@DsMonad@: monadery used in desugaring
\begin{code}
-{-# 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/Commentary/CodingStyle#Warnings
--- for details
-
module DsMonad (
DsM, mapM, mapAndUnzipM,
- initDs, initDsTc, fixDs, mapAndUnzipM,
+ initDs, initDsTc, fixDs,
foldlM, foldrM, ifOptM,
Applicative(..),(<$>),
- newTyVarsDs, newLocalName,
+ newLocalName,
duplicateLocalDs, newSysLocalDs, newSysLocalsDs, newUniqueId,
newFailLocalDs,
getSrcSpanDs, putSrcSpanDs,
CanItFail(..), orFail
) where
-#include "HsVersions.h"
-
import TcRnMonad
import CoreSyn
import HsSyn
import DynFlags
import ErrUtils
import MonadUtils
+import FastString
import Data.IORef
\end{code}
= EqnInfo { eqn_pats :: [Pat Id], -- The patterns for an eqn
eqn_rhs :: MatchResult } -- What to do after match
+instance Outputable EquationInfo where
+ ppr (EqnInfo pats _) = ppr pats
+
type DsWrapper = CoreExpr -> CoreExpr
+idDsWrapper :: DsWrapper
idDsWrapper e = e
-- The semantics of (match vs (EqnInfo wrap pats rhs)) is the MatchResult
data CanItFail = CanFail | CantFail
+orFail :: CanItFail -> CanItFail -> CanItFail
orFail CantFail CantFail = CantFail
-orFail _ _ = CanFail
+orFail _ _ = CanFail
\end{code}
type DsM result = TcRnIf DsGblEnv DsLclEnv result
-- Compatibility functions
+fixDs :: (a -> DsM a) -> DsM a
fixDs = fixM
type DsWarning = (SrcSpan, SDoc)
initDs :: HscEnv
-> Module -> GlobalRdrEnv -> TypeEnv
-> DsM a
- -> IO (Maybe a)
+ -> IO (Messages, Maybe a)
-- Print errors and warnings, if any arise
initDs hsc_env mod rdr_env type_env thing_inside
-- Display any errors and warnings
-- Note: if -Werror is used, we don't signal an error here.
; msgs <- readIORef msg_var
- ; printErrorsAndWarnings dflags msgs
; let final_res | errorsFound dflags msgs = Nothing
| otherwise = case either_res of
-- a UserError exception. Then it should have put an error
-- message in msg_var, so we just discard the exception
- ; return final_res }
+ ; return (msgs, final_res) }
initDsTc :: DsM a -> TcM a
initDsTc thing_inside
mkDsEnvs :: DynFlags -> Module -> GlobalRdrEnv -> TypeEnv -> IORef Messages -> IO (DsGblEnv, DsLclEnv)
mkDsEnvs dflags mod rdr_env type_env msg_var
- = do
- sites_var <- newIORef []
+ = do -- TODO: unnecessarily monadic
let if_genv = IfGblEnv { if_rec_types = Just (mod, return type_env) }
- if_lenv = mkIfLclEnv mod (ptext SLIT("GHC error in desugarer lookup in") <+> ppr mod)
+ if_lenv = mkIfLclEnv mod (ptext (sLit "GHC error in desugarer lookup in") <+> ppr mod)
gbl_env = DsGblEnv { ds_mod = mod,
ds_if_env = (if_genv, if_lenv),
ds_unqual = mkPrintUnqualified dflags rdr_env,
ds_loc = noSrcSpan }
return (gbl_env, lcl_env)
-
\end{code}
%************************************************************************
\begin{code}
-- Make a new Id with the same print name, but different type, and new unique
newUniqueId :: Name -> Type -> DsM Id
-newUniqueId id ty = do
- uniq <- newUnique
- return (mkSysLocal (occNameFS (nameOccName id)) uniq ty)
+newUniqueId id = mkSysLocalM (occNameFS (nameOccName id))
duplicateLocalDs :: Id -> DsM Id
duplicateLocalDs old_local = do
return (setIdUnique old_local uniq)
newSysLocalDs, newFailLocalDs :: Type -> DsM Id
-newSysLocalDs ty = do
- uniq <- newUnique
- return (mkSysLocal FSLIT("ds") uniq ty)
+newSysLocalDs = mkSysLocalM (fsLit "ds")
+newFailLocalDs = mkSysLocalM (fsLit "fail")
+newSysLocalsDs :: [Type] -> DsM [Id]
newSysLocalsDs tys = mapM newSysLocalDs tys
-
-newFailLocalDs ty = do
- uniq <- newUnique
- return (mkSysLocal FSLIT("fail") uniq ty)
- -- The UserLocal bit just helps make the code a little clearer
-\end{code}
-
-\begin{code}
-newTyVarsDs :: [TyVar] -> DsM [TyVar]
-newTyVarsDs tyvar_tmpls = do
- uniqs <- newUniqueSupply
- return (zipWith setTyVarUnique tyvar_tmpls (uniqsFromSupply uniqs))
\end{code}
We can also reach out and either set/grab location information from
warnDs warn = do { env <- getGblEnv
; loc <- getSrcSpanDs
; let msg = mkWarnMsg loc (ds_unqual env)
- (ptext SLIT("Warning:") <+> warn)
+ (ptext (sLit "Warning:") <+> warn)
; updMutVar (ds_msgs env) (\ (w,e) -> (w `snocBag` msg, e)) }
- where
failWithDs :: SDoc -> DsM a
failWithDs err
; let msg = mkErrMsg loc (ds_unqual env) err
; updMutVar (ds_msgs env) (\ (w,e) -> (w, e `snocBag` msg))
; failM }
- where
\end{code}
\begin{code}
+instance MonadThings (IOEnv (Env DsGblEnv DsLclEnv)) where
+ lookupThing = dsLookupGlobal
+
dsLookupGlobal :: Name -> DsM TyThing
-- Very like TcEnv.tcLookupGlobal
dsLookupGlobal name