../../net/sf/saxon/om/SequenceIterator.html" title="interface in net.sf.saxon.om">SequenceIterator</A>&lt;? extends <A HREF="../../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A>&gt;</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getIteratorFromProcessMethod(net.sf.saxon.expr.XPathContext)">getIteratorFromProcessMethod</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Helper method to construct an iterator over the results of the expression when all that
 the expression itself offers is a process() method.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#getSourceLocator()">getSourceLocator</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get a SourceLocator identifying the location of this instruction</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#isXSLT()">isXSLT</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Establish whether this is an XSLT instruction or an XQuery instruction
 (used to produce appropriate diagnostics)</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../../../../net/sf/saxon/om/SequenceIterator.html" title="interface in net.sf.saxon.om">SequenceIterator</A>&lt;? extends <A HREF="../../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A>&gt;</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#iterate(net.sf.saxon.expr.XPathContext)">iterate</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Return an Iterator to iterate over the values of a sequence.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#process(net.sf.saxon.expr.XPathContext)">process</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Process the instruction, without returning any tail calls</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>abstract &nbsp;<A HREF="../../../../../net/sf/saxon/expr/instruct/TailCall.html" title="interface in net.sf.saxon.expr.instruct">TailCall</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#processLeavingTail(net.sf.saxon.expr.XPathContext)">processLeavingTail</A></B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ProcessLeavingTail: called to do the real work of this instruction.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#promote(net.sf.saxon.expr.parser.PromotionOffer, net.sf.saxon.expr.Expression)">promote</A></B>(<A HREF="../../../../../net/sf/saxon/expr/parser/PromotionOffer.html" title="class in net.sf.saxon.expr.parser">PromotionOffer</A>&nbsp;offer,
        <A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>&nbsp;parent)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Offer promotion for this subexpression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>protected &nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#promoteInst(net.sf.saxon.expr.parser.PromotionOffer)">promoteInst</A></B>(<A HREF="../../../../../net/sf/saxon/expr/parser/PromotionOffer.html" title="class in net.sf.saxon.expr.parser">PromotionOffer</A>&nbsp;offer)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Handle promotion offers, that is, non-local tree rewrites.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>abstract &nbsp;<A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../../net/sf/saxon/expr/instruct/Instruction.html#simplify(net.sf.saxon.expr.parser.ExpressionVisitor)">simplify</A></B>(<A HREF="../../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A>&nbsp;visitor)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Simplify an expression.</TD>
</TR>
</TABLE>
&nbsp;<A NAME="methods_inherited_from_class_net.sf.saxon.expr.Expression"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TH ALIGN="left"><B>Methods inherited from class net.sf.saxon.expr.<A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></B></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#addToPathMap(net.sf.saxon.expr.parser.PathMap, net.sf.saxon.expr.parser.PathMap.PathMapNodeSet)">addToPathMap</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#adoptChildExpression(net.sf.saxon.expr.Expression)">adoptChildExpression</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#checkForUpdatingSubexpressions()">checkForUpdatingSubexpressions</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#checkPermittedContents(net.sf.saxon.type.SchemaType, net.sf.saxon.expr.StaticContext, boolean)">checkPermittedContents</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#computeDependencies()">computeDependencies</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#computeStaticProperties()">computeStaticProperties</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#copy()">copy</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#doPromotion(net.sf.saxon.expr.Expression, net.sf.saxon.expr.parser.PromotionOffer)">doPromotion</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#dynamicError(java.lang.String, java.lang.String, net.sf.saxon.expr.XPathContext)">dynamicError</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#effectiveBooleanValue(net.sf.saxon.expr.XPathContext)">effectiveBooleanValue</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#evaluatePendingUpdates(net.sf.saxon.expr.XPathContext, net.sf.saxon.expr.PendingUpdateList)">evaluatePendingUpdates</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#explain(net.sf.saxon.trace.ExpressionPresenter)">explain</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#explain(java.io.OutputStream)">explain</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getCardinality()">getCardinality</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getColumnNumber()">getColumnNumber</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getColumnNumber(long)">getColumnNumber</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getContainer()">getContainer</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getDependencies()">getDependencies</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getEvaluationMethod()">getEvaluationMethod</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getExecutable()">getExecutable</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getHostLanguage()">getHostLanguage</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