C++11 Regex Capture Groups By Name

Question

I am converting my boost-based regular expressions to C++11 regex. I have a capture group called url:

\s*?=\s*?(("(?<url>.*?)")|('?<url>.*?)'))

With boost, if you had an smatch you could call match.str("url") to get the capture group by name. With std::smatch, I am only seeing indexed sub-matches.

How can I get access to the url capture using the std::smatch class?

Solution

You cannot name a capture group with the c++11 standard. C++11 regex conforms to the ECMAScript syntax. Here is a link that explains it all http://www.cplusplus.com/reference/regex/ECMAScript/. Even though this maybe disappointing if you think about it a true regular expression will not support this it is extra.

Comments

[HamZa]

Have you tried (?P<url>.*?) instead of (?<url>.*?) ?

[Travis Parks]

@HamZa I am not sure if C++11 regex supports named capture groups. I just read the entire chapter dedicated to the topic in Stroustrup's new "The C++ Programming Language" and it doesn't even mention it. And many of the online references don't seem to indicate otherwise.

[HamZa]

It seems it doesn't support named groups according to this answer.

[Travis Parks]

Can you post an example extracting a nested group? Perhaps where the match can be on either side of a pipe?

[Travis Parks]

I basically want to see how to efficiently extract my url based on my posted example, updated to not rely on named capture groups.

[Dilawar]

This makes me sad!