\begin{code}
module Type (
- GenType(..), TyNote(..), -- Representation visible to friends
- Type, GenKind, Kind,
- TyVarSubst, GenTyVarSubst,
+ Type(..), TyNote(..), -- Representation visible to friends
+ Kind, TyVarSubst,
- funTyCon, boxedKindCon, unboxedKindCon, openKindCon,
+ superKind, superBoxity, -- :: SuperKind
- boxedTypeKind, unboxedTypeKind, openTypeKind, mkArrowKind, mkArrowKinds,
- hasMoreBoxityInfo, superKind,
+ boxedKind, -- :: Kind :: BX
+ anyBoxKind, -- :: Kind :: BX
+ typeCon, -- :: KindCon :: BX -> KX
+ anyBoxCon, -- :: KindCon :: BX
+
+ boxedTypeKind, unboxedTypeKind, openTypeKind, -- Kind :: superKind
+
+ mkArrowKind, mkArrowKinds, hasMoreBoxityInfo,
+
+ funTyCon,
mkTyVarTy, mkTyVarTys, getTyVar, getTyVar_maybe, isTyVarTy,
mkAppTy, mkAppTys, splitAppTy, splitAppTys, splitAppTy_maybe,
mkFunTy, mkFunTys, splitFunTy_maybe, splitFunTys, funResultTy,
+ zipFunTys,
mkTyConApp, mkTyConTy, splitTyConApp_maybe,
splitAlgTyConApp_maybe, splitAlgTyConApp,
mkDictTy, splitDictTy_maybe, isDictTy,
- mkSynTy, isSynTy,
+ mkSynTy, isSynTy, deNoteType,
mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
applyTy, applyTys, isForAllTy,
mkRhoTy, splitRhoTy,
mkSigmaTy, splitSigmaTy,
- isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType,
+ -- Lifting and boxity
+ isUnLiftedType, isUnboxedType, isUnboxedTupleType, isAlgType, isDataType,
typePrimRep,
+ -- Free variables
tyVarsOfType, tyVarsOfTypes, namesOfType, typeKind,
addFreeTyVars,
- substTy, fullSubstTy, substTyVar,
- substFlexiTy, substFlexiTheta,
+ -- Substitution
+ substTy, substTheta, fullSubstTy, substTyVar,
+ substTopTy, substTopTheta,
- showTypeCategory
+ -- Tidying up for printing
+ tidyType, tidyTypes,
+ tidyOpenType, tidyOpenTypes,
+ tidyTyVar, tidyTyVars,
+ tidyTopType
) where
#include "HsVersions.h"
import {-# SOURCE #-} DataCon( DataCon )
+import {-# SOURCE #-} PprType( pprType ) -- Only called in debug messages
-- friends:
-import Var ( Id, TyVar, GenTyVar, IdOrTyVar,
- removeTyVarFlexi,
- tyVarKind, isId, idType
+import Var ( Id, TyVar, IdOrTyVar,
+ tyVarKind, tyVarName, isId, idType, setTyVarName
)
import VarEnv
import VarSet
import Name ( NamedThing(..), Provenance(..), ExportFlag(..),
- mkWiredInTyConName, mkGlobalName, varOcc
+ mkWiredInTyConName, mkGlobalName, mkLocalName, mkKindOccFS, tcName,
+ tidyOccName, TidyOccEnv
)
import NameSet
import Class ( classTyCon, Class )
-import TyCon ( TyCon, Boxity(..),
- mkFunTyCon, mkKindCon, superKindCon,
+import TyCon ( TyCon, KindCon,
+ mkFunTyCon, mkKindCon, mkSuperKindCon,
matchesTyCon, isUnboxedTupleTyCon, isUnLiftedTyCon,
- isFunTyCon, isEnumerationTyCon,
- isTupleTyCon, maybeTyConSingleCon,
- isPrimTyCon, isAlgTyCon, isSynTyCon, tyConArity,
+ isFunTyCon, isDataTyCon,
+ isAlgTyCon, isSynTyCon, tyConArity,
tyConKind, tyConDataCons, getSynTyConDefn,
tyConPrimRep, tyConClass_maybe
)
-- others
import BasicTypes ( Unused )
-import SrcLoc ( mkBuiltinSrcLoc )
+import SrcLoc ( mkBuiltinSrcLoc, noSrcLoc )
import PrelMods ( pREL_GHC )
import Maybes ( maybeToBool )
import PrimRep ( PrimRep(..), isFollowableRep )
import Unique -- quite a few *Keys
-import Util ( thenCmp )
+import Util ( thenCmp, mapAccumL )
import Outputable
\end{code}
can be entered.
