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Within LTS Haskell 24.50 (ghc-9.10.3)

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

   basement	Basement.Compat.Base

   Convert from an Int.

2. class Enum a

   basement	Basement.Imports

   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
   

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

   basement	Basement.Imports

   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]

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

   basement	Basement.Imports

   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]

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

   basement	Basement.Imports

   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] = []

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

   basement	Basement.Imports

   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] = []

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

   basement	Basement.Imports

   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.

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

   basement	Basement.Imports

   Convert from an Int.

9. type family NatNumMaxBound ty :: Nat

   basement	Basement.Nat

   Get Maximum bounds of different Integral / Natural types related to Nat

10. maxNum :: RealFloat a => a -> a -> a

    ieee754	Numeric.IEEE

    Return the maximum of two values; if one value is NaN, return the other. Prefer the first if both values are NaN.

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