Class LocalParam

All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, Binding, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfo, Locator

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.

See Also:
  • Constructor Details

    • LocalParam

      public LocalParam()
  • Method Details

    • 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.
    • 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 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 containing the sub-expressions of this 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
      Specified by:
      processLeavingTail in interface TailCallReturner
      Specified by:
      processLeavingTail in class Instruction
      Parameters:
      context - 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
    • 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 expression presenter used to display the structure