b1c6694 · typeable/attoparsec

git.iko.soy/typeable/attoparsec

Generalise the concat . reverse thing

commitb1c6694447321db82e5a41d36653fcb8dd8d97c9 authorBryan O'Sullivan <bos@serpentine.com> dateWed 22 Jul 2015, 11:28 (11 years ago) parent72a3e75

3 files changed+16−12

compare with master

unifiedsplit

Data/Attoparsec/ByteString/Internal.hs+3−6 Data/Attoparsec/Internal.hs+10 Data/Attoparsec/Text/Internal.hs+3−6

Data/Attoparsec/ByteString/Internal.hs+3−6

@@ -257,7 +257,7 @@ takeTill p = takeWhile (not . p)

257257-- parsers loop until a failure occurs. Careless use will thus result

258258-- in an infinite loop.

259259takeWhile :: (Word8 -> Bool) -> Parser ByteString

260−takeWhile p = (B.concat . reverse) `fmap` go []

260+takeWhile p = concatReverse `fmap` go []

261261 where

262262 go acc = do

263263 s <- B8.takeWhile p <$> get

@@ -329,16 +329,13 @@ scan_ f s0 p = go [] s0

329329-- parsers loop until a failure occurs. Careless use will thus result

330330-- in an infinite loop.

331331scan :: s -> (s -> Word8 -> Maybe s) -> Parser ByteString

332−scan = scan_ $ \_ chunks ->

333− case chunks of

334− [x] -> return x

335− xs -> return $! B.concat $ reverse xs

332+scan = scan_ $ \_ chunks -> return $! concatReverse chunks

336333{-# INLINE scan #-}

337334

338335-- | Like 'scan', but generalized to return the final state of the

339336-- scanner.

340337runScanner :: s -> (s -> Word8 -> Maybe s) -> Parser (ByteString, s)

341−runScanner = scan_ $ \s xs -> return (B.concat (reverse xs), s)

338+runScanner = scan_ $ \s xs -> let !sx = concatReverse xs in return (sx, s)

342339{-# INLINE runScanner #-}

343340

344341-- | Consume input as long as the predicate returns 'True', and return

Data/Attoparsec/Internal.hs+10

@@ -20,10 +20,12 @@ module Data.Attoparsec.Internal

2020 , endOfInput

2121 , atEnd

2222 , satisfyElem

23+ , concatReverse

2324 ) where

2425

2526#if !MIN_VERSION_base(4,8,0)

2627import Control.Applicative ((<$>))

28+import Data.Monoid (Monoid, mconcat)

2729#endif

2830import Data.Attoparsec.Internal.Types

2931import Data.ByteString (ByteString)

@@ -159,3 +161,11 @@ satisfyElem p = Parser $ \t pos more lose succ ->

159161 | otherwise -> lose t pos more [] "satisfyElem"

160162 Nothing -> satisfySuspended p t pos more lose succ

161163{-# INLINE satisfyElem #-}

164+

165+-- | Concatenate a monoid after reversing its elements. Used to

166+-- glue together a series of textual chunks that have been accumulated

167+-- \"backwards\".

168+concatReverse :: Monoid m => [m] -> m

169+concatReverse [x] = x

170+concatReverse xs = mconcat (reverse xs)

171+{-# INLINE concatReverse #-}

Data/Attoparsec/Text/Internal.hs+3−6

@@ -269,7 +269,7 @@ takeTill p = takeWhile (not . p)

269269-- parsers loop until a failure occurs. Careless use will thus result

270270-- in an infinite loop.

271271takeWhile :: (Char -> Bool) -> Parser Text

272−takeWhile p = (T.concat . reverse) `fmap` go []

272+takeWhile p = concatReverse `fmap` go []

273273 where

274274 go acc = do

275275 h <- T.takeWhile p <$> get

@@ -334,16 +334,13 @@ scan_ f s0 p = go [] s0

334334-- parsers loop until a failure occurs. Careless use will thus result

335335-- in an infinite loop.

336336scan :: s -> (s -> Char -> Maybe s) -> Parser Text

337−scan = scan_ $ \_ chunks ->

338− case chunks of

339− [x] -> return x

340− xs -> return . T.concat . reverse $ xs

337+scan = scan_ $ \_ chunks -> return $! concatReverse chunks

341338{-# INLINE scan #-}

342339

343340-- | Like 'scan', but generalized to return the final state of the

344341-- scanner.

345342runScanner :: s -> (s -> Char -> Maybe s) -> Parser (Text, s)

346−runScanner = scan_ $ \s xs -> return (T.concat (reverse xs), s)

343+runScanner = scan_ $ \s xs -> let !sx = concatReverse xs in return (sx, s)

347344{-# INLINE runScanner #-}

348345

349346-- | Consume input as long as the predicate returns 'True', and return