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1. enumFrom :: Enum a => a -> [a]

   numeric-prelude	NumericPrelude.Base

   Used in Haskell's translation of [n..] with [n..] = enumFrom n, a possible implementation being enumFrom n = n : enumFrom (succ n).

   Examples

   • enumFrom 4 :: [Integer] = [4,5,6,7,...]

   • enumFrom 6 :: [Int] = [6,7,8,9,...,maxBound ::
     Int]

2. enumFromThen :: Enum a => a -> a -> [a]

   numeric-prelude	NumericPrelude.Base

   Used in Haskell's translation of [n,n'..] with [n,n'..] = enumFromThen n n', a possible implementation being enumFromThen n n' = n : n' : worker (f x) (f x n'), worker s v = v : worker s (s v), x = fromEnum n' - fromEnum n and

   f n y
   | n > 0 = f (n - 1) (succ y)
   | n < 0 = f (n + 1) (pred y)
   | otherwise = y
   
   

   Examples

   • enumFromThen 4 6 :: [Integer] = [4,6,8,10...]

   • enumFromThen 6 2 :: [Int] = [6,2,-2,-6,...,minBound ::
     Int]

3. enumFromThenTo :: Enum a => a -> a -> a -> [a]

   numeric-prelude	NumericPrelude.Base

   Used in Haskell's translation of [n,n'..m] with [n,n'..m] = enumFromThenTo n n' m, a possible implementation being enumFromThenTo n n' m = worker (f x) (c x) n m, x = fromEnum n' - fromEnum n, c x = bool (>=) ((x 0)

   f n y
   | n > 0 = f (n - 1) (succ y)
   | n < 0 = f (n + 1) (pred y)
   | otherwise = y
   
   

   and

   worker s c v m
   | c v m = v : worker s c (s v) m
   | otherwise = []
   
   

   Examples

   • enumFromThenTo 4 2 -6 :: [Integer] =
     [4,2,0,-2,-4,-6]

   • enumFromThenTo 6 8 2 :: [Int] = []

4. enumFromTo :: Enum a => a -> a -> [a]

   numeric-prelude	NumericPrelude.Base

   Used in Haskell's translation of [n..m] with [n..m] = enumFromTo n m, a possible implementation being

   enumFromTo n m
   | n <= m = n : enumFromTo (succ n) m
   | otherwise = []
   
   

   Examples

   • enumFromTo 6 10 :: [Int] = [6,7,8,9,10]

   • enumFromTo 42 1 :: [Integer] = []

5. fromEnum :: Enum a => a -> Int

   numeric-prelude	NumericPrelude.Base

   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.

6. toEnum :: Enum a => Int -> a

   numeric-prelude	NumericPrelude.Base

   Convert from an Int.

7. signum :: C a => a -> a

   numeric-prelude	NumericPrelude.Numeric

   No documentation available.

8. signum :: Sign a => a -> a

   numhask	NumHask

   The sign of a number.

   >>> signum (-1)
   -1
   

   abs zero == zero, so any value for signum zero is ok. We choose lawful neutral:

   >>> signum zero == zero
   True
   

9. signum :: Sign a => a -> a

   numhask	NumHask.Algebra.Metric

   The sign of a number.

   >>> signum (-1)
   -1
   

   abs zero == zero, so any value for signum zero is ok. We choose lawful neutral:

   >>> signum zero == zero
   True
   

10. class Enum a

    numhask	NumHask.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:

    • The calls succ maxBound and pred minBound should result in a runtime error.
    • fromEnum and toEnum should give a runtime error if the result value is not representable in the result type. For example, toEnum 7 :: Bool is an error.
    • enumFrom and enumFromThen should be defined with an implicit bound, thus:

    enumFrom     x   = enumFromTo     x maxBound
    enumFromThen x y = enumFromThenTo x y bound
    where
    bound | fromEnum y >= fromEnum x = maxBound
    | otherwise                = minBound
    

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