如何在CMake中使用正则表达式的{n}语法 [英] How to use the {n} syntax of regex with CMake

问题描述

我有此字符串 2017-03-05-02-10-10_78205，我想将其与该模式匹配 [0-9] {4}（-[0-9] {2}）{5} _ [0-9] + ，但在CMake上不起作用。在CMake中查看此示例：

I have this string "2017-03-05-02-10-10_78205" and I want to match it with this pattern [0-9]{4}(-[0-9]{2}){5}_[0-9]+ but it doesn't work on CMake. See this example in CMake :

set(stuff "2017-03-05-02-10-10_78205")
if( "${stuff}" MATCHES "[0-9]{4}(-[0-9]{2}){5}_[0-9]+")
  message("Hello")
endif()

CMake似乎不支持语法 {n} 。显然，我使用该模式 [0-9-] + _ [0-9] +

CMake doesn't seem to support the syntax {n}. Obviously, I solved my problem with that pattern [0-9-]+_[0-9]+

不过，我想知道语法 {n} 是否做错了。 CMake支持吗？如果不是，如何使用CMake定义特定的重复次数？

Nevertheless, I would like to know if I'm doing something wrong with the syntax {n}. Is it supported by CMake ? If not, how to define a specific number of repetition with CMake ?

我正在使用旧的CMake版本（2.8.11.2）。

I'm using an old CMake version (2.8.11.2).

推荐答案

我们可以通过使用Shell命令和 execute_process 解决此问题。
例如，在Linux上使用 echo 和 grep ：

We can get around this problem by using shell commands and execute_process. For instance, with echo and grep on linux :

set(stuff "2017-03-05-02-10-10_78205")
set(regexp "[0-9]{4}(-[0-9]{2}){5}_[0-9]+")
execute_process( COMMAND echo "${stuff}"
                 COMMAND grep -E -o "${regexp}"
                 OUTPUT_VARIABLE thing )
if(thing)
  message("Hello")
endif()

但是我们放弃了CMake的跨平台方面。

But we loose the cross-platform aspect of CMake.

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