X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Futils%2FIOEnv.hs;h=224147f6671a6d40f2f100fc8536e520149ef3b5;hb=36fa8c4890e439fe8c2a4682df2a877fa2cc606b;hp=d01588f47b6b36f5728dd4451b1d3dba76af5acb;hpb=ad94d40948668032189ad22a0ad741ac1f645f50;p=ghc-hetmet.git

diff --git a/compiler/utils/IOEnv.hs b/compiler/utils/IOEnv.hs
index d01588f..224147f 100644
--- a/compiler/utils/IOEnv.hs
+++ b/compiler/utils/IOEnv.hs
@@ -1,23 +1,23 @@
---
--- (c) The University of Glasgow 2002-2006
---
--- The IO Monad with an environment
---
-
 {-# OPTIONS -w #-}
 -- The above warning supression flag is a temporary kludge.
 -- While working on this module you are encouraged to remove it and fix
 -- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/CodingStyle#Warnings
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
 -- for details
 
+--
+-- (c) The University of Glasgow 2002-2006
+--
+-- The IO Monad with an environment
+--
+
 module IOEnv (
 	IOEnv,	-- Instance of Monad
 
 	-- Standard combinators, specialised
 	returnM, thenM, thenM_, failM, failWithM,
 	mappM, mappM_, mapSndM, sequenceM, sequenceM_, 
-	foldlM, foldrM,
+	foldlM, foldrM, anyM,
 	mapAndUnzipM, mapAndUnzip3M, 
 	checkM, ifM, zipWithM, zipWithM_,
 
@@ -28,17 +28,16 @@ module IOEnv (
 	tryM, tryAllM, tryMostM, fixM, 
 
 	-- I/O operations
-	ioToIOEnv,
 	IORef, newMutVar, readMutVar, writeMutVar, updMutVar
   ) where
 #include "HsVersions.h"
 
 import Panic		( try, tryUser, tryMost, Exception(..) )
 
-import Data.IORef	( IORef, newIORef, readIORef, writeIORef )
+import Data.IORef	( IORef, newIORef, readIORef, writeIORef, modifyIORef )
 import System.IO.Unsafe	( unsafeInterleaveIO )
 import System.IO	( fixIO )
-
+import MonadUtils
 
 ----------------------------------------------------------------------
 --		Defining the monad type
@@ -49,13 +48,17 @@ newtype IOEnv env a = IOEnv (env -> IO a)
 unIOEnv (IOEnv m) = m
 
 instance Monad (IOEnv m) where
-  (>>=)  = thenM
-  (>>)   = thenM_
-  return = returnM
-  fail s = failM	-- Ignore the string
+    (>>=)  = thenM
+    (>>)   = thenM_
+    return = returnM
+    fail s = failM	-- Ignore the string
+
+instance Applicative (IOEnv m) where
+    pure = returnM
+    IOEnv f <*> IOEnv x = IOEnv (\ env -> f env <*> x env )
 
 instance Functor (IOEnv m) where
-  fmap f (IOEnv m) = IOEnv (\ env -> fmap f (m env))
+    fmap f (IOEnv m) = IOEnv (\ env -> fmap f (m env))
 
 returnM :: a -> IOEnv env a
 returnM a = IOEnv (\ env -> return a)
@@ -99,7 +102,9 @@ fixM f = IOEnv (\ env -> fixIO (\ r -> unIOEnv (f r) env))
 
 ---------------------------
 tryM :: IOEnv env r -> IOEnv env (Either Exception r)
--- Reflect UserError exceptions into IOEnv monad
+-- Reflect UserError exceptions (only) into IOEnv monad
+-- Other exceptions are not caught; they are simply propagated as exns
+--
 -- The idea is that errors in the program being compiled will give rise
 -- to UserErrors.  But, say, pattern-match failures in GHC itself should
 -- not be caught here, else they'll be reported as errors in the program 
@@ -124,20 +129,20 @@ unsafeInterleaveM (IOEnv m) = IOEnv (\ env -> unsafeInterleaveIO (m env))
 --	Accessing input/output
 ----------------------------------------------------------------------
 
-ioToIOEnv :: IO a -> IOEnv env a
-ioToIOEnv io = IOEnv (\ env -> io)
+instance MonadIO (IOEnv env) where
+    liftIO io = IOEnv (\ env -> io)
 
 newMutVar :: a -> IOEnv env (IORef a)
-newMutVar val = IOEnv (\ env -> newIORef val)
+newMutVar val = liftIO (newIORef val)
 
 writeMutVar :: IORef a -> a -> IOEnv env ()
-writeMutVar var val = IOEnv (\ env -> writeIORef var val)
+writeMutVar var val = liftIO (writeIORef var val)
 
 readMutVar :: IORef a -> IOEnv env a
-readMutVar var = IOEnv (\ env -> readIORef var)
+readMutVar var = liftIO (readIORef var)
 
-updMutVar :: IORef a -> (a->a) -> IOEnv env ()
-updMutVar var upd_fn = IOEnv (\ env -> do { v <- readIORef var; writeIORef var (upd_fn v) })
+updMutVar :: IORef a -> (a -> a) -> IOEnv env ()
+updMutVar var upd = liftIO (modifyIORef var upd)
 
 
 ----------------------------------------------------------------------
@@ -174,6 +179,7 @@ mapAndUnzipM  :: (a -> IOEnv env (b,c))   -> [a] -> IOEnv env ([b],[c])
 mapAndUnzip3M :: (a -> IOEnv env (b,c,d)) -> [a] -> IOEnv env ([b],[c],[d])
 checkM	      :: Bool -> IOEnv env a -> IOEnv env ()	-- Perform arg if bool is False
 ifM	      :: Bool -> IOEnv env a -> IOEnv env ()	-- Perform arg if bool is True
+anyM	      :: (a -> IOEnv env Bool) -> [a] -> IOEnv env Bool
 
 mappM f []     = return []
 mappM f (x:xs) = do { r <- f x; rs <- mappM f xs; return (r:rs) }
@@ -184,6 +190,10 @@ mapSndM f ((a,b):xs) = do { c <- f b; rs <- mapSndM f xs; return ((a,c):rs) }
 mappM_ f []     = return ()
 mappM_ f (x:xs) = f x >> mappM_ f xs
 
+anyM f [] = return False
+anyM f (x:xs) = do { b <- f x; if b then return True 
+				    else anyM f xs }
+
 zipWithM :: (a -> b -> IOEnv env c) -> [a] -> [b] -> IOEnv env [c]
 zipWithM f [] bs = return []
 zipWithM f as [] = return []