ap package:selective

ap :: ApplicativeS f => f a -> f (a -> b) -> f b

Recover the application operator <*> from matchOne.

apS :: Selective f => f (a -> b) -> f a -> f b

Recover the application operator <*> from select. Rigid selective functors satisfy the law <*> = apS and furthermore, the resulting applicative functor satisfies all laws of Applicative:

Identity:
```
pure id <*> v = v
```
Homomorphism:
```
pure f <*> pure x = pure (f x)
```
Interchange:
```
u <*> pure y = pure ($y) <*>
u
```
Composition:
```
(.) <$> u <*> v <*> w = u
<*> (v <*> w)
```

apS :: Selective f => f a -> f (a -> b) -> f b

selective Control.Selective.Multi

Recover the application operator <*> from match.

apply :: (t ~> u) -> Sigma t -> Sigma u

selective Control.Selective.Multi

Update a generalised sum given a generalised product that takes care of all possible cases.

class Functor f => ApplicativeS f

selective Control.Selective.Multi

An alternative definition of applicative functors, as witnessed by ap and matchOne. This class is almost like Selective but has a strict constraint on t.

swapEither :: Either a b -> Either b a

selective Control.Selective

Swap Left and Right.

mapExcept :: (Either e a -> Either e' b) -> Except e a -> Except e' b

selective Control.Selective.Trans.Except

mapExceptT :: (m (Either e a) -> n (Either e' b)) -> ExceptT e m a -> ExceptT e' n b

selective Control.Selective.Trans.Except

unwrap :: ExceptT e f a -> ExceptT e f a

selective Control.Selective.Trans.Except

wrap :: ExceptT e m a -> ExceptT e m a

selective Control.Selective.Trans.Except

Inject an ExceptT value into the newtype wrapper.