Safe Haskell	None
Language	Haskell98

Generic.Applicative

Synopsis

newtype LeftBias tag f g a = LeftBias (Sum f g a)
newtype RightBias tag f g a = RightBias (Sum f g a)
type Idiomatically f sums = Generically1 (NewSums (Served sums) f)
newtype Generically1 f a = Generically1 (f a)
newtype NewSums sums f a = NewSums {
- reduce :: f a
}
module Generic.Applicative.Idiom

Documentation

newtype LeftBias tag f g a Source #

Constructors

LeftBias (Sum f g a)

Instances

Instances details

(Functor f, Functor g) => Functor (LeftBias tag f g) Source #
Instance details Defined in Generic.Applicative Methods fmap :: (a -> b) -> LeftBias tag f g a -> LeftBias tag f g b # (<$) :: a -> LeftBias tag f g b -> LeftBias tag f g a #
Idiom tag f g => Applicative (LeftBias tag f g) Source #	An applicative instance of `Sum` biased to the left. It injects `pure` into the `InL` constructor: pure = LeftBias . InL . pure
Instance details Defined in Generic.Applicative Methods pure :: a -> LeftBias tag f g a # (<>) :: LeftBias tag f g (a -> b) -> LeftBias tag f g a -> LeftBias tag f g b # liftA2 :: (a -> b -> c) -> LeftBias tag f g a -> LeftBias tag f g b -> LeftBias tag f g c # (>) :: LeftBias tag f g a -> LeftBias tag f g b -> LeftBias tag f g b # (<*) :: LeftBias tag f g a -> LeftBias tag f g b -> LeftBias tag f g a #

newtype RightBias tag f g a Source #

An applicative instance of Sum biased to the right.

It injects pure into the InR constructor:

  pure = LeftBias . InR . pure

Constructors

RightBias (Sum f g a)

Instances

Instances details

(Functor f, Functor g) => Functor (RightBias tag f g) Source #
Instance details Defined in Generic.Applicative Methods fmap :: (a -> b) -> RightBias tag f g a -> RightBias tag f g b # (<$) :: a -> RightBias tag f g b -> RightBias tag f g a #
Idiom tag g f => Applicative (RightBias tag f g) Source #
Instance details Defined in Generic.Applicative Methods pure :: a -> RightBias tag f g a # (<>) :: RightBias tag f g (a -> b) -> RightBias tag f g a -> RightBias tag f g b # liftA2 :: (a -> b -> c) -> RightBias tag f g a -> RightBias tag f g b -> RightBias tag f g c # (>) :: RightBias tag f g a -> RightBias tag f g b -> RightBias tag f g b # (<*) :: RightBias tag f g a -> RightBias tag f g b -> RightBias tag f g a #

type Idiomatically f sums = Generically1 (NewSums (Served sums) f) Source #

A modifier that is used to generically derive Applicative for sum types.

Types with a single constructor can derive Applicative using Generically1 from GHC.Generics:

Generically1 f = Idiomatically f '[]

A datatype with multiple constructors requires more input from the user: what constructor should be pure and how to map between two different constructors in a law-abiding way.

This is done by specifying the appliative morphisms (Idiom) between each constructor.

Applicative for Maybe can be derived via the Terminal applicative morphism, biased to the right. RightBias Terminal means that when we lift over Nothing and Just it will result in Nothing.

data Maybe a = Nothing | Just a
  deriving 
  stock Generic1

  deriving (Functor, Applicative) 
  via Idiomatically Maybe '[RightBias Terminal]

The same description derives Applicative for ZipList:

type ZipList :: Type -> Type
data ZipList a = ZNil | a ::: ZipList
  deriving 
  stock Generic1 

  deriving (Functor, Applicative)
  via Idiomatically ZipList '[RightBias Terminal]

newtype Generically1 f a Source #

Constructors

Generically1 (f a)

Instances

Instances details

Generic1 f => Generic1 (Generically1 f :: k -> Type) Source #
Instance details Defined in Generic.Applicative.Internal Associated Types type Rep1 (Generically1 f) :: k -> Type # Methods from1 :: forall (a :: k0). Generically1 f a -> Rep1 (Generically1 f) a # to1 :: forall (a :: k0). Rep1 (Generically1 f) a -> Generically1 f a #
(Generic1 f, Functor (Rep1 f)) => Functor (Generically1 f) Source #
Instance details Defined in Generic.Applicative.Internal Methods fmap :: (a -> b) -> Generically1 f a -> Generically1 f b # (<$) :: a -> Generically1 f b -> Generically1 f a #
(Generic1 f, Applicative (Rep1 f)) => Applicative (Generically1 f) Source #
Instance details Defined in Generic.Applicative.Internal Methods pure :: a -> Generically1 f a # (<>) :: Generically1 f (a -> b) -> Generically1 f a -> Generically1 f b # liftA2 :: (a -> b -> c) -> Generically1 f a -> Generically1 f b -> Generically1 f c # (>) :: Generically1 f a -> Generically1 f b -> Generically1 f b # (<*) :: Generically1 f a -> Generically1 f b -> Generically1 f a #
type Rep1 (Generically1 f :: k -> Type) Source #
Instance details Defined in Generic.Applicative.Internal type Rep1 (Generically1 f :: k -> Type) = Rep1 f

newtype NewSums sums f a Source #

Constructors

NewSums
Fields reduce :: f a

Instances

Instances details

(Generic1 f, ConvBæSum_ (CheckSum (ToSum (Rep1 f) (Const Void :: k -> Type))) (ToSum (Rep1 f) (Const Void :: k -> Type)), ConvSum (Rep1 f)) => Generic1 (NewSums sums f :: k -> Type) Source #
Instance details Defined in Generic.Applicative.Internal Associated Types type Rep1 (NewSums sums f) :: k -> Type # Methods from1 :: forall (a :: k0). NewSums sums f a -> Rep1 (NewSums sums f) a # to1 :: forall (a :: k0). Rep1 (NewSums sums f) a -> NewSums sums f a #
type Rep1 (NewSums sums f :: k -> Type) Source #
Instance details Defined in Generic.Applicative.Internal type Rep1 (NewSums sums f :: k -> Type) = ReplaceSums sums (BæSum_ (CheckSum (ToSum (Rep1 f) (Const Void :: k -> Type))) (ToSum (Rep1 f) (Const Void :: k -> Type)))

module Generic.Applicative.Idiom