Am Dienstag, 23. März 2004 12:31 schrieben Sie: > Op zo 21-03-2004, om 18:54 schreef Wolfgang Jeltsch: > > Hello, > > > > I'm trying to use GHC's deriving mechanism for newtypes in the following > > way: class C a b > > instance C [a] Char > > newtype T = T Char deriving C [a] > > Unfortunately, this isn't possible. Is there a reason for this? Can I > > circumvent this restriction? > > You can use the deriving mechanism for user-defined class such as the > class C above. > (see http://www.haskell.org/onlinereport/decls.html#derived-decls)
Since you refer to The Haskell Report, I think that you wanted to say: "You can *not* use the deriving mechanism..." But you *can* use it if you use -fglasgow-exts. I was refering to GHC's extension concerning deriving and newtypes. > [...] > Instead of the deriving construct, you could use the tool > DrIFT (http://repetae.net/john/computer/haskell/DrIFT/) I don't want to have a tool involved. > [...] > Greetings Arjan Wolfgang _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell