src/main/java/ognl/OgnlContext.java
public void pushEvaluation(Evaluation value)
    {
        if (_currentEvaluation != null) {
            _currentEvaluation.addChild(value);
        } else {
            setRootEvaluation(value);
        }
        setCurrentEvaluation(value);
    }
public void pushEvaluation(Evaluation value)
    {
        if (_currentEvaluation != null) {
            _currentEvaluation.addChild(value);
        } else {
            setRootEvaluation(value);
        }
        setCurrentEvaluation(value);
    }
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>.