WhileNode.java

import java.util.List;
import java.util.LinkedList;

public class WhileNode extends Node
{
    public Node condition;
    public Node body;
    
    public WhileNode() {}
    
    public WhileNode(Node condition, Node body)
    {
        this.condition = condition;
        this.body = body;
    }
    
    public Object eval()
    {
        Object ret = null;        
        while ( ((Boolean) condition.eval()).booleanValue() )
        {            
            ret = body.eval();
        }                       
        return ret;
    }    
}