getIntegerBounds()">getIntegerBounds</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getIntrinsicDependencies()">getIntrinsicDependencies</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getLineNumber()">getLineNumber</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getLineNumber(long)">getLineNumber</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getLocationId()">getLocationId</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getLocationProvider()">getLocationProvider</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getObjectName()">getObjectName</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getProperties()">getProperties</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getProperty(java.lang.String)">getProperty</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getPublicId()">getPublicId</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getSlotsUsed()">getSlotsUsed</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getSpecialProperties()">getSpecialProperties</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getSystemId()">getSystemId</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#getSystemId(long)">getSystemId</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#hasLoopingSubexpression(net.sf.saxon.expr.Expression)">hasLoopingSubexpression</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#hasVariableBinding(net.sf.saxon.expr.Binding)">hasVariableBinding</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#implementsStaticTypeCheck()">implementsStaticTypeCheck</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#isSubtreeExpression()">isSubtreeExpression</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#isUpdatingExpression()">isUpdatingExpression</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#isVacuousExpression()">isVacuousExpression</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#iterateEvents(net.sf.saxon.expr.XPathContext)">iterateEvents</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#iterateSameFocusSubExpressions()">iterateSameFocusSubExpressions</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#iterateSubExpressions()">iterateSubExpressions</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#markTailFunctionCalls(net.sf.saxon.om.StructuredQName, int)">markTailFunctionCalls</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#optimize(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">optimize</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#replaceSubExpression(net.sf.saxon.expr.Expression, net.sf.saxon.expr.Expression)">replaceSubExpression</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#resetLocalStaticProperties()">resetLocalStaticProperties</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#setContainer(net.sf.saxon.expr.Container)">setContainer</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#setEvaluationMethod(int)">setEvaluationMethod</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#setFiltered(boolean)">setFiltered</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#setFlattened(boolean)">setFlattened</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#setLocationId(int)">setLocationId</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#staticTypeCheck(net.sf.saxon.value.SequenceType, boolean, net.sf.saxon.expr.parser.RoleLocator, net.sf.saxon.TypeCheckerEnvironment)">staticTypeCheck</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#suppressValidation(int)">suppressValidation</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#toString()">toString</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#typeCheck(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">typeCheck</A>, <A HREF="../../../../../net/sf/saxon/expr/Expression.html#typeError(java.lang.String, java.lang.String, net.sf.saxon.expr.XPathContext)">typeError</A></CODE></TD>
</TR>
</TABLE>
&nbsp;<A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TH ALIGN="left"><B>Methods inherited from class java.lang.<A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A></B></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#clone()" title="class or interface in java.lang">clone</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#equals(java.lang.Object)" title="class or interface in java.lang">equals</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#finalize()" title="class or interface in java.lang">finalize</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#getClass()" title="class or interface in java.lang">getClass</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#hashCode()" title="class or interface in java.lang">hashCode</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notify()" title="class or interface in java.lang">notify</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notifyAll()" title="class or interface in java.lang">notifyAll</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait()" title="class or interface in java.lang">wait</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long)" title="class or interface in java.lang">wait</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long, int)" title="class or interface in java.lang">wait</A></CODE></TD>
</TR>
</TABLE>
&nbsp;<A NAME="methods_inherited_from_class_javax.xml.transform.SourceLocator"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TH ALIGN="left"><B>Methods inherited from interface javax.xml.transform.<A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A></B></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true#getColumnNumber()" title="class or interface in javax.xml.transform">getColumnNumber</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true#getLineNumber()" title="class or interface in javax.xml.transform">getLineNumber</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true#getPublicId()" title="class or interface in javax.xml.transform">getPublicId</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true#getSystemId()" title="class or interface in javax.xml.transform">getSystemId</A></CODE></TD>
</TR>
</TABLE>
&nbsp;
<P>

