[Koha] Regex backreferences and MARC modification templates in 3.14

[Jason Sherman]

Hi all,

I'm pretty pumped about the marc mod templates, but I have one question.
 Has anyone been able to use regex backreferences?  Or more broadly, is
anyone using the mod templates to concatenate values?

I'm trying to prepend a value to a subfield, but when I look at the
modified marc in the staged records list, I keep getting a literal instead
of a backreference.

Lets say subfield contains the following:
some-old-value

If I run a move or copy action against it using regex, I would expect the
following expression:
s/(.+)/some-new-value--$1/

to result in the following output:
some-new-value--some-old-value

instead, I get:
some-new-value--$1

Note:
I've also tried using other capture group notation (\1 \g1) instead of the
dollar sign and I still get a literal.

Thanks!

-- 
Jason Sherman
Systems Librarian
University of Science and Arts of Oklahoma
405.574.1340