[project @ 1996-01-11 14:06:51 by partain]

[ghc-hetmet.git] / ghc / lib / prelude / Channel.lhs

diff --git a/ghc/lib/prelude/Channel.lhs b/ghc/lib/prelude/Channel.lhs
index 4019287..94ed9c5 100644 (file)
--- a/ghc/lib/prelude/Channel.lhs
+++ b/ghc/lib/prelude/Channel.lhs
@@ -8,15 +8,21 @@ Standard, unbounded channel abstraction.
 \begin{code}
 module Channel
        (
-       {- abstract -}
+        {- abstract type defined -}
         Chan,
 
-       newChan,        -- :: IO (Chan a)
-       putChan,        -- :: Chan a -> a -> IO ()
-       getChan,        -- :: Chan a -> IO a
-       dupChan,        -- :: Chan a -> IO (Chan a)
-       unGetChan,      -- :: Chan a -> a -> IO ()
-       getChanContents -- :: Chan a -> IO [a]
+        {- creator -}
+       newChan,         -- :: IO (Chan a)
+
+        {- operators -}
+       putChan,         -- :: Chan a -> a -> IO ()
+       getChan,         -- :: Chan a -> IO a
+       dupChan,         -- :: Chan a -> IO (Chan a)
+       unGetChan,       -- :: Chan a -> a -> IO ()
+
+        {- stream interface -}
+       getChanContents, -- :: Chan a -> IO [a]
+       putList2Chan     -- :: Chan a -> [a] -> IO ()
 
        ) where
 
@@ -107,14 +113,18 @@ unGetChan (Chan read write) val
 
 \end{code}
 
+Operators for interfacing with functional streams.
+
 \begin{code}
 
 getChanContents :: Chan a -> IO [a]
-getChanContents ch
- = unsafeInterleavePrimIO (
-      getChan ch)         `thenPrimIO` \ ~(Right x) ->
-   unsafeInterleavePrimIO (
-      getChanContents ch) `thenPrimIO` \ ~(Right xs) ->
-   return (x:xs)
+getChanContents ch =
+ unsafeInterleavePrimIO (
+  getChan ch                                  `thenPrimIO` \ ~(Right x) ->
+  unsafeInterleavePrimIO (getChanContents ch)  `thenPrimIO` \ ~(Right xs) ->
+  returnPrimIO  (Right (x:xs)))
+
+putList2Chan :: Chan a -> [a] -> IO ()
+putList2Chan ch ls = sequence (map (putChan ch) ls)
 
 \end{code}