| Copyright | (c) 2017 Harendra Kumar |
|---|---|
| License | BSD3 |
| Maintainer | streamly@composewell.com |
| Stability | experimental |
| Portability | GHC |
| Safe Haskell | None |
| Language | Haskell2010 |
Streamly.Internal.Data.Stream.StreamK
Description
Continuation passing style (CPS) stream implementation. The symbol K below
denotes a function as well as a Kontinuation.
import qualified Streamly.Internal.Data.Stream.StreamK as K
Synopsis
- class (forall m a. MonadAsync m => Semigroup (t m a), forall m a. MonadAsync m => Monoid (t m a), forall m. Monad m => Functor (t m), forall m. MonadAsync m => Applicative (t m)) => IsStream t where
- toStream :: t m a -> Stream m a
- fromStream :: Stream m a -> t m a
- consM :: MonadAsync m => m a -> t m a -> t m a
- (|:) :: MonadAsync m => m a -> t m a -> t m a
- adapt :: (IsStream t1, IsStream t2) => t1 m a -> t2 m a
- newtype Stream m a = MkStream (forall r. State Stream m a -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
- mkStream :: IsStream t => (forall r. State Stream m a -> (a -> t m a -> m r) -> (a -> m r) -> m r -> m r) -> t m a
- nil :: IsStream t => t m a
- nilM :: (IsStream t, Monad m) => m b -> t m a
- cons :: IsStream t => a -> t m a -> t m a
- (.:) :: IsStream t => a -> t m a -> t m a
- foldStream :: IsStream t => State Stream m a -> (a -> t m a -> m r) -> (a -> m r) -> m r -> t m a -> m r
- foldStreamShared :: IsStream t => State Stream m a -> (a -> t m a -> m r) -> (a -> m r) -> m r -> t m a -> m r
- unShare :: IsStream t => t m a -> t m a
- uncons :: (IsStream t, Monad m) => t m a -> m (Maybe (a, t m a))
- unfoldr :: IsStream t => (b -> Maybe (a, b)) -> b -> t m a
- unfoldrM :: (IsStream t, MonadAsync m) => (b -> m (Maybe (a, b))) -> b -> t m a
- repeat :: IsStream t => a -> t m a
- repeatM :: (IsStream t, MonadAsync m) => m a -> t m a
- replicate :: IsStream t => Int -> a -> t m a
- replicateM :: (IsStream t, MonadAsync m) => Int -> m a -> t m a
- fromIndices :: IsStream t => (Int -> a) -> t m a
- fromIndicesM :: (IsStream t, MonadAsync m) => (Int -> m a) -> t m a
- iterate :: IsStream t => (a -> a) -> a -> t m a
- iterateM :: (IsStream t, MonadAsync m) => (a -> m a) -> m a -> t m a
- yield :: IsStream t => a -> t m a
- yieldM :: (Monad m, IsStream t) => m a -> t m a
- fromFoldable :: (IsStream t, Foldable f) => f a -> t m a
- fromList :: IsStream t => [a] -> t m a
- fromStreamK :: IsStream t => Stream m a -> t m a
- foldrS :: IsStream t => (a -> t m b -> t m b) -> t m b -> t m a -> t m b
- foldrSM :: (IsStream t, Monad m) => (m a -> t m b -> t m b) -> t m b -> t m a -> t m b
- buildS :: IsStream t => ((a -> t m a -> t m a) -> t m a -> t m a) -> t m a
- buildM :: (IsStream t, MonadAsync m) => (forall r. (a -> t m a -> m r) -> (a -> m r) -> m r -> m r) -> t m a
- augmentS :: IsStream t => ((a -> t m a -> t m a) -> t m a -> t m a) -> t m a -> t m a
- augmentSM :: (IsStream t, MonadAsync m) => ((m a -> t m a -> t m a) -> t m a -> t m a) -> t m a -> t m a
- foldr :: (IsStream t, Monad m) => (a -> b -> b) -> b -> t m a -> m b
- foldr1 :: (IsStream t, Monad m) => (a -> a -> a) -> t m a -> m (Maybe a)
