net.sf.saxon.expr
Class Assignation

java.lang.Object
  net.sf.saxon.expr.ComputedExpression
      net.sf.saxon.expr.Assignation

All Implemented Interfaces:

Binding, Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator

Direct Known Subclasses:

ForExpression, LetExpression

public abstract class Assignation

extends ComputedExpression

implements Binding

Assignation is an abstract superclass for the kinds of expression that declare range variables: for, some, and every.

See Also:

Serialized Form

Field Summary

protected Expression	action
protected RangeVariableDeclaration	declaration
protected int	nameCode
protected Expression	sequence
protected int	slotNumber
protected java.lang.String	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

Assignation()

Method Summary

ValueRepresentation	evaluateVariable(XPathContext context) Get the value of the range variable
protected Binding[]	extendBindingList(Binding[] in) Extend an array of variable bindings to include the binding(s) defined in this expression
Expression	getAction() Get the action expression
int	getLocalSlotNumber() If this is a local variable held on the local stack frame, return the corresponding slot number.
int	getRequiredSlots() Get the number of slots required.
RangeVariableDeclaration	getVariableDeclaration() Get the variable declaration
int	getVariableFingerprint()
java.lang.String	getVariableName(NamePool pool) Get the display name of the range variable, for diagnostics only
int	getVariableNameCode()
boolean	isAssignable() Test whether it is permitted to assign to the variable using the saxon:assign extension element.
boolean	isGlobal() Indicate whether the binding is local or global.
java.util.Iterator	iterateSubExpressions() Get the immediate subexpressions of this expression
Expression	promote(PromotionOffer offer) Promote this expression if possible
protected Expression	promoteWhereClause(Binding positionBinding) Promote a WHERE clause whose condition doesn't depend on the variable being bound.
void	setAction(Expression action) Add the "return" or "satisfies" expression, and fix up all references to the range variable that occur within that expression
void	setSequence(Expression sequence) Set the "sequence" expression - the one to which the variable is bound
void	setSlotNumber(int nr) Set the slot number for the range variable
void	setVariableDeclaration(RangeVariableDeclaration decl) Set the reference to the variable declaration
Expression	simplify(StaticContext env) Simplify the expression
void	suppressValidation(int validationMode) Suppress validation on contained element constructors, on the grounds that the parent element is already performing validation.

Methods inherited from class net.sf.saxon.expr.ComputedExpression

adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, typeError, 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.expr.Expression

display, getItemType, optimize, typeCheck

Field Detail

slotNumber

protected int slotNumber

sequence

protected Expression sequence

action

protected Expression action

variableName

protected java.lang.String variableName

nameCode

protected int nameCode

declaration

protected transient RangeVariableDeclaration declaration

Constructor Detail

Assignation

public Assignation()

Method Detail

setVariableDeclaration

public void setVariableDeclaration(RangeVariableDeclaration decl)

Set the reference to the variable declaration

getVariableDeclaration

public RangeVariableDeclaration getVariableDeclaration()

Get the variable declaration

setAction

public void setAction(Expression action)

Add the "return" or "satisfies" expression, and fix up all references to the range variable that occur within that expression

Parameters:

action - the expression that occurs after the "return" keyword of a "for" expression, the "satisfies" keyword of "some/every", or the ":=" operator of a "let" expression.

This method must be called after calling setVariableDeclaration()

isGlobal

public final boolean isGlobal()

Indicate whether the binding is local or global. A global binding is one that has a fixed value for the life of a query or transformation; any other binding is local.

Specified by:

isGlobal in interface Binding

isAssignable

public final boolean isAssignable()

Test whether it is permitted to assign to the variable using the saxon:assign extension element. This will only be for an XSLT global variable where the extra attribute saxon:assignable="yes" is present.

Specified by:

isAssignable in interface Binding

getLocalSlotNumber

public int getLocalSlotNumber()

If this is a local variable held on the local stack frame, return the corresponding slot number. In other cases, return -1.

Specified by:

getLocalSlotNumber in interface Binding

getAction

public Expression getAction()

Get the action expression

setSequence

public void setSequence(Expression sequence)

Set the "sequence" expression - the one to which the variable is bound

setSlotNumber

public void setSlotNumber(int nr)

Set the slot number for the range variable

getRequiredSlots

public int getRequiredSlots()

Get the number of slots required. Normally 1, except for a FOR expression with an AT clause, where it is 2.

simplify

public Expression simplify(StaticContext env)
                    throws XPathException

Simplify the expression

Specified by:

simplify in interface Expression

Overrides:

simplify in class ComputedExpression

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

promote

public Expression promote(PromotionOffer offer)
                   throws XPathException

Promote this expression if possible

Specified by:

promote in interface Expression

Overrides:

promote in class ComputedExpression

Parameters:

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

Returns:

if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression

Throws:

XPathException - if any error is detected

suppressValidation

public void suppressValidation(int validationMode)

Suppress validation on contained element constructors, on the grounds that the parent element is already performing validation. The default implementation does nothing.

Overrides:

suppressValidation in class ComputedExpression

extendBindingList

protected Binding[] extendBindingList(Binding[] in)

Extend an array of variable bindings to include the binding(s) defined in this expression

promoteWhereClause

protected Expression promoteWhereClause(Binding positionBinding)

Promote a WHERE clause whose condition doesn't depend on the variable being bound. This rewrites an expression of the form

let $i := SEQ return if (C) then R else ()

to the form:

if (C) then (let $i := SEQ return R) else ()

iterateSubExpressions

public java.util.Iterator iterateSubExpressions()

Get the immediate subexpressions of this expression

Specified by:

iterateSubExpressions in interface Expression

Overrides:

iterateSubExpressions in class ComputedExpression

Returns:

an iterator containing the sub-expressions of this expression

getVariableNameCode

public int getVariableNameCode()

getVariableFingerprint

public int getVariableFingerprint()

getVariableName

public java.lang.String getVariableName(NamePool pool)

Get the display name of the range variable, for diagnostics only

evaluateVariable

public ValueRepresentation evaluateVariable(XPathContext context)
                                     throws XPathException

Get the value of the range variable

Specified by:

evaluateVariable in interface Binding

Throws:

XPathException