Data.Stream.Monadic

Monadic stream combinators.

Box monad

data Box a

Box monad

Constructors

Box

Fields

• unBox :: a

Instances

Monad Box

Defined in Data.Stream.Monadic

Methods

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

(>>) :: Box a -> Box b -> Box b

return :: a -> Box a

Functor Box

Defined in Data.Stream.Monadic

Methods

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

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

Applicative Box

Defined in Data.Stream.Monadic

Methods

pure :: a -> Box a

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

liftA2 :: (a -> b -> c) -> Box a -> Box b -> Box c

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

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

liftBox :: Monad m => Box a -> m a

Stream

data Stream m a

Monadic streams

Constructors

forall s. Stream (s -> m (Step s a)) s

Instances

Monad m => Functor (Stream m)

Defined in Data.Stream.Monadic

Methods

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

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

data Step s a where

Result of taking a single step in a stream

Constructors

Yield :: a -> s -> Step s a

Skip :: s -> Step s a

Done :: Step s a

Instances

Functor (Step s)

Defined in Data.Stream.Monadic

Methods

fmap :: (a -> b) -> Step s a -> Step s b

(<$) :: a -> Step s b -> Step s a

data SPEC

SPEC is used by GHC in the SpecConstr pass in order to inform the compiler when to be particularly aggressive. In particular, it tells GHC to specialize regardless of size or the number of specializations. However, not all loops fall into this category.

Libraries can specify this by using SPEC data type to inform which loops should be aggressively specialized.

Constructors

SPEC

SPEC2

Length

length :: Monad m => Stream m a -> m Int

Length of a Stream

null :: Monad m => Stream m a -> m Bool

Check if a Stream is empty

Construction

empty :: Monad m => Stream m a

Empty Stream

singleton :: Monad m => a -> Stream m a

Singleton Stream

cons :: Monad m => a -> Stream m a -> Stream m a

Prepend an element

snoc :: Monad m => Stream m a -> a -> Stream m a

Append an element

replicate :: Monad m => Int -> a -> Stream m a

Replicate a value to a given length

replicateM :: Monad m => Int -> m a -> Stream m a

Yield a Stream of values obtained by performing the monadic action the given number of times

generate :: Monad m => Int -> (Int -> a) -> Stream m a

generateM :: Monad m => Int -> (Int -> m a) -> Stream m a

Generate a stream from its indices

(++) :: Monad m => Stream m a -> Stream m a -> Stream m a infixr 5

Concatenate two Streams

Accessing elements

head :: (HasCallStack, Monad m) => Stream m a -> m a

First element of the Stream or error if empty

last :: (HasCallStack, Monad m) => Stream m a -> m a

Last element of the Stream or error if empty

(!!) :: (HasCallStack, Monad m) => Stream m a -> Int -> m a infixl 9

Element at the given position

(!?) :: Monad m => Stream m a -> Int -> m (Maybe a) infixl 9

Element at the given position or Nothing if out of bounds

Substreams

slice

Arguments

:: Monad m

=> Int

starting index

-> Int

length

-> Stream m a

-> Stream m a

Extract a substream of the given length starting at the given position.

init :: (HasCallStack, Monad m) => Stream m a -> Stream m a

All but the last element

tail :: (HasCallStack, Monad m) => Stream m a -> Stream m a

All but the first element

take :: Monad m => Int -> Stream m a -> Stream m a

The first n elements

drop :: Monad m => Int -> Stream m a -> Stream m a

All but the first n elements

Mapping

map :: Monad m => (a -> b) -> Stream m a -> Stream m b

Map a function over a Stream

mapM :: Monad m => (a -> m b) -> Stream m a -> Stream m b

Map a monadic function over a Stream

mapM_ :: Monad m => (a -> m b) -> Stream m a -> m ()

Execute a monadic action for each element of the Stream

trans :: (Monad m, Monad m') => (forall z. m z -> m' z) -> Stream m a -> Stream m' a

Transform a Stream to use a different monad

unbox :: Monad m => Stream m (Box a) -> Stream m a

concatMap :: Monad m => (a -> Stream m b) -> Stream m a -> Stream m b

flatten :: Monad m => (a -> m s) -> (s -> m (Step s b)) -> Stream m a -> Stream m b

Create a Stream of values from a Stream of streamable things

Zipping

indexed :: Monad m => Stream m a -> Stream m (Int, a)

Pair each element in a Stream with its index

indexedR :: Monad m => Int -> Stream m a -> Stream m (Int, a)

