实现LEX。读入正规式文件，将各个正规式转换成NFA，再由NFA转化成DFA，然后最小化DFA，根据最小化后的DFA生成Scanner的代码，识别符合每个正规式定义的词法构成的单词。-Achieve LEX. Read the formal style file will be converted into various formal ceremony NFA, then by the NFA into a DFA, then minimized DFA, generate code base