Interesting; I've never had to think about how regex interact with Unicode. I guess what I really meant is that programmers are talking about PCRE in terms of

Interesting; I've never had to think about how regex interact with Unicode. I guess what I really meant is that programmers are talking about PCRE in terms of power, not in terms of exact syntax. In particular, they have recursive patterns, which are sufficient to pull them up to context-free grammars.