Pair each element in a Stream with its index, starting from the right and counting down

zipWithM_ :: Monad m => (a -> b -> m c) -> Stream m a -> Stream m b -> m ()

zipWithM :: Monad m => (a -> b -> m c) -> Stream m a -> Stream m b -> Stream m c

Zip two Streams with the given monadic function

zipWith3M :: Monad m => (a -> b -> c -> m d) -> Stream m a -> Stream m b -> Stream m c -> Stream m d

zipWith4M :: Monad m => (a -> b -> c -> d -> m e) -> Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e

zipWith5M :: Monad m => (a -> b -> c -> d -> e -> m f) -> Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e -> Stream m f

zipWith6M :: Monad m => (a -> b -> c -> d -> e -> f -> m g) -> Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e -> Stream m f -> Stream m g

zipWith :: Monad m => (a -> b -> c) -> Stream m a -> Stream m b -> Stream m c

zipWith3 :: Monad m => (a -> b -> c -> d) -> Stream m a -> Stream m b -> Stream m c -> Stream m d

zipWith4 :: Monad m => (a -> b -> c -> d -> e) -> Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e

zipWith5 :: Monad m => (a -> b -> c -> d -> e -> f) -> Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e -> Stream m f

zipWith6 :: Monad m => (a -> b -> c -> d -> e -> f -> g) -> Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e -> Stream m f -> Stream m g

zip :: Monad m => Stream m a -> Stream m b -> Stream m (a, b)

zip3 :: Monad m => Stream m a -> Stream m b -> Stream m c -> Stream m (a, b, c)

zip4 :: Monad m => Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m (a, b, c, d)

zip5 :: Monad m => Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e -> Stream m (a, b, c, d, e)

zip6 :: Monad m => Stream m a -> Stream m b -> Stream m c -> Stream m d -> Stream m e -> Stream m f -> Stream m (a, b, c, d, e, f)

Comparisons

eqBy :: Monad m => (a -> b -> Bool) -> Stream m a -> Stream m b -> m Bool

Check if two Streams are equal

cmpBy :: Monad m => (a -> b -> Ordering) -> Stream m a -> Stream m b -> m Ordering

Lexicographically compare two Streams

Filtering

filter :: Monad m => (a -> Bool) -> Stream m a -> Stream m a

Drop elements which do not satisfy the predicate

filterM :: Monad m => (a -> m Bool) -> Stream m a -> Stream m a

Drop elements which do not satisfy the monadic predicate

uniq :: (Eq a, Monad m) => Stream m a -> Stream m a

Drop repeated adjacent elements.

mapMaybe :: Monad m => (a -> Maybe b) -> Stream m a -> Stream m b

mapMaybeM :: Monad m => (a -> m (Maybe b)) -> Stream m a -> Stream m b

Apply monadic function to each element and drop all Nothings

Since: 0.12.2.0

catMaybes :: Monad m => Stream m (Maybe a) -> Stream m a

takeWhile :: Monad m => (a -> Bool) -> Stream m a -> Stream m a

Longest prefix of elements that satisfy the predicate

takeWhileM :: Monad m => (a -> m Bool) -> Stream m a -> Stream m a

Longest prefix of elements that satisfy the monadic predicate

dropWhile :: Monad m => (a -> Bool) -> Stream m a -> Stream m a

Drop the longest prefix of elements that satisfy the predicate

dropWhileM :: Monad m => (a -> m Bool) -> Stream m a -> Stream m a

Drop the longest prefix of elements that satisfy the monadic predicate

Searching

elem :: (Monad m, Eq a) => a -> Stream m a -> m Bool infix 4

Check whether the Stream contains an element

notElem :: (Monad m, Eq a) => a -> Stream m a -> m Bool infix 4

Inverse of elem

find :: Monad m => (a -> Bool) -> Stream m a -> m (Maybe a)

Yield Just the first element that satisfies the predicate or Nothing if no such element exists.

findM :: Monad m => (a -> m Bool) -> Stream m a -> m (Maybe a)

Yield Just the first element that satisfies the monadic predicate or Nothing if no such element exists.

findIndex :: Monad m => (a -> Bool) -> Stream m a -> m (Maybe Int)

Yield Just the index of the first element that satisfies the predicate or Nothing if no such element exists.

findIndexM :: Monad m => (a -> m Bool) -> Stream m a -> m (Maybe Int)

Yield Just the index of the first element that satisfies the monadic predicate or Nothing if no such element exists.

