cmake 文档中是使用了什么语言描述 cmake 语言

[gainsurier]

https://cmake.org/cmake/help/latest/manual/cmake-language.7.html

最开始的 file 描述
file ::= file_element*
file_element ::= command_invocation line_ending |
(bracket_comment|space)* line_ending
line_ending ::= line_comment? newline
space ::= <match '[ \t]+'>
newline ::= <match '\n'>

有点像上下文无关文法加上正则表达式

找到了，是巴科斯范式(Backus – Naur form)