[IshKebab]

Yeah the Pomsky one is already way better because you can easily see that &# are literal characters, not some weird regex thing you've forgotten about.

That's one of the biggest issues with regex - mixing up data and control.

But I would still expect a robust codebase to have a proper number parser if you want to parse this sort of thing.

[nerdponx]

What is regex but shorthand notation for a parser?

I agree that a good codebase should generally have its regex segregated into standalone functions with their own tests (ideally property-based tests!).