Folding

foldl :: Monad m => (a -> b -> a) -> a -> Stream m b -> m a

Left fold

foldlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a

Left fold with a monadic operator

foldl1 :: Monad m => (a -> a -> a) -> Stream m a -> m a

Left fold over a non-empty Stream

foldl1M :: (HasCallStack, Monad m) => (a -> a -> m a) -> Stream m a -> m a

Left fold over a non-empty Stream with a monadic operator

foldM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a

Same as foldlM

fold1M :: Monad m => (a -> a -> m a) -> Stream m a -> m a

Same as foldl1M

foldl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> m a

Left fold with a strict accumulator

foldlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a

Left fold with a strict accumulator and a monadic operator

foldl1' :: Monad m => (a -> a -> a) -> Stream m a -> m a

Left fold over a non-empty Stream with a strict accumulator

foldl1M' :: (HasCallStack, Monad m) => (a -> a -> m a) -> Stream m a -> m a

Left fold over a non-empty Stream with a strict accumulator and a monadic operator

foldM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a

Same as foldlM'

fold1M' :: Monad m => (a -> a -> m a) -> Stream m a -> m a

Same as foldl1M'

foldr :: Monad m => (a -> b -> b) -> b -> Stream m a -> m b

Right fold

foldrM :: Monad m => (a -> b -> m b) -> b -> Stream m a -> m b

Right fold with a monadic operator

foldr1 :: Monad m => (a -> a -> a) -> Stream m a -> m a

Right fold over a non-empty stream

foldr1M :: (HasCallStack, Monad m) => (a -> a -> m a) -> Stream m a -> m a

Right fold over a non-empty stream with a monadic operator

Specialised folds

and :: Monad m => Stream m Bool -> m Bool

or :: Monad m => Stream m Bool -> m Bool

concatMapM :: Monad m => (a -> m (Stream m b)) -> Stream m a -> Stream m b

Unfolding

unfoldr :: Monad m => (s -> Maybe (a, s)) -> s -> Stream m a

Unfold

unfoldrM :: Monad m => (s -> m (Maybe (a, s))) -> s -> Stream m a

Unfold with a monadic function

unfoldrN :: Monad m => Int -> (s -> Maybe (a, s)) -> s -> Stream m a

unfoldrNM :: Monad m => Int -> (s -> m (Maybe (a, s))) -> s -> Stream m a

Unfold at most n elements with a monadic function.

unfoldrExactN :: Monad m => Int -> (s -> (a, s)) -> s -> Stream m a

Unfold exactly n elements

Since: 0.12.2.0

unfoldrExactNM :: Monad m => Int -> (s -> m (a, s)) -> s -> Stream m a

Unfold exactly n elements with a monadic function.

Since: 0.12.2.0

iterateN :: Monad m => Int -> (a -> a) -> a -> Stream m a

O(n) Apply function \(\max(n - 1, 0)\) times to an initial value, producing a stream of \(\max(n, 0)\) values.

iterateNM :: Monad m => Int -> (a -> m a) -> a -> Stream m a

O(n) Apply monadic function \(\max(n - 1, 0)\) times to an initial value, producing a stream of \(\max(n, 0)\) values.

Scans

prescanl :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a

Prefix scan

prescanlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a

Prefix scan with a monadic operator

prescanl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a

Prefix scan with strict accumulator

prescanlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a

Prefix scan with strict accumulator and a monadic operator

postscanl :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a

Suffix scan

postscanlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a

Suffix scan with a monadic operator

postscanl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a

Suffix scan with strict accumulator

postscanlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a

Suffix scan with strict acccumulator and a monadic operator

scanl :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a

Haskell-style scan

scanlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a

Haskell-style scan with a monadic operator

scanl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a

Haskell-style scan with strict accumulator

scanlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a

Haskell-style scan with strict accumulator and a monadic operator

scanl1 :: Monad m => (a -> a -> a) -> Stream m a -> Stream m a

Initial-value free scan over a Stream

scanl1M :: Monad m => (a -> a -> m a) -> Stream m a -> Stream m a

Initial-value free scan over a Stream with a monadic operator

scanl1' :: Monad m => (a -> a -> a) -> Stream m a -> Stream m a

Initial-value free scan over a Stream with a strict accumulator

scanl1M' :: Monad m => (a -> a -> m a) -> Stream m a -> Stream m a

Initial-value free scan over a Stream with a strict accumulator and a monadic operator

Enumerations

enumFromStepN :: (Num a, Monad m) => a -> a -> Int -> Stream m a

Yield a Stream of the given length containing the values x, x+y, x+y+y etc.

enumFromTo :: (Enum a, Monad m) => a -> a -> Stream m a

Enumerate values

WARNING: This operation can be very inefficient. If at all possible, use enumFromStepN instead.

enumFromThenTo :: (Enum a, Monad m) => a -> a -> a -> Stream m a

Enumerate values with a given step.

WARNING: This operation is very inefficient. If at all possible, use enumFromStepN instead.

Conversions

toList :: Monad m => Stream m a -> m [a]

Convert a Stream to a list

fromList :: Monad m => [a] -> Stream m a

Convert a list to a Stream

fromListN :: Monad m => Int -> [a] -> Stream m a

Convert the first n elements of a list to a Bundle