编写C ++正则表达式以匹配#include预处理指令 [英] Write c++ regular expression to match a #include preprocessing directive

问题描述

我想用c ++写一个正则表达式来匹配#include预处理指令.所以我写了这个:

I want to write a regular expression in c++ to match a #include preprocessing directive. So I wrote this:

std::regex includePattern("^[[:blank:]|[:space:]]*#[[:blank:]|[:space:]]*include[[:blank:]|[:space:]]+[<|\"]{1}[_[:alpha:]]+[_[:alnum:]]*");

这适用于:

std::string matchString = "#include <vector>";

但仅匹配字符串的一部分，但不包括结尾的>"，但是如果我将正则表达式更改为此:

But only matches parts of the string excluded the trailing ">", but if I change the regex to this:

std::regex includePattern("^[[:blank:]|[:space:]]*#[[:blank:]|[:space:]]*include[[:blank:]|[:space:]]+[<|\"]{1}[_[:alpha:]]+[_[:alnum:]]*[>|\"]{1}");

它只是不会给我想要的结果，只是告诉我未找到"！有什么问题吗?

It just won't give me the desired result, just tell me "not found" ! Is there anything wrong?

有人可以帮我用c ++编写一个准确的正则表达式来匹配#include预处理指令吗?

Can anybody help me to write an accurate regular expression in c++ to match a #include preprocessing directive?

提前谢谢！

推荐答案

这取决于要匹配的输入是否包含新的线? [[:: space:]] 将匹配任何空格，包括新的空格行， [[[:blank:]] 将匹配除换行以外的任何空白(而且我不确定该标准是否支持该功能).反正，像这样:

It depends on whether the input to be matched may contain new lines? [[:space:]] will match any white space, including new lines, [[:blank:]] will match any white space except new lines (and I'm not sure it is supported by the standard). Anyway, something like:

"^\\s*#\\s*include\\s+[<\"][^>\"]*[>\"]\\s*"

应该可以解决问题，但是...

should do the trick, but...

• 如果您的来源中有不应该包含的新行，则仍然可能匹配.

• If your source has new lines where it shouldn't, it still might match.

如果您的来源转义了新行，请在令牌 include 或文件名，它将不匹配.(这是合法的C ++，但没有人愿意这样做.)

If your source has escaped new lines, say in the middle of the token include or the file name, it won't match. (This is legal C++, but no one in their right mind would do it.)

如果您的源中的分隔符不匹配，请在一端加上一个"，以及另一个< 或< ，它们仍然会匹配.

If your source has mismatched delimiters, a " at one end, and a < or a < at the other, it will still match.

并且它不处理行尾的注释.处理方式C ++样式注释(//)只需添加即可(?? .. *)?" 到表达式的末尾.处理C风格评论(特别是因为可以有多个评论)要多一些

And it doesn't handle comments at the end of line. Handling C++ style comments (//) should only be a matter of adding "(?://.*)?" to the end of the expression. Handling C style comments (particularly since there can be several) is a bit more complicated.

为确保定界符匹配，您可能需要输入包含在或之后的所有内容:

To ensure that the delimiters match, you'd probably have to put everything after the include in an or:

"^\\s*#\\s*include\\s+(?:<[^>]*>|\"[^\"]*\")\\s*"

同样，您需要添加到末尾以处理评论.

Again, you'd need to add to the end to handle comments.

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