public void addExpressions(ArrayList<ASTNode> nodes) {
      for (int i = 0; i < nodes.size(); i++) {
        OrderExpression expr = new OrderExpression();
        expr.setExpression(nodes.get(i));
        addExpression(expr);
      }
    }
Add order expressions from the list of expressions in the format of ASTNode
@param nodes
ql/src/java/org/apache/hadoop/hive/ql/parse/PTFInvocationSpec.java