conduit-extra 0.1.0 → 0.1.1

raw patch · 2 files changed

+97/−1 lines, 2 files

Files

• Data/Conduit/Extra/Pipes.hs +94/−0
• conduit-extra.cabal +3/−1

@@ -0,0 +1,94 @@+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE RankNTypes #-}++-- | Provides a convenience layer on top of conduit with functions and+--   operators similar to the pipes library.+module Data.Conduit.Extra.Pipes+    ( (>->), (<-<)+    , runPipe, runPipeR, runEffect+    , forP, each+    , take, peel+    , replicateM+    , tee+    , module X+    , module CL+    ) where++import Control.Monad.Trans.Class+import Data.Conduit as X+import Data.Conduit.List as CL hiding (take)+import Data.Foldable+import Data.Void+import Prelude hiding (take)++-- | The conduit composition operator, ala pipes.  When combined with+--   'runPipe' (or 'runEffect', if you prefer), this is the only operator+--   needed.+(>->) :: forall a b i o m. Monad m+      => ConduitM i a m () -> ConduitM a o m b -> ConduitM i o m b+(>->) = (=$=)++(<-<) :: forall a b i o m. Monad m+      => ConduitM a o m b -> ConduitM i a m () -> ConduitM i o m b+(<-<) = flip (>->)++-- | Run a conduit.  This name may be preferable to the overly generic+--   'runEffect', which pipes uses.+runPipe :: forall m b. Monad m => ConduitM () Void m b -> m b+runPipe c = yield () $$ c++runEffect :: forall m b. Monad m => ConduitM () Void m b -> m b+runEffect = runPipe++-- | Like 'runPipe', except implies a call to 'runResourceT', for running+--   resource-sensitive pipelines.+runPipeR :: forall m b. (MonadBaseControl IO m, Monad m)+         => ConduitM () Void (ResourceT m) b -> m b+runPipeR = runResourceT . runPipe++-- | Iterate over all the elements from source, similar to 'forM' for a monad.+forP :: Monad m => Source m a -> (a -> m ()) -> m ()+forP p a = p $$ CL.mapM_ a++-- | Take N items from a conduit.  Synonym for Conduit's 'isolate'.+take :: Monad m => Int -> Conduit a m a+take = CL.isolate++-- | Peel off N items from a conduit and return them.  Synonym for Conduit's+--   'take'.+peel :: Monad m => Int -> m [()]+peel n = take n $$ CL.consume++-- | Call 'yield' for each element of the 'Foldable' data structure, resulting+--   in a 'Producer' over these elements.+--+-- >>> runPipe $ forP (each [1..3]) $ liftIO . print+-- 1+-- 2+-- 3+each :: (Monad m, Foldable f) => f a -> Producer m a+each = Data.Foldable.mapM_ yield++-- | Replicate a monadic action a given number of times via a producer.+replicateM :: Monad m => Int -> m a -> Producer m a+replicateM 0 _ = return ()+replicateM n m = lift m >>= yield >> replicateM (n-1) m++-- | Injects a sink within a pipeline which receives a copy of every input+--   argument, similar to the Unix command of the same name.+--+-- >>> runPipe $ each [1..3] >-> tee (P.mapM_ f) >-> P.mapM_ f+-- 1+-- 1+-- 2+-- 2+-- 3+-- 3+tee :: Monad m => Sink a (ConduitM a a m) b -> ConduitM a a m b+tee c = go $$ c+  where+    go = do+        x <- lift await+        case x of+            Nothing -> return ()+            Just x' -> yield x' >> lift (yield x') >> go

@@ -1,5 +1,5 @@ Name:                conduit-extra-Version:             0.1.0+Version:             0.1.1 Synopsis:            Experimental helper functions for conduit. Description:     This package is meant as a testing ground for new concepts in conduit. The idea is to have a much lower barrier to entry for this library relative to conduit itself. This way, conduit itself will continue to have a best-practices, minimal, stable API, while people are free to try crazy new features.@@ -14,11 +14,13 @@  Library   Exposed-modules:     Data.Conduit.Extra+                     , Data.Conduit.Extra.Pipes                      , Data.Conduit.Extra.Resumable                      , Data.Conduit.Extra.ZipSink   Build-depends:       base                     >= 4            && < 5                      , conduit                  >= 1.0                      , mtl+                     , transformers                      , void   ghc-options:     -Wall