{-# LANGUAGE UndecidableInstances #-}

#include "inline.hs"

-- |
-- Module      : Streamly.Internal.Data.Stream.StreamK
-- Copyright   : (c) 2017 Composewell Technologies
--
-- License     : BSD3
-- Maintainer  : streamly@composewell.com
-- Stability   : experimental
-- Portability : GHC
--
--
-- 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
-- @
--
module Streamly.Internal.Data.Stream.StreamK
    (
    -- * The stream type
      Stream(..)

    -- * Construction Primitives
    , mkStream
    , nil
    , nilM
    , cons
    , (.:)

    -- * Elimination Primitives
    , foldStream
    , foldStreamShared

    -- * Transformation Primitives
    , unShare

    -- * Deconstruction
    , uncons

    -- * Generation
    -- ** Unfolds
    , unfoldr
    , unfoldrM

    -- ** Specialized Generation
    , repeat
    , repeatM
    , replicate
    , replicateM
    , fromIndices
    , fromIndicesM
    , iterate
    , iterateM

    -- ** Conversions
    , fromPure
    , fromEffect
    , fromFoldable
    , fromList

    -- * foldr/build
    , foldrS
    , foldrSM
    , buildS
    , augmentS

    -- * Elimination
    -- ** General Folds
    , foldr
    , foldr1
    , foldrM
    , foldrT

    , foldl'
    , foldlM'
    , foldlS
    , foldlT
    , foldlx'
    , foldlMx'
    , fold

    -- ** Specialized Folds
    , drain
    , null
    , head
    , tail
    , init
    , elem
    , notElem
    , all
    , any
    , last
    , minimum
    , minimumBy
    , maximum
    , maximumBy
    , findIndices
    , lookup
    , findM
    , find
    , (!!)

    -- ** Map and Fold
    , mapM_

    -- ** Conversions
    , toList
    , hoist

    -- * Transformation
    -- ** By folding (scans)
    , scanl'
    , scanlx'

    -- ** Filtering
    , filter
    , take
    , takeWhile
    , drop
    , dropWhile

    -- ** Mapping
    , map
    , mapM
    , sequence

    -- ** Inserting
    , intersperseM
    , intersperse
    , insertBy

    -- ** Deleting
    , deleteBy

    -- ** Reordering
    , reverse

    -- ** Map and Filter
    , mapMaybe

    -- ** Zipping
    , zipWith
    , zipWithM

    -- ** Merging
    , mergeBy
    , mergeByM

    -- ** Nesting
    , concatMapWith
    , concatMap
    , bindWith
    , concatPairsWith
    , apWith
    , apSerial
    , apSerialDiscardFst
    , apSerialDiscardSnd

    -- ** Transformation comprehensions
    , the

    -- * Semigroup Style Composition
    , serial

    -- * Utilities
    , consM
    , withLocal
    , mfix
    )
where

import Control.Monad.Trans.Class (MonadTrans(lift))
import Control.Monad (void, join)
import Streamly.Internal.Data.SVar.Type (adaptState, defState)

import qualified Streamly.Internal.Data.Fold.Type as FL

import Prelude
       hiding (foldl, foldr, last, map, mapM, mapM_, repeat, sequence,
               take, filter, all, any, takeWhile, drop, dropWhile, minimum,
               maximum, elem, notElem, null, head, tail, init, zipWith, lookup,
               foldr1, (!!), replicate, reverse, concatMap, iterate)

import Streamly.Internal.Data.Stream.StreamK.Type

-- $setup
-- >>> :m

-------------------------------------------------------------------------------
-- Generation
-------------------------------------------------------------------------------

{-# INLINE unfoldrM #-}
unfoldrM :: Monad m => (b -> m (Maybe (a, b))) -> b -> Stream m a
unfoldrM :: forall (m :: * -> *) b a.
Monad m =>
(b -> m (Maybe (a, b))) -> b -> Stream m a
unfoldrM = forall (m :: * -> *) a b.
Monad m =>
(m a -> Stream m a -> Stream m a)
-> (b -> m (Maybe (a, b))) -> b -> Stream m a
unfoldrMWith forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
consM
{-
-- Generalization of concurrent streams/SVar via unfoldr.
--
-- Unfold a value into monadic actions and then run the resulting monadic
-- actions to generate a stream. Since the step of generating the monadic
-- action and running them are decoupled we can run the monadic actions
-- cooncurrently. For example, the seed could be a list of monadic actions or a
-- pure stream of monadic actions.
--
-- We can have different flavors of this depending on the stream type t. The
-- concurrent version could be async or ahead etc. Depending on how we queue
-- back the feedback portion b, it could be DFS or BFS style.
--
unfoldrA :: (IsStream t, MonadAsync m) =>
    (b -> Maybe (m a, b)) -> b -> Stream m a
unfoldrA = undefined
-}

-------------------------------------------------------------------------------
-- Special generation
-------------------------------------------------------------------------------

repeatM :: Monad m => m a -> Stream m a
repeatM :: forall (m :: * -> *) a. Monad m => m a -> Stream m a
repeatM = forall (m :: * -> *) a (t :: (* -> *) -> * -> *).
(m a -> t m a -> t m a) -> m a -> t m a
repeatMWith forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
consM

{-# INLINE replicateM #-}
replicateM :: Monad m => Int -> m a -> Stream m a
replicateM :: forall (m :: * -> *) a. Monad m => Int -> m a -> Stream m a
replicateM = forall (m :: * -> *) a.
(m a -> Stream m a -> Stream m a) -> Int -> m a -> Stream m a
replicateMWith forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
consM
{-# INLINE replicate #-}
replicate :: Int -> a -> Stream m a
replicate :: forall a (m :: * -> *). Int -> a -> Stream m a
replicate Int
n a
a = forall {t} {m :: * -> *}. (Ord t, Num t) => t -> Stream m a
go Int
n
    where
    go :: t -> Stream m a
go t
cnt = if t
cnt forall a. Ord a => a -> a -> Bool
<= t
0 then forall (m :: * -> *) a. Stream m a
nil else a
a forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` t -> Stream m a
go (t
cnt forall a. Num a => a -> a -> a
- t
1)

{-# INLINE fromIndicesM #-}
fromIndicesM :: Monad m => (Int -> m a) -> Stream m a
fromIndicesM :: forall (m :: * -> *) a. Monad m => (Int -> m a) -> Stream m a
fromIndicesM = forall (m :: * -> *) a.
(m a -> Stream m a -> Stream m a) -> (Int -> m a) -> Stream m a
fromIndicesMWith forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
consM
{-# INLINE fromIndices #-}
fromIndices :: (Int -> a) -> Stream m a
fromIndices :: forall a (m :: * -> *). (Int -> a) -> Stream m a
fromIndices Int -> a
gen = forall {m :: * -> *}. Int -> Stream m a
go Int
0
  where
    go :: Int -> Stream m a
go Int
n = Int -> a
gen Int
n forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Int -> Stream m a
go (Int
n forall a. Num a => a -> a -> a
+ Int
1)

{-# INLINE iterate #-}
iterate :: (a -> a) -> a -> Stream m a
iterate :: forall a (m :: * -> *). (a -> a) -> a -> Stream m a
iterate a -> a
step = forall {m :: * -> *}. a -> Stream m a
go
    where
        go :: a -> Stream m a
go !a
s = forall a (m :: * -> *). a -> Stream m a -> Stream m a
cons a
s (a -> Stream m a
go (a -> a
step a
s))

