通过设计编制调试一个具体的词法分析程序，加深对词法分析原理的理解。并掌握在对程序设计语言源程序进行扫描过程中将其分解为各类单词的词法分析方法。(Through the design of the preparation, debugging a specific lexical analysis procedures, deepen the understanding of the principles of lexical analysis. And grasp in the programming language source program scanning process will be decomposed into various words lexical analysis method.)