Named capture groups in vim regex?

Question

Does vim allow us to assign names to capture groups for search/replace that can be used in place of \1, \2 etc... for back-references and substitution?

Like in in Python:

>>> import re
>>> s="ABCD HELLO, WORLD! 1234"
>>> print(re.sub(r"^(?P<foo>\w+).*?(?P<bar>\d+)$", r"\n\g<foo> \g<bar>\n", s))

ABCD 1234

Or Perl:

dade_murphy@darkstar$ \
> printf "ABCD HELLO, WORLD! 1234" \
>   | perl -pe 's/^(?<foo>\w+).*?(?<bar>\d+)$/\n$+{foo} $+{bar}\n/'

ABCD 1234

ie. something like this:

:s/^\(?P<foo>\w\+\)\s*$/\g<foo>/

Neither syntax seems to work. I'm guessing this is not supported-- it doesn't strike me as a feature that would be particularly sought after in a text editor. But search / Google aren't confirming either way, so here I am.

Answer 1

No, named capture groups are not available.

In fact, some design decisions in Vim actually expose the limit of 9 (numbered) capture groups, such as the matchlist() function, which returns a list of 10 strings for each of \0 through \9. (That doesn't mean named groups would be impossible, it's just exposing some internals showing this is quite an ingrained design decision.)

You can also go through the whole :help pattern-searches and you'll see no reference to named capture groups.

Vim also has some regexp features (namely \zs and \ze to mark the start and end of the match) that can replace the use of capture groups and are often more convenient to use in case you're only using capture groups to repeat them as part of the replacement.

So, in short, no, named capture groups are not available as of Vim 8.1.