Use the standard state monad transformer in GHCi

compiler/ghci/ByteCodeAsm.lhs

@@ -37,6 +37,8 @@ import Util
 
 import Control.Monad
 import Control.Monad.ST ( runST )
+import Control.Monad.Trans.Class
+import Control.Monad.Trans.State.Strict
 
 import Data.Array.MArray
 import Data.Array.Unboxed ( listArray )
@@ -151,7 +153,7 @@ assembleBCO dflags (ProtoBCO nm instrs bitmap bsize arity _origin _malloced) = d
 
   -- pass 2: run assembler and generate instructions, literals and pointers
   let initial_state = (emptySS, emptySS, emptySS)
-  (final_insns, final_lits, final_ptrs) <- execState initial_state $ runAsm dflags long_jumps env asm
+  (final_insns, final_lits, final_ptrs) <- flip execStateT initial_state $ runAsm dflags long_jumps env asm
 
   -- precomputed size should be equal to final size
   ASSERT (n_insns == sizeSS final_insns) return ()
@@ -245,20 +247,20 @@ largeOp long_jumps op = case op of
    LabelOp _ -> long_jumps
 -- LargeOp _ -> True
 
-runAsm :: DynFlags -> Bool -> LabelEnv -> Assembler a -> State AsmState IO a
+runAsm :: DynFlags -> Bool -> LabelEnv -> Assembler a -> StateT AsmState IO a
 runAsm dflags long_jumps e = go
   where
     go (NullAsm x) = return x
     go (AllocPtr p_io k) = do
       p <- lift p_io
-      w <- State $ \(st_i0,st_l0,st_p0) -> do
+      w <- state $ \(st_i0,st_l0,st_p0) ->
         let st_p1 = addToSS st_p0 p
-        return ((st_i0,st_l0,st_p1), sizeSS st_p0)
+        in (sizeSS st_p0, (st_i0,st_l0,st_p1))
       go $ k w
     go (AllocLit lits k) = do
-      w <- State $ \(st_i0,st_l0,st_p0) -> do
+      w <- state $ \(st_i0,st_l0,st_p0) ->
         let st_l1 = addListToSS st_l0 lits
-        return ((st_i0,st_l1,st_p0), sizeSS st_l0)
+        in (sizeSS st_l0, (st_i0,st_l1,st_p0))
       go $ k w
     go (AllocLabel _ k) = go k
     go (Emit w ops k) = do
@@ -271,9 +273,9 @@ runAsm dflags long_jumps e = go
           expand (LabelOp w) = expand (Op (e w))
           expand (Op w) = if largeOps then largeArg dflags w else [fromIntegral w]
 --        expand (LargeOp w) = largeArg dflags w
-      State $ \(st_i0,st_l0,st_p0) -> do
+      state $ \(st_i0,st_l0,st_p0) ->
         let st_i1 = addListToSS st_i0 (opcode : words)
-        return ((st_i1,st_l0,st_p0), ())
+        in ((), (st_i1,st_l0,st_p0))
       go k
 
 type LabelEnvMap = Map Word16 Word

compiler/ghci/ByteCodeItbls.lhs

@@ -15,7 +15,6 @@ ByteCodeItbls: Generate infotables for interpreter-made bytecodes
 
 module ByteCodeItbls ( ItblEnv, ItblPtr(..), itblCode, mkITbls
                      , StgInfoTable(..)
-                     , State(..), runState, evalState, execState, MonadT(..)
                      ) where
 
 #include "HsVersions.h"
@@ -29,11 +28,11 @@ import Type             ( flattenRepType, repType, typePrimRep )
 import StgCmmLayout     ( mkVirtHeapOffsets )
 import Util
 
+import Control.Monad.Trans.Class
+import Control.Monad.Trans.State.Strict
 import Foreign
 import Foreign.C
 
-import Control.Monad    ( liftM )
-
 import GHC.Exts         ( Int(I#), addr2Int# )
 import GHC.Ptr          ( Ptr(..) )
 \end{code}
@@ -289,7 +288,7 @@ sizeOfConItbl conInfoTable
 pokeConItbl :: DynFlags -> Ptr StgConInfoTable -> Ptr StgConInfoTable -> StgConInfoTable
             -> IO ()
 pokeConItbl dflags wr_ptr ex_ptr itbl
-      = evalState (castPtr wr_ptr) $ do
+      = flip evalStateT (castPtr wr_ptr) $ do
 #ifdef GHCI_TABLES_NEXT_TO_CODE
            store (conDesc itbl `minusPtr` (ex_ptr `plusPtr` conInfoTableSizeB dflags))
 #endif
@@ -332,7 +331,7 @@ instance Storable StgInfoTable where
       = SIZEOF_VOID_P
 
    poke a0 itbl
-      = evalState (castPtr a0)
+      = flip evalStateT (castPtr a0)
       $ do
 #ifndef GHCI_TABLES_NEXT_TO_CODE
            store (entry  itbl)
@@ -346,7 +345,7 @@ instance Storable StgInfoTable where
 #endif
 
    peek a0
-      = evalState (castPtr a0)
+      = flip evalStateT (castPtr a0)
       $ do
 #ifndef GHCI_TABLES_NEXT_TO_CODE
            entry'  <- load
@@ -375,34 +374,13 @@ instance Storable StgInfoTable where
 fieldSz :: Storable b => (a -> b) -> a -> Int
 fieldSz sel x = sizeOf (sel x)
 
-newtype State s m a = State (s -> m (s, a))
-
-instance Monad m => Monad (State s m) where
-  return a      = State (\s -> return (s, a))
-  State m >>= k = State (\s -> m s >>= \(s', a) -> case k a of State n -> n s')
-  fail str      = State (\_ -> fail str)
-
-class (Monad m, Monad (t m)) => MonadT t m where
-  lift :: m a -> t m a
-
-instance Monad m => MonadT (State s) m where
-  lift m        = State (\s -> m >>= \a -> return (s, a))
-
-runState :: Monad m => s -> State s m a -> m (s, a)
-runState s (State m) = m s
-
-evalState :: Monad m => s -> State s m a -> m a
-evalState s m = liftM snd (runState s m)
-
-execState :: Monad m => s -> State s m a -> m s
-execState s m = liftM fst (runState s m)
-
-type PtrIO = State (Ptr Word8) IO
+type PtrIO = StateT (Ptr Word8) IO
 
 advance :: Storable a => PtrIO (Ptr a)
-advance = State adv where
-    adv addr = case castPtr addr of { addrCast -> return
-        (addr `plusPtr` sizeOfPointee addrCast, addrCast) }
+advance = state adv
+    where adv addr = case castPtr addr of
+                     addrCast ->
+                         (addrCast, addr `plusPtr` sizeOfPointee addrCast)
 
 sizeOfPointee :: (Storable a) => Ptr a -> Int
 sizeOfPointee addr = sizeOf (typeHack addr)