词法分析是编译程序的第一个处理阶段，可以通过两种途径来构造词法分析程序。其一是根据对语言中各类单词的某种描述或定义（如BNF），用手工的方式构造词法分析程序。例如，可根据文法或状态转换图构造相应的状态矩阵，该状态矩阵同控制程序便组成了编译程序的词法分析程序；-Lexical analysis is a compiler of the first processing stage, can be two ways to construct the lexical analysis process. One is based on the language to describe certain types of word or definition (such as the BNF), constructed by hand the way lexical analysis program. For example, according to the grammar or the state transition diagram corresponding state matrix structure, the state matrix with the control program will be composed of a compiler lexical analysis procedures