Tubes.Source

Documentation

newtype Source m a

An exhaustible source of values parameterized over a base monad. It never awaits, it only yields.

Sources are monad transformers in their own right, as they are possibly finite. They may also be synchronously merged as monoids:

    import Data.Monoid

    src1 :: Source IO String
    src1 = Source $ each ["line A1", "line A2", "line A3"]

    src2 :: Source IO String
    src2 = Source $ each ["line B1", "line B2", "line B3", "line B4"]

    src3 :: Source IO String
    src3 = src1 <> src2

    main :: IO ()
    main = runTube $ sample (src1 <> src2) >< pour display
    -- line A1
    -- line B1
    -- line A2
    -- line B2
    -- line A3
    -- line B3
    -- line B4

If one source runs out, the other will continue until completion.

Constructors

Source

Fields

sample :: Tube () a m ()

Instances

MonadTrans Source

Monad m => Monad (Source m)

Monad m => Functor (Source m)

Monad m => Applicative (Source m)

Monad m => Alternative (Source m)

Monad m => MonadPlus (Source m)

MonadIO m => MonadIO (Source m)

Monad m => Monoid (Source m a)

Monad m => Semigroup (Source m a)

reduce :: Monad m => (b -> a -> b) -> b -> Tube () a m () -> m b

Strict left-fold of a Source, using a Pump internally.