{-# LANGUAGE Safe #-}
{-# LANGUAGE NoImplicitPrelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : Data.Word
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : experimental
-- Portability : portable
--
-- Unsigned integer types.
--
-----------------------------------------------------------------------------
module Data.Word
(
-- * Unsigned integral types
Word,
Word8, Word16, Word32, Word64,
-- * byte swapping
byteSwap16, byteSwap32, byteSwap64,
-- * Notes
-- $notes
) where
import GHC.Word
import GHC.Read () -- Need the `Read` instance for types defined in `GHC.Word`.
{- $notes
* All arithmetic is performed modulo 2^n, where n is the number of
bits in the type. One non-obvious consequence of this is that 'Prelude.negate'
should /not/ raise an error on negative arguments.
* 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 to and
from integer types preserves representation, not sign.
* An unbounded size unsigned integer type is available with
'Numeric.Natural.Natural'.
* The rules that hold for 'Prelude.Enum' instances over a bounded type
such as 'Prelude.Int' (see the section of the Haskell report dealing
with arithmetic sequences) also hold for the 'Prelude.Enum' instances
over the various 'Word' types defined here.
* Right and left shifts by amounts greater than or equal to the width
of the type result in a zero result. 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.
-}