gistfile1.txt

diff --git a/src/Data/IntervalSet/ByteString.hs b/src/Data/IntervalSet/ByteString.hs
index 0e569e5..de3a7e8 100644
--- a/src/Data/IntervalSet/ByteString.hs
+++ b/src/Data/IntervalSet/ByteString.hs
@@ -24,6 +24,7 @@ import qualified Data.ByteString as BS
 import qualified Data.ByteString.Internal as BS
 import Control.Monad as CM
 import Foreign
+import System.IO.Unsafe
 
 import Data.IntervalSet.Internal as S
 
@@ -45,7 +46,7 @@ import Data.IntervalSet.Internal as S
 fromByteString :: ByteString -> IntSet
 fromByteString bs =
     let (fptr, off, len) = BS.toForeignPtr bs in
-    BS.inlinePerformIO $ withForeignPtr fptr $ \_ptr -> do
+    unsafePerformIO $ withForeignPtr fptr $ \_ptr -> do
       let ptr = _ptr `advancePtr` off
       let !s = goFrom (castPtr ptr) len
       return $! s
@@ -57,7 +58,7 @@ fromByteString bs =
         go :: Int -> IntSet -> IntSet
         go !x !acc
           |  x + wordSize <= len  = do
-            let !bm = BS.inlinePerformIO (peekByteOff ptr x) -- TODO read little endian
+            let !bm = unsafePerformIO (peekByteOff ptr x) -- TODO read little endian
             let !s  = unionBM (x * wordSize) bm acc
             go (x + wordSize) s
           | otherwise = goBytes x acc
@@ -67,7 +68,7 @@ fromByteString bs =
         goBytes :: Int -> IntSet -> IntSet
         goBytes !i !s
           |   i < len =
-            let wbm = BS.inlinePerformIO (peekByteOff ptr i)
+            let wbm = unsafePerformIO (peekByteOff ptr i)
                 s'  = foldrWord (i * 8) insert s wbm
             in  goBytes (i + 1)  s'
           | otherwise = s
@@ -88,7 +89,7 @@ fromByteString bs =
                bin  px msk (goTree l mid) (goTree mid r)
 
           | r - l == wordSize =
-            let bm = BS.inlinePerformIO (peekByteOff ptr l)
+            let bm = unsafePerformIO (peekByteOff ptr l)
             in tip (l * wordSize) bm
 
           | otherwise = goBytes l r empty
diff --git a/src/Data/IntervalSet/Internal.hs b/src/Data/IntervalSet/Internal.hs
index 00b7900..d3b5600 100644
--- a/src/Data/IntervalSet/Internal.hs
+++ b/src/Data/IntervalSet/Internal.hs
@@ -8,6 +8,7 @@
 --   See documentation for module header in Data.IntSet.Buddy.
 --
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE DeriveGeneric #-}
 
 #if __GLASGOW_HASKELL__
 {-# LANGUAGE DeriveDataTypeable #-}
@@ -125,6 +126,7 @@ import qualified Data.List as L
 import Data.Monoid
 import Data.Ord
 import Data.Word
+import GHC.Generics (Generic)
 
 
 -- machine specific properties of basic types
@@ -201,7 +203,7 @@ data IntSet
   deriving
     ( Eq
 #if defined(__GLASGOW_HASKELL__)
-    , Typeable, Data
+    , Typeable, Data, Generic
 #endif
     )
 
@@ -266,9 +268,11 @@ instance Ord IntSet where
   compare = comparing toList
   -- TODO make it faster
 
+instance Semigroup IntSet where
+  (<>) = union
+
 instance Monoid IntSet where
   mempty  = empty
-  mappend = union
   mconcat = unions
 
 instance Num IntSet where
@@ -298,9 +302,11 @@ instance NFData IntSet where
 newtype Union = Union { getUnion :: IntSet }
                 deriving (Show, Read, Eq, Ord)
 
+instance Semigroup Union where
+  a <> b = Union (getUnion a `union` getUnion b)
+
 instance Monoid Union where
   mempty      = Union empty
-  mappend a b = Union (getUnion a `union` getUnion b)
   mconcat     = Union . unions . L.map getUnion
 
 -- | Monoid under 'intersection'.
@@ -310,9 +316,11 @@ instance Monoid Union where
 newtype Intersection = Intersection { getIntersection :: IntSet }
                        deriving (Show, Read, Eq, Ord)
 
