import Data.Int
import qualified Data.List as List
-import Data.Monoid
import Data.Typeable
{-
-}
#if __GLASGOW_HASKELL__
+import Text.Read (Lexeme(Ident), lexP, parens, prec, readPrec)
import Data.Generics.Basics
import Data.Generics.Instances
#endif
-- tentative implementation. See if more efficient exists.
{--------------------------------------------------------------------
- Monoid
---------------------------------------------------------------------}
-
-instance Monoid IntSet where
- mempty = empty
- mappend = union
- mconcat = unions
-
-{--------------------------------------------------------------------
Show
--------------------------------------------------------------------}
instance Show IntSet where
- showsPrec d s = showSet (toList s)
+ showsPrec p xs = showParen (p > 10) $
+ showString "fromList " . shows (toList xs)
showSet :: [Int] -> ShowS
showSet []
showTail (x:xs) = showChar ',' . shows x . showTail xs
{--------------------------------------------------------------------
+ Read
+--------------------------------------------------------------------}
+instance Read IntSet where
+#ifdef __GLASGOW_HASKELL__
+ readPrec = parens $ prec 10 $ do
+ Ident "fromList" <- lexP
+ xs <- readPrec
+ return (fromList xs)
+#else
+ readsPrec p = readParen (p > 10) $ \ r -> do
+ ("fromList",s) <- lex
+ (xs,t) <- reads
+ return (fromList xs,t)
+#endif
+
+{--------------------------------------------------------------------
Typeable
--------------------------------------------------------------------}