[project @ 2001-02-22 16:10:12 by rrt]

[ghc-hetmet.git] / ghc / lib / std / Monad.lhs

diff --git a/ghc/lib/std/Monad.lhs b/ghc/lib/std/Monad.lhs
index d47921b..ca370ae 100644 (file)
--- a/ghc/lib/std/Monad.lhs
+++ b/ghc/lib/std/Monad.lhs
@@ -1,27 +1,28 @@
+% -----------------------------------------------------------------------------
+% $Id: Monad.lhs,v 1.11 2000/06/30 13:39:35 simonmar Exp $
 %
-% (c) The AQUA Project, Glasgow University, 1994-1999
+% (c) The University of Glasgow, 1994-2000
 %
+
 \section[Monad]{Module @Monad@}
 
 \begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
-
 module Monad 
     ( MonadPlus (   -- class context: Monad
          mzero     -- :: (MonadPlus m) => m a
        , mplus     -- :: (MonadPlus m) => m a -> m a -> m a
        )
-    , join          -- :: (Monad m) => m (m a) -> m a
-    , guard        -- :: (Monad m) => Bool -> m ()
-    , when          -- :: (Monad m) => Bool -> m () -> m ()
-    , unless        -- :: (Monad m) => Bool -> m () -> m ()
-    , ap           -- :: (Monad m) => (m (a -> b)) -> (m a) -> m b
+    , join          -- :: (Monad m) => m (m a) -> m a
+    , guard        -- :: (MonadPlus m) => Bool -> m ()
+    , when          -- :: (Monad m) => Bool -> m () -> m ()
+    , unless        -- :: (Monad m) => Bool -> m () -> m ()
+    , ap           -- :: (Monad m) => (m (a -> b)) -> (m a) -> m b
     , msum         -- :: (MonadPlus m) => [m a] -> m a
     , filterM      -- :: (Monad m) => (a -> m Bool) -> [m a] -> m [a]
-    , mapAndUnzipM  -- :: (Monad m) => (a -> m (b,c)) -> [a] -> m ([b], [c])
-    , zipWithM      -- :: (Monad m) => (a -> b -> m c) -> [a] -> [b] -> m [c]
+    , mapAndUnzipM  -- :: (Monad m) => (a -> m (b,c)) -> [a] -> m ([b], [c])
+    , zipWithM      -- :: (Monad m) => (a -> b -> m c) -> [a] -> [b] -> m [c]
     , zipWithM_     -- :: (Monad m) => (a -> b -> m c) -> [a] -> [b] -> m ()
-    , foldM        -- :: (Monad m) => (a -> b -> m a) -> a -> [b] -> m a 
+    , foldM        -- :: (Monad m) => (a -> b -> m a) -> a -> [b] -> m a 
     
     , liftM        -- :: (Monad m) => (a -> b) -> (m a -> m b)
     , liftM2       -- :: (Monad m) => (a -> b -> c) -> (m a -> m b -> m c)
@@ -39,10 +40,7 @@ module Monad
     , (=<<)         -- :: (Monad m) => (a -> m b) -> m a -> m b
     ) where
 
-import PrelList
-import PrelTup
-import PrelBase
-import PrelMaybe ( Maybe(..) )
+import Prelude
 \end{code}
 
 %*********************************************************
@@ -76,19 +74,6 @@ instance MonadPlus Maybe where
 %*********************************************************
 
 \begin{code}
-sequence       :: Monad m => [m a] -> m [a] 
-sequence []     = return []
-sequence (m:ms) = do { x <- m; xs <- sequence ms; return (x:xs) }
-
-sequence_        :: Monad m => [m a] -> m () 
-sequence_        =  foldr (>>) (return ())
-
-mapM            :: Monad m => (a -> m b) -> [a] -> m [b]
-mapM f as       =  sequence (map f as)
-
-mapM_           :: Monad m => (a -> m b) -> [a] -> m ()
-mapM_ f as      =  sequence_ (map f as)
-
 guard           :: MonadPlus m => Bool -> m ()
 guard pred
  | pred      = return ()
@@ -106,11 +91,8 @@ filterM  predM (x:xs) = do
 -- This subsumes the list-based concat function.
 
 msum        :: MonadPlus m => [m a] -> m a
+{-# INLINE msum #-}
 msum        =  foldr mplus mzero
- 
-{-# SPECIALISE (=<<) :: (a -> [b]) -> [a] -> [b] #-}
-(=<<)           :: Monad m => (a -> m b) -> m a -> m b
-f =<< x                = x >>= f
 \end{code}