The advantages gained from the use of classes to organize the implementation of the parser, making it easier to understand and modify. It is fanly to automate the process of generating parser from BNF style production rules.

• 使用类来组织Parser的实现有很多优点，促使程序易于理解和修改，能方便地实现从BNF生成规则到Parser生成的自动处理。