PL/0 语言的编译程序的一个部件，词法分析器。读入由PL/0语言编写的源代码，识别其中的关键字、标志符、数字，转换成程序可识别的中间符号并输出，包含词法错误检测-PL/0 compiler language of a component, lexical analyzer. Read entry from the PL/0 language source code, to identify one of the keywords, identifier, number, convert the program can be identified between symbols and output, including lexical error detection