This interface provides a collection of sized, signed integers. The types supported are as follows:
| type | number of bits |
| Int8 | 8 |
| Int16 | 16 |
| Int32 | 32 |
| Int64 | 64 |
For each type I above, we provide the following instances.
data I -- Signed Ints instance Eq I instance Ord I instance Show I instance Read I instance Bounded I instance Num I instance Real I instance Integral I instance Enum I instance Ix I instance Bits I |
All arithmetic is performed modulo 2^n.
For coercing between various integer types, use fromIntegral, which is specialized for all the common cases so should be fast enough.
The rules that hold for Enum instances over a bounded type such as Int (see the section of the Haskell report dealing with arithmetic sequences) also hold for the 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.
Hugs does not provide Int64 at the moment.
The following functions are deprecated in the new FFI. Do not use the following functions if you are interested in portability. Most of these functions are here for legacy reasons and may just vanish one day. You have been warned.
The Int module also exports the overloaded operations for converting to and from Haskell Ints. However, for coercing between various integer types, better use fromIntegral, which is specialized for all the common cases so should be fast enough.
toInt :: (Integral a) => a -> Int fromInt :: (Num a) => Int -> a |
Portability note: both Hugs98 and all releases of GHC prior to ghc-4.05 also exports these two via the Prelude. So, to have code that uses toInt and fromInt be maximally portable, make sure you add an import on Int (even if the version of Hugs or GHC you're currently using may not export these two from there.)