- foldrM :: IsStream t => (a -> m b -> m b) -> m b -> t m a -> m b
- foldrT :: (IsStream t, Monad m, Monad (s m), MonadTrans s) => (a -> s m b -> s m b) -> s m b -> t m a -> s m b
- foldl' :: (IsStream t, Monad m) => (b -> a -> b) -> b -> t m a -> m b
- foldlM' :: (IsStream t, Monad m) => (b -> a -> m b) -> b -> t m a -> m b
- foldlS :: IsStream t => (t m b -> a -> t m b) -> t m b -> t m a -> t m b
- foldlT :: (IsStream t, Monad m, Monad (s m), MonadTrans s) => (s m b -> a -> s m b) -> s m b -> t m a -> s m b
- foldlx' :: forall t m a b x. (IsStream t, Monad m) => (x -> a -> x) -> x -> (x -> b) -> t m a -> m b
- foldlMx' :: (IsStream t, Monad m) => (x -> a -> m x) -> m x -> (x -> m b) -> t m a -> m b
- drain :: (Monad m, IsStream t) => t m a -> m ()
- null :: (IsStream t, Monad m) => t m a -> m Bool
- head :: (IsStream t, Monad m) => t m a -> m (Maybe a)
- tail :: (IsStream t, Monad m) => t m a -> m (Maybe (t m a))
- init :: (IsStream t, Monad m) => t m a -> m (Maybe (t m a))
- elem :: (IsStream t, Monad m, Eq a) => a -> t m a -> m Bool
- notElem :: (IsStream t, Monad m, Eq a) => a -> t m a -> m Bool
- all :: (IsStream t, Monad m) => (a -> Bool) -> t m a -> m Bool
- any :: (IsStream t, Monad m) => (a -> Bool) -> t m a -> m Bool
- last :: (IsStream t, Monad m) => t m a -> m (Maybe a)
- minimum :: (IsStream t, Monad m, Ord a) => t m a -> m (Maybe a)
- minimumBy :: (IsStream t, Monad m) => (a -> a -> Ordering) -> t m a -> m (Maybe a)
- maximum :: (IsStream t, Monad m, Ord a) => t m a -> m (Maybe a)
- maximumBy :: (IsStream t, Monad m) => (a -> a -> Ordering) -> t m a -> m (Maybe a)
- findIndices :: IsStream t => (a -> Bool) -> t m a -> t m Int
- lookup :: (IsStream t, Monad m, Eq a) => a -> t m (a, b) -> m (Maybe b)
- findM :: (IsStream t, Monad m) => (a -> m Bool) -> t m a -> m (Maybe a)
- find :: (IsStream t, Monad m) => (a -> Bool) -> t m a -> m (Maybe a)
- (!!) :: (IsStream t, Monad m) => t m a -> Int -> m (Maybe a)
- mapM_ :: (IsStream t, Monad m) => (a -> m b) -> t m a -> m ()
- toList :: (IsStream t, Monad m) => t m a -> m [a]
- toStreamK :: Stream m a -> Stream m a
- hoist :: (IsStream t, Monad m, Monad n) => (forall x. m x -> n x) -> t m a -> t n a
- scanl' :: IsStream t => (b -> a -> b) -> b -> t m a -> t m b
- scanlx' :: IsStream t => (x -> a -> x) -> x -> (x -> b) -> t m a -> t m b
- filter :: IsStream t => (a -> Bool) -> t m a -> t m a
- take :: IsStream t => Int -> t m a -> t m a
- takeWhile :: IsStream t => (a -> Bool) -> t m a -> t m a
- drop :: IsStream t => Int -> t m a -> t m a
- dropWhile :: IsStream t => (a -> Bool) -> t m a -> t m a
- map :: IsStream t => (a -> b) -> t m a -> t m b
- mapM :: (IsStream t, MonadAsync m) => (a -> m b) -> t m a -> t m b
- mapMSerial :: MonadAsync m => (a -> m b) -> Stream m a -> Stream m b
- sequence :: (IsStream t, MonadAsync m) => t m (m a) -> t m a
- intersperseM :: (IsStream t, MonadAsync m) => m a -> t m a -> t m a
- intersperse :: (IsStream t, MonadAsync m) => a -> t m a -> t m a
- insertBy :: IsStream t => (a -> a -> Ordering) -> a -> t m a -> t m a
- deleteBy :: IsStream t => (a -> a -> Bool) -> a -> t m a -> t m a
