Data.Exists

Data types and type classes for working with existentially quantified values. In the event that Quantified Class Constraints ever land in GHC, this package will be considered obsolete. The benefit that most of the typeclasses in this module provide is that they help populate the instances of Exists.

Data Types

data Exists f

Hide a type parameter.

Constructors

Exists !(f a)

Instances

BoundedForall k f => Bounded (Exists k f)

Methods

minBound :: Exists k f

maxBound :: Exists k f

EnumForall k f => Enum (Exists k f)

Methods

succ :: Exists k f -> Exists k f

pred :: Exists k f -> Exists k f

toEnum :: Int -> Exists k f

fromEnum :: Exists k f -> Int

enumFrom :: Exists k f -> [Exists k f]

enumFromThen :: Exists k f -> Exists k f -> [Exists k f]

enumFromTo :: Exists k f -> Exists k f -> [Exists k f]

enumFromThenTo :: Exists k f -> Exists k f -> Exists k f -> [Exists k f]

EqForallPoly k f => Eq (Exists k f)

Methods

(==) :: Exists k f -> Exists k f -> Bool

(/=) :: Exists k f -> Exists k f -> Bool

OrdForallPoly k f => Ord (Exists k f)

Methods

compare :: Exists k f -> Exists k f -> Ordering

(<) :: Exists k f -> Exists k f -> Bool

(<=) :: Exists k f -> Exists k f -> Bool

(>) :: Exists k f -> Exists k f -> Bool

(>=) :: Exists k f -> Exists k f -> Bool

max :: Exists k f -> Exists k f -> Exists k f

min :: Exists k f -> Exists k f -> Exists k f

ReadForall k f => Read (Exists k f)

Methods

readsPrec :: Int -> ReadS (Exists k f)

readList :: ReadS [Exists k f]

readPrec :: ReadPrec (Exists k f)

readListPrec :: ReadPrec [Exists k f]

ShowForall k f => Show (Exists k f)

Methods

showsPrec :: Int -> Exists k f -> ShowS

show :: Exists k f -> String

showList :: [Exists k f] -> ShowS

HashableForall k f => Hashable (Exists k f)

Methods

hashWithSalt :: Int -> Exists k f -> Int

hash :: Exists k f -> Int

ToJSONForall k f => ToJSON (Exists k f)

Methods

toJSON :: Exists k f -> Value

toEncoding :: Exists k f -> Encoding

toJSONList :: [Exists k f] -> Value

toEncodingList :: [Exists k f] -> Encoding

(ToJSONKeyForall k f, ToJSONForall k f) => ToJSONKey (Exists k f)

Methods

toJSONKey :: ToJSONKeyFunction (Exists k f)

toJSONKeyList :: ToJSONKeyFunction [Exists k f]

FromJSONForall k f => FromJSON (Exists k f)

Methods

parseJSON :: Value -> Parser (Exists k f)

parseJSONList :: Value -> Parser [Exists k f]

(FromJSONKeyForall k f, FromJSONForall k f) => FromJSONKey (Exists k f)

Methods

fromJSONKey :: FromJSONKeyFunction (Exists k f)

fromJSONKeyList :: FromJSONKeyFunction [Exists k f]

PathPieceForall k f => PathPiece (Exists k f)

Methods

fromPathPiece :: Text -> Maybe (Exists k f)

toPathPiece :: Exists k f -> Text

data Exists2 f

Constructors

Exists2 !(f a b)

data Exists3 f

Constructors

Exists3 !(f a b c)

Type Classes

class EqForall f where

Minimal complete definition

eqForall

Methods

eqForall :: f a -> f a -> Bool

Instances

EqForall k (Proxy k)

Methods

eqForall :: f a -> f a -> Bool

Eq a => EqForall k (Const k a)

Methods

eqForall :: f a -> f a -> Bool

EqForall k ((:~:) k a)

Methods

eqForall :: f a -> f a -> Bool

(EqForall k f, EqForall k g) => EqForall k (Sum k f g)

Methods

eqForall :: f a -> f a -> Bool

(EqForall k f, EqForall k g) => EqForall k (Product k f g)

Methods

eqForall :: f a -> f a -> Bool

EqForall k1 f => EqForall k (Compose k k1 f g)

