%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[DsMonad]{@DsMonad@: monadery used in desugaring}
\begin{code}
-#include "HsVersions.h"
-
module DsMonad (
- DsM(..),
- initDs, returnDs, thenDs, andDs, mapDs, listDs,
- mapAndUnzipDs, zipWithDs,
+ DsM,
+ initDs, returnDs, thenDs, mapDs, listDs,
+ mapAndUnzipDs, zipWithDs, foldlDs,
uniqSMtoDsM,
newTyVarsDs, cloneTyVarsDs,
- duplicateLocalDs, newSysLocalDs, newSysLocalsDs,
+ duplicateLocalDs, newSysLocalDs, newSysLocalsDs, newUniqueId,
newFailLocalDs,
getSrcLocDs, putSrcLocDs,
- getModuleAndGroupDs,
- extendEnvDs, lookupEnvDs, lookupEnvWithDefaultDs,
- DsIdEnv(..),
- lookupId,
+ getModuleDs,
+ getUniqueDs, getUniquesDs,
+ getDOptsDs,
+ dsLookupGlobalId, dsLookupTyCon,
+
+ DsMetaEnv, DsMetaVal(..), dsLookupMetaEnv, dsExtendMetaEnv,
- dsShadowError,
- DsMatchContext(..), DsMatchKind(..), pprDsWarnings
+ dsWarn,
+ DsWarnings,
+ DsMatchContext(..)
) where
-import Ubiq
-
-import Bag ( emptyBag, snocBag, bagToList )
-import CmdLineOpts ( opt_SccGroup )
-import CoreSyn ( CoreExpr(..) )
-import CoreUtils ( substCoreExpr )
-import HsSyn ( OutPat )
-import Id ( mkSysLocal, mkIdWithNewUniq,
- lookupIdEnv, growIdEnvList, GenId, IdEnv(..)
- )
-import PprType ( GenType, GenTyVar )
-import PprStyle ( PprStyle(..) )
-import Pretty
-import SrcLoc ( unpackSrcLoc, mkUnknownSrcLoc, SrcLoc )
-import TcHsSyn ( TypecheckedPat(..) )
-import TyVar ( nullTyVarEnv, cloneTyVar, GenTyVar{-instance Eq-} )
-import Unique ( Unique{-instances-} )
-import UniqSupply ( splitUniqSupply, getUnique, getUniques,
- mapUs, thenUs, returnUs, UniqSM(..) )
-import Util ( assoc, mapAccumL, zipWithEqual, panic )
+#include "HsVersions.h"
+
+import TcHsSyn ( TypecheckedPat, TypecheckedMatchContext, TypecheckedHsExpr )
+import HscTypes ( TyThing(..) )
+import Bag ( emptyBag, snocBag, Bag )
+import TyCon ( TyCon )
+import ErrUtils ( WarnMsg )
+import Id ( mkSysLocal, setIdUnique, Id )
+import Module ( Module )
+import Var ( TyVar, setTyVarUnique )
+import Outputable
+import SrcLoc ( noSrcLoc, SrcLoc )
+import Type ( Type )
+import UniqSupply ( initUs_, getUniqueUs, getUniquesUs, thenUs, returnUs,
+ UniqSM, UniqSupply )
+import Unique ( Unique )
+import Name ( Name, nameOccName )
+import NameEnv
+import OccName ( occNameFS )
+import CmdLineOpts ( DynFlags )
infixr 9 `thenDs`
\end{code}
a @UniqueSupply@ and some annotations, which
presumably include source-file location information:
\begin{code}
-type DsM result =
- UniqSupply
- -> SrcLoc -- to put in pattern-matching error msgs
- -> (FAST_STRING, FAST_STRING) -- "module"+"group" : for SCC profiling
- -> DsIdEnv
- -> DsWarnings
- -> (result, DsWarnings)
-
-type DsWarnings = Bag DsMatchContext -- The desugarer reports matches which are
- -- completely shadowed
-{-# INLINE andDs #-}
+newtype DsM result
+ = DsM (DsEnv -> DsWarnings -> UniqSM (result, DsWarnings))
+
+unDsM (DsM x) = x
+
+data DsEnv = DsEnv {
+ ds_dflags :: DynFlags,
+ ds_globals :: Name -> TyThing, -- Lookup well-known Ids
+ ds_meta :: DsMetaEnv, -- Template Haskell bindings
+ ds_loc :: SrcLoc, -- to put in pattern-matching error msgs
+ ds_mod :: Module -- module: for SCC profiling
+ }
+