{-# INLINE iterateM #-}
iterateM :: Monad m => (a -> m a) -> m a -> Stream m a
iterateM :: forall (m :: * -> *) a. Monad m => (a -> m a) -> m a -> Stream m a
iterateM = forall (m :: * -> *) a.
Monad m =>
(m a -> Stream m a -> Stream m a)
-> (a -> m a) -> m a -> Stream m a
iterateMWith forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
consM

-------------------------------------------------------------------------------
-- Conversions
-------------------------------------------------------------------------------

{-# INLINE fromList #-}
fromList :: [a] -> Stream m a
fromList :: forall a (m :: * -> *). [a] -> Stream m a
fromList = forall (f :: * -> *) a (m :: * -> *).
Foldable f =>
f a -> Stream m a
fromFoldable

-------------------------------------------------------------------------------
-- Elimination by Folding
-------------------------------------------------------------------------------

-- | Lazy right associative fold.
{-# INLINE foldr #-}
foldr :: Monad m => (a -> b -> b) -> b -> Stream m a -> m b
foldr :: forall (m :: * -> *) a b.
Monad m =>
(a -> b -> b) -> b -> Stream m a -> m b
foldr a -> b -> b
step b
acc = forall a (m :: * -> *) b.
(a -> m b -> m b) -> m b -> Stream m a -> m b
foldrM (\a
x m b
xs -> m b
xs forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \b
b -> forall (m :: * -> *) a. Monad m => a -> m a
return (a -> b -> b
step a
x b
b)) (forall (m :: * -> *) a. Monad m => a -> m a
return b
acc)

-- | Right associative fold to an arbitrary transformer monad.
{-# INLINE foldrT #-}
foldrT :: (Monad m, Monad (s m), MonadTrans s)
    => (a -> s m b -> s m b) -> s m b -> Stream m a -> s m b
foldrT :: forall (m :: * -> *) (s :: (* -> *) -> * -> *) a b.
(Monad m, Monad (s m), MonadTrans s) =>
(a -> s m b -> s m b) -> s m b -> Stream m a -> s m b
foldrT a -> s m b -> s m b
step s m b
final = Stream m a -> s m b
go
  where
    go :: Stream m a -> s m b
go Stream m a
m1 = do
        Maybe (a, Stream m a)
res <- forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *) a.
Applicative m =>
Stream m a -> m (Maybe (a, Stream m a))
uncons Stream m a
m1
        case Maybe (a, Stream m a)
res of
            Just (a
h, Stream m a
t) -> a -> s m b -> s m b
step a
h (Stream m a -> s m b
go Stream m a
t)
            Maybe (a, Stream m a)
Nothing -> s m b
final

{-# INLINE foldr1 #-}
foldr1 :: Monad m => (a -> a -> a) -> Stream m a -> m (Maybe a)
foldr1 :: forall (m :: * -> *) a.
Monad m =>
(a -> a -> a) -> Stream m a -> m (Maybe a)
foldr1 a -> a -> a
step Stream m a
m = do
    Maybe (a, Stream m a)
r <- forall (m :: * -> *) a.
Applicative m =>
Stream m a -> m (Maybe (a, Stream m a))
uncons Stream m a
m
    case Maybe (a, Stream m a)
r of
        Maybe (a, Stream m a)
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
        Just (a
h, Stream m a
t) -> forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap forall a. a -> Maybe a
Just (forall {m :: * -> *}. Monad m => a -> Stream m a -> m a
go a
h Stream m a
t)
    where
    go :: a -> Stream m a -> m a
go a
p Stream m a
m1 =
        let stp :: m a
stp = forall (m :: * -> *) a. Monad m => a -> m a
return a
p
            single :: a -> m a
single a
a = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ a -> a -> a
step a
a a
p
            yieldk :: a -> Stream m a -> m a
yieldk a
a Stream m a
r = forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (a -> a -> a
step a
p) (a -> Stream m a -> m a
go a
a Stream m a
r)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m a
yieldk forall {m :: * -> *}. Monad m => a -> m a
single m a
stp Stream m a
m1

-- XXX replace the recursive "go" with explicit continuations.
-- | Like 'foldx', but with a monadic step function.
{-# INLINABLE foldlMx' #-}
foldlMx' :: Monad m
    => (x -> a -> m x) -> m x -> (x -> m b) -> Stream m a -> m b
foldlMx' :: forall (m :: * -> *) x a b.
Monad m =>
(x -> a -> m x) -> m x -> (x -> m b) -> Stream m a -> m b
foldlMx' x -> a -> m x
step m x
begin x -> m b
done = m x -> Stream m a -> m b
go m x
begin
    where
    go :: m x -> Stream m a -> m b
go !m x
acc Stream m a
m1 =
        let stop :: m b
stop = m x
acc forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= x -> m b
done
            single :: a -> m b
single a
a = m x
acc forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \x
b -> x -> a -> m x
step x
b a
a forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= x -> m b
done
            yieldk :: a -> Stream m a -> m b
yieldk a
a Stream m a
r = m x
acc forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \x
b -> x -> a -> m x
step x
b a
a forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \x
x -> m x -> Stream m a -> m b
go (forall (m :: * -> *) a. Monad m => a -> m a
return x
x) Stream m a
r
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m b
yieldk a -> m b
single m b
stop Stream m a
m1

{-# INLINABLE fold #-}
fold :: Monad m => FL.Fold m a b -> Stream m a -> m b
fold :: forall (m :: * -> *) a b.
Monad m =>
Fold m a b -> Stream m a -> m b
fold (FL.Fold s -> a -> m (Step s b)
step m (Step s b)
begin s -> m b
done) Stream m a
m = do
    Step s b
res <- m (Step s b)
begin
    case Step s b
res of
        FL.Partial s
fs -> s -> Stream m a -> m b
go s
fs Stream m a
m
        FL.Done b
fb -> forall (m :: * -> *) a. Monad m => a -> m a
return b
fb

    where
    go :: s -> Stream m a -> m b
go !s
acc Stream m a
m1 =
        let stop :: m b
stop = s -> m b
done s
acc
            single :: a -> m b
single a
a = s -> a -> m (Step s b)
step s
acc a
a
              forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \case
                        FL.Partial s
s -> s -> m b
done s
s
                        FL.Done b
b1 -> forall (m :: * -> *) a. Monad m => a -> m a
return b
b1
            yieldk :: a -> Stream m a -> m b
yieldk a
a Stream m a
r = s -> a -> m (Step s b)
step s
acc a
a
              forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \case
                        FL.Partial s
s -> s -> Stream m a -> m b
go s
s Stream m a
r
                        FL.Done b
b1 -> forall (m :: * -> *) a. Monad m => a -> m a
return b
b1
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m b
yieldk a -> m b
single m b
stop Stream m a
m1

-- | Like 'foldl'' but with a monadic step function.
{-# INLINE foldlM' #-}
foldlM' :: Monad m => (b -> a -> m b) -> m b -> Stream m a -> m b
foldlM' :: forall (m :: * -> *) b a.
Monad m =>
(b -> a -> m b) -> m b -> Stream m a -> m b
foldlM' b -> a -> m b
step m b
begin = forall (m :: * -> *) x a b.
Monad m =>
(x -> a -> m x) -> m x -> (x -> m b) -> Stream m a -> m b
foldlMx' b -> a -> m b
step m b
begin forall (m :: * -> *) a. Monad m => a -> m a
return

