Copyright | (c) Roman Leshchinskiy 2008-2010 |
---|---|
License | BSD-style |
Maintainer | Roman Leshchinskiy <rl@cse.unsw.edu.au> |
Stability | experimental |
Portability | non-portable |
Safe Haskell | None |
Language | Haskell2010 |
Monadic stream combinators.
Synopsis
- data Stream m a = forall s. Stream (s -> m (Step s a)) s
- data Step s a where
- data SPEC
- length :: Monad m => Stream m a -> m Int
- null :: Monad m => Stream m a -> m Bool
- empty :: Monad m => Stream m a
- singleton :: Monad m => a -> Stream m a
- cons :: Monad m => a -> Stream m a -> Stream m a
- snoc :: Monad m => Stream m a -> a -> Stream m a
- replicate :: Monad m => Int -> a -> Stream m a
- replicateM :: Monad m => Int -> m a -> Stream m a
- generate :: Monad m => Int -> (Int -> a) -> Stream m a
- generateM :: Monad m => Int -> (Int -> m a) -> Stream m a
- (++) :: Monad m => Stream m a -> Stream m a -> Stream m a
- head :: Monad m => Stream m a -> m a
- last :: Monad m => Stream m a -> m a
- (!!) :: Monad m => Stream m a -> Int -> m a
- (!?) :: Monad m => Stream m a -> Int -> m (Maybe a)
- slice :: Monad m => Int -> Int -> Stream m a -> Stream m a
- init :: Monad m => Stream m a -> Stream m a
- tail :: Monad m => Stream m a -> Stream m a
- take :: Monad m => Int -> Stream m a -> Stream m a
- drop :: Monad m => Int -> Stream m a -> Stream m a
- map :: Monad m => (a -> b) -> Stream m a -> Stream m b
- mapM :: Monad m => (a -> m b) -> Stream m a -> Stream m b
- mapM_ :: Monad m => (a -> m b) -> Stream m a -> m ()
- trans :: (Monad m, Monad m') => (forall z. m z -> m' z) -> Stream m a -> Stream m' a
- 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
- indexed :: Monad m => Stream m a -> Stream m (Int, a)
- indexedR :: Monad m => Int -> Stream m a -> Stream m (Int, a)
- 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
- 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)
- eqBy :: Monad m => (a -> b -> Bool) -> Stream m a -> Stream m b -> m Bool
- cmpBy :: Monad m => (a -> b -> Ordering) -> Stream m a -> Stream m b -> m Ordering
- filter :: Monad m => (a -> Bool) -> Stream m a -> Stream m a
- filterM :: Monad m => (a -> m Bool) -> Stream m a -> Stream m a
- uniq :: (Eq a, Monad m) => Stream m a -> Stream m a
- 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
- catMaybes :: Monad m => Stream m (Maybe a) -> Stream m a
- takeWhile :: Monad m => (a -> Bool) -> Stream m a -> Stream m a
- takeWhileM :: Monad m => (a -> m Bool) -> Stream m a -> Stream m a
- dropWhile :: Monad m => (a -> Bool) -> Stream m a -> Stream m a
- dropWhileM :: Monad m => (a -> m Bool) -> Stream m a -> Stream m a
- elem :: (Monad m, Eq a) => a -> Stream m a -> m Bool
- notElem :: (Monad m, Eq a) => a -> Stream m a -> m Bool
- find :: Monad m => (a -> Bool) -> Stream m a -> m (Maybe a)
- findM :: Monad m => (a -> m Bool) -> Stream m a -> m (Maybe a)
- findIndex :: Monad m => (a -> Bool) -> Stream m a -> m (Maybe Int)
- findIndexM :: Monad m => (a -> m Bool) -> Stream m a -> m (Maybe Int)
- foldl :: Monad m => (a -> b -> a) -> a -> Stream m b -> m a
- foldlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a
- foldl1 :: Monad m => (a -> a -> a) -> Stream m a -> m a
- foldl1M :: Monad m => (a -> a -> m a) -> Stream m a -> m a
- foldM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a
- fold1M :: Monad m => (a -> a -> m a) -> Stream m a -> m a
- foldl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> m a
- foldlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a
- foldl1' :: Monad m => (a -> a -> a) -> Stream m a -> m a
- foldl1M' :: Monad m => (a -> a -> m a) -> Stream m a -> m a
- foldM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a
- fold1M' :: Monad m => (a -> a -> m a) -> Stream m a -> m a
- foldr :: Monad m => (a -> b -> b) -> b -> Stream m a -> m b
- foldrM :: Monad m => (a -> b -> m b) -> b -> Stream m a -> m b
- foldr1 :: Monad m => (a -> a -> a) -> Stream m a -> m a
- foldr1M :: Monad m => (a -> a -> m a) -> Stream m a -> m a