+-- 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 String
+
+ | Splice TypecheckedHsExpr -- These bindings are introduced by
+ -- the PendingSplices on a HsBracketOut
+
+instance Monad DsM where
+ return = returnDs
+ (>>=) = thenDs
+
+type DsWarnings = Bag DsWarning -- The desugarer reports matches which are
+ -- completely shadowed or incomplete patterns
+type DsWarning = (SrcLoc, SDoc)
+
{-# INLINE thenDs #-}
{-# INLINE returnDs #-}
-- initDs returns the UniqSupply out the end (not just the result)
-initDs :: UniqSupply
- -> DsIdEnv
- -> FAST_STRING -- module name: for profiling; (group name: from switches)
+initDs :: DynFlags
+ -> UniqSupply
+ -> (Name -> TyThing)
+ -> Module -- module name: for profiling
-> DsM a
-> (a, DsWarnings)
-initDs init_us env mod_name action
- = action init_us mkUnknownSrcLoc module_and_group env emptyBag
+initDs dflags init_us lookup mod (DsM action)
+ = initUs_ init_us (action ds_env emptyBag)
where
- module_and_group = (mod_name, grp_name)
- grp_name = case opt_SccGroup of
- Just xx -> _PK_ xx
- Nothing -> mod_name -- default: module name
+ ds_env = DsEnv { ds_dflags = dflags, ds_globals = lookup,
+ ds_loc = noSrcLoc, ds_mod = mod,
+ ds_meta = emptyNameEnv }
thenDs :: DsM a -> (a -> DsM b) -> DsM b
-andDs :: (a -> a -> a) -> DsM a -> DsM a -> DsM a
-
-thenDs m1 m2 us loc mod_and_grp env warns
- = case splitUniqSupply us of { (s1, s2) ->
- case (m1 s1 loc mod_and_grp env warns) of { (result, warns1) ->
- m2 result s2 loc mod_and_grp env warns1}}
-andDs combiner m1 m2 us loc mod_and_grp env warns
- = case splitUniqSupply us of { (s1, s2) ->
- case (m1 s1 loc mod_and_grp env warns) of { (result1, warns1) ->
- case (m2 s2 loc mod_and_grp env warns1) of { (result2, warns2) ->
- (combiner result1 result2, warns2) }}}
+thenDs (DsM m1) m2 = DsM( \ env warns ->
+ m1 env warns `thenUs` \ (result, warns1) ->
+ unDsM (m2 result) env warns1)
returnDs :: a -> DsM a
-returnDs result us loc mod_and_grp env warns = (result, warns)
+returnDs result = DsM (\ env warns -> returnUs (result, warns))
listDs :: [DsM a] -> DsM [a]
listDs [] = returnDs []
mapDs f xs `thenDs` \ rs ->
returnDs (r:rs)
+foldlDs :: (a -> b -> DsM a) -> a -> [b] -> DsM a
+
+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])
mapAndUnzipDs f [] = returnDs ([], [])
zipWithDs :: (a -> b -> DsM c) -> [a] -> [b] -> DsM [c]
-zipWithDs f [] [] = returnDs []
+zipWithDs f [] ys = returnDs []
zipWithDs f (x:xs) (y:ys)
= f x y `thenDs` \ r ->
zipWithDs f xs ys `thenDs` \ rs ->
returnDs (r:rs)
--- Note: crashes if lists not equal length (like zipWithEqual)
\end{code}
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}
-newLocalDs :: FAST_STRING -> Type -> DsM Id
-newLocalDs nm ty us loc mod_and_grp env warns
- = case (getUnique us) of { assigned_uniq ->
- (mkSysLocal nm assigned_uniq ty loc, warns) }
-newSysLocalDs = newLocalDs SLIT("ds")
-newSysLocalsDs tys = mapDs (newLocalDs SLIT("ds")) tys
-newFailLocalDs = newLocalDs SLIT("fail")
+\begin{code}
+uniqSMtoDsM :: UniqSM a -> DsM a
+uniqSMtoDsM u_action = DsM(\ env warns ->
+ u_action `thenUs` \ res ->
+ returnUs (res, warns))
+
+
+getUniqueDs :: DsM Unique
+getUniqueDs = DsM (\ env warns ->
