X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FInt.hs;h=c9c9036d53b49ac3ee5d0d1ad7e64b8b1845d3f2;hb=HEAD;hp=182152c1e5b6b9bc83a4a8b56dba7e1b76b3ed8f;hpb=f7a485978f04e84b086f1974b88887cc72d832d0;p=ghc-base.git

diff --git a/Data/Int.hs b/Data/Int.hs
index 182152c..c9c9036 100644
--- a/Data/Int.hs
+++ b/Data/Int.hs
@@ -1,4 +1,5 @@
-{-# OPTIONS -fno-implicit-prelude #-}
+{-# LANGUAGE CPP, NoImplicitPrelude #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.Int
@@ -9,19 +10,57 @@
 -- Stability   :  experimental
 -- Portability :  portable
 --
--- Sized Integer types.
+-- Signed integer types
 --
 -----------------------------------------------------------------------------
 
 module Data.Int
-	( Int8
-	, Int16
-	, Int32
-	, Int64
-	-- instances: Eq, Ord, Num, Bounded, Real, Integral, Ix, Enum, Read,
-	-- Show, Bits, CCallable, CReturnable (last two are GHC specific.)
-	) where
+  ( 
+        -- * Signed integer types
+        Int,
+        Int8, Int16, Int32, Int64,
+
+        -- * Notes
+
+        -- $notes
+        ) where
 
 #ifdef __GLASGOW_HASKELL__
-import GHC.Int
+import GHC.Base ( Int )
+import GHC.Int  ( Int8, Int16, Int32, Int64 )
+#endif
+
+#ifdef __HUGS__
+import Hugs.Int ( Int8, Int16, Int32, Int64 )
+#endif
+
+#ifdef __NHC__
+import Prelude
+import Prelude (Int)
+import NHC.FFI (Int8, Int16, Int32, Int64)
+import NHC.SizedTypes (Int8, Int16, Int32, Int64)       -- instances of Bits
 #endif
+
+{- $notes
+
+* All arithmetic is performed modulo 2^n, where @n@ is the number of
+  bits in the type.
+
+* For coercing between any two integer types, use 'Prelude.fromIntegral',
+  which is specialized for all the common cases so should be fast
+  enough.  Coercing word types (see "Data.Word") to and from integer
+  types preserves representation, not sign.
+
+* The rules that hold for 'Prelude.Enum' instances over a
+  bounded type such as 'Int' (see the section of the
+  Haskell report dealing with arithmetic sequences) also hold for the
+  'Prelude.Enum' instances over the various
+  'Int' types defined here.
+
+* Right and left shifts by amounts greater than or equal to the width
+  of the type result in either zero or -1, depending on the sign of
+  the value being shifted.  This is contrary to the behaviour in C,
+  which is undefined; a common interpretation is to truncate the shift
+  count to the width of the type, for example @1 \<\< 32
+  == 1@ in some C implementations.
+-}