-- | Lazy left fold to an arbitrary transformer monad.
{-# INLINE foldlT #-}
foldlT :: (Monad m, Monad (s m), MonadTrans s)
    => (s m b -> a -> s m b) -> s m b -> Stream m a -> s m b
foldlT :: forall (m :: * -> *) (s :: (* -> *) -> * -> *) b a.
(Monad m, Monad (s m), MonadTrans s) =>
(s m b -> a -> s m b) -> s m b -> Stream m a -> s m b
foldlT s m b -> a -> s m b
step = s m b -> Stream m a -> s m b
go
  where
    go :: s m b -> Stream m a -> s m b
go s m b
acc Stream m a
m1 = do
        Maybe (a, Stream m a)
res <- forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *) a.
Applicative m =>
Stream m a -> m (Maybe (a, Stream m a))
uncons Stream m a
m1
        case Maybe (a, Stream m a)
res of
            Just (a
h, Stream m a
t) -> s m b -> Stream m a -> s m b
go (s m b -> a -> s m b
step s m b
acc a
h) Stream m a
t
            Maybe (a, Stream m a)
Nothing -> s m b
acc

------------------------------------------------------------------------------
-- Specialized folds
------------------------------------------------------------------------------

{-# INLINE head #-}
head :: Monad m => Stream m a -> m (Maybe a)
-- head = foldrM (\x _ -> return $ Just x) (return Nothing)
head :: forall (m :: * -> *) a. Monad m => Stream m a -> m (Maybe a)
head Stream m a
m =
    let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
        single :: a -> m (Maybe a)
single a
a  = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
        yieldk :: a -> p -> m (Maybe a)
yieldk a
a p
_ = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
    in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState forall {m :: * -> *} {a} {p}. Monad m => a -> p -> m (Maybe a)
yieldk forall {m :: * -> *} {a}. Monad m => a -> m (Maybe a)
single forall {a}. m (Maybe a)
stop Stream m a
m

{-# INLINE elem #-}
elem :: (Monad m, Eq a) => a -> Stream m a -> m Bool
elem :: forall (m :: * -> *) a.
(Monad m, Eq a) =>
a -> Stream m a -> m Bool
elem a
e = forall {m :: * -> *}. Monad m => Stream m a -> m Bool
go
    where
    go :: Stream m a -> m Bool
go Stream m a
m1 =
        let stop :: m Bool
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False
            single :: a -> m Bool
single a
a  = forall (m :: * -> *) a. Monad m => a -> m a
return (a
a forall a. Eq a => a -> a -> Bool
== a
e)
            yieldk :: a -> Stream m a -> m Bool
yieldk a
a Stream m a
r = if a
a forall a. Eq a => a -> a -> Bool
== a
e then forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True else Stream m a -> m Bool
go Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m Bool
yieldk forall {m :: * -> *}. Monad m => a -> m Bool
single m Bool
stop Stream m a
m1

{-# INLINE notElem #-}
notElem :: (Monad m, Eq a) => a -> Stream m a -> m Bool
notElem :: forall (m :: * -> *) a.
(Monad m, Eq a) =>
a -> Stream m a -> m Bool
notElem a
e = forall {m :: * -> *}. Monad m => Stream m a -> m Bool
go
    where
    go :: Stream m a -> m Bool
go Stream m a
m1 =
        let stop :: m Bool
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True
            single :: a -> m Bool
single a
a  = forall (m :: * -> *) a. Monad m => a -> m a
return (a
a forall a. Eq a => a -> a -> Bool
/= a
e)
            yieldk :: a -> Stream m a -> m Bool
yieldk a
a Stream m a
r = if a
a forall a. Eq a => a -> a -> Bool
== a
e then forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False else Stream m a -> m Bool
go Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m Bool
yieldk forall {m :: * -> *}. Monad m => a -> m Bool
single m Bool
stop Stream m a
m1

{-# INLINABLE all #-}
all :: Monad m => (a -> Bool) -> Stream m a -> m Bool
all :: forall (m :: * -> *) a.
Monad m =>
(a -> Bool) -> Stream m a -> m Bool
all a -> Bool
p = forall {m :: * -> *}. Monad m => Stream m a -> m Bool
go
    where
    go :: Stream m a -> m Bool
go Stream m a
m1 =
        let single :: a -> m Bool
single a
a   | a -> Bool
p a
a       = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True
                       | Bool
otherwise = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False
            yieldk :: a -> Stream m a -> m Bool
yieldk a
a Stream m a
r | a -> Bool
p a
a       = Stream m a -> m Bool
go Stream m a
r
                       | Bool
otherwise = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m Bool
yieldk forall {m :: * -> *}. Monad m => a -> m Bool
single (forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True) Stream m a
m1

{-# INLINABLE any #-}
any :: Monad m => (a -> Bool) -> Stream m a -> m Bool
any :: forall (m :: * -> *) a.
Monad m =>
(a -> Bool) -> Stream m a -> m Bool
any a -> Bool
p = forall {m :: * -> *}. Monad m => Stream m a -> m Bool
go
    where
    go :: Stream m a -> m Bool
go Stream m a
m1 =
        let single :: a -> m Bool
single a
a   | a -> Bool
p a
a       = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True
                       | Bool
otherwise = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False
            yieldk :: a -> Stream m a -> m Bool
yieldk a
a Stream m a
r | a -> Bool
p a
a       = forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True
                       | Bool
otherwise = Stream m a -> m Bool
go Stream m a
r
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m Bool
yieldk forall {m :: * -> *}. Monad m => a -> m Bool
single (forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False) Stream m a
m1

-- | Extract the last element of the stream, if any.
{-# INLINE last #-}
last :: Monad m => Stream m a -> m (Maybe a)
last :: forall (m :: * -> *) a. Monad m => Stream m a -> m (Maybe a)
last = forall (m :: * -> *) a b x.
Monad m =>
(x -> a -> x) -> x -> (x -> b) -> Stream m a -> m b
foldlx' (\Maybe a
_ a
y -> forall a. a -> Maybe a
Just a
y) forall a. Maybe a
Nothing forall a. a -> a
id

{-# INLINE minimum #-}
minimum :: (Monad m, Ord a) => Stream m a -> m (Maybe a)
minimum :: forall (m :: * -> *) a.
(Monad m, Ord a) =>
Stream m a -> m (Maybe a)
minimum = forall {m :: * -> *} {a}.
(Ord a, Monad m) =>
Maybe a -> Stream m a -> m (Maybe a)
go forall a. Maybe a
Nothing
    where
    go :: Maybe a -> Stream m a -> m (Maybe a)
go Maybe a
Nothing Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
            single :: a -> m (Maybe a)
single a
a  = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r = Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *} {a}. Monad m => a -> m (Maybe a)
single forall {a}. m (Maybe a)
stop Stream m a
m1

    go (Just a
res) Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
            single :: a -> m (Maybe a)
single a
a  =
                if a
res forall a. Ord a => a -> a -> Bool
<= a
a
                then forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
                else forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r =
                if a
res forall a. Ord a => a -> a -> Bool
<= a
a
                then Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
res) Stream m a
r
                else Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *}. Monad m => a -> m (Maybe a)
single m (Maybe a)
stop Stream m a
m1

