8b565b3 · typeable/yaml

git.iko.soy/typeable/yaml

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decodeFileEither

8b565b3Michael Snoyman13 years ago

Data/Yaml.hs+29−1

compare with master

unifiedsplit

@@ -52,6 +52,7 @@ module Data.Yaml

52 -- ** Better error information

53 , decodeEither

54 , decodeEither'

55+ , decodeFileEither

55 -- ** More control over decoding

56 -- ** More control over decoding

56 , decodeHelper

57 , decodeHelper

57 ) where

58 ) where

@@ -68,7 +69,7 @@ import Data.ByteString (ByteString)

68import qualified Data.ByteString.Char8 as S8

69import qualified Data.ByteString.Char8 as S8

69import qualified Data.Map as Map

70import qualified Data.Map as Map

70import System.IO.Unsafe (unsafePerformIO)

71import System.IO.Unsafe (unsafePerformIO)

71−import Control.Exception (try, throwIO, fromException, Exception)

72+import Control.Exception (try, throwIO, fromException, Exception, SomeException, AsyncException)

72import Control.Monad.Trans.State

73import Control.Monad.Trans.State

73import qualified Data.Conduit as C

74import qualified Data.Conduit as C

74import qualified Data.Conduit.List as CL

75import qualified Data.Conduit.List as CL

@@ -142,6 +143,7 @@ data ParseException = NonScalarKey

142 }

143 }

143 | InvalidYaml (Maybe YamlException)

144 | InvalidYaml (Maybe YamlException)

144 | AesonException String

145 | AesonException String

146+ | OtherParseException SomeException

145 deriving (Show, Typeable)

147 deriving (Show, Typeable)

146instance Exception ParseException

148instance Exception ParseException

147

149

@@ -278,6 +280,32 @@ decodeFile :: FromJSON a

278 -> IO (Maybe a)

280 -> IO (Maybe a)

279decodeFile fp = decodeHelper (Y.decodeFile fp) >>= either throwIO (return . either (const Nothing) id)

281decodeFile fp = decodeHelper (Y.decodeFile fp) >>= either throwIO (return . either (const Nothing) id)

280

282

283+-- | A version of 'decodeFile' which should not throw runtime exceptions.

284+--

285+-- Since 0.8.4

286+decodeFileEither

287+ :: FromJSON a

288+ => FilePath

289+ -> IO (Either ParseException a)

290+decodeFileEither fp = do

291+ x <- try $ C.runResourceT $ flip evalStateT Map.empty $ Y.decodeFile fp C.$$ parse

292+ case x of

293+ Left e

294+ | Just pe <- fromException e -> return $ Left pe

295+ | Just ye <- fromException e -> return $ Left $ InvalidYaml $ Just (ye :: YamlException)

296+ | shouldBeCaught e -> return $ Left $ OtherParseException e

297+ | otherwise -> throwIO e

298+ Right y ->

299+ return $ case parseEither parseJSON y of

300+ Left s -> Left $ AesonException s

301+ Right v -> Right v

302+ where

303+ -- FIXME this function needs more thought

304+ shouldBeCaught e

305+ | Just (_ :: AsyncException) <- fromException e = False

306+ -- Would be nice... | Just (_ :: Timeout) <- fromException e = False

307+ | otherwise = True

308+

281decodeEither :: FromJSON a => ByteString -> Either String a

309decodeEither :: FromJSON a => ByteString -> Either String a

282decodeEither bs = unsafePerformIO

310decodeEither bs = unsafePerformIO

283 $ fmap (either (Left . show) id)

311 $ fmap (either (Left . show) id)

yaml.cabal+1−1

@@ -1,5 +1,5 @@

1name: yaml

2−version: 0.8.3

2+version: 0.8.4

3license: BSD3

4license-file: LICENSE

5author: Michael Snoyman <michael@snoyman.com>, Anton Ageev <antage@gmail.com>,Kirill Simonov