Class Assign
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.instruct.Instruction
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- com.saxonica.xsltextn.instruct.Assign
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- All Implemented Interfaces:
BindingReference,ExportAgent,TailCallReturner,Locatable,IdentityComparable,Traceable
public class Assign extends Instruction implements BindingReference
Compiled instruction deriving from saxon:assign element in stylesheet.The saxon:assign element has mandatory attribute name and optional attribute expr. It also allows xsl:extension-element-prefixes etc.
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Field Summary
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Fields inherited from class net.sf.saxon.expr.Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD
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Constructor Summary
Constructors Constructor Description Assign(Expression select)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Expressioncopy(RebindingMap rebindings)Copy an expression.voidexport(ExpressionPresenter out)Diagnostic print of expression structure.voidfixup(Binding binding)Fix up this binding reference to a bindingintgetInstructionNameCode()Get the name of this instruction for diagnostic and tracing purposesintgetIntrinsicDependencies()Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.ExpressiongetSelectExpr()java.lang.Iterable<Operand>operands()Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.TailCallprocessLeavingTail(Outputter output, XPathContext context)ProcessLeavingTail: called to do the real work of this instruction.voidsetSelectExpr(Expression select)voidsetStaticType(SequenceType type, GroundedValue constantValue, int properties)Fix up the static type of this variable reference; optionally, supply a constant value for the variable.ExpressiontypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)Perform type checking of an expression and its subexpressions.-
Methods inherited from class net.sf.saxon.expr.instruct.Instruction
alwaysCreatesNewNodes, assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getExpressionName, getImplementationMethod, getItemType, getNetCost, getSourceLocator, isInstruction, isXSLT, iterate, mayCreateNewNodes, process, someOperandCreatesNewNodes
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeHashCode, computeStaticProperties, dynamicError, effectiveBooleanValue, equals, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getStreamerName, getTracingTag, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operandSparseList, optimize, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeCheckChildren, typeError, unordered, verifyParentPointers
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface net.sf.saxon.trace.Traceable
gatherProperties
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Constructor Detail
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Assign
public Assign(Expression select)
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Method Detail
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setStaticType
public void setStaticType(SequenceType type, GroundedValue constantValue, int properties)
Description copied from interface:BindingReferenceFix up the static type of this variable reference; optionally, supply a constant value for the variable. Also supplies other static properties of the expression to which the variable is bound, for example whether it is an ordered node-set.- Specified by:
setStaticTypein interfaceBindingReference- Parameters:
type- The static type of the variable reference, typically either the declared type of the variable, or the static type of the expression to which the variable is boundconstantValue- if non-null, indicates that the value of the variable is known at compile time, and supplies the valueproperties- static properties of the expression to which the variable is bound
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setSelectExpr
public void setSelectExpr(Expression select)
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getSelectExpr
public Expression getSelectExpr()
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operands
public java.lang.Iterable<Operand> operands()
Description copied from class:ExpressionGet the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.
- Specified by:
operandsin classInstruction- Returns:
- an iterator containing the sub-expressions of this expression
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fixup
public void fixup(Binding binding)
Description copied from interface:BindingReferenceFix up this binding reference to a binding- Specified by:
fixupin interfaceBindingReference- Parameters:
binding- the Binding to which the variable refers
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
Description copied from class:ExpressionPerform type checking of an expression and its subexpressions. This is the second phase of static optimization.This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.
- Overrides:
typeCheckin classExpression- Parameters:
visitor- an expression visitorcontextInfo- Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException- if an error is discovered during this phase (typically a type error)
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getIntrinsicDependencies
public int getIntrinsicDependencies()
Description copied from class:ExpressionDetermine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".- Overrides:
getIntrinsicDependenciesin classExpression- Returns:
- a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
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copy
public Expression copy(RebindingMap rebindings)
Copy an expression. This makes a deep copy.- Specified by:
copyin classExpression- Parameters:
rebindings- variables that need to be re-bound- Returns:
- the copy of the original expression
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getInstructionNameCode
public int getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes- Overrides:
getInstructionNameCodein classInstruction- Returns:
- a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace
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processLeavingTail
public TailCall processLeavingTail(Outputter output, XPathContext context) throws XPathException
Description copied from class:InstructionProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.- Specified by:
processLeavingTailin interfaceTailCallReturner- Specified by:
processLeavingTailin classInstruction- Parameters:
output- the destination for the resultcontext- The dynamic context of the transformation, giving access to the current node, the current variables, etc.- Returns:
- null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.
- Throws:
XPathException- if a dynamic error occurs during the evaluation of the instruction
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export
public void export(ExpressionPresenter out) throws XPathException
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
exportin interfaceExportAgent- Specified by:
exportin classExpression- Parameters:
out- the expression presenter used to display the structure- Throws:
XPathException- if the export fails, for example if an expression is found that won't work in the target environment.
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