- reverse :: IsStream t => t m a -> t m a
- mapMaybe :: IsStream t => (a -> Maybe b) -> t m a -> t m b
- zipWith :: IsStream t => (a -> b -> c) -> t m a -> t m b -> t m c
- zipWithM :: (IsStream t, Monad m) => (a -> b -> m c) -> t m a -> t m b -> t m c
- mergeBy :: (IsStream t, Monad m) => (a -> a -> Ordering) -> t m a -> t m a -> t m a
- mergeByM :: (IsStream t, Monad m) => (a -> a -> m Ordering) -> t m a -> t m a -> t m a
- concatMapBy :: IsStream t => (forall c. t m c -> t m c -> t m c) -> (a -> t m b) -> t m a -> t m b
- concatMap :: IsStream t => (a -> t m b) -> t m a -> t m b
- bindWith :: IsStream t => (forall c. t m c -> t m c -> t m c) -> t m a -> (a -> t m b) -> t m b
- the :: (Eq a, IsStream t, Monad m) => t m a -> m (Maybe a)
- serial :: IsStream t => t m a -> t m a -> t m a
- consMStream :: Monad m => m a -> Stream m a -> Stream m a
- withLocal :: MonadReader r m => (r -> r) -> Stream m a -> Stream m a
- mfix :: (IsStream t, Monad m) => (m a -> t m a) -> t m a
- type Streaming = IsStream
- once :: (Monad m, IsStream t) => m a -> t m a
A class for streams
class (forall m a. MonadAsync m => Semigroup (t m a), forall m a. MonadAsync m => Monoid (t m a), forall m. Monad m => Functor (t m), forall m. MonadAsync m => Applicative (t m)) => IsStream t where Source #
Class of types that can represent a stream of elements of some type a in
some monad m.
Since: 0.2.0
Methods
toStream :: t m a -> Stream m a Source #
fromStream :: Stream m a -> t m a Source #
consM :: MonadAsync m => m a -> t m a -> t m a infixr 5 Source #
Constructs a stream by adding a monadic action at the head of an existing stream. For example:
> toList $ getLine `consM` getLine `consM` nil hello world ["hello","world"]
Concurrent (do not use parallely to construct infinite streams)
Since: 0.2.0
(|:) :: MonadAsync m => m a -> t m a -> t m a infixr 5 Source #
Operator equivalent of consM. We can read it as "parallel colon"
to remember that | comes before :.
> toList $ getLine |: getLine |: nil hello world ["hello","world"]
let delay = threadDelay 1000000 >> print 1 drain $ serially $ delay |: delay |: delay |: nil drain $ parallely $ delay |: delay |: delay |: nil
Concurrent (do not use parallely to construct infinite streams)
Since: 0.2.0
Instances
adapt :: (IsStream t1, IsStream t2) => t1 m a -> t2 m a Source #
Adapt any specific stream type to any other specific stream type.
Since: 0.1.0
The stream type
The type Stream m a represents a monadic stream of values of type a
constructed using actions in monad m. It uses stop, singleton and yield
continuations equivalent to the following direct style type:
data Stream m a = Stop | Singleton a | Yield a (Stream m a)
To facilitate parallel composition we maintain a local state in an SVar
that is shared across and is used for synchronization of the streams being
composed.
The singleton case can be expressed in terms of stop and yield but we have
it as a separate case to optimize composition operations for streams with
single element. We build singleton streams in the implementation of pure
for Applicative and Monad, and in lift for MonadTrans.
