Box.Emitter

emit

Documentation

newtype Emitter m a

an Emitter "emits" values of type a. A Source & a Producer (of a's) are the two other alternative but overloaded metaphors out there.

An Emitter "reaches into itself" for the value to emit, where itself is an opaque thing from the pov of usage. An Emitter is named for its main action: it emits.

Constructors

Emitter

Fields

• emit :: m (Maybe a)

Instances

Monad m => Monad (Emitter m)

Defined in Box.Emitter

Methods

(>>=) :: Emitter m a -> (a -> Emitter m b) -> Emitter m b

(>>) :: Emitter m a -> Emitter m b -> Emitter m b

return :: a -> Emitter m a

fail :: String -> Emitter m a

Functor m => Functor (Emitter m)

Defined in Box.Emitter

Methods

fmap :: (a -> b) -> Emitter m a -> Emitter m b

(<$) :: a -> Emitter m b -> Emitter m a

Applicative m => Applicative (Emitter m)

Defined in Box.Emitter

Methods

pure :: a -> Emitter m a

(<*>) :: Emitter m (a -> b) -> Emitter m a -> Emitter m b

liftA2 :: (a -> b -> c) -> Emitter m a -> Emitter m b -> Emitter m c

(*>) :: Emitter m a -> Emitter m b -> Emitter m b

(<*) :: Emitter m a -> Emitter m b -> Emitter m a

(Monad m, Alternative m) => Alternative (Emitter m)

Defined in Box.Emitter

Methods

empty :: Emitter m a

(<|>) :: Emitter m a -> Emitter m a -> Emitter m a

some :: Emitter m a -> Emitter m [a]

many :: Emitter m a -> Emitter m [a]

(Alternative m, Monad m) => MonadPlus (Emitter m)

Defined in Box.Emitter

Methods

mzero :: Emitter m a

mplus :: Emitter m a -> Emitter m a -> Emitter m a

MFunctor Emitter

Defined in Box.Emitter

Methods

hoist :: Monad m => (forall a. m a -> n a) -> Emitter m b -> Emitter n b

(Alternative m, Monad m) => Semigroup (Emitter m a)

Defined in Box.Emitter

Methods

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

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

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

(Alternative m, Monad m) => Monoid (Emitter m a)

Defined in Box.Emitter

Methods

mempty :: Emitter m a

mappend :: Emitter m a -> Emitter m a -> Emitter m a

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

mapE :: Monad m => (a -> m (Maybe b)) -> Emitter m a -> Emitter m b

like a monadic mapMaybe. (See witherable)

readE :: (Functor m, Read a) => Emitter m Text -> Emitter m (Either Text a)

read parse emitter, returning the original string on error

readE_ :: (Monad m, Read a) => Emitter m Text -> Emitter m a

no error-reporting reading

parseE :: Functor m => Parser a -> Emitter m Text -> Emitter m (Either Text a)

parse emitter which returns the original text on failure

parseE_ :: Monad m => Parser a -> Emitter m Text -> Emitter m a

no error-reporting parsing

premapE :: Applicative m => (Emitter m a -> m ()) -> Emitter m a -> Emitter m a

adds a pre-emit monadic action to the emitter

postmapE :: Monad m => (Emitter m a -> m ()) -> Emitter m a -> Emitter m a

adds a post-emit monadic action to the emitter

postmapM :: Monad m => (a -> m ()) -> Emitter m a -> Emitter m a

add a post-emit monadic action on the emitted value (if there was any)

toListE :: Monad m => Emitter m a -> m [a]

turn an emitter into a list

unlistE :: Monad m => Emitter m [a] -> Emitter (StateT [a] m) a

convert a list emitter to a Stateful element emitter

stateE :: Monad m => Emitter (StateT [a] m) a

emit from a StateT list

This compiles but is an infinite "a" emitter:

let e1 = hoist (flip evalStateT ["a", "b"::Text]) stateE :: Emitter IO Text

takeE :: Monad m => Int -> Emitter m a -> Emitter (StateT Int m) a

takeUntilE :: Monad m => (a -> Bool) -> Emitter m a -> Emitter m a

Take from an emitter until predicate

filterE :: Monad m => (a -> Bool) -> Emitter m a -> Emitter m a

Filter emissions according to a predicate.