(NOTE: previously "pointed").
- *algebraic* A type with one or more constructors. An algebraic
- type is one that can be deconstructed with a case
- expression. *NOT* the same as lifted types,
- because we also include unboxed tuples in this
- classification.
+ *algebraic* A type with one or more constructors, whether declared
+ with "data" or "newtype".
+ An algebraic type is one that can be deconstructed
+ with a case expression.
+
+ *NOT* the same as lifted types, because we also
+ include unboxed tuples in this classification.
+
+ *data* A type declared with "data". Also boxed tuples.
*primitive* iff it is a built-in type that can't be expressed
in Haskell.
\begin{code}
-type Type = GenType Unused -- Used after typechecker
-
-type GenKind flexi = GenType flexi
-type Kind = Type
+type SuperKind = Type
+type Kind = Type
type TyVarSubst = TyVarEnv Type
-type GenTyVarSubst flexi = TyVarEnv (GenType flexi)
-data GenType flexi -- Parameterised over the "flexi" part of a type variable
- = TyVarTy (GenTyVar flexi)
+data Type
+ = TyVarTy TyVar
| AppTy
- (GenType flexi) -- Function is *not* a TyConApp
- (GenType flexi)
+ Type -- Function is *not* a TyConApp
+ Type
| TyConApp -- Application of a TyCon
TyCon -- *Invariant* saturated appliations of FunTyCon and
-- synonyms have their own constructors, below.
- [GenType flexi] -- Might not be saturated.
+ [Type] -- Might not be saturated.
| FunTy -- Special case of TyConApp: TyConApp FunTyCon [t1,t2]
- (GenType flexi)
- (GenType flexi)
+ Type
+ Type
| NoteTy -- Saturated application of a type synonym
- (TyNote flexi)
- (GenType flexi) -- The expanded version
+ TyNote
+ Type -- The expanded version
| ForAllTy
- (GenTyVar flexi)
- (GenType flexi) -- TypeKind
+ TyVar
+ Type -- TypeKind
-data TyNote flexi
- = SynNote (GenType flexi) -- The unexpanded version of the type synonym; always a TyConApp
- | FTVNote (GenTyVarSet flexi) -- The free type variables of the noted expression
+data TyNote
+ = SynNote Type -- The unexpanded version of the type synonym; always a TyConApp
+ | FTVNote TyVarSet -- The free type variables of the noted expression
\end{code}
%************************************************************************
%* *
-\subsection{Wired-in type constructors
+\subsection{Kinds}
%* *
%************************************************************************
-We define a few wired-in type constructors here to avoid module knots
+Kinds
+~~~~~
+k::K = Type bx
+ | k -> k
+ | kv
-\begin{code}
-funTyConName = mkWiredInTyConName funTyConKey pREL_GHC SLIT("->") funTyCon
-funTyCon = mkFunTyCon funTyConName (mkArrowKinds [boxedTypeKind, boxedTypeKind] boxedTypeKind)
-\end{code}
+kv :: KX is a kind variable
+
+Type :: BX -> KX
+
+bx::BX = Boxed
+ | Unboxed
+ | AnyBox -- Used *only* for special built-in things
+ -- like error :: forall (a::*?). String -> a
+ -- Here, the 'a' can be instantiated to a boxed or
+ -- unboxed type.
+ | bv
+
+bxv :: BX is a boxity variable
+
+sk = KX -- A kind
+ | BX -- A boxity
+ | sk -> sk -- In ptic (BX -> KX)
\begin{code}
-mk_kind_name key str = mkGlobalName key pREL_GHC (varOcc str)
- (LocalDef mkBuiltinSrcLoc NotExported)
+mk_kind_name key str = mkGlobalName key pREL_GHC (mkKindOccFS tcName str)
+ (LocalDef mkBuiltinSrcLoc NotExported)
-- mk_kind_name is a bit of a hack
-- The LocalDef means that we print the name without
-- a qualifier, which is what we want for these kinds.
