Implement slicesepby, add tests and benchmarks

benchmark/Streamly/Benchmark/Data/Parser.hs

@@ -161,6 +161,12 @@ split_ value =
             (PR.drainWhile (<= value))
         )
 
+{-# INLINE sliceSepBy #-}
+sliceSepBy :: MonadCatch m
+    => Int -> SerialT m Int -> m()
+sliceSepBy value = IP.parse (PR.sliceSepBy (>= value) (PR.many FL.drain
+                    (PR.satisfy (const True))))
+
 {-# INLINE teeAllAny #-}
 teeAllAny :: MonadCatch m
     => Int -> SerialT m Int -> m ((), ())
@@ -281,6 +287,7 @@ o_1_space_serial value =
     , benchIOSink value "splitApBefore" $ splitApBefore value
     , benchIOSink value "splitApAfter" $ splitApAfter value
     , benchIOSink value "splitWith" $ splitWith value
+    , benchIOSink value "sliceSepBy" $ sliceSepBy value
     , benchIOSink value "many" many
     , benchIOSink value "many (wordBy even)" $ manyWordByEven
     , benchIOSink value "some" some

benchmark/Streamly/Benchmark/Data/Parser/ParserD.hs

@@ -100,6 +100,10 @@ someAlt xs = do
     x <- IP.parseD (AP.some (PR.satisfy (> 0))) xs
     return $ Prelude.length x
 
+{-#INLINE sliceSepBy #-}
+sliceSepBy :: MonadCatch m => Int -> SerialT m Int -> m ()
+sliceSepBy value = IP.parseD (PR.sliceSepBy (>= value) (PR.many FL.drain
+                    (PR.satisfy (const True))))
 {-# INLINE manyTill #-}
 manyTill :: MonadCatch m => Int -> SerialT m Int -> m Int
 manyTill value =
@@ -214,6 +218,7 @@ o_1_space_serial value =
     , benchIOSink value "many" many
     , benchIOSink value "many (wordBy even)" $ manyWordByEven
     , benchIOSink value "some" some
+    , benchIOSink value "sliceSepBy" $ sliceSepBy value
     , benchIOSink value "manyTill" $ manyTill value
     , benchIOSink value "tee (all,any)" $ teeAllAny value
     , benchIOSink value "teeFst (all,any)" $ teeFstAllAny value

src/Streamly/Internal/Data/Parser.hs

@@ -487,12 +487,13 @@ drainWhile p = takeWhile p FL.drain
 -- sliceSepByBetween cond m n p = sliceBy cond (takeBetween m n p)
 -- @
 --
--- /Unimplemented/
+-- /Internal/
 --
 {-# INLINABLE sliceSepBy #-}
-sliceSepBy :: -- MonadCatch m =>
+sliceSepBy ::
+    MonadCatch m =>
     (a -> Bool) -> Parser m a b -> Parser m a b
-sliceSepBy _cond = undefined -- K.toParserK . D.sliceSepBy cond
+sliceSepBy cond = K.toParserK . D.sliceSepBy cond . K.fromParserK
 
 -- | Like 'sliceSepBy' but does not drop the separator element, instead
 -- separator is emitted as a separate element in the output.

src/Streamly/Internal/Data/Parser/ParserD.hs

@@ -487,9 +487,22 @@ takeWhile1 predicate (Fold fstep finitial fextract) =
 --
 -- /Internal/
 --
-sliceSepBy :: -- MonadCatch m =>
+sliceSepBy :: MonadCatch m =>
     (a -> Bool) -> Parser m a b -> Parser m a b
-sliceSepBy _cond = undefined
+sliceSepBy cond (Parser pstep pinitial pextract) =
+
+    Parser step initial pextract
+
+    where
+
+    initial = pinitial
+
+    step s a =
+        if cond a
+        then do
+            res <- pextract s
+            return $ Done 0 res
+        else pstep s a
 
 -- | See 'Streamly.Internal.Data.Parser.sliceBeginWith'.
 --

test/Streamly/Test/Data/Parser.hs

@@ -311,6 +311,17 @@ takeProperties =
 --                         where
 --                             list_length = Prelude.length ls
 
+sliceSepBy :: Property
+sliceSepBy =
+    forAll (listOf (chooseInt (min_value, max_value )))  $ \ls ->
+        case S.parse (P.sliceSepBy predicate prsr) (S.fromList ls) of
+            Right parsed_list -> checkListEqual parsed_list (Prelude.takeWhile
+                        (not. predicate) ls)
+            Left _ -> property False
+        where
+            predicate = (>= 100)
+            prsr = P.many FL.toList (P.satisfy (const True))
+
 takeWhile :: Property
 takeWhile =
     forAll (listOf (chooseInt (0, 1))) $ \ ls ->
@@ -693,6 +704,7 @@ main =
         -- prop "lookAhead . take n >> lookAhead . take n = lookAhead . take n" lookAheadPass
         -- prop "Fail when stream length exceeded" lookAheadFail
         -- prop "lookAhead . take n >> lookAhead . take n = lookAhead . take n, else fail" lookAhead
+        prop "P.sliceSepBy test" Main.sliceSepBy
         prop "P.takeWhile = Prelude.takeWhile" Main.takeWhile
         prop ("P.takeWhile1 = Prelude.takeWhile if taken something,"
                 ++ " else check why failed") takeWhile1

test/Streamly/Test/Data/Parser/ParserD.hs

@@ -292,6 +292,7 @@ lookAhead =
                         where
                             list_length = Prelude.length ls
 
+
 takeWhile :: Property
 takeWhile =
     forAll (listOf (chooseInt (0, 1))) $ \ ls ->
@@ -336,12 +337,15 @@ groupBy =
 
 sliceSepBy :: Property
 sliceSepBy =
-    forAll (listOf (chooseInt (0, 1))) $ \ls ->
-        case S.parseD (P.fromFold $ FL.sliceSepBy predicate FL.toList) (S.fromList ls) of
-            Right parsed_list -> checkListEqual parsed_list (Prelude.takeWhile (not . predicate) ls)
+    forAll (listOf (chooseInt (min_value, max_value )))  $ \ls ->
+        case S.parseD (P.sliceSepBy predicate prsr) (S.fromList ls) of
+            Right parsed_list -> checkListEqual parsed_list (Prelude.takeWhile
+                        (not. predicate) ls)
             Left _ -> property False
         where
-            predicate = (== 1)
+            predicate = (>= 100)
+            prsr = P.many FL.toList (P.satisfy (const True))
+
 
 sliceSepByMax :: Property
 sliceSepByMax =