[Haskell-cafe] Package for regular expressions

Hi, everyone! Due to the recent discussions discussions about regex- packages on libraries@ and cafe, as well as due to the unicode bug in darcs that Erik Kow and I have stumbled upon I wanted to ask the Haskell community the following: What is up with the regular expression packages? Which one is the go-to package? There are really a bunch of them around (regex-compat, regex-tdfa, regex-posicx, regex-compat-tdfa,, ..) and it's not obvious at all what is the difference between them and which one should I use. Any advice or comments are appreciated. Sincerely yours, -- Daniil Frumin