Portability | portable |
---|---|
Stability | experimental |
Maintainer | libraries@haskell.org |
Unsigned integer types.
Unsigned integral types
8-bit unsigned integer type
16-bit unsigned integer type
32-bit unsigned integer type
64-bit unsigned integer type
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. - It would be very natural to add a type
Natural
providing an unbounded size unsigned integer, just asPrelude.Integer
provides unbounded size signed integers. We do not do that yet since there is no demand for it. - The rules that hold for
Prelude.Enum
instances over a bounded type such asPrelude.Int
(see the section of the Haskell report dealing with arithmetic sequences) also hold for thePrelude.Enum
instances over the variousWord
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.