eff3255 · streamly · git.iko.soy

src/Streamly/Internal/Control/Exception.hsnew file+50

compare with master

unifiedsplit

@@ -0,0 +1,50 @@

1+-- |

2+-- Module : Streamly.Internal.Control.Exception

4+--

5+-- License : BSD3

6+-- Maintainer : streamly@composewell.com

7+-- Stability : experimental

8+-- Portability : GHC

9+--

10+-- Additional "Control.Exception" utilities.

11+

12+module Streamly.Internal.Control.Exception

13+ ( assertM

14+ , verify

15+ , verifyM

16+ )

17+where

18+

19+import Control.Exception (assert)

20+

21+-- Like 'assert' but returns @()@ in an 'Applicative' context so that it can be

22+-- used as an independent statement in a @do@ block.

23+--

24+-- /Internal/

25+--

26+{-# INLINE assertM #-}

27+assertM :: Applicative f => Bool -> f ()

28+assertM predicate = assert predicate (pure ())

29+

30+-- | Like 'assert' but is not removed by the compiler, it is always present in

31+-- production code.

32+--

33+-- /Internal/

34+--

35+{-# INLINE verify #-}

36+verify :: Bool -> a -> a

37+verify predicate val =

38+ if predicate

39+ -- XXX it would be nice if we can print the predicate expr.

40+ then error "verify failed"

41+ else val

42+

43+-- Like 'verify' but returns @()@ in an 'Applicative' context so that it can be

44+-- used as an independent statement in a @do@ block.

45+--

46+-- /Internal/

47+--

48+{-# INLINE verifyM #-}

49+verifyM :: Applicative f => Bool -> f ()

50+verifyM predicate = verify predicate (pure ())

src/Streamly/Internal/Data/Parser/ParserK/Types.hs+10−1

@@ -40,6 +40,7 @@ import qualified Control.Monad.Fail as Fail

40#if !(MIN_VERSION_base(4,10,0))

41import Data.Semigroup ((<>))

42#endif

43+import Streamly.Internal.Control.Exception

43

44

44import qualified Streamly.Internal.Data.Parser.ParserD.Types as D

45import qualified Streamly.Internal.Data.Parser.ParserD.Types as D

45

46

@@ -205,6 +206,9 @@ data FromParserK b e c = FPKDone !Int !b | FPKError !e | FPKCont c

205

206

206-- | Convert a CPS style 'Parser' to a direct style 'D.Parser'.

207-- | Convert a CPS style 'Parser' to a direct style 'D.Parser'.

207--

208--

209+-- "initial" returns a continuation which can be called one input at a time

210+-- using the "step" function.

211+--

208-- /Internal/

212-- /Internal/

209--

213--

210{-# INLINE_LATE fromParserK #-}

214{-# INLINE_LATE fromParserK #-}

@@ -221,7 +225,12 @@ fromParserK parser = D.Parser step initial extract

221 Partial _ cont -> FPKCont cont -- XXX can we get this?

225 Partial _ cont -> FPKCont cont -- XXX can we get this?

222 Continue _ cont -> FPKCont cont

226 Continue _ cont -> FPKCont cont

223

227

228+ -- Note, we can only reach FPKDone and FPKError from "initial". FPKCont

229+ -- always transitions to only FPKCont. The input remains unconsumed in

230+ -- this case so we use "n + 1".

231+ step (FPKDone n b) _ = do

232+ assertM (n == 0)

224− step (FPKDone n b) _ = return $ D.Done (n + 1) b

233+ return $ D.Done (n + 1) b

225 step (FPKError e) _ = return $ D.Error e

234 step (FPKError e) _ = return $ D.Error e

226 step (FPKCont cont) a = do

235 step (FPKCont cont) a = do

227 r <- cont (Just a)

236 r <- cont (Just a)

streamly.cabal+1

@@ -383,6 +383,7 @@ library

383

384 -- Internal modules

385 , Streamly.Internal.BaseCompat

386+ , Streamly.Internal.Control.Exception

386 , Streamly.Internal.Control.Monad

387 , Streamly.Internal.Control.Monad

387 , Streamly.Internal.Data.Tuple.Strict

388 , Streamly.Internal.Data.Tuple.Strict

388 , Streamly.Internal.Data.Maybe.Strict

389 , Streamly.Internal.Data.Maybe.Strict