Box.Committer

Committer wraps a consumer destructor.

"Commitment is an act, not a word." ~ Jean-Paul Sartre

Documentation

newtype Committer m a

A Committer commits values of type a and signals success or otherwise. A sink or a consumer are some other metaphors for this. A Committer absorbs the value being committed; the value disappears into the opaque thing that is a Committer from the pov of usage.

>>> commit toStdout "I'm committed!"
I'm committed!
True

Constructors

Committer

Fields

• commit :: a -> m Bool

Instances

FFunctor Committer

Defined in Box.Committer

Methods

foist :: (forall x. f x -> g x) -> Committer f a -> Committer g a

Contravariant (Committer m)

Defined in Box.Committer

Methods

contramap :: (a' -> a) -> Committer m a -> Committer m a'

(>$) :: b -> Committer m b -> Committer m a

Applicative m => Decidable (Committer m)

Defined in Box.Committer

Methods

lose :: (a -> Void) -> Committer m a

choose :: (a -> Either b c) -> Committer m b -> Committer m c -> Committer m a

Applicative m => Divisible (Committer m)

Defined in Box.Committer

Methods

divide :: (a -> (b, c)) -> Committer m b -> Committer m c -> Committer m a

conquer :: Committer m a

Applicative m => Monoid (Committer m a)

Defined in Box.Committer

Methods

mempty :: Committer m a

mappend :: Committer m a -> Committer m a -> Committer m a

mconcat :: [Committer m a] -> Committer m a

Applicative m => Semigroup (Committer m a)

Defined in Box.Committer

Methods

(<>) :: Committer m a -> Committer m a -> Committer m a

sconcat :: NonEmpty (Committer m a) -> Committer m a

stimes :: Integral b => b -> Committer m a -> Committer m a

type CoCommitter m a = Codensity m (Committer m a)

Committer continuation.

witherC :: Monad m => (b -> m (Maybe a)) -> Committer m a -> Committer m b

A monadic Witherable

>>> glue (witherC (\x -> pure $ bool Nothing (Just x) (even x)) showStdout) <$|> qList [0..5]
0
2
4

listC :: Monad m => Committer m a -> Committer m [a]

Convert a committer to be a list committer.

>>> glue showStdout <$|> qList [[1..3]]
[1,2,3]

>>> glue (listC showStdout) <$|> qList [[1..3]]
1
2
3

push :: Monad m => Committer (StateT (Seq a) m) a

Push to a state sequence.

>>> import Control.Monad.State.Lazy
>>> import qualified Data.Sequence as Seq
>>> flip execStateT Seq.empty . glue push . foist lift <$|> qList [1..3]
fromList [1,2,3]