On Sun, Feb 9, 2014 at 6:14 AM, Daniil Frumin
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.
The great bulk of those packages accompany regex-base. They provide "backends" which you then use through the pcre-base interface. pcre-base has a heavily overloaded interface. It's novel, but I think understanding what it is really doing is not at all straightforward. This is exemplified by the chapter about regular expressions in Real World Haskell, which dismisses explaining what one of the functions does with "As a result, the type signature of the (=~) operator is difficult to understand, so we will not explain it here." http://book.realworldhaskell.org/read/efficient-file-processing-regular-expr... For something easier to understand, I recommend pcre-light. Its types are straightforward.