Portability | portable |
---|---|
Stability | provisional |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Safe Haskell | None |
- class Functor f where
- (<$>) :: Functor f => (a -> b) -> f a -> f b
- ($>) :: Functor f => f a -> b -> f b
- class Functor f => Apply f where
- (<..>) :: Apply w => w a -> w (a -> b) -> w b
- liftF2 :: Apply w => (a -> b -> c) -> w a -> w b -> w c
- liftF3 :: Apply w => (a -> b -> c -> d) -> w a -> w b -> w c -> w d
- newtype WrappedApplicative f a = WrapApplicative {
- unwrapApplicative :: f a
- newtype MaybeApply f a = MaybeApply {
- runMaybeApply :: Either (f a) a
Functors
class Functor f where
The Functor
class is used for types that can be mapped over.
Instances of Functor
should satisfy the following laws:
fmap id == id fmap (f . g) == fmap f . fmap g
The instances of Functor
for lists, Maybe
and IO
satisfy these laws.
($>) :: Functor f => f a -> b -> f b
Replace the contents of a functor uniformly with a constant value.
Apply - a strong lax semimonoidal endofunctor
class Functor f => Apply f whereSource
A strong lax semi-monoidal endofunctor.
This is equivalent to an Applicative
without pure
.
Laws:
associative composition: (.) <$> u <.> v <.> w = u <.> (v <.> w)
(<.>) :: f (a -> b) -> f a -> f bSource
(.>) :: f a -> f b -> f bSource
a .> b = const id <$> a <.> b
(<.) :: f a -> f b -> f aSource
a <. b = const <$> a <.> b
liftF2 :: Apply w => (a -> b -> c) -> w a -> w b -> w cSource
Lift a binary function into a comonad with zipping
liftF3 :: Apply w => (a -> b -> c -> d) -> w a -> w b -> w c -> w dSource
Lift a ternary function into a comonad with zipping
Wrappers
newtype WrappedApplicative f a Source
Wrap an Applicative
to be used as a member of Apply
WrapApplicative | |
|
Functor f => Functor (WrappedApplicative f) | |
Applicative f => Applicative (WrappedApplicative f) | |
Alternative f => Alternative (WrappedApplicative f) | |
Applicative f => Apply (WrappedApplicative f) | |
Alternative f => Alt (WrappedApplicative f) | |
Alternative f => Plus (WrappedApplicative f) |
newtype MaybeApply f a Source
Transform a Apply into an Applicative by adding a unit.
MaybeApply | |
|
Functor f => Functor (MaybeApply f) | |
Apply f => Applicative (MaybeApply f) | |
Comonad f => Comonad (MaybeApply f) | |
Extend f => Extend (MaybeApply f) | |
Apply f => Apply (MaybeApply f) |