LaTeX3 Regex using control sequence

Question

I'd like replace some words/characters using l3regex on a arbitrary variable.

Instead of doing this

\tl_set:Nn \l_myname_tl {Hello}
\regex_replace_all:nnN {(\w+)} {\1 World!} \l_myname_tl

which works, I'd like to do something like that

\def\myname{tmpname}
\cs_new_protected:cpn { l_\myname _tl } {Hello}
\regex_replace_all:nnN {(\w+)} {\1 World!} \use:c {l_\myname _tl}

I've an error saying I've an extra parenthesis }. I'm not very familiar with LaTeX3 but If I understand well, the problem comes from the \use:c {l_myname _tl} not considered as an single token (no braced) as expected by :nnN.

What is the way of doing that ?

Thanks in advance.

Answer 1

You can define a variant:

\cs_generate_variant:Nn \regex_replace_all:nnN { nnc }

so you can call

\tl_set:cn { l_ \myname _tl } {Hello}
\regex_replace_all:nnc {(\w+)} {\1 World!} {l_ \myname _tl}