\begin{code}
module DsMonad (
- DsM,
- initDs, returnDs, thenDs, andDs, mapDs, listDs,
- mapAndUnzipDs, zipWithDs, foldlDs,
- uniqSMtoDsM,
- newTyVarsDs, cloneTyVarsDs,
- duplicateLocalDs, newSysLocalDs, newSysLocalsDs,
+ DsM, mappM, mapAndUnzipM,
+ initDs, returnDs, thenDs, listDs, fixDs, mapAndUnzipDs,
+ foldlDs, foldrDs,
+
+ newTyVarsDs, newLocalName,
+ duplicateLocalDs, newSysLocalDs, newSysLocalsDs, newUniqueId,
newFailLocalDs,
- getSrcLocDs, putSrcLocDs,
+ getSrcSpanDs, putSrcSpanDs,
getModuleDs,
- getUniqueDs, getUniquesDs,
+ newUnique,
+ UniqSupply, newUniqueSupply,
getDOptsDs,
- dsLookupGlobalValue,
+ dsLookupGlobal, dsLookupGlobalId, dsLookupTyCon, dsLookupDataCon,
+
+ DsMetaEnv, DsMetaVal(..), dsLookupMetaEnv, dsExtendMetaEnv,
- dsWarn,
- DsWarnings,
- DsMatchContext(..)
+ -- Warnings
+ DsWarning, dsWarn,
+
+ -- Data types
+ DsMatchContext(..),
+ EquationInfo(..), MatchResult(..), DsWrapper, idWrapper,
+ CanItFail(..), orFail
) where
#include "HsVersions.h"
-import HsSyn ( HsMatchContext )
+import TcRnMonad
+import CoreSyn ( CoreExpr )
+import HsSyn ( HsExpr, HsMatchContext, Pat )
+import TcIface ( tcIfaceGlobal )
+import RdrName ( GlobalRdrEnv )
+import HscTypes ( TyThing(..), TypeEnv, HscEnv,
+ tyThingId, tyThingTyCon, tyThingDataCon, unQualInScope )
import Bag ( emptyBag, snocBag, Bag )
-import ErrUtils ( WarnMsg )
+import DataCon ( DataCon )
+import TyCon ( TyCon )
import Id ( mkSysLocal, setIdUnique, Id )
import Module ( Module )
import Var ( TyVar, setTyVarUnique )
import Outputable
-import SrcLoc ( noSrcLoc, SrcLoc )
-import TcHsSyn ( TypecheckedPat )
+import SrcLoc ( noSrcSpan, SrcSpan )
import Type ( Type )
-import UniqSupply ( initUs_, splitUniqSupply, uniqFromSupply, uniqsFromSupply,
- UniqSM, UniqSupply )
-import Unique ( Unique )
-import Util ( zipWithEqual )
-import Name ( Name )
-import CmdLineOpts ( DynFlags )
+import UniqSupply ( UniqSupply, uniqsFromSupply )
+import Name ( Name, nameOccName )
+import NameEnv
+import OccName ( occNameFS )
+import DynFlags ( DynFlags )
+import ErrUtils ( WarnMsg, mkWarnMsg )
+import Bag ( mapBag )
+
+import DATA_IOREF ( newIORef, readIORef )
infixr 9 `thenDs`
\end{code}
-Now the mondo monad magic (yes, @DsM@ is a silly name)---carry around
-a @UniqueSupply@ and some annotations, which
-presumably include source-file location information:
-\begin{code}
-type DsM result =
- DynFlags
- -> UniqSupply
- -> (Name -> Id) -- Lookup well-known Ids
- -> SrcLoc -- to put in pattern-matching error msgs
- -> Module -- module: for SCC profiling
- -> DsWarnings
- -> (result, DsWarnings)
-
-type DsWarnings = Bag WarnMsg -- The desugarer reports matches which are
- -- completely shadowed or incomplete patterns
-
-{-# INLINE andDs #-}
-{-# INLINE thenDs #-}
-{-# INLINE returnDs #-}
-
--- initDs returns the UniqSupply out the end (not just the result)
-
-initDs :: DynFlags
- -> UniqSupply
- -> (Name -> Id)
- -> Module -- module name: for profiling
- -> DsM a
- -> (a, DsWarnings)
-
-initDs dflags init_us lookup mod action
- = action dflags init_us lookup noSrcLoc mod emptyBag
+%************************************************************************
+%* *
+ Data types for the desugarer
+%* *
+%************************************************************************
-thenDs :: DsM a -> (a -> DsM b) -> DsM b
-andDs :: (a -> a -> a) -> DsM a -> DsM a -> DsM a
+\begin{code}
+data DsMatchContext
