I don't see the problem here. The regex itself is exactly the same, it's just that different languages have different string literal syntaxes (and some have dedicated regex syntax, thus solving the problem of double-escaping).

The only regex engine where this is a problem is Vim's, because there are characters that a special unless escaped, and characters that are normal but become special when escaped. And as if that wasn't enough, there are config options to determine which characters those are. My usual practice is to prefix all Vim regexes with \v so that all the special characters are at least consistent.