Re: [Regex] \r matching \n

John Maddock via Boost <[email protected]>
Newsgroups gmane.comp.lib.boost.devel
Message-ID <[email protected]>
On 20/03/2026 07:29, Olaf van der Spek via Boost wrote:
> Hi,
>
> In this regex the \n matches \r. How is this defined / controlled? Is
> there a way to only match \n?
>
>      std::string s = "[*] A\rB\n";
>      s = boost::regex_replace(s, boost::regex(R"(\[\*\](.+?)(\n|$))"),
> "<li>\\1</li>");
>      std::println("{}", js_encode(s)); // <li> A</li>\rB\n

\n is a regular expression meaning "Match any newline character", which 
happens to include \r and a few other things as well.  If you want to 
match a literal '\n' then you need to escape it and the appropriate 
regular expression string is therefore R"\\n"

HTH, John.

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