162a14a · streamly · git.iko.soy

git.iko.soy/streamly

Move fold smart constructors along with the type

So that we can use them without having to import the high level fold module.

commit162a14aa27d1cc1c2afa2409924125c24d3a20d8 authorHarendra Kumar <harendra@composewell.com> dateThu 21 Jan 2021, 15:25 (6 years ago) parent7e9f2a5

2 files changed+105−86

compare with master

unifiedsplit

src/Streamly/Internal/Data/Fold.hs−86 src/Streamly/Internal/Data/Fold/Types.hs+105

src/Streamly/Internal/Data/Fold.hs−86

@@ -251,92 +251,6 @@ import Prelude hiding

251251 , span, splitAt, break, mapM)

252252import Streamly.Internal.Data.Fold.Types

253253

254−------------------------------------------------------------------------------

255−-- Smart constructors

256−------------------------------------------------------------------------------

257−

258−-- | Make an accumulating (non-terminating) fold using a pure step function, a

259−-- pure initial state and a pure state extraction function.

260−--

261−-- /Internal/

262−--

263−{-# INLINE mkAccum #-}

264−mkAccum :: Monad m => (s -> a -> s) -> s -> (s -> b) -> Fold m a b

265−mkAccum step initial extract =

266− Fold

267− (\s a -> return $ Partial $ step s a)

268− (return (Partial initial))

269− (return . extract)

270−

271−-- | Similar to 'mkAccum' but the final state extracted is identical to the

272−-- intermediate state.

273−--

274−-- /Internal/

275−--

276−{-# INLINE mkAccum_ #-}

277−mkAccum_ :: Monad m => (b -> a -> b) -> b -> Fold m a b

278−mkAccum_ step initial = mkAccum step initial id

279−

280−-- | Make an accumulating (non-terminating) fold with an effectful step

281−-- function, an initial state, and a state extraction function.

282−--

283−-- /Internal/

284−--

285−{-# INLINE mkAccumM #-}

286−mkAccumM :: Functor m => (s -> a -> m s) -> m s -> (s -> m b) -> Fold m a b

287−mkAccumM step initial =

288− Fold (\s a -> Partial <$> step s a) (Partial <$> initial)

289−

290−-- | Similar to 'mkAccumM' but the final state extracted is identical to the

291−-- intermediate state.

292−--

293−-- /Internal/

294−--

295−{-# INLINE mkAccumM_ #-}

296−mkAccumM_ :: Monad m => (b -> a -> m b) -> m b -> Fold m a b

297−mkAccumM_ step initial = mkAccumM step initial return

298−

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

300−-- and a pure state extraction function.

301−--

302−-- /Internal/

303−--

304−{-# INLINE mkFold #-}

305−mkFold :: Monad m => (s -> a -> Step s b) -> Step s b -> (s -> b) -> Fold m a b

306−mkFold step initial extract =

307− Fold (\s a -> return $ step s a) (return initial) (return . extract)

308−

309−-- | Similar to 'mkFold' but the final state extracted is identical to the

310−-- intermediate state.

311−--

312−-- /Internal/

313−--

314−{-# INLINE mkFold_ #-}

315−mkFold_ :: Monad m => (b -> a -> Step b b) -> Step b b -> Fold m a b

316−mkFold_ step initial = mkFold step initial id

317−

318−-- | Make a terminating fold with an effectful step function and initial state,

319−-- and a state extraction function.

320−--

321−-- > mkFoldM = Fold

322−--

323−-- We can just use 'Fold' but it is provided for completeness.

324−--

325−-- /Internal/

326−--

327−{-# INLINE mkFoldM #-}

328−mkFoldM :: (s -> a -> m (Step s b)) -> m (Step s b) -> (s -> m b) -> Fold m a b

329−mkFoldM = Fold

330−

331−-- | Similar to 'mkFoldM' but the final state extracted is identical to the

332−-- intermediate state.

333−--

334−-- /Internal/

335−--

336−{-# INLINE mkFoldM_ #-}

337−mkFoldM_ :: Monad m => (b -> a -> m (Step b b)) -> m (Step b b) -> Fold m a b

338−mkFoldM_ step initial = mkFoldM step initial return

339−

340254------------------------------------------------------------------------------

341255-- hoist

342256------------------------------------------------------------------------------

src/Streamly/Internal/Data/Fold/Types.hs+105

@@ -171,6 +171,17 @@ module Streamly.Internal.Data.Fold.Types

171171 Step (..)

172172 , Fold (..)

173173

174+ -- * Fold constructors

175+ , mkAccum

176+ , mkAccum_

177+ , mkAccumM

178+ , mkAccumM_

179+ , mkFold

180+ , mkFold_

181+ , mkFoldM

182+ , mkFoldM_

183+

184+ -- * Fold2

174185 , Fold2 (..)

