How does {m}{n} (“exactly n times” twice) work?

Question

So, some way or another (playing around), I found myself with a regex like \\d{1}{2}.

Logically, to me, it should mean:

(A digit exac

Answer 1

IEEE-Standard 1003.1 says:

The behavior of multiple adjacent duplication symbols ( '*' and intervals) produces undefined results.

So every implementation can do as it pleases, just don't rely on anything specific...