net.sf.saxon.expr
Class EagerLetExpression

java.lang.Object
  extended bynet.sf.saxon.expr.ComputedExpression
      extended bynet.sf.saxon.expr.Assignation
          extended bynet.sf.saxon.expr.LetExpression
              extended bynet.sf.saxon.expr.EagerLetExpression
All Implemented Interfaces:
Binding, Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator, TailCallReturner

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, declaration, nameCode, sequence, slotNumber, variableName
 
Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
 
Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
 
Constructor Summary
EagerLetExpression()
           
 
Method Summary
 Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
          Perform optimisation of an expression and its subexpressions.
 
Methods inherited from class net.sf.saxon.expr.LetExpression
checkPermittedContents, computeCardinality, computeSpecialProperties, display, eval, evaluateItem, getItemType, iterate, markTailFunctionCalls, process, processLeavingTail, promote, setIndexedVariable, typeCheck
 
Methods inherited from class net.sf.saxon.expr.Assignation
evaluateVariable, extendBindingList, getAction, getLocalSlotNumber, getRequiredSlots, getSequence, getVariableDeclaration, getVariableFingerprint, getVariableName, getVariableNameCode, isAssignable, isGlobal, iterateSubExpressions, promoteWhereClause, replaceSubExpression, setAction, setSequence, setSlotNumber, setVariableDeclaration, simplify, suppressValidation
 
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, typeError
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

EagerLetExpression

public EagerLetExpression()
Method Detail

optimize

public Expression optimize(Optimizer opt,
                           StaticContext env,
                           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.

Specified by:
optimize in interface Expression
Overrides:
optimize in class LetExpression
Parameters:
opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
env - the static context of the expression
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
Returns:
the original expression, rewritten if appropriate to optimize execution
Throws:
XPathException