Data.Fin.Enum

This module is designed to be imported qualified:

import qualified Data.Fin.Enum as E

Documentation

class Enum a where

Generic enumerations.

Examples:

>>> from ()
0

>>> to 0 :: ()
()

>>> to 0 :: Bool
False

>>> map to F.universe :: [Bool]
[False,True]

>>> map (to . (+1) . from) [LT, EQ, GT] :: [Ordering] -- Num Fin is modulo arithmetic
[EQ,GT,LT]

Minimal complete definition

Nothing

Associated Types

type EnumSize a :: Nat

The size of an enumeration.

Methods

from :: a -> Fin (EnumSize a)

Converts a value to its index.

from :: (Generic a, GFrom a, EnumSize a ~ GEnumSize a) => a -> Fin (EnumSize a)

Converts a value to its index.

to :: Fin (EnumSize a) -> a

Converts from index to the original value.

to :: (Generic a, GTo a, EnumSize a ~ GEnumSize a) => Fin (EnumSize a) -> a

Converts from index to the original value.

Instances

Enum Bool

Bool ~ 2

Defined in Data.Fin.Enum

Associated Types

type EnumSize Bool :: Nat

Methods

from :: Bool -> Fin (EnumSize Bool)

to :: Fin (EnumSize Bool) -> Bool

Enum Ordering

Ordering ~ 3

Defined in Data.Fin.Enum

Associated Types

type EnumSize Ordering :: Nat

Methods

from :: Ordering -> Fin (EnumSize Ordering)

to :: Fin (EnumSize Ordering) -> Ordering

Enum ()

() ~ 1

Defined in Data.Fin.Enum

Associated Types

type EnumSize () :: Nat

Methods

from :: () -> Fin (EnumSize ())

to :: Fin (EnumSize ()) -> ()

Enum Void

Void ~ 0

Defined in Data.Fin.Enum

Associated Types

type EnumSize Void :: Nat

Methods

from :: Void -> Fin (EnumSize Void)

to :: Fin (EnumSize Void) -> Void

(Enum a, Enum b, InlineInduction (EnumSize a)) => Enum (Either a b)

Either ~ +

Defined in Data.Fin.Enum

Associated Types

type EnumSize (Either a b) :: Nat

Methods

from :: Either a b -> Fin (EnumSize (Either a b))

to :: Fin (EnumSize (Either a b)) -> Either a b

Generic implementation

gfrom :: (Generic a, GFrom a) => a -> Fin (GEnumSize a)

Generic version of from.

type GFrom a = GFromRep (Rep a)

Constraint for the class that computes gfrom.

gto :: (Generic a, GTo a) => Fin (GEnumSize a) -> a

Generic version of to.

type GTo a = GToRep (Rep a)

Constraint for the class that computes gto.

type GEnumSize a = EnumSizeRep (Rep a) Nat0

Compute the size from the type.