--- /dev/null
+-- !!! Deriving Show/Read for type with labelled fields.
+-- (based on a Hugs bug report.)
+module Main(main) where
+
+data Options =
+ Options { s :: OptionKind }
+ deriving (Show, Read)
+
+data OptionKind =
+ SpecialOptions { test :: Int }
+ deriving (Show, Read)
+
+x = Options{s=SpecialOptions{test=42}}
+
+main = do
+ print x
+ print ((read (show x))::Options)
--- /dev/null
+-- !!! Deriving Show/Read for nullary constructors.
+module Main(main) where
+
+data A = B | C deriving ( Show, Read )
+
+data Opt = N | Y A deriving (Show, Read)
+
+x = Y B
+
+{-
+ If the Haskell report's specification of how Show instances
+ are to be derived is followed to the letter, the code for
+ a nullary constructor would put parens around the constructor
+ when (showsPrec 10) is used. This would cause
+
+ Y A
+
+ to be showed as
+
+ Y (A)
+
+ Overkill, so ghc's derived Show code treats nullary
+ constructors specially.
+-}
+
+main = do
+ print x
+ print ((read (show x))::Opt)
+ print ((read "Y (B)")::Opt)
+