+ -- It's used for both Kinds and Boxities
+\end{code}
-boxedKindConName = mk_kind_name boxedKindConKey SLIT("*")
-boxedKindCon = mkKindCon boxedKindConName superKind Boxed
+Define KX, BX.
-unboxedKindConName = mk_kind_name unboxedKindConKey SLIT("*#")
-unboxedKindCon = mkKindCon unboxedKindConName superKind Unboxed
+\begin{code}
+superKind :: SuperKind -- KX, the type of all kinds
+superKindName = mk_kind_name kindConKey SLIT("KX")
+superKind = TyConApp (mkSuperKindCon superKindName) []
-openKindConName = mk_kind_name openKindConKey SLIT("*?")
-openKindCon = mkKindCon openKindConName superKind Open
+superBoxity :: SuperKind -- BX, the type of all boxities
+superBoxityName = mk_kind_name boxityConKey SLIT("BX")
+superBoxity = TyConApp (mkSuperKindCon superBoxityName) []
\end{code}
+Define Boxed, Unboxed, AnyBox
-%************************************************************************
-%* *
-\subsection{Kinds}
-%* *
-%************************************************************************
+\begin{code}
+boxedKind, unboxedKind, anyBoxKind :: Kind -- Of superkind superBoxity
+
+boxedConName = mk_kind_name boxedConKey SLIT("*")
+boxedKind = TyConApp (mkKindCon boxedConName superBoxity) []
+
+unboxedConName = mk_kind_name unboxedConKey SLIT("#")
+unboxedKind = TyConApp (mkKindCon unboxedConName superBoxity) []
+
+anyBoxConName = mk_kind_name anyBoxConKey SLIT("?")
+anyBoxCon = mkKindCon anyBoxConName superBoxity -- A kind of wild card
+anyBoxKind = TyConApp anyBoxCon []
+\end{code}
+
+Define Type
\begin{code}
-superKind :: GenKind flexi -- Box, the type of all kinds
-superKind = TyConApp superKindCon []
+typeCon :: KindCon
+typeConName = mk_kind_name typeConKey SLIT("Type")
+typeCon = mkKindCon typeConName (superBoxity `FunTy` superKind)
+\end{code}
-boxedTypeKind, unboxedTypeKind, openTypeKind :: GenKind flexi
-boxedTypeKind = TyConApp boxedKindCon []
-unboxedTypeKind = TyConApp unboxedKindCon []
-openTypeKind = TyConApp openKindCon []
+Define (Type Boxed), (Type Unboxed), (Type AnyBox)
-mkArrowKind :: GenKind flexi -> GenKind flexi -> GenKind flexi
-mkArrowKind = FunTy
+\begin{code}
+boxedTypeKind, unboxedTypeKind, openTypeKind :: Kind
+boxedTypeKind = TyConApp typeCon [boxedKind]
+unboxedTypeKind = TyConApp typeCon [unboxedKind]
+openTypeKind = TyConApp typeCon [anyBoxKind]
+
+mkArrowKind :: Kind -> Kind -> Kind
+mkArrowKind k1 k2 = k1 `FunTy` k2
-mkArrowKinds :: [GenKind flexi] -> GenKind flexi -> GenKind flexi
-mkArrowKinds arg_kinds result_kind = foldr FunTy result_kind arg_kinds
+mkArrowKinds :: [Kind] -> Kind -> Kind
+mkArrowKinds arg_kinds result_kind = foldr mkArrowKind result_kind arg_kinds
\end{code}
\begin{code}
-hasMoreBoxityInfo :: GenKind flexi -> GenKind flexi -> Bool
+hasMoreBoxityInfo :: Kind -> Kind -> Bool
+hasMoreBoxityInfo k1 k2
+ | k2 == openTypeKind = ASSERT( is_type_kind k1) True
+ | otherwise = k1 == k2
+ where
+ -- Returns true for things of form (Type x)
+ is_type_kind k = case splitTyConApp_maybe k of
+ Just (tc,[_]) -> tc == typeCon
+ Nothing -> False
+\end{code}
-(NoteTy _ k1) `hasMoreBoxityInfo` k2 = k1 `hasMoreBoxityInfo` k2
-k1 `hasMoreBoxityInfo` (NoteTy _ k2) = k1 `hasMoreBoxityInfo` k2
-(TyConApp kc1 ts1) `hasMoreBoxityInfo` (TyConApp kc2 ts2)
- = ASSERT( null ts1 && null ts2 )
- kc2 `matchesTyCon` kc1 -- NB the reversal of arguments
+%************************************************************************
+%* *
+\subsection{Wired-in type constructors
+%* *
+%************************************************************************
-kind1@(FunTy _ _) `hasMoreBoxityInfo` kind2@(FunTy _ _)
- = ASSERT( kind1 == kind2 )
- True
- -- The two kinds can be arrow kinds; for example when unifying
- -- (m1 Int) and (m2 Int) we end up unifying m1 and m2, which should
- -- have the same kind.