+ getUniqueUs `thenUs` \ uniq ->
+ returnUs (uniq, warns))
+
+getUniquesDs :: DsM [Unique]
+getUniquesDs = DsM(\ env warns ->
+ getUniquesUs `thenUs` \ uniqs ->
+ returnUs (uniqs, warns))
+
+-- Make a new Id with the same print name, but different type, and new unique
+newUniqueId :: Name -> Type -> DsM Id
+newUniqueId id ty
+ = getUniqueDs `thenDs` \ uniq ->
+ returnDs (mkSysLocal (occNameFS (nameOccName id)) uniq ty)
duplicateLocalDs :: Id -> DsM Id
-duplicateLocalDs old_local us loc mod_and_grp env warns
- = case (getUnique us) of { assigned_uniq ->
- (mkIdWithNewUniq old_local assigned_uniq, warns) }
+duplicateLocalDs old_local
+ = getUniqueDs `thenDs` \ uniq ->
+ returnDs (setIdUnique old_local uniq)
-cloneTyVarsDs :: [TyVar] -> DsM [TyVar]
-cloneTyVarsDs tyvars us loc mod_and_grp env warns
- = case (getUniques (length tyvars) us) of { uniqs ->
- (zipWithEqual "cloneTyVarsDs" cloneTyVar tyvars uniqs, warns) }
+newSysLocalDs, newFailLocalDs :: Type -> DsM Id
+newSysLocalDs ty
+ = getUniqueDs `thenDs` \ uniq ->
+ returnDs (mkSysLocal FSLIT("ds") uniq ty)
+
+newSysLocalsDs tys = mapDs newSysLocalDs tys
+
+newFailLocalDs ty
+ = getUniqueDs `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]
+cloneTyVarsDs :: [TyVar] -> DsM [TyVar]
+cloneTyVarsDs tyvars
+ = getUniquesDs `thenDs` \ uniqs ->
+ returnDs (zipWith setTyVarUnique tyvars uniqs)
-newTyVarsDs tyvar_tmpls us loc mod_and_grp env warns
- = case (getUniques (length tyvar_tmpls) us) of { uniqs ->
- (zipWithEqual "newTyVarsDs" cloneTyVar tyvar_tmpls uniqs, warns) }
+newTyVarsDs :: [TyVar] -> DsM [TyVar]
+newTyVarsDs tyvar_tmpls
+ = getUniquesDs `thenDs` \ uniqs ->
+ returnDs (zipWith setTyVarUnique tyvar_tmpls 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
+getDOptsDs :: DsM DynFlags
+getDOptsDs = DsM(\ env warns -> returnUs (ds_dflags env, warns))
-uniqSMtoDsM u_action us loc mod_and_grp env warns
- = (u_action us, warns)
+getModuleDs :: DsM Module
+getModuleDs = DsM(\ env warns -> returnUs (ds_mod env, warns))
-getSrcLocDs :: DsM (String, String)
-getSrcLocDs us loc mod_and_grp env warns
- = case (unpackSrcLoc loc) of { (x,y) ->
- ((_UNPK_ x, _UNPK_ y), warns) }
+getSrcLocDs :: DsM SrcLoc
+getSrcLocDs = DsM(\ env warns -> returnUs (ds_loc env, warns))
putSrcLocDs :: SrcLoc -> DsM a -> DsM a
-putSrcLocDs new_loc expr us old_loc mod_and_grp env warns
- = expr us new_loc mod_and_grp env warns
+putSrcLocDs new_loc (DsM expr) = DsM(\ env warns ->
+ expr (env { ds_loc = new_loc }) warns)
-dsShadowError :: DsMatchContext -> DsM ()
-dsShadowError cxt us loc mod_and_grp env warns
- = ((), warns `snocBag` cxt)
+dsWarn :: DsWarning -> DsM ()
+dsWarn warn = DsM(\ env warns -> returnUs ((), warns `snocBag` warn))
\end{code}
\begin{code}
-getModuleAndGroupDs :: DsM (FAST_STRING, FAST_STRING)
-getModuleAndGroupDs us loc mod_and_grp env warns
- = (mod_and_grp, warns)
+dsLookupGlobalId :: Name -> DsM Id
+dsLookupGlobalId name = DsM(\ env warns ->
+ returnUs (get_id name (ds_globals env name), warns))
+
+dsLookupTyCon :: Name -> DsM TyCon
+dsLookupTyCon name = DsM(\ env warns ->
+ returnUs (get_tycon name (ds_globals env name), warns))
+
+get_id name (AnId id) = id
