Data.Functor.Plus

Documentation

class Alt f => Plus f where

Laws:

zero <!> m = m
m <!> zero = m

If extended to an Alternative then zero should equal empty.

Methods

zero :: f a

Instances

Plus First

Defined in Data.Functor.Plus

Methods

zero :: First a

Plus Last

Defined in Data.Functor.Plus

Methods

zero :: Last a

Plus IntMap

Defined in Data.Functor.Plus

Methods

zero :: IntMap a

Plus Seq

Defined in Data.Functor.Plus

Methods

zero :: Seq a

Plus IO

Defined in Data.Functor.Plus

Methods

zero :: IO a

Plus Maybe

Defined in Data.Functor.Plus

Methods

zero :: Maybe a

Plus []

Defined in Data.Functor.Plus

Methods

zero :: [a]

MonadPlus m => Plus (WrappedMonad m)

Defined in Data.Functor.Plus

Methods

zero :: WrappedMonad m a

Plus (Proxy :: Type -> Type)

Defined in Data.Functor.Plus

Methods

zero :: Proxy a

Plus (U1 :: Type -> Type)

Defined in Data.Functor.Plus

Methods

zero :: U1 a

Ord k => Plus (Map k)

Defined in Data.Functor.Plus

Methods

zero :: Map k a

Alternative f => Plus (WrappedApplicative f)

Defined in Data.Functor.Plus

Methods

zero :: WrappedApplicative f a

Plus f => Plus (Lift f)

Defined in Data.Functor.Plus

Methods

zero :: Lift f a

(Apply f, Applicative f) => Plus (ListT f)

Defined in Data.Functor.Plus

Methods

zero :: ListT f a

(Functor f, Monad f) => Plus (MaybeT f)

Defined in Data.Functor.Plus

Methods

zero :: MaybeT f a

(Hashable k, Eq k) => Plus (HashMap k)

Defined in Data.Functor.Plus

Methods

zero :: HashMap k a

ArrowPlus a => Plus (WrappedArrow a b)

Defined in Data.Functor.Plus

Methods

zero :: WrappedArrow a b a0

Plus f => Plus (Rec1 f)

Defined in Data.Functor.Plus

Methods

zero :: Rec1 f a

Plus f => Plus (Static f a)

Defined in Data.Semigroupoid.Static

Methods

zero :: Static f a a0

Plus f => Plus (Backwards f)

Defined in Data.Functor.Plus

Methods

zero :: Backwards f a

(Functor f, Monad f, Error e) => Plus (ErrorT e f)

Defined in Data.Functor.Plus

Methods

zero :: ErrorT e f a

(Functor f, Monad f, Semigroup e, Monoid e) => Plus (ExceptT e f)

Defined in Data.Functor.Plus

Methods

zero :: ExceptT e f a

Plus f => Plus (IdentityT f)

Defined in Data.Functor.Plus

Methods

zero :: IdentityT f a

Plus f => Plus (ReaderT e f)

Defined in Data.Functor.Plus

Methods

zero :: ReaderT e f a

Plus f => Plus (StateT e f)

Defined in Data.Functor.Plus

Methods

zero :: StateT e f a

Plus f => Plus (StateT e f)

Defined in Data.Functor.Plus

Methods

zero :: StateT e f a

Plus f => Plus (WriterT w f)

Since: 5.3.6

Defined in Data.Functor.Plus

Methods

zero :: WriterT w f a

Plus f => Plus (WriterT w f)

Defined in Data.Functor.Plus

Methods

zero :: WriterT w f a

Plus f => Plus (WriterT w f)

Defined in Data.Functor.Plus

Methods

zero :: WriterT w f a

Plus f => Plus (Reverse f)

Defined in Data.Functor.Plus

Methods

zero :: Reverse f a

(Plus f, Plus g) => Plus (Product f g)

Defined in Data.Functor.Plus

Methods

zero :: Product f g a

(Plus f, Plus g) => Plus (f :*: g)

Defined in Data.Functor.Plus

Methods

zero :: (f :*: g) a

Monoid c => Plus (K1 i c :: Type -> Type)

Since: 5.3.8

Defined in Data.Functor.Plus

Methods

zero :: K1 i c a

(Plus f, Functor g) => Plus (Compose f g)

Defined in Data.Functor.Plus

Methods

zero :: Compose f g a

(Plus f, Functor g) => Plus (f :.: g)

Since: 5.3.8

Defined in Data.Functor.Plus

Methods

zero :: (f :.: g) a

Plus f => Plus (M1 i c f)

Defined in Data.Functor.Plus

Methods

zero :: M1 i c f a

Plus f => Plus (RWST r w s f)

Since: 5.3.6

Defined in Data.Functor.Plus

Methods

zero :: RWST r w s f a

Plus f => Plus (RWST r w s f)

Defined in Data.Functor.Plus

Methods

zero :: RWST r w s f a

Plus f => Plus (RWST r w s f)

Defined in Data.Functor.Plus

Methods

zero :: RWST r w s f a

psum :: (Foldable t, Plus f) => t (f a) -> f a

The sum of a collection of actions, generalizing concat.

>>> psum [Just "Hello", Nothing, Just "World"]
Just "Hello"

Since: 5.3.6

gzero :: (Plus (Rep1 f), Generic1 f) => f a

Generic zero. Caveats:

1. Will not compile if f is a sum type.
2. Any types where the a does not appear must have a Monoid instance.

Since: 5.3.8

module Data.Functor.Alt