74ce247 · streamly · git.iko.soy

git.iko.soy/streamly

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Add Prelude#find, Prelude#lookup

74ce247Veladus8 years ago

src/Streamly/Prelude.hs+14−1

compare with master

unifiedsplit

@@ -105,6 +105,8 @@ module Streamly.Prelude

105 , minimum

106 , sum

107 , product

108+ , lookup

109+ , find

108

110

109 -- *** Indices

111 -- *** Indices

110 , findIndices

112 , findIndices

@@ -170,7 +172,7 @@ import Prelude

170 hiding (filter, drop, dropWhile, take, takeWhile, zipWith, foldr,

172 hiding (filter, drop, dropWhile, take, takeWhile, zipWith, foldr,

171 foldl, map, mapM, mapM_, sequence, all, any, sum, product, elem,

173 foldl, map, mapM, mapM_, sequence, all, any, sum, product, elem,

172 notElem, maximum, minimum, head, last, tail, length, null,

174 notElem, maximum, minimum, head, last, tail, length, null,

173− reverse, iterate, init, and, or)

175+ reverse, iterate, init, and, or, lookup)

174import qualified Prelude

176import qualified Prelude

175import qualified System.IO as IO

177import qualified System.IO as IO

176

178

@@ -612,6 +614,17 @@ minimum m = S.minimum (toStreamS m)

612maximum :: (Monad m, Ord a) => SerialT m a -> m (Maybe a)

614maximum :: (Monad m, Ord a) => SerialT m a -> m (Maybe a)

613maximum m = S.maximum (toStreamS m)

615maximum m = S.maximum (toStreamS m)

614

616

617+-- | Looks the given key up, treating the given stream as an association list.

618+{-# INLINE lookup #-}

619+lookup :: (Monad m, Eq a) => a -> SerialT m (a, b) -> m (Maybe b)

620+lookup = K.lookup

621+

622+-- | Returns the first element of the stream satisfying the given predicate,

623+-- if any.

624+{-# INLINE find #-}

625+find :: Monad m => (a -> Bool) -> SerialT m a -> m (Maybe a)

626+find = K.find

627+

615-- | Finds all the indices of elements satisfying the given predicate.

628-- | Finds all the indices of elements satisfying the given predicate.

616{-# INLINE findIndices #-}

629{-# INLINE findIndices #-}

617findIndices :: IsStream t => (a -> Bool) -> t m a -> t m Int

630findIndices :: IsStream t => (a -> Bool) -> t m a -> t m Int

src/Streamly/Streams/StreamK.hs+25−1

@@ -90,6 +90,8 @@ module Streamly.Streams.StreamK

90 , minimum

91 , maximum

92 , findIndices

93+ , lookup

94+ , find

94 -- ** Map and Fold

96 -- ** Map and Fold

95 , mapM_

97 , mapM_

@@ -143,7 +145,7 @@ import Data.Semigroup (Semigroup(..))

143import Prelude

145import Prelude

144 hiding (foldl, foldr, last, map, mapM, mapM_, repeat, sequence,

146 hiding (foldl, foldr, last, map, mapM, mapM_, repeat, sequence,

145 take, filter, all, any, takeWhile, drop, dropWhile, minimum,

147 take, filter, all, any, takeWhile, drop, dropWhile, minimum,

146− maximum, elem, notElem, null, head, tail, init, zipWith)

148+ maximum, elem, notElem, null, head, tail, init, zipWith, lookup)

147import qualified Prelude

149import qualified Prelude

148

150

149import Streamly.SVar

151import Streamly.SVar

@@ -675,6 +677,28 @@ maximum m = go Nothing (toStream m)

675 else go (Just res) r

677 else go (Just res) r

676 in unStream m1 defState stop single yieldk

678 in unStream m1 defState stop single yieldk

677

679

680+{-# INLINE lookup #-}

681+lookup :: (IsStream t, Monad m, Eq a) => a -> t m (a, b) -> m (Maybe b)

682+lookup e m = go (toStream m)

683+ where

684+ go m1 =

685+ let single (a, b) | a == e = return $ Just b

686+ | otherwise = return Nothing

687+ yieldk (a, b) x | a == e = return $ Just b

688+ | otherwise = go x

689+ in unStream m1 defState (return Nothing) single yieldk

690+

691+{-# INLINE find #-}

692+find :: (IsStream t, Monad m) => (a -> Bool) -> t m a -> m (Maybe a)

693+find p m = go (toStream m)

694+ where

695+ go m1 =

696+ let single a | p a = return $ Just a

697+ | otherwise = return Nothing

698+ yieldk a x | p a = return $ Just a

699+ | otherwise = go x

700+ in unStream m1 defState (return Nothing) single yieldk

701+

678{-# INLINE findIndices #-}

702{-# INLINE findIndices #-}

679findIndices :: IsStream t => (a -> Bool) -> t m a -> t m Int

703findIndices :: IsStream t => (a -> Bool) -> t m a -> t m Int

680findIndices p = fromStream . go 0 . toStream

704findIndices p = fromStream . go 0 . toStream

test/Prop.hs+3−1

@@ -10,7 +10,7 @@ import Control.Concurrent (MVar, takeMVar, putMVar, newEmptyMVar)

10import Control.Monad (replicateM, replicateM_)

11import Data.IORef (readIORef, modifyIORef, newIORef)

12import Data.List (sort, foldl', scanl', findIndices, findIndex, elemIndices,

13− elemIndex)

13+ elemIndex, find)

14import Data.Maybe (mapMaybe)

15import GHC.Word (Word8)

@@ -489,6 +489,8 @@ eliminationOps constr desc t = do

489 prop (desc ++ " findIndex") $ eliminateOp constr (findIndex odd) $ (S.findIndex odd) . t

490 prop (desc ++ " elemIndex") $ eliminateOp constr (elemIndex 3) $ (S.elemIndex 3) . t

491

492+ prop (desc ++ " find") $ eliminateOp constr (find even) $ (S.find even) . t

493+

492-- head/tail/last may depend on the order in case of parallel streams

494-- head/tail/last may depend on the order in case of parallel streams

493-- so we test these only for serial streams.

495-- so we test these only for serial streams.

494serialEliminationOps

496serialEliminationOps