[klyrs]

Gotta agree with the sibling comments here. The performance difference is definitely smaller than it used to be, but there's still good reasons to keep compiled regexes in a module scope.

Caveat: I write libraries, not "production" code; my requirements are significantly more strict. One thing I can't do is make assumptions about where my code will run. If you're using my library, and you compile a whole bunch of regexes, they'll evict my regexes from the cache. I don't want the performance of my library to suffer, so I'll keep them in the module scope.