[project @ 2005-01-21 11:44:08 by ross]

alter the interface of splitLookup and splitMember, placing the match
between the trees of smaller and larger elements in the returned triple.

diff --git a/Data/IntMap.hs b/Data/IntMap.hs
index 1e8c3e4..25b1558 100644 (file)
--- a/Data/IntMap.hs
+++ b/Data/IntMap.hs
@@ -807,17 +807,17 @@ split k t
 
 -- | /O(log n)/. Performs a 'split' but also returns whether the pivot
 -- key was found in the original map.
-splitLookup :: Key -> IntMap a -> (Maybe a,IntMap a,IntMap a)
+splitLookup :: Key -> IntMap a -> (IntMap a,Maybe a,IntMap a)
 splitLookup k t
   = case t of
       Bin p m l r
-        | zero k m  -> let (found,lt,gt) = splitLookup k l in (found,lt,union gt r)
-        | otherwise -> let (found,lt,gt) = splitLookup k r in (found,union l lt,gt)
+        | zero k m  -> let (lt,found,gt) = splitLookup k l in (lt,found,union gt r)
+        | otherwise -> let (lt,found,gt) = splitLookup k r in (union l lt,found,gt)
       Tip ky y 
-        | k>ky      -> (Nothing,t,Nil)
-        | k<ky      -> (Nothing,Nil,t)
-        | otherwise -> (Just y,Nil,Nil)
-      Nil -> (Nothing,Nil,Nil)
+        | k>ky      -> (t,Nothing,Nil)
+        | k<ky      -> (Nil,Nothing,t)
+        | otherwise -> (Nil,Just y,Nil)
+      Nil -> (Nil,Nothing,Nil)
 
 {--------------------------------------------------------------------
   Fold

diff --git a/Data/IntSet.hs b/Data/IntSet.hs
index f86f40b..a3cb766 100644 (file)
--- a/Data/IntSet.hs
+++ b/Data/IntSet.hs
@@ -465,17 +465,17 @@ split x t
 
 -- | /O(log n)/. Performs a 'split' but also returns whether the pivot
 -- element was found in the original set.
-splitMember :: Int -> IntSet -> (Bool,IntSet,IntSet)
+splitMember :: Int -> IntSet -> (IntSet,Bool,IntSet)
 splitMember x t
   = case t of
       Bin p m l r
-        | zero x m  -> let (found,lt,gt) = splitMember x l in (found,lt,union gt r)
-        | otherwise -> let (found,lt,gt) = splitMember x r in (found,union l lt,gt)
+        | zero x m  -> let (lt,found,gt) = splitMember x l in (lt,found,union gt r)
+        | otherwise -> let (lt,found,gt) = splitMember x r in (union l lt,found,gt)
       Tip y 
-        | x>y       -> (False,t,Nil)
-        | x<y       -> (False,Nil,t)
-        | otherwise -> (True,Nil,Nil)
-      Nil -> (False,Nil,Nil)
+        | x>y       -> (t,False,Nil)
+        | x<y       -> (Nil,False,t)
+        | otherwise -> (Nil,True,Nil)
+      Nil -> (Nil,False,Nil)
 
 {----------------------------------------------------------------------
   Map

diff --git a/Data/Map.hs b/Data/Map.hs
index 65a538f..b92bc36 100644 (file)
--- a/Data/Map.hs
+++ b/Data/Map.hs
@@ -675,7 +675,7 @@ intersectWithKey f t (Bin _ kx x l r)
       Nothing -> merge tl tr
       Just y  -> join kx (f kx y x) tl tr
   where
-    (found,lt,gt) = splitLookup kx t
+    (lt,found,gt) = splitLookup kx t
     tl            = intersectWithKey f lt l
     tr            = intersectWithKey f gt r
 
@@ -717,7 +717,7 @@ submap' f (Bin _ kx x l r) t
       Nothing -> False
       Just y  -> f x y && submap' f l lt && submap' f r gt
   where
-    (found,lt,gt) = splitLookup kx t
+    (lt,found,gt) = splitLookup kx t
 
 -- | /O(n+m)/. Is this a proper submap? (ie. a submap but not equal). 
 -- Defined as (@'isProperSubmapOf' = 'isProperSubmapOfBy' (==)@).
@@ -1104,13 +1104,13 @@ split k (Bin sx kx x l r)
 
 -- | /O(log n)/. The expression (@'splitLookup' k map@) splits a map just
 -- like 'split' but also returns @'lookup' k map@.
-splitLookup :: Ord k => k -> Map k a -> (Maybe a,Map k a,Map k a)
-splitLookup k Tip = (Nothing,Tip,Tip)
+splitLookup :: Ord k => k -> Map k a -> (Map k a,Maybe a,Map k a)
+splitLookup k Tip = (Tip,Nothing,Tip)
 splitLookup k (Bin sx kx x l r)
   = case compare k kx of
-      LT -> let (z,lt,gt) = splitLookup k l in (z,lt,join kx x gt r)
-      GT -> let (z,lt,gt) = splitLookup k r in (z,join kx x l lt,gt)
-      EQ -> (Just x,l,r)
+      LT -> let (lt,z,gt) = splitLookup k l in (lt,z,join kx x gt r)
+      GT -> let (lt,z,gt) = splitLookup k r in (join kx x l lt,z,gt)
+      EQ -> (l,Just x,r)
 
 {--------------------------------------------------------------------
   Utility functions that maintain the balance properties of the tree.

diff --git a/Data/Set.hs b/Data/Set.hs
index fb58ce2..7e07fbe 100644 (file)
--- a/Data/Set.hs
+++ b/Data/Set.hs
@@ -250,7 +250,7 @@ isSubsetOfX t Tip = False
 isSubsetOfX (Bin _ x l r) t
   = found && isSubsetOfX l lt && isSubsetOfX r gt
   where
-    (found,lt,gt) = splitMember x t
+    (lt,found,gt) = splitMember x t
 
 
 {--------------------------------------------------------------------
@@ -347,7 +347,7 @@ intersect' t (Bin _ x l r)
   | found     = join x tl tr
   | otherwise = merge tl tr
   where
-    (found,lt,gt) = splitMember x t
+    (lt,found,gt) = splitMember x t
     tl            = intersect' lt l
     tr            = intersect' gt r
 
@@ -616,13 +616,13 @@ split x (Bin sy y l r)
 
 -- | /O(log n)/. Performs a 'split' but also returns whether the pivot
 -- element was found in the original set.
-splitMember :: Ord a => a -> Set a -> (Bool,Set a,Set a)
-splitMember x Tip = (False,Tip,Tip)
+splitMember :: Ord a => a -> Set a -> (Set a,Bool,Set a)
+splitMember x Tip = (Tip,False,Tip)
 splitMember x (Bin sy y l r)
   = case compare x y of
-      LT -> let (found,lt,gt) = splitMember x l in (found,lt,join y gt r)
-      GT -> let (found,lt,gt) = splitMember x r in (found,join y l lt,gt)
-      EQ -> (True,l,r)
+      LT -> let (lt,found,gt) = splitMember x l in (lt,found,join y gt r)
+      GT -> let (lt,found,gt) = splitMember x r in (join y l lt,found,gt)
+      EQ -> (l,True,r)
 
 {--------------------------------------------------------------------
   Utility functions that maintain the balance properties of the tree.