说明：  词法分析器制作与应用 .程序中先判断这个句语句中每个单元为关键字、常数、运算符、界符，对与不同的单词符号给出不同编码形式的编码，用以区分之
(Production and application of lexical analyzer. Proceedings to determine whether this sentence statement for each unit keywords, constants, operators, industry icons, with different symbols are given a different word encoding form of coding, to distinguish the)