net.sf.saxon.expr.flwor
Class LetClause

java.lang.Object
  net.sf.saxon.expr.flwor.Clause
      net.sf.saxon.expr.flwor.LetClause

public class LetClause
extends Clause

A "let" clause in a FLWOR expression

Field Summary

Fields inherited from class net.sf.saxon.expr.flwor.Clause

COUNT, FOR, GROUPBYCLAUSE, LET, ORDERBYCLAUSE, WHERE, WINDOW

Constructor Summary

LetClause()

Method Summary

LetClause	copy()
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
void	gatherVariableReferences(ExpressionVisitor visitor, Binding binding, List<VariableReference> references) Build a list of all references to a variables declared in this clause
int	getClauseKey() Get a keyword identifying what kind of clause this is
TuplePull	getPullStream(TuplePull base, XPathContext context) Get a tuple stream that implements the functionality of this clause, taking its input from another tuple stream which this clause modifies
TuplePush	getPushStream(TuplePush destination, XPathContext context) Get a push-mode tuple stream that implements the functionality of this clause, supplying its output to another tuple stream
LocalVariableBinding	getRangeVariable()
LocalVariableBinding[]	getRangeVariables() Get the number of variables bound by this clause
Expression	getSequence()
void	processSubExpressions(ExpressionProcessor processor) Process the subexpressions of this clause
void	refineVariableType(ExpressionVisitor visitor, List<VariableReference> references, Expression returnExpr) Supply improved type information to the expressions that contain references to the variables declared in this clause
void	refineVariableType(ItemType type, int cardinality, Value constantValue, int properties, ExpressionVisitor visitor) Provide additional information about the type of the variable, typically derived by analyzing the initializer of the variable binding
void	setRangeVariable(LocalVariableBinding binding)
void	setSequence(Expression sequence)
String	toString()
void	typeCheck(ExpressionVisitor visitor) Type-check the expression

Methods inherited from class net.sf.saxon.expr.flwor.Clause

optimize

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LetClause

public LetClause()

Method Detail

getClauseKey

public int getClauseKey()

Description copied from class: Clause

Get a keyword identifying what kind of clause this is

Specified by:

getClauseKey in class Clause

Returns:

the kind of clause

copy

public LetClause copy()

Specified by:

copy in class Clause

setSequence

public void setSequence(Expression sequence)

getSequence

public Expression getSequence()

setRangeVariable

public void setRangeVariable(LocalVariableBinding binding)

getRangeVariable

public LocalVariableBinding getRangeVariable()

getRangeVariables

public LocalVariableBinding[] getRangeVariables()

Get the number of variables bound by this clause

Overrides:

getRangeVariables in class Clause

Returns:

the number of variable bindings

getPullStream

public TuplePull getPullStream(TuplePull base,
                               XPathContext context)

Get a tuple stream that implements the functionality of this clause, taking its input from another tuple stream which this clause modifies

Specified by:

getPullStream in class Clause

Parameters:

base - the input tuple stream

context -

Returns:

the output tuple stream

getPushStream

public TuplePush getPushStream(TuplePush destination,
                               XPathContext context)

Get a push-mode tuple stream that implements the functionality of this clause, supplying its output to another tuple stream

Specified by:

getPushStream in class Clause

Parameters:

destination - the output tuple stream

context -

Returns:

the push tuple stream that implements the functionality of this clause of the FLWOR expression

processSubExpressions

public void processSubExpressions(ExpressionProcessor processor)
                           throws XPathException

Process the subexpressions of this clause

Specified by:

processSubExpressions in class Clause

Parameters:

processor - the expression processor used to process the subexpressions

Throws:

XPathException - if any error is detected

typeCheck

public void typeCheck(ExpressionVisitor visitor)
               throws XPathException

Type-check the expression

Overrides:

typeCheck in class Clause

Parameters:

visitor - the ExpressionVisitor, providing access to static context information

Throws:

XPathException - if any error is detected

gatherVariableReferences

public void gatherVariableReferences(ExpressionVisitor visitor,
                                     Binding binding,
                                     List<VariableReference> references)

Description copied from class: Clause

Build a list of all references to a variables declared in this clause

Overrides:

gatherVariableReferences in class Clause

Parameters:

visitor - the expression visitor

binding - a variable declared in this clause

references - the list of variable references, initially empty, to which the method will append

refineVariableType

public void refineVariableType(ExpressionVisitor visitor,
                               List<VariableReference> references,
                               Expression returnExpr)

Description copied from class: Clause

Supply improved type information to the expressions that contain references to the variables declared in this clause

Overrides:

refineVariableType in class Clause

Parameters:

visitor - the expression visitor

references - the list of variable references

returnExpr - the expression in the return clause

refineVariableType

public void refineVariableType(ItemType type,
                               int cardinality,
                               Value constantValue,
                               int properties,
                               ExpressionVisitor visitor)

Provide additional information about the type of the variable, typically derived by analyzing the initializer of the variable binding

Parameters:

type - the item type of the variable

cardinality - the cardinality of the variable

constantValue - the actual value of the variable, if this is known statically, otherwise null

properties - additional static properties of the variable's initializer

visitor - an ExpressionVisitor

explain

public void explain(ExpressionPresenter out)

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

explain in class Clause

Parameters:

out - the expression presenter used to display the structure

toString

public String toString()

Overrides:

toString in class Object