Methods

eqForall :: f a -> f a -> Bool

class EqForall f => EqForallPoly f where

Minimal complete definition

eqForallPoly

Methods

eqForallPoly :: f a -> f b -> Bool

Instances

Eq a => EqForallPoly k (Const k a)

Methods

eqForallPoly :: f a -> f b -> Bool

(EqForallPoly k f, EqForallPoly k g) => EqForallPoly k (Product k f g)

Methods

eqForallPoly :: f a -> f b -> Bool

EqForallPoly k1 f => EqForallPoly k (Compose k k1 f g)

Methods

eqForallPoly :: f a -> f b -> Bool

class EqForall f => OrdForall f where

Minimal complete definition

compareForall

Methods

compareForall :: f a -> f a -> Ordering

Instances

OrdForall k (Proxy k)

Methods

compareForall :: f a -> f a -> Ordering

Ord a => OrdForall k (Const k a)

Methods

compareForall :: f a -> f a -> Ordering

(OrdForall k f, OrdForall k g) => OrdForall k (Sum k f g)

Methods

compareForall :: f a -> f a -> Ordering

(OrdForall k f, OrdForall k g) => OrdForall k (Product k f g)

Methods

compareForall :: f a -> f a -> Ordering

class (OrdForall f, EqForallPoly f) => OrdForallPoly f where

Minimal complete definition

compareForallPoly

Methods

compareForallPoly :: f a -> f b -> Ordering

Instances

Ord a => OrdForallPoly k (Const k a)

Methods

compareForallPoly :: f a -> f b -> Ordering

(OrdForallPoly k f, OrdForallPoly k g) => OrdForallPoly k (Product k f g)

Methods

compareForallPoly :: f a -> f b -> Ordering

class ShowForall f where

Minimal complete definition

showsPrecForall

Methods

showsPrecForall :: Int -> f a -> ShowS

Instances

ShowForall k (Proxy k)

Methods

showsPrecForall :: Int -> f a -> ShowS

(ShowForall k f, ShowForall k g) => ShowForall k (Product k f g)

Methods

showsPrecForall :: Int -> f a -> ShowS

class ReadForall f where

Minimal complete definition

readPrecForall

Methods

readPrecForall :: ReadPrec (Exists f)

Instances

ReadForall k (Proxy k)

Methods

readPrecForall :: ReadPrec (Exists (Proxy k) f)

class EnumForall f where

Minimal complete definition

toEnumForall, fromEnumForall

Methods

toEnumForall :: Int -> Exists f

fromEnumForall :: f a -> Int

class BoundedForall f where

Minimal complete definition

minBoundForall, maxBoundForall

Methods

minBoundForall :: Exists f

maxBoundForall :: Exists f

class MonoidForall f where

Minimal complete definition

memptyForall, mappendForall

Methods

memptyForall :: f a

mappendForall :: f a -> f a -> f a

Instances

MonoidForall k (Proxy k)

Methods

memptyForall :: f a

mappendForall :: f a -> f a -> f a

class HashableForall f where

Minimal complete definition

hashWithSaltForall

Methods

hashWithSaltForall :: Int -> f a -> Int

Instances

Hashable a => HashableForall k (Const k a)

Methods

hashWithSaltForall :: Int -> f a -> Int

class PathPieceForall f where

Minimal complete definition

fromPathPieceForall, toPathPieceForall

Methods

fromPathPieceForall :: Text -> Maybe (Exists f)

toPathPieceForall :: f a -> Text

class ToJSONKeyForall f where

Minimal complete definition

toJSONKeyForall

Methods

toJSONKeyForall :: ToJSONKeyFunctionForall f

class FromJSONKeyForall f where

Minimal complete definition

fromJSONKeyForall

Methods

fromJSONKeyForall :: FromJSONKeyFunction (Exists f)

Higher Rank Classes

class EqForall2 f where

Minimal complete definition

eqForall2

Methods

eqForall2 :: f a b -> f a b -> Bool

Instances

EqForall2 k k ((:~:) k)

Methods

eqForall2 :: f a b -> f a b -> Bool

class EqForallPoly2 f where

Minimal complete definition

eqForallPoly2

Methods

eqForallPoly2 :: f a b -> f c d -> Bool

Functions

showsForall :: ShowForall f => f a -> ShowS

showForall :: ShowForall f => f a -> String