<!-- ========= CONSTRUCTOR DETAIL ======== -->

<A NAME="constructor_detail"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
<B>Constructor Detail</B></FONT></TH>
</TR>
</TABLE>

<A NAME="Instruction()"><!-- --></A><H3>
Instruction</H3>
<PRE>
public <B>Instruction</B>()</PRE>
<DL>
<DD>Constructor
<P>
</DL>

<!-- ============ METHOD DETAIL ========== -->

<A NAME="method_detail"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
<B>Method Detail</B></FONT></TH>
</TR>
</TABLE>

<A NAME="getImplementationMethod()"><!-- --></A><H3>
getImplementationMethod</H3>
<PRE>
public int <B>getImplementationMethod</B>()</PRE>
<DL>
<DD>An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
 This method indicates which of these methods is prefered. For instructions this is the process() method.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#getImplementationMethod()">getImplementationMethod</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the implementation method, for example <A HREF="../../../../../net/sf/saxon/expr/Expression.html#ITERATE_METHOD"><CODE>Expression.ITERATE_METHOD</CODE></A> or <A HREF="../../../../../net/sf/saxon/expr/Expression.html#EVALUATE_METHOD"><CODE>Expression.EVALUATE_METHOD</CODE></A> or
 <A HREF="../../../../../net/sf/saxon/expr/Expression.html#PROCESS_METHOD"><CODE>Expression.PROCESS_METHOD</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="getInstructionNameCode()"><!-- --></A><H3>
getInstructionNameCode</H3>
<PRE>
public int <B>getInstructionNameCode</B>()</PRE>
<DL>
<DD>Get the namecode of the instruction for use in diagnostics
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>a code identifying the instruction: typically but not always
 the fingerprint of a name in the XSLT namespace</DL>
</DD>
</DL>
<HR>

<A NAME="getInstructionName()"><!-- --></A><H3>
getInstructionName</H3>
<PRE>
public <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A> <B>getInstructionName</B>()</PRE>
<DL>
<DD>Get a name identifying the kind of instruction, in terms meaningful to a user. This method
 is not used in the case where the instruction name code is a standard name (<1024).
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>a name identifying the kind of instruction, in terms meaningful to a user.
         The name will always be in the form of a lexical XML QName, and should match the name used
         in explain() output displaying the instruction.</DL>
</DD>
</DL>
<HR>

<A NAME="getExpressionName()"><!-- --></A><H3>
getExpressionName</H3>
<PRE>
public <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A> <B>getExpressionName</B>()</PRE>
<DL>
<DD>Get a name identifying the kind of expression, in terms meaningful to a user.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#getExpressionName()">getExpressionName</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>a name identifying the kind of expression, in terms meaningful to a user.
         The name will always be in the form of a lexical XML QName, and should match the name used
         in explain() output displaying the expression.</DL>
</DD>
</DL>
<HR>

<A NAME="getItemType(net.sf.saxon.type.TypeHierarchy)"><!-- --></A><H3>
getItemType</H3>
<PRE>
public <A HREF="../../../../../net/sf/saxon/type/ItemType.html" title="interface in net.sf.saxon.type">ItemType</A> <B>getItemType</B>(<A HREF="../../../../../net/sf/saxon/type/TypeHierarchy.html" title="class in net.sf.saxon.type">TypeHierarchy</A>&nbsp;th)</PRE>
<DL>
<DD>Get the item type of the items returned by evaluating this instruction
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#getItemType(net.sf.saxon.type.TypeHierarchy)">getItemType</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>th</CODE> - the type hierarchy cache
<DT><B>Returns:</B><DD>the static item type of the instruction</DL>
</DD>
</DL>
<HR>

<A NAME="computeCardinality()"><!-- --></A><H3>
computeCardinality</H3>
<PRE>
public int <B>computeCardinality</B>()</PRE>
<DL>
<DD>Get the cardinality of the sequence returned by evaluating this instruction
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#computeCardinality()">computeCardinality</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the static cardinality</DL>
</DD>
</DL>
<HR>

