通过手工构造词法分析器，理解词法分析的过程原理，从而更好的理解编译原理。

通过构造过程中代码的编写，锻炼自己动手解决问题的能力和编程能力。

-Lexical analyzer constructed by hand, understanding the process of lexical analysis principles in order to better understand the compiler theory. Through the process of preparation of the code structure, to exercise their own hands and programming problem solving skills.