{-# INLINE minimumBy #-}
minimumBy
    :: (Monad m)
    => (a -> a -> Ordering) -> Stream m a -> m (Maybe a)
minimumBy :: forall (m :: * -> *) a.
Monad m =>
(a -> a -> Ordering) -> Stream m a -> m (Maybe a)
minimumBy a -> a -> Ordering
cmp = forall {m :: * -> *}.
Monad m =>
Maybe a -> Stream m a -> m (Maybe a)
go forall a. Maybe a
Nothing
    where
    go :: Maybe a -> Stream m a -> m (Maybe a)
go Maybe a
Nothing Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
            single :: a -> m (Maybe a)
single a
a  = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r = Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *} {a}. Monad m => a -> m (Maybe a)
single forall {a}. m (Maybe a)
stop Stream m a
m1

    go (Just a
res) Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
            single :: a -> m (Maybe a)
single a
a  = case a -> a -> Ordering
cmp a
res a
a of
                Ordering
GT -> forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
                Ordering
_  -> forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r = case a -> a -> Ordering
cmp a
res a
a of
                Ordering
GT -> Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
                Ordering
_  -> Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
res) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *}. Monad m => a -> m (Maybe a)
single m (Maybe a)
stop Stream m a
m1

{-# INLINE maximum #-}
maximum :: (Monad m, Ord a) => Stream m a -> m (Maybe a)
maximum :: forall (m :: * -> *) a.
(Monad m, Ord a) =>
Stream m a -> m (Maybe a)
maximum = forall {m :: * -> *} {a}.
(Ord a, Monad m) =>
Maybe a -> Stream m a -> m (Maybe a)
go forall a. Maybe a
Nothing
    where
    go :: Maybe a -> Stream m a -> m (Maybe a)
go Maybe a
Nothing Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
            single :: a -> m (Maybe a)
single a
a  = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r = Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *} {a}. Monad m => a -> m (Maybe a)
single forall {a}. m (Maybe a)
stop Stream m a
m1

    go (Just a
res) Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
            single :: a -> m (Maybe a)
single a
a  =
                if a
res forall a. Ord a => a -> a -> Bool
<= a
a
                then forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
                else forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r =
                if a
res forall a. Ord a => a -> a -> Bool
<= a
a
                then Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
                else Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
res) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *}. Monad m => a -> m (Maybe a)
single m (Maybe a)
stop Stream m a
m1

{-# INLINE maximumBy #-}
maximumBy :: Monad m => (a -> a -> Ordering) -> Stream m a -> m (Maybe a)
maximumBy :: forall (m :: * -> *) a.
Monad m =>
(a -> a -> Ordering) -> Stream m a -> m (Maybe a)
maximumBy a -> a -> Ordering
cmp = forall {m :: * -> *}.
Monad m =>
Maybe a -> Stream m a -> m (Maybe a)
go forall a. Maybe a
Nothing
    where
    go :: Maybe a -> Stream m a -> m (Maybe a)
go Maybe a
Nothing Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
            single :: a -> m (Maybe a)
single a
a  = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r = Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *} {a}. Monad m => a -> m (Maybe a)
single forall {a}. m (Maybe a)
stop Stream m a
m1

    go (Just a
res) Stream m a
m1 =
        let stop :: m (Maybe a)
stop      = forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
            single :: a -> m (Maybe a)
single a
a  = case a -> a -> Ordering
cmp a
res a
a of
                Ordering
GT -> forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
res)
                Ordering
_  -> forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. a -> Maybe a
Just a
a)
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r = case a -> a -> Ordering
cmp a
res a
a of
                Ordering
GT -> Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
res) Stream m a
r
                Ordering
_  -> Maybe a -> Stream m a -> m (Maybe a)
go (forall a. a -> Maybe a
Just a
a) Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *}. Monad m => a -> m (Maybe a)
single m (Maybe a)
stop Stream m a
m1

{-# INLINE (!!) #-}
(!!) :: Monad m => Stream m a -> Int -> m (Maybe a)
Stream m a
m !! :: forall (m :: * -> *) a. Monad m => Stream m a -> Int -> m (Maybe a)
!! Int
i = forall {m :: * -> *} {t} {a}.
(Ord t, Monad m, Num t) =>
t -> Stream m a -> m (Maybe a)
go Int
i Stream m a
m
    where
    go :: t -> Stream m a -> m (Maybe a)
go t
n Stream m a
m1 =
      let single :: a -> m (Maybe a)
single a
a | t
n forall a. Eq a => a -> a -> Bool
== t
0 = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
a
                   | Bool
otherwise = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
          yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
x | t
n forall a. Ord a => a -> a -> Bool
< t
0 = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
                     | t
n forall a. Eq a => a -> a -> Bool
== t
0 = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
a
                     | Bool
otherwise = t -> Stream m a -> m (Maybe a)
go (t
n forall a. Num a => a -> a -> a
- t
1) Stream m a
x
      in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *} {a}. Monad m => a -> m (Maybe a)
single (forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing) Stream m a
m1

{-# INLINE lookup #-}
lookup :: (Monad m, Eq a) => a -> Stream m (a, b) -> m (Maybe b)
lookup :: forall (m :: * -> *) a b.
(Monad m, Eq a) =>
a -> Stream m (a, b) -> m (Maybe b)
lookup a
e = forall {m :: * -> *} {a}. Monad m => Stream m (a, a) -> m (Maybe a)
go
    where
    go :: Stream m (a, a) -> m (Maybe a)
go Stream m (a, a)
m1 =
        let single :: (a, a) -> m (Maybe a)
single (a
a, a
b) | a
a forall a. Eq a => a -> a -> Bool
== a
e = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
b
                          | Bool
otherwise = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
            yieldk :: (a, a) -> Stream m (a, a) -> m (Maybe a)
yieldk (a
a, a
b) Stream m (a, a)
x | a
a forall a. Eq a => a -> a -> Bool
== a
e = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
b
                            | Bool
otherwise = Stream m (a, a) -> m (Maybe a)
go Stream m (a, a)
x
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState (a, a) -> Stream m (a, a) -> m (Maybe a)
yieldk forall {m :: * -> *} {a}. Monad m => (a, a) -> m (Maybe a)
single (forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing) Stream m (a, a)
m1

{-# INLINE findM #-}
findM :: Monad m => (a -> m Bool) -> Stream m a -> m (Maybe a)
findM :: forall (m :: * -> *) a.
Monad m =>
(a -> m Bool) -> Stream m a -> m (Maybe a)
findM a -> m Bool
p = Stream m a -> m (Maybe a)
go
    where
    go :: Stream m a -> m (Maybe a)
go Stream m a
m1 =
        let single :: a -> m (Maybe a)
single a
a = do
                Bool
b <- a -> m Bool
p a
a
                if Bool
b then forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
a else forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
x = do
                Bool
b <- a -> m Bool
p a
a
                if Bool
b then forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
a else Stream m a -> m (Maybe a)
go Stream m a
x
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk a -> m (Maybe a)
single (forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing) Stream m a
m1

{-# INLINE find #-}
find :: Monad m => (a -> Bool) -> Stream m a -> m (Maybe a)
find :: forall (m :: * -> *) a.
Monad m =>
(a -> Bool) -> Stream m a -> m (Maybe a)
find a -> Bool
p = forall (m :: * -> *) a.
Monad m =>
(a -> m Bool) -> Stream m a -> m (Maybe a)
findM (forall (m :: * -> *) a. Monad m => a -> m a
return forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> Bool
p)

