They have broken the regulargrammar rules, and have an active effect in special contexts.
它们突破了正常的语法结构规则，在特定语境中产生积极的表达效果。
2
The paper describes symbolic structure of word of program language with regulargrammar and regular expression, constructs converted-state chart to identify word symbol.
用正规文法和正规表达式描述了程序语言的单词符号的结构，用状态转换图构造了识别单词符号。
3
If you discover or invent some slightly new variant of the language, it is a lot easier to play with the EBNF grammar than with those regular expressions.