+ = DsMatchContext (HsMatchContext Name) SrcSpan
+ | NoMatchContext
+ deriving ()
-thenDs m1 m2 dflags us genv loc mod warns
- = case splitUniqSupply us of { (s1, s2) ->
- case (m1 dflags s1 genv loc mod warns) of { (result, warns1) ->
- m2 result dflags s2 genv loc mod warns1}}
+data EquationInfo
+ = EqnInfo { eqn_wrap :: DsWrapper, -- Bindings
+ eqn_pats :: [Pat Id], -- The patterns for an eqn
+ eqn_rhs :: MatchResult } -- What to do after match
-andDs combiner m1 m2 dflags us genv loc mod warns
- = case splitUniqSupply us of { (s1, s2) ->
- case (m1 dflags s1 genv loc mod warns) of { (result1, warns1) ->
- case (m2 dflags s2 genv loc mod warns1) of { (result2, warns2) ->
- (combiner result1 result2, warns2) }}}
+type DsWrapper = CoreExpr -> CoreExpr
+idWrapper e = e
-returnDs :: a -> DsM a
-returnDs result dflags us genv loc mod warns = (result, warns)
+-- The semantics of (match vs (EqnInfo wrap pats rhs)) is the MatchResult
+-- \fail. wrap (case vs of { pats -> rhs fail })
+-- where vs are not bound by wrap
-listDs :: [DsM a] -> DsM [a]
-listDs [] = returnDs []
-listDs (x:xs)
- = x `thenDs` \ r ->
- listDs xs `thenDs` \ rs ->
- returnDs (r:rs)
-mapDs :: (a -> DsM b) -> [a] -> DsM [b]
+-- A MatchResult is an expression with a hole in it
+data MatchResult
+ = MatchResult
+ CanItFail -- Tells whether the failure expression is used
+ (CoreExpr -> DsM CoreExpr)
+ -- Takes a expression to plug in at the
+ -- failure point(s). The expression should
+ -- be duplicatable!
-mapDs f [] = returnDs []
-mapDs f (x:xs)
- = f x `thenDs` \ r ->
- mapDs f xs `thenDs` \ rs ->
- returnDs (r:rs)
+data CanItFail = CanFail | CantFail
-foldlDs :: (a -> b -> DsM a) -> a -> [b] -> DsM a
+orFail CantFail CantFail = CantFail
+orFail _ _ = CanFail
+\end{code}
-foldlDs k z [] = returnDs z
-foldlDs k z (x:xs) = k z x `thenDs` \ r ->
- foldlDs k r xs
-mapAndUnzipDs :: (a -> DsM (b, c)) -> [a] -> DsM ([b], [c])
+%************************************************************************
+%* *
+ Monad stuff
+%* *
+%************************************************************************
-mapAndUnzipDs f [] = returnDs ([], [])
-mapAndUnzipDs f (x:xs)
- = f x `thenDs` \ (r1, r2) ->
- mapAndUnzipDs f xs `thenDs` \ (rs1, rs2) ->
- returnDs (r1:rs1, r2:rs2)
+Now the mondo monad magic (yes, @DsM@ is a silly name)---carry around
+a @UniqueSupply@ and some annotations, which
+presumably include source-file location information:
+\begin{code}
+type DsM result = TcRnIf DsGblEnv DsLclEnv result
+
+-- Compatibility functions
+fixDs = fixM
+thenDs = thenM
+returnDs = returnM
+listDs = sequenceM
+foldlDs = foldlM
+foldrDs = foldrM
+mapAndUnzipDs = mapAndUnzipM
+
+
+type DsWarning = (SrcSpan, SDoc)
+ -- Not quite the same as a WarnMsg, we have an SDoc here
+ -- and we'll do the print_unqual stuff later on to turn it
+ -- into a Doc.
+
+data DsGblEnv = DsGblEnv {
+ ds_mod :: Module, -- For SCC profiling
+ ds_warns :: IORef (Bag DsWarning), -- Warning messages
+ ds_if_env :: (IfGblEnv, IfLclEnv) -- Used for looking up global,
+ -- possibly-imported things
+ }
+
+data DsLclEnv = DsLclEnv {
+ ds_meta :: DsMetaEnv, -- Template Haskell bindings
+ ds_loc :: SrcSpan -- to put in pattern-matching error msgs
+ }
+
+-- Inside [| |] brackets, the desugarer looks
+-- up variables in the DsMetaEnv
+type DsMetaEnv = NameEnv DsMetaVal
+
+data DsMetaVal
+ = Bound Id -- Bound by a pattern inside the [| |].
