CMake：如何获取反斜杠文字在Regexp中替换？ [英] CMake: how to get the backslash literal in Regexp replace?

问题描述

我尝试用反斜线替换正斜杠。为了做到这一点，我有以下代码行：

  STRING（REGEX REPLACE/\\\ \\SourceGroup $ {SourceGroupPath}）
  

SourceGroupPath = A / File /
SourceGroup是将结果设置为的变量。

我遇到的问题是，代码的\\部分。
我尝试了几种方法来使用反斜杠文字像\\
和使用unicode，但没有什么似乎工作。

CMake错误在CMakeLists.txt：41
（STRING）命令REGEX，
mode REPLACE：replace-expression以反斜杠结尾
。

感谢，

Wouter

解决方案

原因是在CMake字符串文字中，反斜杠是一个转义字符（就像在C，Java或JavaScript中），在regex中，反斜杠是一个转义字符井。

因此，要将正则表达式表示为字符串字面值，需要双重转义。 （这就是为什么许多较高级别语言具有正则表达式符号，BTW。）

字符串文字 \\\表示内存中字符串\，这是一个无效的正则表达式，因此结束于反斜杠错误。

字符串文字\\\\代表\\ \\\在内存中，这是一个有效的正则表达式（表示单个反斜杠）。

I am trying to replace forwardslashes with backslashes. To do that i have the following line of code:

STRING(REGEX REPLACE "/" "\\" SourceGroup ${SourceGroupPath} )

SourceGroupPath = A/File/Path. SourceGroup is the variable to set the result to.

The problem i am having is with, the "\\" part to the code. I have tried several ways to getting to use the backslash literal like "\\" and using unicode but nothing seems to work.

The error i get in CMake is:

CMake Error at CMakeLists.txt:41 (STRING): string sub-command REGEX, mode REPLACE: replace-expression ends in a backslash.

Can someone please help me out?

Thanks,

Wouter

解决方案

The reason is that in a CMake string literal, the backslash is an escape character (just like in C, Java or JavaScript) and in regex, the backslash is an escape character as well.

So to represent a regex as a string literal, you need double escaping. (That's why many "higher level" languages have regex literal notation, BTW.)

The string literal "\\" represents the in-memory string "\" and that's an invalid regex, hence the "ends in a backslash" error.

The string literal "\\\\" represents "\\" in memory which is a valid regex (representing a single backslash).

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