[Haskell-cafe] Type classes... popular for newbies, isn't it?
guhaarju at grinnell.edu
Sat Aug 7 02:15:08 EDT 2004
I'd rather not do that, but even if I did, the type-variable action
would not be reachable in the terminal function. I could specify a
functional dependency st -> action (though I've never used it, it would
be a fun to learn). I'm curious as to why my class declaration
compiles in GHC, as there doesn't seem to be any way to use it.
On Aug 7, 2004, at 01:06, camarao at dcc.ufmg.br wrote:
> Hi Arjun.
> How about inserting one more parameter, "action", in your class
> class (Ord st) => MinimaxState st action where
> successors:: st -> [(action,st)]
> terminal:: st -> Bool
> instance MinimaxState Int Int where
> terminal i = i == 0
> successors i = [(1,i+1), (-1,i-1)]
> Then don't forget to start the compiler/interpreter with
> Hope this helps.
More information about the Haskell-Cafe