175186 , simplify

176187

@@ -295,6 +306,96 @@ data Fold m a b =

295306 -- | @Fold @ @ step @ @ initial @ @ extract@

296307 forall s. Fold (s -> a -> m (Step s b)) (m (Step s b)) (s -> m b)

297308

309+------------------------------------------------------------------------------

310+-- Smart constructors

311+------------------------------------------------------------------------------

312+

313+-- | Make an accumulating (non-terminating) fold using a pure step function, a

314+-- pure initial state and a pure state extraction function.

315+--

316+-- /Internal/

317+--

318+{-# INLINE mkAccum #-}

319+mkAccum :: Monad m => (s -> a -> s) -> s -> (s -> b) -> Fold m a b

320+mkAccum step initial extract =

321+ Fold

322+ (\s a -> return $ Partial $ step s a)

323+ (return (Partial initial))

324+ (return . extract)

325+

326+-- | Similar to 'mkAccum' but the final state extracted is identical to the

327+-- intermediate state.

328+--

329+-- /Internal/

330+--

331+{-# INLINE mkAccum_ #-}

332+mkAccum_ :: Monad m => (b -> a -> b) -> b -> Fold m a b

333+mkAccum_ step initial = mkAccum step initial id

334+

335+-- | Make an accumulating (non-terminating) fold with an effectful step

336+-- function, an initial state, and a state extraction function.

337+--

338+-- /Internal/

339+--

340+{-# INLINE mkAccumM #-}

341+mkAccumM :: Functor m => (s -> a -> m s) -> m s -> (s -> m b) -> Fold m a b

342+mkAccumM step initial =

343+ Fold (\s a -> Partial <$> step s a) (Partial <$> initial)

344+

345+-- | Similar to 'mkAccumM' but the final state extracted is identical to the

346+-- intermediate state.

347+--

348+-- /Internal/

349+--

350+{-# INLINE mkAccumM_ #-}

351+mkAccumM_ :: Monad m => (b -> a -> m b) -> m b -> Fold m a b

352+mkAccumM_ step initial = mkAccumM step initial return

353+

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

355+-- and a pure state extraction function.

356+--

357+-- /Internal/

358+--

359+{-# INLINE mkFold #-}

360+mkFold :: Monad m => (s -> a -> Step s b) -> Step s b -> (s -> b) -> Fold m a b

361+mkFold step initial extract =

362+ Fold (\s a -> return $ step s a) (return initial) (return . extract)

363+

364+-- | Similar to 'mkFold' but the final state extracted is identical to the

365+-- intermediate state.

366+--

367+-- /Internal/

368+--

369+{-# INLINE mkFold_ #-}

370+mkFold_ :: Monad m => (b -> a -> Step b b) -> Step b b -> Fold m a b

371+mkFold_ step initial = mkFold step initial id

372+

373+-- | Make a terminating fold with an effectful step function and initial state,

374+-- and a state extraction function.

375+--

376+-- > mkFoldM = Fold

377+--

378+-- We can just use 'Fold' but it is provided for completeness.

379+--

380+-- /Internal/

381+--

382+{-# INLINE mkFoldM #-}

383+mkFoldM :: (s -> a -> m (Step s b)) -> m (Step s b) -> (s -> m b) -> Fold m a b

384+mkFoldM = Fold

385+

386+-- | Similar to 'mkFoldM' but the final state extracted is identical to the

387+-- intermediate state.

388+--

389+-- /Internal/

390+--

391+{-# INLINE mkFoldM_ #-}

392+mkFoldM_ :: Monad m => (b -> a -> m (Step b b)) -> m (Step b b) -> Fold m a b

393+mkFoldM_ step initial = mkFoldM step initial return

394+

395+------------------------------------------------------------------------------

396+-- Fold2

397+------------------------------------------------------------------------------

398+

298399-- | Experimental type to provide a side input to the fold for generating the

299400-- initial state. For example, if we have to fold chunks of a stream and write

300401-- each chunk to a different file, then we can generate the file name using a

@@ -309,6 +410,10 @@ simplify :: Functor m => Fold2 m c a b -> c -> Fold m a b

309410simplify (Fold2 step inject extract) c =

310411 Fold (\x a -> Partial <$> step x a) (Partial <$> inject c) extract

311412

413+------------------------------------------------------------------------------

414+-- Instances

415+------------------------------------------------------------------------------

416+

312417-- | Maps a function on the output of the fold (the type @b@).

313418instance Functor m => Functor (Fold m a) where

314419 {-# INLINE fmap #-}