Potoki.Core.Fetch

Documentation

newtype Fetch element

Passive producer of elements.

Constructors

Fetch (forall x. x -> (element -> x) -> IO x)

Something close to a Church encoding of IO (Maybe element).

Instances

Monad Fetch

Methods

(>>=) :: Fetch a -> (a -> Fetch b) -> Fetch b

(>>) :: Fetch a -> Fetch b -> Fetch b

return :: a -> Fetch a

fail :: String -> Fetch a

Functor Fetch

Methods

fmap :: (a -> b) -> Fetch a -> Fetch b

(<$) :: a -> Fetch b -> Fetch a

Applicative Fetch

Methods

pure :: a -> Fetch a

(<*>) :: Fetch (a -> b) -> Fetch a -> Fetch b

(*>) :: Fetch a -> Fetch b -> Fetch b

(<*) :: Fetch a -> Fetch b -> Fetch a

Alternative Fetch

Methods

empty :: Fetch a

(<|>) :: Fetch a -> Fetch a -> Fetch a

some :: Fetch a -> Fetch [a]

many :: Fetch a -> Fetch [a]

MonadPlus Fetch

Methods

mzero :: Fetch a

mplus :: Fetch a -> Fetch a -> Fetch a

duplicate :: Fetch element -> IO (Fetch element, Fetch element)

list :: IORef [element] -> Fetch element