9148b4d · streamly · git.iko.soy

git.iko.soy/streamly

Improve documentation of scan routines and "before"

Add definitions illustrating relationships between different combinators.

commit9148b4d65b5d6f0811c134763dbdab0dfdceca3a authorHarendra Kumar <harendra@composewell.com> dateSun 8 Aug 2021, 02:16 (5 years ago) parent1af9389

4 files changed+17−3

compare with master

unifiedsplit

.github/workflows/haskell.yml+1−1 src/Streamly/Internal/Data/Stream/IsStream/Common.hs+2 src/Streamly/Internal/Data/Stream/IsStream/Exception.hs+9−1 src/Streamly/Internal/Data/Stream/IsStream/Transform.hs+5−1

.github/workflows/haskell.yml+1−1

@@ -158,7 +158,7 @@ jobs:

158158 cabal update

159159 cabal build all

160160 $HOME/.cabal/bin/cabal-docspec --version

161− $HOME/.cabal/bin/cabal-docspec --timeout 60

161+ $HOME/.cabal/bin/cabal-docspec --timeout 60 --check-properties --property-variables xs

162162 elif test -z "$COVERAGE"

163163 then

164164 export TOOLS_DIR=/opt

src/Streamly/Internal/Data/Stream/IsStream/Common.hs+2

@@ -313,6 +313,8 @@ scanlMAfter' step initial done stream =

313313-- XXX this needs to be concurrent

314314-- | Like 'postscanl'' but with a monadic step function and a monadic seed.

315315--

316+-- >>> postscanlM' f z xs = Stream.drop 1 $ Stream.scanlM' f z xs

317+--

316318-- /Since: 0.7.0/

317319--

318320-- /Since: 0.8.0 (signature change)/

src/Streamly/Internal/Data/Stream/IsStream/Exception.hs+9−1

@@ -34,13 +34,21 @@ import Streamly.Internal.Data.SVar (MonadAsync)

3434

3535import qualified Streamly.Internal.Data.Stream.StreamD as D

3636

37+-- $setup

38+-- >>> :m

39+-- >>> import qualified Streamly.Prelude as Stream

40+-- >>> import qualified Streamly.Internal.Data.Stream.IsStream as Stream (nilM)

41+

3742------------------------------------------------------------------------------

3843-- Exceptions

3944------------------------------------------------------------------------------

4045

4146-- | Run the action @m b@ before the stream yields its first element.

4247--

43−-- > before action xs = 'nilM' action <> xs

48+-- Same as the following but more efficient due to fusion:

49+--

50+-- >>> before action xs = Stream.nilM action <> xs

51+-- >>> before action xs = Stream.concatMap (const xs) (Stream.fromEffect action)

4452--

4553-- @since 0.7.0

4654{-# INLINE before #-}

src/Streamly/Internal/Data/Stream/IsStream/Transform.hs+5−1

@@ -713,6 +713,9 @@ scanlM' step begin m = fromStreamD $ D.scanlM' step begin $ toStreamD m

713713-- lazy expressions inside the accumulator, it is recommended that a strict

714714-- data structure is used for accumulator.

715715--

716+-- >>> scanl' f z xs = scanlM' (\a b -> return (f a b)) (return z) xs

717+-- >>> scanl' f z xs = z `Stream.cons` postscanl' f z xs

718+--

716719-- See also: 'usingStateT'

717720--

718721-- @since 0.2.0

@@ -722,7 +725,8 @@ scanl' step z m = fromStreamS $ S.scanl' step z $ toStreamS m

722725

723726-- | Like 'scanl'' but does not stream the initial value of the accumulator.

724727--

725−-- > postscanl' f z xs = Stream.drop 1 $ Stream.scanl' f z xs

728+-- >>> postscanl' f z = postscanlM' (\a b -> return (f a b)) (return z)

729+-- >>> postscanl' f z xs = Stream.drop 1 $ Stream.scanl' f z xs

726730--

727731-- @since 0.7.0

728732{-# INLINE postscanl' #-}