[Haskell-cafe] Hello and help request

[enrico.santoemma at tin.it]

Hello to everyone :)
My name is Enrico, 40, and I write software for the industry at Beta 80
Group.

After this short introduction, here is the help request:
I'm managing the rewrite of an application, to port it to the 'classic'
Java three-tiers architecture.
Before I begin to feed the team, I want to see a fully functional prototype
of the problem. I mean the app's functions, not the graphic. What I imagine
is a data base of types and groups of functions. The idea is to study the
problem, inject new functions while checking their coerence with the existing
type infrastructure, and so on.

In plain Java, I'd have wrote the Business Idea in informal language, extracted
the types from it, assigned methods to types and then glued things together
in some way.
In Haskell I (should) have the opportunity to stay on the problem, decomposing
it into sub-problems until I come to the soil.
What I ask to this list is if and where Haskell is different from the object
oriented way to decompose the problem.

I'm very fresh on Haskell. Exactly... chapter 13 of SOE :)
Are type classes different from Java classes? I think so, but I guess this
means that one should ask different things to type classes, respect to what
is being asked to Java classes.
It is this difference that's unclear to me.

Any help would be very appreciated
Enrico