XXX remove the Stream type parameter from State as it is always constant. We can remove it from SVar as well
Constructors
| MkStream (forall r. State Stream m a -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r) |
Instances
| MonadTrans Stream Source # | |
Defined in Streamly.Internal.Data.Stream.StreamK.Type | |
| IsStream Stream Source # | |
Defined in Streamly.Internal.Data.Stream.StreamK.Type | |
| Monad m => Monad (Stream m) Source # | |
| Monad m => Functor (Stream m) Source # | |
| Monad m => Applicative (Stream m) Source # | |
Defined in Streamly.Internal.Data.Stream.StreamK.Type | |
| Semigroup (Stream m a) Source # | |
| Monoid (Stream m a) Source # | |
Construction Primitives
mkStream :: IsStream t => (forall r. State Stream m a -> (a -> t m a -> m r) -> (a -> m r) -> m r -> m r) -> t m a Source #
Build a stream from an SVar, a stop continuation, a singleton stream
continuation and a yield continuation.
nilM :: (IsStream t, Monad m) => m b -> t m a Source #
An empty stream producing a side effect.
> toList (nilM (print "nil")) "nil" []
Internal
cons :: IsStream t => a -> t m a -> t m a infixr 5 Source #
Construct a stream by adding a pure value at the head of an existing
stream. For serial streams this is the same as (return a) `consM` r but
more efficient. For concurrent streams this is not concurrent whereas
consM is concurrent. For example:
> toList $ 1 `cons` 2 `cons` 3 `cons` nil [1,2,3]
Since: 0.1.0
Elimination Primitives
foldStream :: IsStream t => State Stream m a -> (a -> t m a -> m r) -> (a -> m r) -> m r -> t m a -> m r Source #
Fold a stream by providing a State, stop continuation, a singleton continuation and a yield continuation. The stream will not use the SVar passed via State.
foldStreamShared :: IsStream t => State Stream m a -> (a -> t m a -> m r) -> (a -> m r) -> m r -> t m a -> m r Source #
Fold a stream by providing an SVar, a stop continuation, a singleton continuation and a yield continuation. The stream would share the current SVar passed via the State.
Transformation Primitives
Deconstruction
Generation
Unfolds
Specialized Generation
repeatM :: (IsStream t, MonadAsync m) => m a -> t m a Source #
repeatM = fix . cons repeatM = cycle1 . yield
Generate an infinite stream by repeating a monadic value.
Internal
replicateM :: (IsStream t, MonadAsync m) => Int -> m a -> t m a Source #
fromIndices :: IsStream t => (Int -> a) -> t m a Source #
fromIndicesM :: (IsStream t, MonadAsync m) => (Int -> m a) -> t m a Source #
iterateM :: (IsStream t, MonadAsync m) => (a -> m a) -> m a -> t m a Source #
Conversions
fromFoldable :: (IsStream t, Foldable f) => f a -> t m a Source #
fromStreamK :: IsStream t => Stream m a -> t m a Source #
foldr/build
foldrS :: IsStream t => (a -> t m b -> t m b) -> t m b -> t m a -> t m b Source #
Lazy right associative fold to a stream.
buildM :: (IsStream t, MonadAsync m) => (forall r. (a -> t m a -> m r) -> (a -> m r) -> m r -> m r) -> t m a Source #
augmentSM :: (IsStream t, MonadAsync m) => ((m a -> t m a -> t m a) -> t m a -> t m a) -> t m a -> t m a Source #
Elimination
General Folds
foldr :: (IsStream t, Monad m) => (a -> b -> b) -> b -> t m a -> m b Source #
Lazy right associative fold.
foldrM :: IsStream t => (a -> m b -> m b) -> m b -> t m a -> m b Source #
Lazy right fold with a monadic step function.
foldrT :: (IsStream t, Monad m, Monad (s m), MonadTrans s) => (a -> s m b -> s m b) -> s m b -> t m a -> s m b Source #
Right associative fold to an arbitrary transformer monad.
