This language, Roy, is perhaps not really Haskell (?), but it seems very similar:
http://roy.brianmckenna.org/
Roy seems to be alive; there are many forks in the GitHub repo: https://github.com/pufuwozu/roy
and it seems to be alive: https://github.com/pufuwozu/roy/graphs
If you're using Play Framework 2.0, then there's a plugin, Ray, to run Roy on Play Framework 2.0:
http://brianmckenna.org/blog/ray
https://github.com/pufuwozu/ray
The last commit was four months ago, which is rather long ago keeping in mind that Play Framework 2 was released perhaps 4 or 5 months ago.