--- a/src/System/IO/Streams/Concurrent/Unagi.hs Thu Dec 18 10:56:53 2014 -0600
+++ b/src/System/IO/Streams/Concurrent/Unagi.hs Thu Dec 18 11:43:53 2014 -0600
@@ -6,13 +6,16 @@
, chanToInput
, chanToOutput
, makeChanPipe
+ , chanToPipe
+ , dupStream
) where
------------------------------------------------------------------------------
import Control.Applicative ((<$>), (<*>))
-import Control.Concurrent.Chan.Unagi (InChan, OutChan, newChan,
- readChan, writeChan)
+import Control.Concurrent.Chan.Unagi (InChan, OutChan, dupChan,
+ newChan, readChan, writeChan)
+import Control.Monad ((>=>))
import Prelude hiding (read)
import System.IO.Streams.Internal (InputStream, OutputStream,
makeInputStream,
@@ -56,3 +59,20 @@
makeChanPipe = do
(inChan, outChan) <- newChan
(,) <$> chanToInput outChan <*> chanToOutput inChan
+
+
+--------------------------------------------------------------------------------
+-- | Create a new pair of streams form the given 'Chan'. Everything written
+-- to the 'OutputStream' will appear as-is on the 'InputStream'.
+--
+-- Since reading from the 'InputStream' and writing to the 'OutputStream' are
+-- blocking calls, be sure to do so in different threads.
+chanToPipe :: (InChan (Maybe a), OutChan (Maybe a)) -> IO (InputStream a, OutputStream a)
+chanToPipe (inChan, outChan) = (,) <$> chanToInput outChan <*> chanToOutput inChan
+
+
+--------------------------------------------------------------------------------
+-- | Create a new input stream duplicated from the 'InChan'
+--
+dupStream :: InChan (Maybe a) -> IO (InputStream a)
+dupStream = dupChan >=> chanToInput