<A NAME="processLeavingTail(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
processLeavingTail</H3>
<PRE>
public abstract <A HREF="../../../../../net/sf/saxon/expr/instruct/TailCall.html" title="interface in net.sf.saxon.expr.instruct">TailCall</A> <B>processLeavingTail</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
                                     throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>ProcessLeavingTail: called to do the real work of this instruction. This method
 must be implemented in each subclass. The results of the instruction are written
 to the current Receiver, which can be obtained via the Controller.
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/instruct/TailCallReturner.html#processLeavingTail(net.sf.saxon.expr.XPathContext)">processLeavingTail</A></CODE> in interface <CODE><A HREF="../../../../../net/sf/saxon/expr/instruct/TailCallReturner.html" title="interface in net.sf.saxon.expr.instruct">TailCallReturner</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - The dynamic context of the transformation, giving access to the current node,
 the current variables, etc.
<DT><B>Returns:</B><DD>null if the instruction has completed execution; or a TailCall indicating
 a function call or template call that is delegated to the caller, to be made after the stack has
 been unwound so as to save stack space.
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if a dynamic error occurs during the evaluation
 of the instruction</DL>
</DD>
</DL>
<HR>

<A NAME="process(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
process</H3>
<PRE>
public void <B>process</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
             throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Process the instruction, without returning any tail calls
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#process(net.sf.saxon.expr.XPathContext)">process</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - The dynamic context, giving access to the current node,
 the current variables, etc.
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if a dynamic error occurs</DL>
</DD>
</DL>
<HR>

<A NAME="getSourceLocator()"><!-- --></A><H3>
getSourceLocator</H3>
<PRE>
public <A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A> <B>getSourceLocator</B>()</PRE>
<DL>
<DD>Get a SourceLocator identifying the location of this instruction
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the location of this instruction in the source stylesheet or query</DL>
</DD>
</DL>
<HR>

<A NAME="dynamicError(javax.xml.transform.SourceLocator, net.sf.saxon.trans.XPathException, net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
dynamicError</H3>
<PRE>
protected static <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A> <B>dynamicError</B>(<A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A>&nbsp;loc,
                                             <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A>&nbsp;error,
                                             <A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</PRE>
<DL>
<DD>Construct an exception with diagnostic information. Note that this method
 returns the exception, it does not throw it: that is up to the caller.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>loc</CODE> - the location of the error<DD><CODE>error</CODE> - The exception containing information about the error<DD><CODE>context</CODE> - The controller of the transformation
<DT><B>Returns:</B><DD>an exception based on the supplied exception, but with location information
 added relating to this instruction</DL>
</DD>
</DL>
<HR>

<A NAME="assembleParams(net.sf.saxon.expr.XPathContext, net.sf.saxon.expr.instruct.WithParam[])"><!-- --></A><H3>
assembleParams</H3>
<PRE>
public static <A HREF="../../../../../net/sf/saxon/expr/instruct/ParameterSet.html" title="class in net.sf.saxon.expr.instruct">ParameterSet</A> <B>assembleParams</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context,
                                          <A HREF="../../../../../net/sf/saxon/expr/instruct/WithParam.html" title="class in net.sf.saxon.expr.instruct">WithParam</A>[]&nbsp;actualParams)
                                   throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Assemble a ParameterSet. Method used by instructions that have xsl:with-param
 children. This method is used for the non-tunnel parameters.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - the XPath dynamic context<DD><CODE>actualParams</CODE> - the set of with-param parameters that specify tunnel="no"
<DT><B>Returns:</B><DD>a ParameterSet
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if an error occurs evaluating one of the
 parameters</DL>
</DD>
</DL>
<HR>

<A NAME="assembleTunnelParams(net.sf.saxon.expr.XPathContext, net.sf.saxon.expr.instruct.WithParam[])"><!-- --></A><H3>
assembleTunnelParams</H3>
<PRE>
public static <A HREF="../../../../../net/sf/saxon/expr/instruct/ParameterSet.html" title="class in net.sf.saxon.expr.instruct">ParameterSet</A> <B>assembleTunnelParams</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context,
                                                <A HREF="../../../../../net/sf/saxon/expr/instruct/WithParam.html" title="class in net.sf.saxon.expr.instruct">WithParam</A>[]&nbsp;actualParams)
                                         throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Assemble a ParameterSet. Method used by instructions that have xsl:with-param
 children. This method is used for the tunnel parameters.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - the XPath dynamic context<DD><CODE>actualParams</CODE> - the set of with-param parameters that specify tunnel="yes"
<DT><B>Returns:</B><DD>a ParameterSet
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if an error occurs evaluating one of the
 tunnel parameters</DL>
</DD>
</DL>
<HR>

