From 1b07fb994363495a102d6b86a5f847a771a6f3b9 Mon Sep 17 00:00:00 2001
From: Luke Hoersten <luke@hoersten.org>
Date: Thu, 18 Dec 2014 11:43:53 -0600
Subject: Added some functions to help exposed chans to streams.

---
 src/System/IO/Streams/Concurrent/Unagi.hs         | 24 +++++++++++++++++++++--
 src/System/IO/Streams/Concurrent/Unagi/Bounded.hs | 24 +++++++++++++++++++++--
 unagi-streams.cabal                               |  6 +++---
 3 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/src/System/IO/Streams/Concurrent/Unagi.hs b/src/System/IO/Streams/Concurrent/Unagi.hs
index 7ee3fd5..141902f 100644
--- a/src/System/IO/Streams/Concurrent/Unagi.hs
+++ b/src/System/IO/Streams/Concurrent/Unagi.hs
@@ -6,13 +6,16 @@ module System.IO.Streams.Concurrent.Unagi
        , chanToInput
        , chanToOutput
        , makeChanPipe
+       , chanToPipe
+       , dupStream
        ) where
 
 
 ------------------------------------------------------------------------------
 import           Control.Applicative           ((<$>), (<*>))
-import           Control.Concurrent.Chan.Unagi (InChan, OutChan, newChan,
-                                                readChan, writeChan)
+import           Control.Concurrent.Chan.Unagi (InChan, OutChan, dupChan,
+                                                newChan, readChan, writeChan)
+import           Control.Monad                 ((>=>))
 import           Prelude                       hiding (read)
 import           System.IO.Streams.Internal    (InputStream, OutputStream,
                                                 makeInputStream,
@@ -56,3 +59,20 @@ makeChanPipe :: IO (InputStream a, OutputStream a)
 makeChanPipe = do
     (inChan, outChan) <- newChan
     (,) <$> 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
diff --git a/src/System/IO/Streams/Concurrent/Unagi/Bounded.hs b/src/System/IO/Streams/Concurrent/Unagi/Bounded.hs
index fe1e856..96fc6e4 100644
--- a/src/System/IO/Streams/Concurrent/Unagi/Bounded.hs
+++ b/src/System/IO/Streams/Concurrent/Unagi/Bounded.hs
@@ -6,14 +6,17 @@ module System.IO.Streams.Concurrent.Unagi.Bounded
        , chanToInput
        , chanToOutput
        , makeChanPipe
+       , chanToPipe
+       , dupStream
        ) where
 
 
 ------------------------------------------------------------------------------
 import           Control.Applicative                   ((<$>), (<*>))
 import           Control.Concurrent.Chan.Unagi.Bounded (InChan, OutChan,
-                                                        newChan, readChan,
-                                                        writeChan)
+                                                        dupChan, newChan,
+                                                        readChan, writeChan)
+import           Control.Monad                         ((>=>))
 import           Prelude                               hiding (read)
 import           System.IO.Streams.Internal            (InputStream,
                                                         OutputStream,
@@ -57,3 +60,20 @@ makeChanPipe :: Int -> IO (InputStream a, OutputStream a)
 makeChanPipe size = do
     (inChan, outChan) <- newChan size
     (,) <$> 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
diff --git a/unagi-streams.cabal b/unagi-streams.cabal
index ed91f29..b2d0d1b 100644
--- a/unagi-streams.cabal
+++ b/unagi-streams.cabal
@@ -1,9 +1,9 @@
 name:                unagi-streams
 version:             0.1.1.0
 synopsis:            Unagi Chan IO-Streams
-description:         IO-Streams implemented underneath with Unagi
-                     channels. This library is a straight port of Greg Collins' IO-Streams
-                     Chan implementation.
+description:         Io-streams chans implemented underneath with
+                     unagi-chans. This library is a straight port of
+                     the default io-streams chan implementation.
 License:             BSD3
 License-file:        LICENSE
 author:              Luke Hoersten
-- 
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