e689788 · streamly · git.iko.soy

git.iko.soy/streamly

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Add smart constructors to create parsers

e689788Adithya Kumar5 years ago

src/Streamly/Internal/Data/Fold/Type.hs+3

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unifiedsplit

@@ -454,6 +454,9 @@ foldrM g z =

454-- need that?

455--

456-- Until we investigate this we are not releasing these.

457+--

458+-- XXX The above text would apply to

459+-- Streamly.Internal.Data.Parser.ParserD.Type.parser

457

460

458-- | Make a terminating fold using a pure step function, a pure initial state

461-- | Make a terminating fold using a pure step function, a pure initial state

459-- and a pure state extraction function.

462-- and a pure state extraction function.

src/Streamly/Internal/Data/Parser/ParserD.hs+4−4

@@ -331,14 +331,14 @@ next = Parser step initial extract

331--

332{-# INLINE maybe #-}

333maybe :: MonadThrow m => (a -> Maybe b) -> Parser m a b

334−maybe parser = Parser step initial extract

334+maybe parserF = Parser step initial extract

335

336 where

337

338 initial = return $ IPartial ()

339

340 step () a = return $

341− case parser a of

341+ case parserF a of

342 Just b -> Done 0 b

343 Nothing -> Error "maybe: predicate failed"

344

@@ -350,14 +350,14 @@ maybe parser = Parser step initial extract

350--

351{-# INLINE either #-}

352either :: MonadThrow m => (a -> Either String b) -> Parser m a b

353−either parser = Parser step initial extract

353+either parserF = Parser step initial extract

354

355 where

356

357 initial = return $ IPartial ()

358

359 step () a = return $

360− case parser a of

360+ case parserF a of

361 Right b -> Done 0 b

362 Left err -> Error $ "either: " ++ err

363

src/Streamly/Internal/Data/Parser/ParserD/Type.hs+30

@@ -112,12 +112,17 @@

112

113module Streamly.Internal.Data.Parser.ParserD.Type

114 (

115+ -- * Types

115 Initial (..)

116 Initial (..)

116 , Step (..)

117 , Step (..)

117 , Parser (..)

118 , Parser (..)

118 , ParseError (..)

119 , ParseError (..)

119 , rmapM

120 , rmapM

120

121

122+ -- * Constructors

123+ , parser

124+ , parserM

125+

121 , fromPure

126 , fromPure

122 , fromEffect

127 , fromEffect

123 , serialWith

128 , serialWith

@@ -160,6 +165,7 @@ import Prelude hiding (concatMap)

160-- >>> import qualified Streamly.Prelude as Stream

165-- >>> import qualified Streamly.Prelude as Stream

161-- >>> import qualified Streamly.Internal.Data.Stream.IsStream as Stream (parse)

166-- >>> import qualified Streamly.Internal.Data.Stream.IsStream as Stream (parse)

162-- >>> import qualified Streamly.Internal.Data.Parser as Parser

167-- >>> import qualified Streamly.Internal.Data.Parser as Parser

168+-- >>> import qualified Streamly.Internal.Data.Parser.ParserD as ParserD

163

169

164-- XXX The only differences between Initial and Step types are:

170-- XXX The only differences between Initial and Step types are:

165--

171--

@@ -348,6 +354,30 @@ instance Functor m => Functor (Parser m a) where

348 step s b = fmap2 f (step1 s b)

354 step s b = fmap2 f (step1 s b)

349 fmap2 g = fmap (fmap g)

355 fmap2 g = fmap (fmap g)

350

356

357+------------------------------------------------------------------------------

358+-- General parser constructors

359+------------------------------------------------------------------------------

360+

361+-- | Make a parser using a parsing step and a starting value.

362+--

363+-- /Pre-release/

364+--

365+{-# INLINE parser #-}

366+parser :: Monad m => (b -> a -> Step b b) -> Initial b b -> Parser m a b

367+parser step initial =

368+ Parser (\s a -> return $ step s a) (return initial) return

369+

370+-- | Like 'parser' but with a monadic step function.

371+--

372+-- >>> parserM step initial = ParserD.Parser step initial return

373+--

374+-- /Pre-release/

375+--

376+{-# INLINE parserM #-}

377+parserM ::

378+ Monad m => (b -> a -> m (Step b b)) -> m (Initial b b) -> Parser m a b

379+parserM step initial = Parser step initial return

380+

351------------------------------------------------------------------------------

381------------------------------------------------------------------------------

352-- Mapping on the output

382-- Mapping on the output

353------------------------------------------------------------------------------

383------------------------------------------------------------------------------