+ -- Will be dynamically alpha renamed.
+ -- The Id has type THSyntax.Var
+
+ | Splice (HsExpr Id) -- These bindings are introduced by
+ -- the PendingSplices on a HsBracketOut
-zipWithDs :: (a -> b -> DsM c) -> [a] -> [b] -> DsM [c]
+-- initDs returns the UniqSupply out the end (not just the result)
-zipWithDs f [] ys = returnDs []
-zipWithDs f (x:xs) (y:ys)
- = f x y `thenDs` \ r ->
- zipWithDs f xs ys `thenDs` \ rs ->
- returnDs (r:rs)
+initDs :: HscEnv
+ -> Module -> GlobalRdrEnv -> TypeEnv
+ -> DsM a
+ -> IO (a, Bag WarnMsg)
+
+initDs hsc_env mod rdr_env type_env thing_inside
+ = do { warn_var <- newIORef emptyBag
+ ; 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)
+ ; gbl_env = DsGblEnv { ds_mod = mod,
+ ds_if_env = (if_genv, if_lenv),
+ ds_warns = warn_var }
+ ; lcl_env = DsLclEnv { ds_meta = emptyNameEnv,
+ ds_loc = noSrcSpan } }
+
+ ; res <- initTcRnIf 'd' hsc_env gbl_env lcl_env thing_inside
+
+ ; warns <- readIORef warn_var
+ ; return (res, mapBag mk_warn warns)
+ }
+ where
+ print_unqual = unQualInScope rdr_env
+
+ mk_warn :: (SrcSpan,SDoc) -> WarnMsg
+ mk_warn (loc,sdoc) = mkWarnMsg loc print_unqual sdoc
\end{code}
+%************************************************************************
+%* *
+ Operations in the monad
+%* *
+%************************************************************************
+
And all this mysterious stuff is so we can occasionally reach out and
grab one or more names. @newLocalDs@ isn't exported---exported
functions are defined with it. The difference in name-strings makes
it easier to read debugging output.
\begin{code}
-newSysLocalDs, newFailLocalDs :: Type -> DsM Id
-newSysLocalDs ty dflags us genv loc mod warns
- = case uniqFromSupply us of { assigned_uniq ->
- (mkSysLocal SLIT("ds") assigned_uniq ty, warns) }
-
-newSysLocalsDs tys = mapDs newSysLocalDs tys
-
-newFailLocalDs ty dflags us genv loc mod warns
- = case uniqFromSupply us of { assigned_uniq ->
- (mkSysLocal SLIT("fail") assigned_uniq ty, warns) }
- -- The UserLocal bit just helps make the code a little clearer
-
-getUniqueDs :: DsM Unique
-getUniqueDs dflags us genv loc mod warns
- = (uniqFromSupply us, warns)
+-- Make a new Id with the same print name, but different type, and new unique
+newUniqueId :: Name -> Type -> DsM Id
+newUniqueId id ty
+ = newUnique `thenDs` \ uniq ->
+ returnDs (mkSysLocal (occNameFS (nameOccName id)) uniq ty)
-getUniquesDs :: DsM [Unique]
-getUniquesDs dflags us genv loc mod warns
- = (uniqsFromSupply us, warns)
+duplicateLocalDs :: Id -> DsM Id
+duplicateLocalDs old_local
+ = newUnique `thenDs` \ uniq ->
+ returnDs (setIdUnique old_local uniq)
-getDOptsDs :: DsM DynFlags
-getDOptsDs dflags us genv loc mod warns
- = (dflags, warns)
+newSysLocalDs, newFailLocalDs :: Type -> DsM Id
+newSysLocalDs ty
+ = newUnique `thenDs` \ uniq ->
+ returnDs (mkSysLocal FSLIT("ds") uniq ty)
-duplicateLocalDs :: Id -> DsM Id
-duplicateLocalDs old_local dflags us genv loc mod warns
- = case uniqFromSupply us of { assigned_uniq ->
- (setIdUnique old_local assigned_uniq, warns) }
+newSysLocalsDs tys = mappM newSysLocalDs tys
-cloneTyVarsDs :: [TyVar] -> DsM [TyVar]
-cloneTyVarsDs tyvars dflags us genv loc mod warns
- = (zipWith setTyVarUnique tyvars (uniqsFromSupply us), warns)
+newFailLocalDs ty
+ = newUnique `thenDs` \ uniq ->
+ returnDs (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 dflags us genv loc mod warns
- = (zipWith setTyVarUnique tyvar_tmpls (uniqsFromSupply us), warns)
+newTyVarsDs tyvar_tmpls
+ = newUniqueSupply `thenDs` \ uniqs ->
+ returnDs (zipWith setTyVarUnique tyvar_tmpls (uniqsFromSupply uniqs))
\end{code}
We can also reach out and either set/grab location information from
-the @SrcLoc@ being carried around.
