Copyright | (C) 2011-2018 Edward Kmett |
---|---|
License | BSD-style (see the file LICENSE) |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Stability | provisional |
Portability | portable |
Safe Haskell | Trustworthy |
Language | Haskell98 |
This module is used to resolve the cyclic we get from defining these
classes here rather than in a package upstream. Otherwise we'd get
orphaned heads for many instances on the types in transformers
and bifunctors
.
Synopsis
- class Functor f => Apply f where
- newtype WrappedApplicative f a = WrapApplicative {
- unwrapApplicative :: f a
- newtype MaybeApply f a = MaybeApply {
- runMaybeApply :: Either (f a) a
- class Apply m => Bind m where
- apDefault :: Bind f => f (a -> b) -> f a -> f b
- returning :: Functor f => f a -> (a -> b) -> f b
- class Bifunctor p => Biapply p where
Applyable functors
class Functor f => Apply f where Source #
A strong lax semi-monoidal endofunctor.
This is equivalent to an Applicative
without pure
.
Laws:
(.
)<$>
u<.>
v<.>
w = u<.>
(v<.>
w) x<.>
(f<$>
y) = (.
f)<$>
x<.>
y f<$>
(x<.>
y) = (f.
)<$>
x<.>
y
The laws imply that .>
and <.
really ignore their
left and right results, respectively, and really
return their right and left results, respectively.
Specifically,
(mf<$>
m).>
(nf<$>
n) = nf<$>
(m.>
n) (mf<$>
m)<.
(nf<$>
n) = mf<$>
(m<.
n)
(<.>) :: f (a -> b) -> f a -> f b infixl 4 Source #
(.>) :: f a -> f b -> f b infixl 4 Source #
(<.) :: f a -> f b -> f a infixl 4 Source #
liftF2 :: (a -> b -> c) -> f a -> f b -> f c Source #
Lift a binary function into a comonad with zipping
Instances
Wrappers
newtype WrappedApplicative f a Source #
Wrap an Applicative
to be used as a member of Apply
WrapApplicative | |
|
Instances
newtype MaybeApply f a Source #
Transform a Apply into an Applicative by adding a unit.
MaybeApply | |
|
Instances
Bindable functors
class Apply m => Bind m where Source #
Minimal definition: Either join
or >>-
If defining both, then the following laws (the default definitions) must hold:
join = (>>- id) m >>- f = join (fmap f m)
Laws:
induced definition of <.>: f <.> x = f >>- (<$> x)
Finally, there are two associativity conditions:
associativity of (>>-): (m >>- f) >>- g == m >>- (\x -> f x >>- g) associativity of join: join . join = join . fmap join
These can both be seen as special cases of the constraint that
associativity of (->-): (f ->- g) ->- h = f ->- (g ->- h)
Instances
Biappliable bifunctors
class Bifunctor p => Biapply p where Source #
(<<.>>) :: p (a -> b) (c -> d) -> p a c -> p b d infixl 4 Source #
Instances
Biapply (,) Source # | |
Biapply Arg Source # | |
Semigroup x => Biapply ((,,) x) Source # | |
Biapply (Const :: * -> * -> *) Source # | |
Biapply (Tagged :: * -> * -> *) Source # | |
(Semigroup x, Semigroup y) => Biapply ((,,,) x y) Source # | |
(Semigroup x, Semigroup y, Semigroup z) => Biapply ((,,,,) x y z) Source # | |
Biapply p => Biapply (WrappedBifunctor p) Source # | |
Defined in Data.Functor.Bind.Class (<<.>>) :: WrappedBifunctor p (a -> b) (c -> d) -> WrappedBifunctor p a c -> WrappedBifunctor p b d Source # (.>>) :: WrappedBifunctor p a b -> WrappedBifunctor p c d -> WrappedBifunctor p c d Source # (<<.) :: WrappedBifunctor p a b -> WrappedBifunctor p c d -> WrappedBifunctor p a b Source # | |
Apply g => Biapply (Joker g :: * -> * -> *) Source # | |
Biapply p => Biapply (Flip p) Source # | |
Apply f => Biapply (Clown f :: * -> * -> *) Source # | |
(Biapply p, Biapply q) => Biapply (Product p q) Source # | |
(Apply f, Biapply p) => Biapply (Tannen f p) Source # | |
(Biapply p, Apply f, Apply g) => Biapply (Biff p f g) Source # | |