How about: *Main> fromJValue (JBool True) :: Either JSONError Bool Right True *Main>
Doaitse On 26 jul 2010, at 15:16, Angel de Vicente wrote: > data JValue = JString String > | JNumber Double > | JBool Bool > | JNull > | JObject [(String, JValue)] > | JArray [JValue] > deriving (Eq, Ord, Show) > > type JSONError = String > > class JSON a where > toJValue :: a -> JValue > fromJValue :: JValue -> Either JSONError a > > instance JSON JValue where > toJValue = id > fromJValue = Right > > instance JSON Bool where > toJValue = JBool > fromJValue (JBool b) = Right b > fromJValue _ = Left "not a JSON boolean" _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