{-# INLINE findIndices #-}
findIndices :: (a -> Bool) -> Stream m a -> Stream m Int
findIndices :: forall a (m :: * -> *). (a -> Bool) -> Stream m a -> Stream m Int
findIndices a -> Bool
p = forall {t} {m :: * -> *}. Num t => t -> Stream m a -> Stream m t
go Int
0
    where
    go :: t -> Stream m a -> Stream m t
go t
offset Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m t
st t -> Stream m t -> m r
yld t -> m r
sng m r
stp ->
        let single :: a -> m r
single a
a | a -> Bool
p a
a = t -> m r
sng t
offset
                     | Bool
otherwise = m r
stp
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
x | a -> Bool
p a
a = t -> Stream m t -> m r
yld t
offset forall a b. (a -> b) -> a -> b
$ t -> Stream m a -> Stream m t
go (t
offset forall a. Num a => a -> a -> a
+ t
1) Stream m a
x
                       | Bool
otherwise = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m t
st) t -> Stream m t -> m r
yld t -> m r
sng m r
stp forall a b. (a -> b) -> a -> b
$
                            t -> Stream m a -> Stream m t
go (t
offset forall a. Num a => a -> a -> a
+ t
1) Stream m a
x
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m t
st) a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m1

------------------------------------------------------------------------------
-- Map and Fold
------------------------------------------------------------------------------

-- | Apply a monadic action to each element of the stream and discard the
-- output of the action.
{-# INLINE mapM_ #-}
mapM_ :: Monad m => (a -> m b) -> Stream m a -> m ()
mapM_ :: forall (m :: * -> *) a b.
Monad m =>
(a -> m b) -> Stream m a -> m ()
mapM_ a -> m b
f = Stream m a -> m ()
go
    where
    go :: Stream m a -> m ()
go Stream m a
m1 =
        let stop :: m ()
stop = forall (m :: * -> *) a. Monad m => a -> m a
return ()
            single :: a -> m ()
single a
a = forall (f :: * -> *) a. Functor f => f a -> f ()
void (a -> m b
f a
a)
            yieldk :: a -> Stream m a -> m ()
yieldk a
a Stream m a
r = a -> m b
f a
a forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>> Stream m a -> m ()
go Stream m a
r
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m ()
yieldk a -> m ()
single m ()
stop Stream m a
m1

{-# INLINE mapM #-}
mapM :: Monad m => (a -> m b) -> Stream m a -> Stream m b
mapM :: forall (m :: * -> *) a b.
Monad m =>
(a -> m b) -> Stream m a -> Stream m b
mapM = forall (m :: * -> *) b a.
(m b -> Stream m b -> Stream m b)
-> (a -> m b) -> Stream m a -> Stream m b
mapMWith forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
consM

------------------------------------------------------------------------------
-- Converting folds
------------------------------------------------------------------------------

{-# INLINABLE toList #-}
toList :: Monad m => Stream m a -> m [a]
toList :: forall (m :: * -> *) a. Monad m => Stream m a -> m [a]
toList = forall (m :: * -> *) a b.
Monad m =>
(a -> b -> b) -> b -> Stream m a -> m b
foldr (:) []

-- Based on suggestions by David Feuer and Pranay Sashank
{-# INLINE hoist #-}
hoist :: (Monad m, Monad n)
    => (forall x. m x -> n x) -> Stream m a -> Stream n a
hoist :: forall (m :: * -> *) (n :: * -> *) a.
(Monad m, Monad n) =>
(forall x. m x -> n x) -> Stream m a -> Stream n a
hoist forall x. m x -> n x
f Stream m a
str =
    forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream n a
st a -> Stream n a -> n r
yld a -> n r
sng n r
stp ->
            let single :: a -> m (n r)
single = forall (m :: * -> *) a. Monad m => a -> m a
return forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> n r
sng
                yieldk :: a -> Stream m a -> m (n r)
yieldk a
a Stream m a
s = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ a -> Stream n a -> n r
yld a
a (forall (m :: * -> *) (n :: * -> *) a.
(Monad m, Monad n) =>
(forall x. m x -> n x) -> Stream m a -> Stream n a
hoist forall x. m x -> n x
f Stream m a
s)
                stop :: m (n r)
stop = forall (m :: * -> *) a. Monad m => a -> m a
return n r
stp
                state :: State Stream n b
state = forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream n a
st
             in forall (m :: * -> *) a. Monad m => m (m a) -> m a
join forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall x. m x -> n x
f forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared forall {n :: * -> *} {b}. State Stream n b
state forall {m :: * -> *}. Monad m => a -> Stream m a -> m (n r)
yieldk a -> m (n r)
single m (n r)
stop Stream m a
str

-------------------------------------------------------------------------------
-- Transformation by folding (Scans)
-------------------------------------------------------------------------------

{-# INLINE scanlx' #-}
scanlx' :: (x -> a -> x) -> x -> (x -> b) -> Stream m a -> Stream m b
scanlx' :: forall x a b (m :: * -> *).
(x -> a -> x) -> x -> (x -> b) -> Stream m a -> Stream m b
scanlx' x -> a -> x
step x
begin x -> b
done Stream m a
m =
    forall a (m :: * -> *). a -> Stream m a -> Stream m a
cons (x -> b
done x
begin) forall a b. (a -> b) -> a -> b
$ forall {m :: * -> *}. Stream m a -> x -> Stream m b
go Stream m a
m x
begin
    where
    go :: Stream m a -> x -> Stream m b
go Stream m a
m1 !x
acc = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m b
st b -> Stream m b -> m r
yld b -> m r
sng m r
stp ->
        let single :: a -> m r
single a
a = b -> m r
sng (x -> b
done forall a b. (a -> b) -> a -> b
$ x -> a -> x
step x
acc a
a)
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r =
                let s :: x
s = x -> a -> x
step x
acc a
a
                in b -> Stream m b -> m r
yld (x -> b
done x
s) (Stream m a -> x -> Stream m b
go Stream m a
r x
s)
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m b
st) a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m1

{-# INLINE scanl' #-}
scanl' :: (b -> a -> b) -> b -> Stream m a -> Stream m b
scanl' :: forall b a (m :: * -> *).
(b -> a -> b) -> b -> Stream m a -> Stream m b
scanl' b -> a -> b
step b
begin = forall x a b (m :: * -> *).
(x -> a -> x) -> x -> (x -> b) -> Stream m a -> Stream m b
scanlx' b -> a -> b
step b
begin forall a. a -> a
id

-------------------------------------------------------------------------------
-- Filtering
-------------------------------------------------------------------------------

{-# INLINE filter #-}
filter :: (a -> Bool) -> Stream m a -> Stream m a
filter :: forall a (m :: * -> *). (a -> Bool) -> Stream m a -> Stream m a
filter a -> Bool
p = forall {m :: * -> *}. Stream m a -> Stream m a
go
    where
    go :: Stream m a -> Stream m a
go Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let single :: a -> m r
single a
a   | a -> Bool
p a
a       = a -> m r
sng a
a
                       | Bool
otherwise = m r
stp
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r | a -> Bool
p a
a       = a -> Stream m a -> m r
yld a
a (Stream m a -> Stream m a
go Stream m a
r)
                       | Bool
otherwise = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
r
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m1