+instance Semigroup Intersection where
+  a <> b = Intersection (getIntersection a `intersection` getIntersection b)
+
 instance Monoid Intersection where
   mempty      = Intersection universe
-  mappend a b = Intersection (getIntersection a `intersection` getIntersection b)
   mconcat     = Intersection . intersections . L.map getIntersection
 
 -- | Monoid under 'symDiff'.
@@ -322,9 +330,11 @@ instance Monoid Intersection where
 newtype Difference = Difference { getDifference :: IntSet }
                      deriving (Show, Read, Eq, Ord)
 
+instance Semigroup Difference where
+  a <> b = Difference (getDifference a `symDiff` getDifference b)
+
 instance Monoid Difference where
   mempty      = Difference empty
-  mappend a b = Difference (getDifference a `symDiff` getDifference b)
 
 {--------------------------------------------------------------------
   Query
@@ -591,9 +601,9 @@ union t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
       |    zero p1 m2    = binI p2 m2 (t1 `union` l2) r2
       |     otherwise    = binI p2 m2 l2 (t1 `union` r2)
 
-union t@ Bin {}       (Tip p bm) = insertBM  p bm t
-union t@ Bin {}       (Fin p m ) = insertFin p m  t
-union t@ Bin {}        Nil       = t
+union t@Bin {}       (Tip p bm) = insertBM  p bm t
+union t@Bin {}       (Fin p m ) = insertFin p m  t
+union t@Bin {}        Nil       = t
 union   (Fin p m )     t         = insertFin p m t
 union   (Tip p bm)     t         = insertBM p bm t
 union    Nil           t         = t
@@ -667,8 +677,8 @@ intersection t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
       |     zero p1 m2   = intersection t1 l2
       |     otherwise    = intersection t1 r2
 
-intersection t@ Bin {}         (Tip p bm)    = intersectBM p bm t
-intersection t@ Bin {}         (Fin p m)     = intersectFin p m t
+intersection t@Bin {}         (Tip p bm)    = intersectBM p bm t
+intersection t@Bin {}         (Fin p m)     = intersectFin p m t
 intersection    Bin {}          Nil          = Nil
 intersection   (Tip p bm)       t            = intersectBM p bm t
 intersection   (Fin p m)        t            = intersectFin p m t
@@ -752,7 +762,7 @@ difference t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
       |    zero p1 m2    = difference t1 l2
       |     otherwise    = difference t1 r2
 
-difference t1@ Bin {}            (Tip p bm)    = deleteBM p bm t1
+difference t1@Bin {}            (Tip p bm)    = deleteBM p bm t1
 difference t1@(Bin p1 m1 _ _)    (Fin p2 m2)
     | m1 `shorter` finMask m2
     = if match p2 p1 m1
@@ -767,13 +777,13 @@ difference t1@(Bin p1 m1 _ _)    (Fin p2 m2)
     | p1 == p2  = Nil
     | otherwise = t1
 
-difference t1@ Bin {}           Nil            = t1
+difference t1@Bin {}           Nil            = t1
 difference t1@(Tip p _ )       (Bin p2 m2 l r)
   | nomatch p p2 m2 = t1
   |   zero p m2     = difference t1 l
   |   otherwise     = difference t1 r
 
-difference t1@ Tip {}          (Tip p bm)      = deleteBM p bm t1
+difference t1@Tip {}          (Tip p bm)      = deleteBM p bm t1
 difference t1@(Tip p1 _)       (Fin p2 m2 ) --
   | nomatch p1 p2 (finMask m2) = t1         --
   |          otherwise         = Nil        --
@@ -844,9 +854,9 @@ symDiff t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
       |    zero p1 m2    = bin  p2 m2 (symDiff l2 t1) r2 -- TODO tune (symDiff l1 t2)
       |    otherwise     = bin  p2 m2 l2 (symDiff r2 t1)
 
-symDiff t1@ Bin {}             (Tip p2 bm2    ) = symDiffTip p2 bm2 t1
-symDiff t1@ Bin {}             (Fin p2 m2     ) = symDiffFin p2 m2  t1
-symDiff t1@ Bin {}              Nil             = t1
+symDiff t1@Bin {}             (Tip p2 bm2    ) = symDiffTip p2 bm2 t1
+symDiff t1@Bin {}             (Fin p2 m2     ) = symDiffFin p2 m2  t1
+symDiff t1@Bin {}              Nil             = t1
 symDiff    (Tip p1 bm1    ) t2                  = symDiffTip p1 bm1 t2
 symDiff    (Fin p1 m1     ) t2                  = symDiffFin p1 m1  t2
 symDiff     Nil             t2                  = t2