+get_id name other = pprPanic "dsLookupGlobalId" (ppr name)
+
+get_tycon name (ATyCon tc) = tc
+get_tycon name other = pprPanic "dsLookupTyCon" (ppr name)
\end{code}
\begin{code}
-type DsIdEnv = IdEnv CoreExpr
-
-extendEnvDs :: [(Id, CoreExpr)] -> DsM a -> DsM a
+dsLookupMetaEnv :: Name -> DsM (Maybe DsMetaVal)
+dsLookupMetaEnv name = DsM(\ env warns -> returnUs (lookupNameEnv (ds_meta env) name, warns))
-extendEnvDs pairs then_do us loc mod_and_grp old_env warns
- = case splitUniqSupply us of { (s1, s2) ->
- let
- revised_pairs = subst_all pairs s1
- in
- then_do s2 loc mod_and_grp (growIdEnvList old_env revised_pairs) warns
- }
- where
- subst_all pairs = mapUs subst pairs
-
- subst (v, expr)
- = substCoreExpr old_env nullTyVarEnv expr `thenUs` \ new_expr ->
- returnUs (v, new_expr)
-
-lookupEnvDs :: Id -> DsM (Maybe CoreExpr)
-lookupEnvDs id us loc mod_and_grp env warns
- = (lookupIdEnv env id, warns)
- -- Note: we don't assert anything about the Id
- -- being looked up. There's not really anything
- -- much to say about it. (WDP 94/06)
-
-lookupEnvWithDefaultDs :: Id -> CoreExpr -> DsM CoreExpr
-lookupEnvWithDefaultDs id deflt us loc mod_and_grp env warns
- = (case (lookupIdEnv env id) of
- Nothing -> deflt
- Just xx -> xx,
- warns)
-
-lookupId :: [(Id, a)] -> Id -> a
-lookupId env id
- = assoc "lookupId" env id
+dsExtendMetaEnv :: DsMetaEnv -> DsM a -> DsM a
+dsExtendMetaEnv menv (DsM m)
+ = DsM (\ env warns -> m (env { ds_meta = ds_meta env `plusNameEnv` menv }) warns)
\end{code}
+
%************************************************************************
%* *
-%* type synonym EquationInfo and access functions for its pieces *
+\subsection{Type synonym @EquationInfo@ and access functions for its pieces}
%* *
%************************************************************************
\begin{code}
data DsMatchContext
- = DsMatchContext DsMatchKind [TypecheckedPat] SrcLoc
+ = DsMatchContext TypecheckedMatchContext [TypecheckedPat] SrcLoc
| NoMatchContext
-
-data DsMatchKind
- = FunMatch Id
- | CaseMatch
- | LambdaMatch
- | PatBindMatch
-
-pprDsWarnings :: PprStyle -> Bag DsMatchContext -> Pretty
-pprDsWarnings sty warns
- = ppAboves (map pp_cxt (bagToList warns))
- where
- pp_cxt NoMatchContext = ppPStr SLIT("Some match is shadowed; I don't know what")
- pp_cxt (DsMatchContext kind pats loc)
- = ppHang (ppBesides [ppr PprForUser loc, ppPStr SLIT(": ")])
- 4 (ppHang (ppPStr SLIT("Pattern match(es) completely overlapped:"))
- 4 (pp_match kind pats))
-
- pp_match (FunMatch fun) pats
- = ppHang (ppr sty fun)
- 4 (ppSep [ppSep (map (ppr sty) pats), ppPStr SLIT("= ...")])
-
- pp_match CaseMatch pats
- = ppHang (ppPStr SLIT("in a case alternative:"))
- 4 (ppSep [ppSep (map (ppr sty) pats), pp_arrow_dotdotdot])
-
- pp_match PatBindMatch pats
- = ppHang (ppPStr SLIT("in a pattern binding:"))
- 4 (ppSep [ppSep (map (ppr sty) pats), pp_arrow_dotdotdot])
-
- pp_match LambdaMatch pats
- = ppHang (ppPStr SLIT("in a lambda abstraction:"))
- 4 (ppSep [ppSep (map (ppr sty) pats), pp_arrow_dotdotdot])
-
- pp_arrow_dotdotdot = ppPStr SLIT("-> ...")
+ deriving ()
\end{code}
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