<A NAME="simplify(net.sf.saxon.expr.parser.ExpressionVisitor)"><!-- --></A><H3>
simplify</H3>
<PRE>
public abstract <A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> <B>simplify</B>(<A HREF="../../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A>&nbsp;visitor)
                             throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Simplify an expression. This performs any static optimization (by rewriting the expression
 as a different expression). The default implementation does nothing.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#simplify(net.sf.saxon.expr.parser.ExpressionVisitor)">simplify</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>visitor</CODE> - an expression visitor
<DT><B>Returns:</B><DD>the simplified expression
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if an error is discovered during expression
     rewriting</DL>
</DD>
</DL>
<HR>

<A NAME="computeSpecialProperties()"><!-- --></A><H3>
computeSpecialProperties</H3>
<PRE>
public int <B>computeSpecialProperties</B>()</PRE>
<DL>
<DD>Get the static properties of this expression (other than its type). The result is
 bit-signficant. These properties are used for optimizations. In general, if
 property bit is set, it is true, but if it is unset, the value is unknown.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#computeSpecialProperties()">computeSpecialProperties</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>a set of flags indicating static properties of this expression</DL>
</DD>
</DL>
<HR>

<A NAME="createsNewNodes()"><!-- --></A><H3>
createsNewNodes</H3>
<PRE>
public boolean <B>createsNewNodes</B>()</PRE>
<DL>
<DD>Determine whether this instruction creates new nodes.
 This implementation returns a default value of false
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>true if the instruction creates new nodes (or if it can't be proved that it doesn't)</DL>
</DD>
</DL>
<HR>

<A NAME="promoteInst(net.sf.saxon.expr.parser.PromotionOffer)"><!-- --></A><H3>
promoteInst</H3>
<PRE>
protected void <B>promoteInst</B>(<A HREF="../../../../../net/sf/saxon/expr/parser/PromotionOffer.html" title="class in net.sf.saxon.expr.parser">PromotionOffer</A>&nbsp;offer)
                    throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Handle promotion offers, that is, non-local tree rewrites.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>offer</CODE> - The type of rewrite being offered
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if an error occurs</DL>
</DD>
</DL>
<HR>

<A NAME="promote(net.sf.saxon.expr.parser.PromotionOffer, net.sf.saxon.expr.Expression)"><!-- --></A><H3>
promote</H3>
<PRE>
public <A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> <B>promote</B>(<A HREF="../../../../../net/sf/saxon/expr/parser/PromotionOffer.html" title="class in net.sf.saxon.expr.parser">PromotionOffer</A>&nbsp;offer,
                          <A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>&nbsp;parent)
                   throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Offer promotion for this subexpression. The offer will be accepted if the subexpression
 is not dependent on the factors (e.g. the context item) identified in the PromotionOffer.
 This method is always called at compile time.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#promote(net.sf.saxon.expr.parser.PromotionOffer, net.sf.saxon.expr.Expression)">promote</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>offer</CODE> - details of the offer, for example the offer to move
     expressions that don't depend on the context to an outer level in
     the containing expression<DD><CODE>parent</CODE> - the parent of the subexpression
<DT><B>Returns:</B><DD>if the offer is not accepted, return this expression unchanged.
      Otherwise return the result of rewriting the expression to promote
      this subexpression
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if any error is detected</DL>
</DD>
</DL>
<HR>

<A NAME="evaluateItem(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
evaluateItem</H3>
<PRE>
public <A HREF="../../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A> <B>evaluateItem</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
                  throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Evaluate an expression as a single item. This always returns either a single Item or
 null (denoting the empty sequence). No conversion is done. This method should not be
 used unless the static type of the expression is a subtype of "item" or "item?": that is,
 it should not be called if the expression may return a sequence. There is no guarantee that
 this condition will be detected.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#evaluateItem(net.sf.saxon.expr.XPathContext)">evaluateItem</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - The context in which the expression is to be evaluated
<DT><B>Returns:</B><DD>the node or atomic value that results from evaluating the
     expression; or null to indicate that the result is an empty
     sequence
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if any dynamic error occurs evaluating the
     expression</DL>
</DD>
</DL>
<HR>

