Num -package:base-prelude package:basic-prelude
Class
Enum defines operations on sequentially ordered types.
The
enumFrom... methods are used in Haskell's translation of
arithmetic sequences.
Instances of
Enum may be derived for any enumeration type
(types whose constructors have no fields). The nullary constructors
are assumed to be numbered left-to-right by
fromEnum from
0 through
n-1. See Chapter 10 of the
Haskell
Report for more details.
For any type that is an instance of class
Bounded as well as
Enum, the following should hold:
enumFrom x = enumFromTo x maxBound
enumFromThen x y = enumFromThenTo x y bound
where
bound | fromEnum y >= fromEnum x = maxBound
| otherwise = minBound
Used in Haskell's translation of [n..].
Used in Haskell's translation of [n,n'..].
Used in Haskell's translation of [n,n'..m].
Used in Haskell's translation of [n..m].
Convert to an
Int. It is implementation-dependent what
fromEnum returns when applied to a value that is too large to
fit in an
Int.
Sign of a number. The functions
abs and
signum should
satisfy the law:
abs x * signum x == x
For real numbers, the
signum is either
-1 (negative),
0 (zero) or
1 (positive).