Interface CallbackEvaluationI

All Known Implementing Classes:
AbstractInc, Assign, Case, If, LazyLogical, NullLazyLogical, NullWrappedIf, OpEquals, PostDec, PostInc, PreDec, PreInc, Switch, SwitchDefault

public interface CallbackEvaluationI

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

Rich Morris Created on 18-Nov-2003

Nested Class Summary
static interface CallbackEvaluationI.Runnable
          Callback functions which have a working run(stack) method.
Method Summary
 java.lang.Object evaluate(Node node, Evaluator pv)
          Performs some special evaluation on the node.

Method Detail


java.lang.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
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.

node - The current node
pv - The visitor, can be used evaluate the children
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>
See Also:

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