这些正则表达式可以相互递归地引用，在以前的正则表达式不能进行模式匹配的字符串中进行模式匹配。

These regular expressions can refer to each other recursively, matching patterns in strings that ordinary regular expressions cannot.

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这些正则表达式可以相互递归地引用，在以前的正则表达式不能进行模式匹配的字符串中进行模式匹配。

These regular expressions can refer to each other recursively, matching patterns in strings that ordinary regular expressions cannot.

youdao