349c9d7 · streamly · git.iko.soy

git.iko.soy/streamly

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Use an IORef for the counts in hashmap

349c9d7Harendra Kumar7 years ago

examples/WordClassifier.hs+7−3

compare with master

unifiedsplit

@@ -12,6 +12,7 @@ import Data.Function ((&))

12import Data.Functor.Identity (Identity(..))

13import qualified Data.HashMap.Strict as Map

14import Data.Hashable

15+import Data.IORef

15import qualified Data.List as List

16import qualified Data.List as List

16import qualified Data.Ord as Ord

17import qualified Data.Ord as Ord

17import Foreign.Storable (Storable(..))

18import Foreign.Storable (Storable(..))

@@ -48,7 +49,8 @@ isAlpha c

48main :: IO ()

49main :: IO ()

49main =

50main =

50 let

51 let

51− increment m str = Map.insertWith (+) str (1 :: Int) m

52+ alter Nothing = fmap Just $ newIORef (1 :: Int)

53+ alter (Just ref) = modifyIORef' ref (+ 1) >> return (Just ref)

52 in do

54 in do

53 name <- fmap head getArgs

55 name <- fmap head getArgs

54 src <- openFile name ReadMode

56 src <- openFile name ReadMode

@@ -57,6 +59,8 @@ main =

57 & Streamly.map toLower -- SerialT IO Char

59 & Streamly.map toLower -- SerialT IO Char

58 & Streamly.foldWords FL.toList -- SerialT IO String

60 & Streamly.foldWords FL.toList -- SerialT IO String

59 & Streamly.filter (all isAlpha)

61 & Streamly.filter (all isAlpha)

60− & Streamly.foldl' increment Map.empty

62+ & Streamly.foldlM' (flip (Map.alterF alter)) Map.empty

63+ & fmap Map.toList

64+ >>= mapM (\(w, ref) -> readIORef ref >>= \cnt -> return (w, cnt))

61− & fmap (List.take 25 . List.sortOn (Ord.Down . snd) . Map.toList)

65+ & fmap (List.take 25 . List.sortOn (Ord.Down . snd))

62 >>= traverse_ print

66 >>= traverse_ print