[project @ 2005-10-12 10:57:40 by simonpj]

[haskell-directory.git] / GHC / Arr.lhs

diff --git a/GHC/Arr.lhs b/GHC/Arr.lhs
index 9e52c71..0b29db0 100644 (file)
--- a/GHC/Arr.lhs
+++ b/GHC/Arr.lhs
@@ -72,21 +72,19 @@ class (Ord a) => Ix a where
     rangeSize          :: (a,a) -> Int
     -- | like 'rangeSize', but without checking that the upper bound is
     -- in range.
-    --
-    -- As long as you don't override the default 'rangeSize', you can
-    -- specify 'unsafeRangeSize' as follows, to speed up some operations:
-    --
-    -- >  unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-    --
     unsafeRangeSize     :: (a,a) -> Int
 
        -- Must specify one of index, unsafeIndex
-    index b i | inRange b i = unsafeIndex b i
+    index b i | inRange b i = unsafeIndex b i  
              | otherwise   = error "Error in array index"
     unsafeIndex b i = index b i
 
     rangeSize b@(_l,h) | inRange b h = unsafeIndex b h + 1
-                      | otherwise   = 0
+                      | otherwise   = 0        -- This case is only here to
+                                               -- check for an empty range
+       -- NB: replacing (inRange b h) by (l <= h) fails for
+       --     tuples.  E.g.  (1,2) <= (2,1) but the range is empty
+
     unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
 \end{code}
 
@@ -131,8 +129,6 @@ instance  Ix Char  where
 
     inRange (m,n) i    =  m <= i && i <= n
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
 ----------------------------------------------------------------------
 instance  Ix Int  where
     {-# INLINE range #-}
@@ -149,8 +145,6 @@ instance  Ix Int  where
     {-# INLINE inRange #-}
     inRange (I# m,I# n) (I# i) =  m <=# i && i <=# n
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
 ----------------------------------------------------------------------
 instance  Ix Integer  where
     {-# INLINE range #-}
@@ -164,8 +158,6 @@ instance  Ix Integer  where
 
     inRange (m,n) i    =  m <= i && i <= n
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
 ----------------------------------------------------------------------
 instance Ix Bool where -- as derived
     {-# INLINE range #-}
@@ -179,8 +171,6 @@ instance Ix Bool where -- as derived
 
     inRange (l,u) i = fromEnum i >= fromEnum l && fromEnum i <= fromEnum u
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
 ----------------------------------------------------------------------
 instance Ix Ordering where -- as derived
     {-# INLINE range #-}
@@ -194,8 +184,6 @@ instance Ix Ordering where -- as derived
 
     inRange (l,u) i = fromEnum i >= fromEnum l && fromEnum i <= fromEnum u
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
 ----------------------------------------------------------------------
 instance Ix () where
     {-# INLINE range #-}
@@ -207,8 +195,6 @@ instance Ix () where
     {-# INLINE index #-}
     index b i = unsafeIndex b i
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
 ----------------------------------------------------------------------
 instance (Ix a, Ix b) => Ix (a, b) where -- as derived
     {-# SPECIALISE instance Ix (Int,Int) #-}
@@ -225,8 +211,6 @@ instance (Ix a, Ix b) => Ix (a, b) where -- as derived
     inRange ((l1,l2),(u1,u2)) (i1,i2) =
       inRange (l1,u1) i1 && inRange (l2,u2) i2
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
     -- Default method for index
 
 ----------------------------------------------------------------------
@@ -247,8 +231,6 @@ instance  (Ix a1, Ix a2, Ix a3) => Ix (a1,a2,a3)  where
       inRange (l1,u1) i1 && inRange (l2,u2) i2 &&
       inRange (l3,u3) i3
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
     -- Default method for index
 
 ----------------------------------------------------------------------
@@ -269,8 +251,6 @@ instance  (Ix a1, Ix a2, Ix a3, Ix a4) => Ix (a1,a2,a3,a4)  where
       inRange (l1,u1) i1 && inRange (l2,u2) i2 &&
       inRange (l3,u3) i3 && inRange (l4,u4) i4
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
     -- Default method for index
 
 instance  (Ix a1, Ix a2, Ix a3, Ix a4, Ix a5) => Ix (a1,a2,a3,a4,a5)  where
@@ -293,8 +273,6 @@ instance  (Ix a1, Ix a2, Ix a3, Ix a4, Ix a5) => Ix (a1,a2,a3,a4,a5)  where
       inRange (l3,u3) i3 && inRange (l4,u4) i4 && 
       inRange (l5,u5) i5
 
-    unsafeRangeSize b@(_l,h) = unsafeIndex b h + 1
-
     -- Default method for index
 \end{code}