I'll condense my remaining replies to this thread into a single message, to save people a little noise. Henning Thielemann:
I guess there will also be some lines about how to write efficient code by using ByteString et. al.?
You bet!
What about a public darcs repository where people can constantly download and review modifications? People could even send patches to the authors (editors?).
We'll certainly consider those possibilities. I don't know how our publisher will feel about them, but they've been great so far. Alfonso Acosta:
Existential types are a must [...]
Yes, we'll be sure to cover existentials. Thanks for the nudge (and ndm, and others too). Hans van Thiel:
Compared to Erlang. While other functional languages are mentioned occoasionally on this list, Erlang is notably absent.
I'm reluctant to do comparisons with other languages; that's too easy to interpret as evangelism, a game I don't want to play. It also invites the plaintive cry that someone's favourite language was dissed through omission.
Number two on my wish list: interfacing with Java.
The temptation to cover new and exciting material is of course strong. LambdaVM is both, but it's also an in-progress one-person master's project. We think we'd do best to focus on libraries and extensions that are either distributed as standard or widely used.
How about 'Applying Haskell' or something like that as the working title; what is the 'real world' anyway?
The details may vary, but it's roughly this:
newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #))
:-)