编写一个词法器，让你输入的代码有合适的标号如：if标号为1，a标号为2，；标号为3 <,>标号为4.等等。-The preparation of a lexical, and let you enter the code a suitable label such as: if labeling for 1, a label for 2 labeling 3 <,> grade 4. And so on.