Accepted patch from Daniel Lyons

Data/Heap/Pairing.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE RankNTypes #-}
 --
 -- Copyright (c) 2010 Brendan Hickey - http://bhickey.net
 -- New BSD License (see http://www.opensource.org/licenses/bsd-license.php)
@@ -8,7 +9,6 @@ module Data.Heap.Pairing
 where
 
 import Prelude hiding (head, tail, null)
-import qualified Data.List as L
 
 data (Ord a) => PairingHeap a =
       EmptyHeap
@@ -60,7 +60,10 @@ toList = toAscList
 fromList :: (Ord a) => [a] -> PairingHeap a
 fromList = fromAscList
 
+mergeList :: forall a. (Ord a) => [PairingHeap a] -> PairingHeap a
 mergeList [a] = a
 mergeList x = mergeList (mergePairs x)
+
+mergePairs :: forall a. (Ord a) => [PairingHeap a] -> [PairingHeap a]
 mergePairs (a:b:c) = merge a b : mergePairs c
 mergePairs x = x

Data/Heap/Skew.hs

@@ -8,7 +8,6 @@ module Data.Heap.Skew
 where
 
 import Prelude hiding (head, tail, null)
-import qualified Data.List as L
 
 data (Ord a) => SkewHeap a =
     SkewLeaf

Data/Tree/AVL.hs

@@ -8,13 +8,17 @@ module Data.Tree.AVL
 where
 
 import Prelude hiding (head, tail, (!!), lookup, null)
-import Data.Maybe
-
 
 data AVLTree k v =
     Leaf
   | AVLTree !k !v !Int !Int !(AVLTree k v) !(AVLTree k v) deriving (Ord, Eq, Show)
 
+
+instance Functor (AVLTree k) where
+  fmap _ Leaf = Leaf
+  fmap f (AVLTree k v lh rh l r) = AVLTree k (f v) lh rh (fmap f l) (fmap f r)
+
+
 -- | /O(1)/. 'singleton' constructs a singleton AVL tree
 singleton :: (Ord k) => k -> v -> AVLTree k v
 singleton k v = AVLTree k v 1 1 Leaf Leaf

Data/Tree/Splay.hs

@@ -13,6 +13,12 @@ data (Ord k) => SplayTree k v =
     Leaf
   | SplayTree k v Int (SplayTree k v) (SplayTree k v) deriving (Ord, Eq)
 
+
+instance (Ord k) => Functor (SplayTree k) where
+    fmap _ Leaf = Leaf
+    fmap f (SplayTree k v h l r) = SplayTree k (f v) h (fmap f l) (fmap f r)
+
+
 -- | /O(1)/. 'singleton' constructs a splay tree containing one element.
 singleton :: (Ord k) => (k,v) -> SplayTree k v
 singleton (k,v) = SplayTree k v 0 Leaf Leaf
@@ -83,7 +89,7 @@ zig _ Leaf = error "tree corruption"
 zig (SplayTree k1 v1 _ l1 r1) (SplayTree k v d _ r) =
   SplayTree k1 v1 d l1 (SplayTree k v (d - size l1 - 1) r1 r)
 
--- | /O(1)/. zig rotates its second argument up
+-- | /O(1)/. zag rotates its second argument up
 zag :: (Ord k) => SplayTree k v -> SplayTree k v -> SplayTree k v
 zag Leaf _ = error "tree corruption"
 zag _ Leaf = error "tree corruption"