+instance Traversable (Map k) where
+ traverse f Tip = pure Tip
+ traverse f (Bin s k v l r)
+ = flip (Bin s k) <$> traverse f l <*> f v <*> traverse f r
+
+instance Foldable (Map k) where
+ foldMap _f Tip = mempty
+ foldMap f (Bin _s _k v l r)
+ = foldMap f l `mappend` f v `mappend` foldMap f r
+
+{--------------------------------------------------------------------
+ Read
+--------------------------------------------------------------------}
+instance (Ord k, Read k, Read e) => Read (Map k e) where
+#ifdef __GLASGOW_HASKELL__
+ readPrec = parens $ prec 10 $ do
+ Ident "fromList" <- lexP
+ xs <- readPrec
+ return (fromList xs)
+
+ readListPrec = readListPrecDefault
+#else
+ readsPrec p = readParen (p > 10) $ \ r -> do
+ ("fromList",s) <- lex r
+ (xs,t) <- reads s
+ return (fromList xs,t)
+#endif
+
+-- parses a pair of things with the syntax a:=b
+readPair :: (Read a, Read b) => ReadS (a,b)
+readPair s = do (a, ct1) <- reads s
+ (":=", ct2) <- lex ct1
+ (b, ct3) <- reads ct2
+ return ((a,b), ct3)
+