@Override
    public Object getChild( Object parent, int index )
    {
    	if(parent instanceof ReadContext)
    		return ((ReadContext)parent).getChild(1);
    	if(parent instanceof PrintContext)
    		return ((PrintContext)parent).getChild(1);
        if(parent instanceof ParseTree)
            return ((ParseTree)parent).getChild( index );
        return null;
    }