通过设计、变形和调试词法分析器（又称扫描器），了解词法分析的组成 结果，不同种类单词的识别方法，掌握由单词的词法规则出发，然后再用程序实现词法分析器的设计方法。-By design, deformation and debugging the lexical analyzer (also known as scanner), to understand the composition of the results of lexical analysis, different types of w