Solving that issue isn't trivial. I just read it and I wouldn't know where to begin, probably because I don't understand the requirements.
I think what's being called "trivial" is doing a bit of regex searching. It's probably accurate to call that trivial for an experienced Rust programmer, but if you're just beginning, I don't think it's helpful to call anything trivial. I still remember my first exposure to Rust. It was different. It took a bit to grok. But once it clicked, things were much better.
As the maintainer of the regex crate, I invite you or anyone to ask for help using regexes. The regex repo has Discussions opened up, so it's appropriate to ask for help, even if they are beginner questions: https://github.com/rust-lang/regex/discussions
As usual though, try to provide as many details as you can. Giving the source code you have but can't get to work is a great start, for example.
Looking at their current iteration of the code, the problem is not in the regex crate's API, but rather on them not having the ownership system internalized yet.
> the problem is not in the regex crate's API, but rather on them not having the ownership system internalized yet
Yes, I figured that to be the case, but still wanted to say, "Discussions are open for questions, even if they are beginner related, as long as it's related to regex'ing somehow." :-)
I wrote code recently to parse a file with regexes and generate rust code from it. It's get-the-job-done code, not super clean, but you might find it useful.
But what you really want is to get your head around ownership and borrowing, especially when it comes to the scoped RAII that rust has (e.g. freeing a String while a reference to it still exists and is being used would give you the "temporary value dropped while borrowed" error).
Just lol at the idea that you won't run into borrow checker issues when dealing with strings though.