foldl' :: (IsStream t, Monad m) => (b -> a -> b) -> b -> t m a -> m b Source #
Strict left associative fold.
foldlM' :: (IsStream t, Monad m) => (b -> a -> m b) -> b -> t m a -> m b Source #
Like foldl' but with a monadic step function.
foldlS :: IsStream t => (t m b -> a -> t m b) -> t m b -> t m a -> t m b Source #
Lazy left fold to a stream.
foldlT :: (IsStream t, Monad m, Monad (s m), MonadTrans s) => (s m b -> a -> s m b) -> s m b -> t m a -> s m b Source #
Lazy left fold to an arbitrary transformer monad.
foldlx' :: forall t m a b x. (IsStream t, Monad m) => (x -> a -> x) -> x -> (x -> b) -> t m a -> m b Source #
Strict left fold with an extraction function. Like the standard strict
left fold, but applies a user supplied extraction function (the third
argument) to the folded value at the end. This is designed to work with the
foldl library. The suffix x is a mnemonic for extraction.
Note that the accumulator is always evaluated including the initial value.
foldlMx' :: (IsStream t, Monad m) => (x -> a -> m x) -> m x -> (x -> m b) -> t m a -> m b Source #
Like foldx, but with a monadic step function.
Specialized Folds
drain :: (Monad m, IsStream t) => t m a -> m () Source #
drain = foldl' (\_ _ -> ()) () drain = mapM_ (\_ -> return ())
last :: (IsStream t, Monad m) => t m a -> m (Maybe a) Source #
Extract the last element of the stream, if any.
Map and Fold
mapM_ :: (IsStream t, Monad m) => (a -> m b) -> t m a -> m () Source #
Apply a monadic action to each element of the stream and discard the output of the action.
Conversions
Transformation
By folding (scans)
Filtering
Mapping
mapM :: (IsStream t, MonadAsync m) => (a -> m b) -> t m a -> t m b Source #
mapMSerial :: MonadAsync m => (a -> m b) -> Stream m a -> Stream m b Source #
sequence :: (IsStream t, MonadAsync m) => t m (m a) -> t m a Source #
Inserting
intersperseM :: (IsStream t, MonadAsync m) => m a -> t m a -> t m a Source #
intersperse :: (IsStream t, MonadAsync m) => a -> t m a -> t m a Source #
Deleting
Reordering
Map and Filter
Zipping
zipWith :: IsStream t => (a -> b -> c) -> t m a -> t m b -> t m c Source #
Zip two streams serially using a pure zipping function.
Since: 0.1.0
zipWithM :: (IsStream t, Monad m) => (a -> b -> m c) -> t m a -> t m b -> t m c Source #
Zip two streams serially using a monadic zipping function.
Since: 0.1.0
Merging
Nesting
concatMapBy :: IsStream t => (forall c. t m c -> t m c -> t m c) -> (a -> t m b) -> t m a -> t m b Source #
bindWith :: IsStream t => (forall c. t m c -> t m c -> t m c) -> t m a -> (a -> t m b) -> t m b Source #
Transformation comprehensions
Semigroup Style Composition
Utilities
mfix :: (IsStream t, Monad m) => (m a -> t m a) -> t m a Source #
Iterate a lazy function f of the shape `m a -> t m a` until it gets
fully defined i.e. becomes independent of its argument action, then return
the resulting value of the function (`t m a`).
It can be used to construct a stream that uses a cyclic definition. For example:
import Streamly.Internal.Prelude as S
import System.IO.Unsafe (unsafeInterleaveIO)
main = do
S.mapM_ print $ S.mfix $ x -> do
a <- S.fromList [1,2]
b <- S.fromListM [return 3, unsafeInterleaveIO (fmap fst x)]
return (a, b)
Note that the function f must be lazy in its argument, that's why we use
unsafeInterleaveIO because IO monad is strict.
Internal