Package com.singularsys.jep.functions

# Interface CallbackEvaluationI

All Known Implementing Classes:
  `AbstractInc`, `AlternateFunctions`, `Assign`, `Case`, `If`, `LazyLogical`, `ModifiedParserTest.BadFun`, `NullWrappedAbstractInc`, `NullWrappedIf`, `NullWrappedLazyLogical`, `OpEquals`, `OverloadedFunctionByStructure`, `PostDec`, `PostInc`, `PreDec`, `PreInc`, `Switch`, `SwitchDefault`, `TernaryConditional`, `ThreadSafeAssign`

public interface CallbackEvaluationI
Functions which require greater control over their evaluation should implement this interface.

Since Jep 4.0 this interface should not be used with `UnaryFunction`, `BinaryFunction`, `NaryFunction`, `NaryBinaryFunction`, or `NullaryFunction` the `eval()` of those classes will be called rather than the `evaluate(Node, Evaluator)`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Object`
  `evaluate(Node node, Evaluator pv)`
  Performs some special evaluation on the node.

- ## Method Details

  - ### evaluate

    Object evaluate(Node node, Evaluator pv) throws EvaluationException
    Performs some special evaluation on the node. This method has the responsibility for evaluating the children of the node, and it should generally call

         pv.eval(node.jjtGetChild(i))

    for each child. The SymbolTable is not passed as an argument. This is because it is better practice to get and set variable values by using node.getVar().setValue() rather that through the SymbolTable with requires a hashtable lookup.
    Parameters:
      `node` - The current node
      `pv` - The visitor, can be used evaluate the children
    Returns:
      the value after evaluation. This value will be passed to other functions higher up the node tree. The value can be any type including Double or Vector<Object>
    Throws:
      `EvaluationException` - if the calculation cannot be performed
    See Also:
      - `Evaluator`