- 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
- unfoldr :: Monad m => (s -> Maybe (a, s)) -> s -> Stream m a
- unfoldrM :: Monad m => (s -> m (Maybe (a, s))) -> s -> Stream m a
- 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
- unfoldrExactN :: Monad m => Int -> (s -> (a, s)) -> s -> Stream m a
- unfoldrExactNM :: Monad m => Int -> (s -> m (a, s)) -> s -> Stream m a
- iterateN :: Monad m => Int -> (a -> a) -> a -> Stream m a
- iterateNM :: Monad m => Int -> (a -> m a) -> a -> Stream m a
- prescanl :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a
- prescanlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a
- prescanl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a
- prescanlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a
- postscanl :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a
- postscanlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a
- postscanl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a
- postscanlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a
- scanl :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a
- scanlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a
- scanl' :: Monad m => (a -> b -> a) -> a -> Stream m b -> Stream m a
- scanlM' :: Monad m => (a -> b -> m a) -> a -> Stream m b -> Stream m a
- scanl1 :: Monad m => (a -> a -> a) -> Stream m a -> Stream m a
- scanl1M :: Monad m => (a -> a -> m a) -> Stream m a -> Stream m a
- scanl1' :: Monad m => (a -> a -> a) -> Stream m a -> Stream m a
- scanl1M' :: Monad m => (a -> a -> m a) -> Stream m a -> Stream m a
- enumFromStepN :: (Num a, Monad m) => a -> a -> Int -> Stream m a
- enumFromTo :: (Enum a, Monad m) => a -> a -> Stream m a
- enumFromThenTo :: (Enum a, Monad m) => a -> a -> a -> Stream m a
- toList :: Monad m => Stream m a -> m [a]
- fromList :: Monad m => [a] -> Stream m a
- fromListN :: Monad m => Int -> [a] -> Stream m a
Documentation
Monadic streams
Result of taking a single step in a stream
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.
Length
Construction
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
Accessing elements
(!?) :: Monad m => Stream m a -> Int -> m (Maybe a) infixl 9 #
Element at the given position or Nothing
if out of bounds
Substreams
Extract a substream of the given length starting at the given position.
Mapping
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
Zipping
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 -> Stream m c #
Zip two Stream
s 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 #
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 #
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 Stream
s are equal
cmpBy :: Monad m => (a -> b -> Ordering) -> Stream m a -> Stream m b -> m Ordering #
Lexicographically compare two Stream
s
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
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
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
Folding
foldl1M :: Monad m => (a -> a -> m a) -> Stream m a -> m a #
Left fold over a non-empty Stream
with a monadic operator
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' :: 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
foldr1M :: Monad m => (a -> a -> m a) -> Stream m a -> m a #
Right fold over a non-empty stream with a monadic operator
Specialised folds
Unfolding
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
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
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
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
scanl1M :: Monad m => (a -> a -> m a) -> Stream m a -> Stream m a #
Scan over a non-empty Stream
with a monadic operator
scanl1' :: Monad m => (a -> a -> a) -> Stream m a -> Stream m a #
Scan over a non-empty Stream
with a strict accumulator
scanl1M' :: Monad m => (a -> a -> m a) -> Stream m a -> Stream m a #
Scan over a non-empty 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.