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java.lang.Object | +--net.sf.saxon.expr.ComputedExpression | +--net.sf.saxon.expr.Assignation | +--net.sf.saxon.expr.LetExpression
A LetExpression is modelled on the XQuery syntax let $x := expr return expr. This syntax is not available in the surface XPath language, but it is used internally in an optimized expression tree.
Field Summary |
Fields inherited from class net.sf.saxon.expr.Assignation |
action, declaration, sequence, slotNumber, variableName |
Fields inherited from class net.sf.saxon.expr.ComputedExpression |
lineNumber, NO_ARGUMENTS, staticProperties |
Constructor Summary | |
LetExpression()
|
Method Summary | |
Expression |
analyze(StaticContext env)
Type-check the expression |
int |
computeCardinality()
Determine the static cardinality of the expression |
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type). |
void |
display(int level,
NamePool pool)
Diagnostic print of expression structure |
Item |
evaluateItem(XPathContext context)
Evaluate the expression as a singleton |
ItemType |
getItemType()
Determine the data type of the items returned by the expression, if possible |
SequenceType |
getRequiredType()
Get data type of the range variable (part of the Binding interface) |
SequenceIterator |
iterate(XPathContext context)
Iterate over the sequence of values |
boolean |
markTailFunctionCalls()
Mark tail function calls |
void |
process(XPathContext context)
Process this expression as an instruction, writing results to the current outputter |
TailCall |
processLeavingTail(XPathContext context)
Process the instruction, optionally returning an uncompleted tail call to be invoked by the caller |
Expression |
promote(PromotionOffer offer)
Promote this expression if possible |
Methods inherited from class net.sf.saxon.expr.Assignation |
evaluateVariable, getSubExpressions, getVariableName, setAction, setSequence, setSlotNumber, setVariableDeclaration, simplify |
Methods inherited from class net.sf.saxon.expr.ComputedExpression |
computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSourceLocator, getSpecialProperties, setLineNumber, typeError |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface net.sf.saxon.instruct.Locatable |
getSourceLocator |
Constructor Detail |
public LetExpression()
Method Detail |
public Expression analyze(StaticContext env) throws XPathException
analyze
in interface Expression
env
- the static context of the expression
XPathException
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface Expression
iterate
in class ComputedExpression
context
- supplies the context for evaluation
XPathException
- if any dynamic error occurs evaluating the
expressionpublic Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in interface Expression
evaluateItem
in class ComputedExpression
context
- The context in which the expression is to be evaluated
XPathException
- if any dynamic error occurs evaluating the
expressionpublic void process(XPathContext context) throws javax.xml.transform.TransformerException
process
in interface Instr
context
- The dynamic context, giving access to the current node,
the current variables, etc.
javax.xml.transform.TransformerException
public TailCall processLeavingTail(XPathContext context) throws javax.xml.transform.TransformerException
processLeavingTail
in interface Instr
context
- The dynamic context, giving access to the current node,
the current variables, etc.
javax.xml.transform.TransformerException
public ItemType getItemType()
getItemType
in interface Expression
public SequenceType getRequiredType()
getRequiredType
in class Assignation
public int computeCardinality()
computeCardinality
in class ComputedExpression
public int computeSpecialProperties()
computeSpecialProperties
in class ComputedExpression
public boolean markTailFunctionCalls()
markTailFunctionCalls
in class ComputedExpression
public Expression promote(PromotionOffer offer) throws XPathException
promote
in interface Expression
promote
in class Assignation
offer
- 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
XPathException
- if any error is detectedpublic void display(int level, NamePool pool)
display
in interface Expression
level
- indentation level for this expression
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