Sittampalam, Ganesh wrote:
We've discussed replacing it with transformers+monads-fd+an mtl compatiblity layer on libraries@. Ross and I plan to propose doing this for the second release of the platform - it's not fair to disrupt the first release at this stage.
transformers+monads-fd is quite a small evolution over mtl - it factors out the fundeps into a separate package, tightens up some of the class constraints, and makes State = StateT Identity etc rather than a separate type. Even this breaks a few packages, but doing anything more substantial would be quite disruptive. That's not to say that we shouldn't do it, though.
For those of us wishing to target applications to the Haskell platform (e.g. our software works on Haskell Platform 2009.2, 2009.8, etc) will there be an easy way to determine which Haskell platform is currently installed so that we can accommodate any such incompatible changes? E.g. if Haskell platform = 2009.2 then use libraries mtl, parsec and #define HP_VERSION 200902, if Haskell platform = 2009.8 then use libraries transformers+monads-fd, parsec-compatibility, and #define HP_VERSION 200908. Or am I looking at things the wrong way, and we should instead just use autoconf-like tests for individual libraries, regardless of the platform (if they have mtl, use mtl and #define USE_MTL, otherwise try transformers+monads-fd, otherwise error)? Thanks, Neil.