{-# INLINE take #-}
take :: Int -> Stream m a -> Stream m a
take :: forall (m :: * -> *) a. Int -> Stream m a -> Stream m a
take = forall {t} {m :: * -> *} {a}.
(Ord t, Num t) =>
t -> Stream m a -> Stream m a
go
    where
    go :: t -> Stream m a -> Stream m a
go t
n1 Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r = a -> Stream m a -> m r
yld a
a (t -> Stream m a -> Stream m a
go (t
n1 forall a. Num a => a -> a -> a
- t
1) Stream m a
r)
        in if t
n1 forall a. Ord a => a -> a -> Bool
<= t
0
           then m r
stp
           else forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
sng m r
stp Stream m a
m1

{-# INLINE takeWhile #-}
takeWhile :: (a -> Bool) -> Stream m a -> Stream m a
takeWhile :: forall a (m :: * -> *). (a -> Bool) -> Stream m a -> Stream m a
takeWhile a -> Bool
p = forall {m :: * -> *}. Stream m a -> Stream m a
go
    where
    go :: Stream m a -> Stream m a
go Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let single :: a -> m r
single a
a   | a -> Bool
p a
a       = a -> m r
sng a
a
                       | Bool
otherwise = m r
stp
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r | a -> Bool
p a
a       = a -> Stream m a -> m r
yld a
a (Stream m a -> Stream m a
go Stream m a
r)
                       | Bool
otherwise = m r
stp
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m1

{-# INLINE drop #-}
drop :: Int -> Stream m a -> Stream m a
drop :: forall (m :: * -> *) a. Int -> Stream m a -> Stream m a
drop Int
n Stream m a
m = forall (m :: * -> *) a. Stream m a -> Stream m a
unShare (forall {t} {m :: * -> *} {a}.
(Ord t, Num t) =>
t -> Stream m a -> Stream m a
go Int
n Stream m a
m)
    where
    go :: t -> Stream m a -> Stream m a
go t
n1 Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let single :: p -> m r
single p
_ = m r
stp
            yieldk :: p -> Stream m a -> m r
yieldk p
_ Stream m a
r = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp forall a b. (a -> b) -> a -> b
$ t -> Stream m a -> Stream m a
go (t
n1 forall a. Num a => a -> a -> a
- t
1) Stream m a
r
        -- Somehow "<=" check performs better than a ">"
        in if t
n1 forall a. Ord a => a -> a -> Bool
<= t
0
           then forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp Stream m a
m1
           else forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared State Stream m a
st forall {p}. p -> Stream m a -> m r
yieldk forall {p}. p -> m r
single m r
stp Stream m a
m1

{-# INLINE dropWhile #-}
dropWhile :: (a -> Bool) -> Stream m a -> Stream m a
dropWhile :: forall a (m :: * -> *). (a -> Bool) -> Stream m a -> Stream m a
dropWhile a -> Bool
p = forall {m :: * -> *}. Stream m a -> Stream m a
go
    where
    go :: Stream m a -> Stream m a
go Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let single :: a -> m r
single a
a   | a -> Bool
p a
a       = m r
stp
                       | Bool
otherwise = a -> m r
sng a
a
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r | a -> Bool
p a
a = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
r
                       | Bool
otherwise = a -> Stream m a -> m r
yld a
a Stream m a
r
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m1

-------------------------------------------------------------------------------
-- Mapping
-------------------------------------------------------------------------------

-- Be careful when modifying this, this uses a consM (|:) deliberately to allow
-- other stream types to overload it.
{-# INLINE sequence #-}
sequence :: Monad m => Stream m (m a) -> Stream m a
sequence :: forall (m :: * -> *) a. Monad m => Stream m (m a) -> Stream m a
sequence = forall (m :: * -> *) a. Monad m => Stream m (m a) -> Stream m a
go
    where
    go :: Stream m (m a) -> Stream m a
go Stream m (m a)
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let single :: m a -> m r
single m a
ma = m a
ma forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= a -> m r
sng
            yieldk :: m a -> Stream m (m a) -> m r
yieldk m a
ma Stream m (m a)
r = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp forall a b. (a -> b) -> a -> b
$ m a
ma forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
`consM` Stream m (m a) -> Stream m a
go Stream m (m a)
r
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m a
st) m a -> Stream m (m a) -> m r
yieldk m a -> m r
single m r
stp Stream m (m a)
m1

-------------------------------------------------------------------------------
-- Inserting
-------------------------------------------------------------------------------

{-# INLINE intersperseM #-}
intersperseM :: Monad m => m a -> Stream m a -> Stream m a
intersperseM :: forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
intersperseM m a
a = Stream m a -> Stream m a
prependingStart
    where
    prependingStart :: Stream m a -> Stream m a
prependingStart Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let yieldk :: a -> Stream m a -> m r
yieldk a
i Stream m a
x =
                forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *) a. Monad m => a -> m a
return a
i forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
`consM` Stream m a -> Stream m a
go Stream m a
x
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
sng m r
stp Stream m a
m1
    go :: Stream m a -> Stream m a
go Stream m a
m2 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let single :: a -> m r
single a
i = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp forall a b. (a -> b) -> a -> b
$ m a
a forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
`consM` forall a (m :: * -> *). a -> Stream m a
fromPure a
i
            yieldk :: a -> Stream m a -> m r
yieldk a
i Stream m a
x =
                forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStreamShared
                    State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp forall a b. (a -> b) -> a -> b
$ m a
a forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
`consM` forall (m :: * -> *) a. Monad m => a -> m a
return a
i forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
`consM` Stream m a -> Stream m a
go Stream m a
x
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m2

{-# INLINE intersperse #-}
intersperse :: Monad m => a -> Stream m a -> Stream m a
intersperse :: forall (m :: * -> *) a. Monad m => a -> Stream m a -> Stream m a
intersperse a
a = forall (m :: * -> *) a. Monad m => m a -> Stream m a -> Stream m a
intersperseM (forall (m :: * -> *) a. Monad m => a -> m a
return a
a)

{-# INLINE insertBy #-}
insertBy :: (a -> a -> Ordering) -> a -> Stream m a -> Stream m a
insertBy :: forall a (m :: * -> *).
(a -> a -> Ordering) -> a -> Stream m a -> Stream m a
insertBy a -> a -> Ordering
cmp a
x = forall {m :: * -> *}. Stream m a -> Stream m a
go
  where
    go :: Stream m a -> Stream m a
go Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
_ m r
_ ->
        let single :: a -> m r
single a
a = case a -> a -> Ordering
cmp a
x a
a of
                Ordering
GT -> a -> Stream m a -> m r
yld a
a (forall a (m :: * -> *). a -> Stream m a
fromPure a
x)
                Ordering
_  -> a -> Stream m a -> m r
yld a
x (forall a (m :: * -> *). a -> Stream m a
fromPure a
a)
            stop :: m r
stop = a -> Stream m a -> m r
yld a
x forall (m :: * -> *) a. Stream m a
nil
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r = case a -> a -> Ordering
cmp a
x a
a of
                Ordering
GT -> a -> Stream m a -> m r
yld a
a (Stream m a -> Stream m a
go Stream m a
r)
                Ordering
_  -> a -> Stream m a -> m r
yld a
x (a
a forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
r)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stop Stream m a
m1

------------------------------------------------------------------------------
-- Deleting
------------------------------------------------------------------------------

