lexer

基本解释

Whenever possible, try to develop separate tests for your lexer and your parser.
只要有可能，请尝试为您的 lexer 和解析器开发单独的测试。
It uses start states -- a feature allowing the lexer to match some rules only some of the time.
它使用了 start 声明 —— 这项功能使 lexer 能够只在一些时候去匹配某些规则。
For lexing purposes, this means that the lexer definition of an integer number, for example, can be used to build the lexer definition of a real number and a fraction.
例如，对于词法分析目的而言，这意味着可以用整数的词法分析器定义来构建实数和分数的词法分析器定义。