Class EagerLetExpression

  extended by net.sf.saxon.expr.Expression
      extended by net.sf.saxon.expr.Assignation
          extended by net.sf.saxon.expr.LetExpression
              extended by net.sf.saxon.expr.EagerLetExpression
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, Binding, EvaluableItem, TailCallReturner, SequenceIterable, InstructionInfo, Locator

public class EagerLetExpression
extends LetExpression

An EagerLetExpression is the same as a LetExpression except that the variable is evaluated using eager evaluation rather than lazy evaluation. This is used when performing diagnostic tracing.

See Also:
Serialized Form

Field Summary
Fields inherited from class net.sf.saxon.expr.Assignation
action, requiredType, sequence, slotNumber, variableName
Fields inherited from class net.sf.saxon.expr.Expression
Constructor Summary
Method Summary
 Expression optimize(ExpressionVisitor visitor, ItemType contextItemType)
          Perform optimisation of an expression and its subexpressions.
Methods inherited from class net.sf.saxon.expr.LetExpression
checkPermittedContents, computeCardinality, computeSpecialProperties, copy, effectiveBooleanValue, eval, evaluateItem, evaluatePendingUpdates, explain, getExpressionName, getItemType, implementsStaticTypeCheck, isVacuousExpression, iterate, iterateEvents, markTailFunctionCalls, process, processLeavingTail, promote, staticTypeCheck, toString, typeCheck
Methods inherited from class net.sf.saxon.expr.Assignation
addReference, addToPathMap, checkForUpdatingSubexpressions, evaluateVariable, extendBindingList, getAction, getLocalSlotNumber, getNominalReferenceCount, getObjectName, getRequiredSlots, getRequiredType, getSequence, getVariableName, getVariableQName, isAssignable, isGlobal, isIndexedVariable, isUpdatingExpression, iterateSubExpressions, promoteWhereClause, refineTypeInformation, replaceSubExpression, replaceVariable, setAction, setIndexedVariable, setRequiredType, setSequence, setSlotNumber, setVariableQName, simplify, suppressValidation
Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, computeDependencies, computeStaticProperties, doPromotion, dynamicError, evaluateAsString, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, isSubtreeExpression, iterateSameFocusSubExpressions, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, typeError
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail


public EagerLetExpression()
Method Detail


public Expression optimize(ExpressionVisitor visitor,
                           ItemType contextItemType)
                    throws XPathException
Description copied from class: LetExpression
Perform optimisation of an expression and its subexpressions.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

optimize in class LetExpression
visitor - an expression visitor
contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
the original expression, rewritten if appropriate to optimize execution
XPathException - if an error is discovered during this phase (typically a type error)

Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.