///<summary>
/// Pushes a new Evaluation onto the stack. This is done
/// before a node evaluates. When evaluation is complete
/// it should be popped from the stack via <code>popEvaluation()</code>.
///</summary>
public void pushEvaluation(Evaluation value)
{
if (currentEvaluation != null)
{
currentEvaluation.addChild(value);
}
else
{
setRootEvaluation(value);
}
setCurrentEvaluation(value);
}
