TXPathVariableNode.Evaluate function

Member of TXPathVariableNodepublicIn unit Laz2_XPath

Evaluates the XPath expression.

Declaration

pascal

function Evaluate(AContext: TXPathContext; 
 AEnvironment: TXPathEnvironment): TXPathVariable
 ; override

Arguments

`AContext`	Context node for the function.
`AEnvironment`	XPath environment for the evaluation.

Function result

Result for the evaluated expression.

Description

Evaluate is an overridden method used to evaluate the XPath expression and return its derived value. Evaluate implements the abstract method defined in the ancestor class.

For TXPathVariableNode, Evaluate uses the XPath environment passed in the AEnvironment argument to retrieve the value for the variable. If a variable is not found with the required name in the XPath environment, the EvaluationError method is called to raise an exception with the message in lrsEvalUnknownVariable.

Errors

Raises an exception (in EvaluationError) when the variable name does not exist in the XPath environment. Raised with the exception message in lrsEvalUnknownVariable.