On Mon, 2008-11-10 at 10:09 +0100, Johannes Waldmann wrote:
Hello.
Should I migrate from parsec-2 to parsec-3? Why? And if yes, then how?
I don't think there is any need to do so unless you need the extra features. The parsec-3 package is a somewhat experimental generalisation to a monad transformer that can be layered on top of other monadic input layers with state, effects etc. It has not yet had much optimisation and the performance for [Char] is reported to be slower. On the other hand it can now work with bytestring input or lexers which gives the potential for improved performance.
The hackage description (of version 3) says "it's well documented ... on the home page", but when I go there, I find docs for version 2 only.
The api is mostly compatible for parsers that stick to the Char subset and do not use the parsec-2 state feature.
If I'm still using parsec-2 for teaching, will this harm my students?
No. GHC and the Haskell Platform will ship with parsec-2 until such a time as the community decides (via this mailing list) that we should all switch. The people proposing that change will have to make a convincing argument. Duncan