On Sun, Jun 21, 2009 at 09:16:12PM +0100, Andrew Coppin wrote: > Niklas Broberg wrote: >> That's what GADTs are for: >> >> data Flag = HasZoo | NoZoo >> >> data Foobar a where >> Foo :: Foobar a -> Foobar a >> Bar :: Foobar a -> Foobar a >> Zoo :: Foobar a -> Foobar HasZoo >> > > Ouch #1: This appears to instantly disable deriving the Eq, Ord and Show > instances I want. :-/
Ah, yes, that is a pain. Maybe try playing around with tools like Data.Derive? I haven't played with them much myself so I don't know if they will help. -Brent _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