-\begin{code}
-uniqSMtoDsM :: UniqSM a -> DsM a
+the @SrcSpan@ being carried around.
-uniqSMtoDsM u_action dflags us genv loc mod warns
- = (initUs_ us u_action, warns)
+\begin{code}
+getDOptsDs :: DsM DynFlags
+getDOptsDs = getDOpts
-getSrcLocDs :: DsM SrcLoc
-getSrcLocDs dflags us genv loc mod warns
- = (loc, warns)
+getModuleDs :: DsM Module
+getModuleDs = do { env <- getGblEnv; return (ds_mod env) }
-putSrcLocDs :: SrcLoc -> DsM a -> DsM a
-putSrcLocDs new_loc expr dflags us genv old_loc mod warns
- = expr dflags us genv new_loc mod warns
+getSrcSpanDs :: DsM SrcSpan
+getSrcSpanDs = do { env <- getLclEnv; return (ds_loc env) }
-dsWarn :: WarnMsg -> DsM ()
-dsWarn warn dflags us genv loc mod warns = ((), warns `snocBag` warn)
+putSrcSpanDs :: SrcSpan -> DsM a -> DsM a
+putSrcSpanDs new_loc thing_inside = updLclEnv (\ env -> env {ds_loc = new_loc}) thing_inside
+dsWarn :: SDoc -> DsM ()
+dsWarn warn = do { env <- getGblEnv
+ ; loc <- getSrcSpanDs
+ ; updMutVar (ds_warns env) (`snocBag` (loc,msg)) }
+ where
+ msg = ptext SLIT("Warning:") <+> warn
\end{code}
\begin{code}
-getModuleDs :: DsM Module
-getModuleDs dflags us genv loc mod warns = (mod, warns)
+dsLookupGlobal :: Name -> DsM TyThing
+-- Very like TcEnv.tcLookupGlobal
+dsLookupGlobal name
+ = do { env <- getGblEnv
+ ; setEnvs (ds_if_env env)
+ (tcIfaceGlobal name) }
+
+dsLookupGlobalId :: Name -> DsM Id
+dsLookupGlobalId name
+ = dsLookupGlobal name `thenDs` \ thing ->
+ returnDs (tyThingId thing)
+
+dsLookupTyCon :: Name -> DsM TyCon
+dsLookupTyCon name
+ = dsLookupGlobal name `thenDs` \ thing ->
+ returnDs (tyThingTyCon thing)
+
+dsLookupDataCon :: Name -> DsM DataCon
+dsLookupDataCon name
+ = dsLookupGlobal name `thenDs` \ thing ->
+ returnDs (tyThingDataCon thing)
\end{code}
\begin{code}
-dsLookupGlobalValue :: Name -> DsM Id
-dsLookupGlobalValue name dflags us genv loc mod warns
- = (genv name, warns)
+dsLookupMetaEnv :: Name -> DsM (Maybe DsMetaVal)
+dsLookupMetaEnv name = do { env <- getLclEnv; return (lookupNameEnv (ds_meta env) name) }
+
+dsExtendMetaEnv :: DsMetaEnv -> DsM a -> DsM a
+dsExtendMetaEnv menv thing_inside
+ = updLclEnv (\env -> env { ds_meta = ds_meta env `plusNameEnv` menv }) thing_inside
\end{code}
-%************************************************************************
-%* *
-\subsection{Type synonym @EquationInfo@ and access functions for its pieces}
-%* *
-%************************************************************************
-
-\begin{code}
-data DsMatchContext
- = DsMatchContext HsMatchContext [TypecheckedPat] SrcLoc
- | NoMatchContext
- deriving ()
-\end{code}
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