<A NAME="iterate(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
iterate</H3>
<PRE>
public <A HREF="../../../../../net/sf/saxon/om/SequenceIterator.html" title="interface in net.sf.saxon.om">SequenceIterator</A>&lt;? extends <A HREF="../../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A>&gt; <B>iterate</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
                                         throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Return an Iterator to iterate over the values of a sequence. The value of every
 expression can be regarded as a sequence, so this method is supported for all
 expressions. This default implementation handles iteration for expressions that
 return singleton values: for non-singleton expressions, the subclass must
 provide its own implementation.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#iterate(net.sf.saxon.expr.XPathContext)">iterate</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - supplies the context for evaluation
<DT><B>Returns:</B><DD>a SequenceIterator that can be used to iterate over the result
     of the expression
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if any dynamic error occurs evaluating the
     expression</DL>
</DD>
</DL>
<HR>

<A NAME="getIteratorFromProcessMethod(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
getIteratorFromProcessMethod</H3>
<PRE>
protected final <A HREF="../../../../../net/sf/saxon/om/SequenceIterator.html" title="interface in net.sf.saxon.om">SequenceIterator</A>&lt;? extends <A HREF="../../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A>&gt; <B>getIteratorFromProcessMethod</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
                                                                       throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Helper method to construct an iterator over the results of the expression when all that
 the expression itself offers is a process() method. This builds the entire results of the
 expression as a sequence in memory and then iterates over it.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - the dynamic evaluation context
<DT><B>Returns:</B><DD>an iterator over the results of the expression
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if a dynamic error occurs</DL>
</DD>
</DL>
<HR>

<A NAME="evaluateAsString(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
evaluateAsString</H3>
<PRE>
public final <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/CharSequence.html?is-external=true" title="class or interface in java.lang">CharSequence</A> <B>evaluateAsString</B>(<A HREF="../../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
                                    throws <A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Evaluate an expression as a String. This function must only be called in contexts
 where it is known that the expression will return a single string (or where an empty sequence
 is to be treated as a zero-length string). Implementations should not attempt to convert
 the result to a string, other than converting () to "". This method is used mainly to
 evaluate expressions produced by compiling an attribute value template.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#evaluateAsString(net.sf.saxon.expr.XPathContext)">evaluateAsString</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - The context in which the expression is to be evaluated
<DT><B>Returns:</B><DD>the value of the expression, evaluated in the current context.
     The expression must return a string or (); if the value of the
     expression is (), this method returns "".
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if any dynamic error occurs evaluating the
     expression
<DD><CODE><A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/ClassCastException.html?is-external=true" title="class or interface in java.lang">ClassCastException</A></CODE> - if the result type of the
     expression is not xs:string?</DL>
</DD>
</DL>
<HR>

<A NAME="getConstructType()"><!-- --></A><H3>
getConstructType</H3>
<PRE>
public int <B>getConstructType</B>()</PRE>
<DL>
<DD>Get the type of this expression for use in tracing and diagnostics
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/trace/InstructionInfo.html#getConstructType()">getConstructType</A></CODE> in interface <CODE><A HREF="../../../../../net/sf/saxon/trace/InstructionInfo.html" title="interface in net.sf.saxon.trace">InstructionInfo</A></CODE><DT><B>Overrides:</B><DD><CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html#getConstructType()">getConstructType</A></CODE> in class <CODE><A HREF="../../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the type of expression, as enumerated in class <A HREF="../../../../../net/sf/saxon/trace/Location.html" title="class in net.sf.saxon.trace"><CODE>Location</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="isXSLT()"><!-- --></A><H3>
isXSLT</H3>
<PRE>
public boolean <B>isXSLT</B>()</PRE>
<DL>
<DD>Establish whether this is an XSLT instruction or an XQuery instruction
 (used to produce appropriate diagnostics)
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>true for XSLT, false for XQuery</DL>
</DD>
</DL>
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