{-# INLINE deleteBy #-}
deleteBy :: (a -> a -> Bool) -> a -> Stream m a -> Stream m a
deleteBy :: forall a (m :: * -> *).
(a -> a -> Bool) -> a -> Stream m a -> Stream m a
deleteBy a -> a -> Bool
eq a
x = forall {m :: * -> *}. Stream m a -> Stream m a
go
  where
    go :: Stream m a -> Stream m a
go Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
        let single :: a -> m r
single a
a = if a -> a -> Bool
eq a
x a
a then m r
stp else a -> m r
sng a
a
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r = if a -> a -> Bool
eq a
x a
a
              then forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp Stream m a
r
              else a -> Stream m a -> m r
yld a
a (Stream m a -> Stream m a
go Stream m a
r)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m1

-------------------------------------------------------------------------------
-- Map and Filter
-------------------------------------------------------------------------------

{-# INLINE mapMaybe #-}
mapMaybe :: (a -> Maybe b) -> Stream m a -> Stream m b
mapMaybe :: forall a b (m :: * -> *).
(a -> Maybe b) -> Stream m a -> Stream m b
mapMaybe a -> Maybe b
f = forall {m :: * -> *}. Stream m a -> Stream m b
go
  where
    go :: Stream m a -> Stream m b
go Stream m a
m1 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m b
st b -> Stream m b -> m r
yld b -> m r
sng m r
stp ->
        let single :: a -> m r
single a
a = forall b a. b -> (a -> b) -> Maybe a -> b
maybe m r
stp b -> m r
sng (a -> Maybe b
f a
a)
            yieldk :: a -> Stream m a -> m r
yieldk a
a Stream m a
r = case a -> Maybe b
f a
a of
                Just b
b  -> b -> Stream m b -> m r
yld b
b forall a b. (a -> b) -> a -> b
$ Stream m a -> Stream m b
go Stream m a
r
                Maybe b
Nothing -> forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m b
st) a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
r
        in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m b
st) a -> Stream m a -> m r
yieldk a -> m r
single m r
stp Stream m a
m1

------------------------------------------------------------------------------
-- Serial Zipping
------------------------------------------------------------------------------

-- | Zip two streams serially using a pure zipping function.
--
-- @since 0.1.0
{-# INLINE zipWith #-}
zipWith :: Monad m => (a -> b -> c) -> Stream m a -> Stream m b -> Stream m c
zipWith :: forall (m :: * -> *) a b c.
Monad m =>
(a -> b -> c) -> Stream m a -> Stream m b -> Stream m c
zipWith a -> b -> c
f = forall (m :: * -> *) a b c.
Monad m =>
(a -> b -> m c) -> Stream m a -> Stream m b -> Stream m c
zipWithM (\a
a b
b -> forall (m :: * -> *) a. Monad m => a -> m a
return (a -> b -> c
f a
a b
b))

-- | Zip two streams serially using a monadic zipping function.
--
-- @since 0.1.0
{-# INLINE zipWithM #-}
zipWithM :: Monad m =>
    (a -> b -> m c) -> Stream m a -> Stream m b -> Stream m c
zipWithM :: forall (m :: * -> *) a b c.
Monad m =>
(a -> b -> m c) -> Stream m a -> Stream m b -> Stream m c
zipWithM a -> b -> m c
f = Stream m a -> Stream m b -> Stream m c
go

    where

    go :: Stream m a -> Stream m b -> Stream m c
go Stream m a
mx Stream m b
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m c
st c -> Stream m c -> m r
yld c -> m r
sng m r
stp -> do
        let merge :: a -> Stream m a -> m r
merge a
a Stream m a
ra =
                let single2 :: b -> m r
single2 b
b   = a -> b -> m c
f a
a b
b forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= c -> m r
sng
                    yield2 :: b -> Stream m b -> m r
yield2 b
b Stream m b
rb = a -> b -> m c
f a
a b
b forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \c
x -> c -> Stream m c -> m r
yld c
x (Stream m a -> Stream m b -> Stream m c
go Stream m a
ra Stream m b
rb)
                 in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m c
st) b -> Stream m b -> m r
yield2 b -> m r
single2 m r
stp Stream m b
my
        let single1 :: a -> m r
single1 a
a = a -> Stream m a -> m r
merge a
a forall (m :: * -> *) a. Stream m a
nil
            yield1 :: a -> Stream m a -> m r
yield1 = a -> Stream m a -> m r
merge
        forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream (forall (t :: (* -> *) -> * -> *) (m :: * -> *) a (n :: * -> *) b.
State t m a -> State t n b
adaptState State Stream m c
st) a -> Stream m a -> m r
yield1 a -> m r
single1 m r
stp Stream m a
mx

------------------------------------------------------------------------------
-- Merging
------------------------------------------------------------------------------

{-# INLINE mergeByM #-}
mergeByM :: Monad m =>
    (a -> a -> m Ordering) -> Stream m a -> Stream m a -> Stream m a
mergeByM :: forall (m :: * -> *) a.
Monad m =>
(a -> a -> m Ordering) -> Stream m a -> Stream m a -> Stream m a
mergeByM a -> a -> m Ordering
cmp = Stream m a -> Stream m a -> Stream m a
go

    where

    go :: Stream m a -> Stream m a -> Stream m a
go Stream m a
mx Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp -> do
        let stop :: m r
stop = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp Stream m a
my
            single :: a -> m r
single a
x = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp (a -> Stream m a -> Stream m a
goX0 a
x Stream m a
my)
            yield :: a -> Stream m a -> m r
yield a
x Stream m a
rx = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp (a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
rx Stream m a
my)
        forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
mx

    goX0 :: a -> Stream m a -> Stream m a
goX0 a
x Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
_ -> do
        let stop :: m r
stop = a -> m r
sng a
x
            single :: a -> m r
single a
y = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (forall a (m :: * -> *). a -> Stream m a
fromPure a
x)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (forall a (m :: * -> *). a -> Stream m a
fromPure a
y)
            yield :: a -> Stream m a -> m r
yield a
y Stream m a
ry = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a -> Stream m a -> Stream m a
goX0 a
x Stream m a
ry)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (a
y forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
ry)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
my

    goX :: a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
mx Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
_ m r
_ -> do
        let stop :: m r
stop = a -> Stream m a -> m r
yld a
x Stream m a
mx
            single :: a -> m r
single a
y = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a
x forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
mx)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (Stream m a -> a -> Stream m a
goY0 Stream m a
mx a
y)
            yield :: a -> Stream m a -> m r
yield a
y Stream m a
ry = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
mx Stream m a
ry)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (Stream m a -> a -> Stream m a -> Stream m a
goY Stream m a
mx a
y Stream m a
ry)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
my

    goY0 :: Stream m a -> a -> Stream m a
goY0 Stream m a
mx a
y = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
_ -> do
        let stop :: m r
stop = a -> m r
sng a
y
            single :: a -> m r
single a
x = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (forall a (m :: * -> *). a -> Stream m a
fromPure a
x)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (forall a (m :: * -> *). a -> Stream m a
fromPure a
y)
            yield :: a -> Stream m a -> m r
yield a
x Stream m a
rx = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a
x forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
rx)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (Stream m a -> a -> Stream m a
goY0 Stream m a
rx a
y)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
mx

    goY :: Stream m a -> a -> Stream m a -> Stream m a
goY Stream m a
mx a
y Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
_ m r
_ -> do
        let stop :: m r
stop = a -> Stream m a -> m r
yld a
y Stream m a
my
            single :: a -> m r
single a
x = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a -> Stream m a -> Stream m a
goX0 a
x Stream m a
my)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (a
y forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
my)
            yield :: a -> Stream m a -> m r
yield a
x Stream m a
rx = do
                Ordering
r <- a -> a -> m Ordering
cmp a
x a
y
                case Ordering
r of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
rx Stream m a
my)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (Stream m a -> a -> Stream m a -> Stream m a
goY Stream m a
rx a
y Stream m a
my)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
mx

