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## net.sf.saxon.expr.instruct
Class LocalParam

    java.lang.Object
      net.sf.saxon.expr.instruct.GeneralVariable
          net.sf.saxon.expr.instruct.LocalParam

All Implemented Interfaces:
  SourceLocator, Binding

    public final class LocalParam

extends GeneralVariable

The compiled form of an xsl:param element within a template in an XSLT stylesheet.

The xsl:param element in XSLT has mandatory attribute name and optional attribute select. It can also be specified as required="yes" or required="no".

This is used only for parameters to XSLT templates. For function calls, the caller of the function places supplied arguments onto the callee's stackframe and the callee does not need to do anything. Global parameters (XQuery external variables) are handled using `GlobalParam`.

The LocalParam class is also used to represent parameters with the saxon:iterate instruction

Field Summary

Fields inherited from class net.sf.saxon.expr.instruct.GeneralVariable
`evaluationMode, referenceCount, slotNumber, variableQName`

Constructor Summary
`LocalParam()`

Method Summary
`ValueRepresentation` | `evaluateVariable(XPathContext c)` Evaluate the variable
`void` | `explain(ExpressionPresenter out)` Diagnostic print of expression structure.
`Expression` | `getConversion()` Get the conversion expression
`int` | `getConversionEvaluationMode()`
`int` | `getInstructionNameCode()` Get the name of this instruction for diagnostic and tracing purposes
`IntegerValue[]` | `getIntegerBoundsForVariable()` If the variable is bound to an integer, get the minimum and maximum possible values.
`int` | `getParameterId()` Get the parameter id, which is essentially an alias for the parameter name, unique within a stylesheet
`Iterator<Expression>` | `iterateSubExpressions()` Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)
`TailCall` | `processLeavingTail(XPathContext context)` Process the local parameter declaration
`boolean` | `replaceSubExpression(Expression original, Expression replacement)` Replace one subexpression by a replacement subexpression
`void` | `setConversion(Expression convertor)` Define a conversion that is to be applied to the supplied parameter value.
`void` | `setParameterId(int id)` Allocate a number which is essentially an alias for the parameter name, unique within a stylesheet

Methods inherited from class net.sf.saxon.expr.instruct.GeneralVariable
`addReference, checkAgainstRequiredType, computeEvaluationMode, copy, getCardinality, getColumnNumber, getContainer, getEvaluationMode, getExecutable, getLineNumber, getLocalSlotNumber, getLocationId, getLocationProvider, getPublicId, getRequiredType, getSelectExpression, getSelectValue, getSlotNumber, getSystemId, getSystemId, getVariableQName, init, isAssignable, isGlobal, isImplicitlyRequiredParam, isRequiredParam, isTunnelParam, optimize, setAssignable, setContainer, setImplicitlyRequiredParam, setLocationId, setReferenceCount, setRequiredParam, setRequiredType, setSelectExpression, setSlotNumber, setTunnel, setVariableQName, simplify, typeCheck`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### LocalParam

    public LocalParam()

Method Detail

### setParameterId

    public void setParameterId(int id)

  Allocate a number which is essentially an alias for the parameter name, unique within a stylesheet

  Parameters:
    `id` - the parameter id

### getParameterId

    public int getParameterId()

  Get the parameter id, which is essentially an alias for the parameter name, unique within a stylesheet

  Returns:
    the parameter id

### setConversion

    public void setConversion(Expression convertor)

  Define a conversion that is to be applied to the supplied parameter value.

  Parameters:
    `convertor` - The expression to be applied. This performs type checking, and the basic conversions implied by function calling rules, for example numeric promotion, atomization, and conversion of untyped atomic values to a required type. The conversion uses the actual parameter value as input, referencing it using a VariableReference. The argument can be null to indicate that no conversion is required.

### getConversion

    public Expression getConversion()

  Get the conversion expression

  Returns:
    the expression used to convert the value to the required type, or null if there is none

### getConversionEvaluationMode

    public int getConversionEvaluationMode()

### getInstructionNameCode

    public int getInstructionNameCode()

  Get the name of this instruction for diagnostic and tracing purposes

  Overrides:
    `getInstructionNameCode` in class `GeneralVariable`
  Returns:
    the name of this instruction, as a name pool name code

### iterateSubExpressions

    public Iterator<Expression> iterateSubExpressions()

  Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)

  Overrides:
    `iterateSubExpressions` in class `GeneralVariable`
  Returns:
    an iterator over all the contained expressions (in practice, the select expression)

### replaceSubExpression

    public boolean replaceSubExpression(Expression original,
                                        Expression replacement)

  Replace one subexpression by a replacement subexpression

  Overrides:
    `replaceSubExpression` in class `GeneralVariable`
  Parameters:
    `original` - the original subexpression
    `replacement` - the replacement subexpression
  Returns:
    true if the original subexpression is found

### processLeavingTail

    public TailCall processLeavingTail(XPathContext context)
                                throws XPathException

  Process the local parameter declaration

  Parameters:
    `context` - the dynamic context
  Returns:
    either null if processing is complete, or a tailcall if one is left outstanding
  Throws:
    `XPathException` - if a dynamic error occurs in the evaluation

### getIntegerBoundsForVariable

    public IntegerValue[] getIntegerBoundsForVariable()

  If the variable is bound to an integer, get the minimum and maximum possible values. Return null if unknown or not applicable

  Specified by:
    `getIntegerBoundsForVariable` in interface `Binding`
  Overrides:
    `getIntegerBoundsForVariable` in class `GeneralVariable`
  Returns:
    a pair of integers containing the minimum and maximum values for the integer value; or null if the value is not an integer or the range is unknown

### evaluateVariable

    public ValueRepresentation evaluateVariable(XPathContext c)

  Evaluate the variable

  Parameters:
    `c` - the XPath dynamic evaluation context
  Returns:
    the result of evaluating the variable

### explain

    public void explain(ExpressionPresenter out)

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

  Overrides:
    `explain` in class `GeneralVariable`
  Parameters:
    `out` - the object used to present the output

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Copyright (c) 2004-2011 Saxonica Limited. All rights reserved.