{-# INLINE mergeBy #-}
mergeBy :: (a -> a -> Ordering) -> Stream m a -> Stream m a -> Stream m a
-- XXX GHC: This has slightly worse performance than replacing "r <- cmp x y"
-- with "let r = cmp x y" in the monadic version. The definition below is
-- exactly the same as mergeByM except this change.
-- mergeBy cmp = mergeByM (\a b -> return $ cmp a b)
mergeBy :: forall a (m :: * -> *).
(a -> a -> Ordering) -> Stream m a -> Stream m a -> Stream m a
mergeBy a -> a -> Ordering
cmp = forall {m :: * -> *}. Stream m a -> Stream m a -> Stream m a
go

    where

    go :: Stream m a -> Stream m a -> Stream m a
go Stream m a
mx Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp -> do
        let stop :: m r
stop = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp Stream m a
my
            single :: a -> m r
single a
x = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp (forall {m :: * -> *}. a -> Stream m a -> Stream m a
goX0 a
x Stream m a
my)
            yield :: a -> Stream m a -> m r
yield a
x Stream m a
rx = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp (forall {m :: * -> *}. a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
rx Stream m a
my)
        forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
mx

    goX0 :: a -> Stream m a -> Stream m a
goX0 a
x Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
_ -> do
        let stop :: m r
stop = a -> m r
sng a
x
            single :: a -> m r
single a
y = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (forall a (m :: * -> *). a -> Stream m a
fromPure a
x)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (forall a (m :: * -> *). a -> Stream m a
fromPure a
y)
            yield :: a -> Stream m a -> m r
yield a
y Stream m a
ry = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a -> Stream m a -> Stream m a
goX0 a
x Stream m a
ry)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (a
y forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
ry)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
my

    goX :: a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
mx Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
_ m r
_ -> do
        let stop :: m r
stop = a -> Stream m a -> m r
yld a
x Stream m a
mx
            single :: a -> m r
single a
y = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a
x forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
mx)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (forall {m :: * -> *}. Stream m a -> a -> Stream m a
goY0 Stream m a
mx a
y)
            yield :: a -> Stream m a -> m r
yield a
y Stream m a
ry = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
mx Stream m a
ry)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (Stream m a -> a -> Stream m a -> Stream m a
goY Stream m a
mx a
y Stream m a
ry)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
my

    goY0 :: Stream m a -> a -> Stream m a
goY0 Stream m a
mx a
y = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
_ -> do
        let stop :: m r
stop = a -> m r
sng a
y
            single :: a -> m r
single a
x = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (forall a (m :: * -> *). a -> Stream m a
fromPure a
x)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (forall a (m :: * -> *). a -> Stream m a
fromPure a
y)
            yield :: a -> Stream m a -> m r
yield a
x Stream m a
rx = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a
x forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
rx)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (Stream m a -> a -> Stream m a
goY0 Stream m a
rx a
y)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
mx

    goY :: Stream m a -> a -> Stream m a -> Stream m a
goY Stream m a
mx a
y Stream m a
my = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
_ m r
_ -> do
        let stop :: m r
stop = a -> Stream m a -> m r
yld a
y Stream m a
my
            single :: a -> m r
single a
x = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (forall {m :: * -> *}. a -> Stream m a -> Stream m a
goX0 a
x Stream m a
my)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (a
y forall a (m :: * -> *). a -> Stream m a -> Stream m a
`cons` Stream m a
my)
            yield :: a -> Stream m a -> m r
yield a
x Stream m a
rx = do
                case a -> a -> Ordering
cmp a
x a
y of
                    Ordering
GT -> a -> Stream m a -> m r
yld a
y (a -> Stream m a -> Stream m a -> Stream m a
goX a
x Stream m a
rx Stream m a
my)
                    Ordering
_  -> a -> Stream m a -> m r
yld a
x (Stream m a -> a -> Stream m a -> Stream m a
goY Stream m a
rx a
y Stream m a
my)
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yield a -> m r
single m r
stop Stream m a
mx

------------------------------------------------------------------------------
-- Transformation comprehensions
------------------------------------------------------------------------------

{-# INLINE the #-}
the :: (Eq a, Monad m) => Stream m a -> m (Maybe a)
the :: forall a (m :: * -> *).
(Eq a, Monad m) =>
Stream m a -> m (Maybe a)
the Stream m a
m = do
    Maybe (a, Stream m a)
r <- forall (m :: * -> *) a.
Applicative m =>
Stream m a -> m (Maybe (a, Stream m a))
uncons Stream m a
m
    case Maybe (a, Stream m a)
r of
        Maybe (a, Stream m a)
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
        Just (a
h, Stream m a
t) -> forall {m :: * -> *} {a}.
(Monad m, Eq a) =>
a -> Stream m a -> m (Maybe a)
go a
h Stream m a
t
    where
    go :: a -> Stream m a -> m (Maybe a)
go a
h Stream m a
m1 =
        let single :: a -> m (Maybe a)
single a
a   | a
h forall a. Eq a => a -> a -> Bool
== a
a    = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
h
                       | Bool
otherwise = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
            yieldk :: a -> Stream m a -> m (Maybe a)
yieldk a
a Stream m a
r | a
h forall a. Eq a => a -> a -> Bool
== a
a    = a -> Stream m a -> m (Maybe a)
go a
h Stream m a
r
                       | Bool
otherwise = forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
         in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. State t m a
defState a -> Stream m a -> m (Maybe a)
yieldk forall {m :: * -> *}. Monad m => a -> m (Maybe a)
single (forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just a
h) Stream m a
m1

------------------------------------------------------------------------------
-- Alternative & MonadPlus
------------------------------------------------------------------------------

_alt :: Stream m a -> Stream m a -> Stream m a
_alt :: forall (m :: * -> *) a. Stream m a -> Stream m a -> Stream m a
_alt Stream m a
m1 Stream m a
m2 = forall (m :: * -> *) a.
(forall r.
 State Stream m a
 -> (a -> Stream m a -> m r) -> (a -> m r) -> m r -> m r)
-> Stream m a
mkStream forall a b. (a -> b) -> a -> b
$ \State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp ->
    let stop :: m r
stop  = forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stp Stream m a
m2
    in forall (m :: * -> *) a r.
State Stream m a
-> (a -> Stream m a -> m r)
-> (a -> m r)
-> m r
-> Stream m a
-> m r
foldStream State Stream m a
st a -> Stream m a -> m r
yld a -> m r
sng m r
stop Stream m a
m1

------------------------------------------------------------------------------
-- MonadError
------------------------------------------------------------------------------

{-
-- XXX handle and test cross thread state transfer
withCatchError
    :: MonadError e m
    => Stream m a -> (e -> Stream m a) -> Stream m a
withCatchError m h =
    mkStream $ \_ stp sng yld ->
        let run x = unStream x Nothing stp sng yieldk
            handle r = r `catchError` \e -> run $ h e
            yieldk a r = yld a (withCatchError r h)
        in handle $ run m
-}