+We define a few wired-in type constructors here to avoid module knots
--- Other cases are impossible
+\begin{code}
+funTyConName = mkWiredInTyConName funTyConKey pREL_GHC SLIT("(->)") funTyCon
+funTyCon = mkFunTyCon funTyConName (mkArrowKinds [boxedTypeKind, boxedTypeKind] boxedTypeKind)
\end{code}
+
%************************************************************************
%* *
\subsection{Constructor-specific functions}
TyVarTy
~~~~~~~
\begin{code}
-mkTyVarTy :: GenTyVar flexi -> GenType flexi
+mkTyVarTy :: TyVar -> Type
mkTyVarTy = TyVarTy
-mkTyVarTys :: [GenTyVar flexi] -> [GenType flexi]
+mkTyVarTys :: [TyVar] -> [Type]
mkTyVarTys = map mkTyVarTy -- a common use of mkTyVarTy
-getTyVar :: String -> GenType flexi -> GenTyVar flexi
+getTyVar :: String -> Type -> TyVar
getTyVar msg (TyVarTy tv) = tv
getTyVar msg (NoteTy _ t) = getTyVar msg t
getTyVar msg other = panic ("getTyVar: " ++ msg)
-getTyVar_maybe :: GenType flexi -> Maybe (GenTyVar flexi)
+getTyVar_maybe :: Type -> Maybe TyVar
getTyVar_maybe (TyVarTy tv) = Just tv
getTyVar_maybe (NoteTy _ t) = getTyVar_maybe t
getTyVar_maybe other = Nothing
-isTyVarTy :: GenType flexi -> Bool
+isTyVarTy :: Type -> Bool
isTyVarTy (TyVarTy tv) = True
isTyVarTy (NoteTy _ ty) = isTyVarTy ty
isTyVarTy other = False
mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ [orig_ty2])
mk_app ty1 = AppTy orig_ty1 orig_ty2
-mkAppTys :: GenType flexi -> [GenType flexi] -> GenType flexi
+mkAppTys :: Type -> [Type] -> Type
mkAppTys orig_ty1 [] = orig_ty1
-- This check for an empty list of type arguments
-- avoids the needless of a type synonym constructor.
mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ orig_tys2)
mk_app ty1 = foldl AppTy orig_ty1 orig_tys2
-splitAppTy_maybe :: GenType flexi -> Maybe (GenType flexi, GenType flexi)
+splitAppTy_maybe :: Type -> Maybe (Type, Type)
splitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [ty1], ty2)
splitAppTy_maybe (AppTy ty1 ty2) = Just (ty1, ty2)
splitAppTy_maybe (NoteTy _ ty) = splitAppTy_maybe ty
splitAppTy_maybe other = Nothing
-splitAppTy :: GenType flexi -> (GenType flexi, GenType flexi)
+splitAppTy :: Type -> (Type, Type)
splitAppTy ty = case splitAppTy_maybe ty of
Just pr -> pr
Nothing -> panic "splitAppTy"
-splitAppTys :: GenType flexi -> (GenType flexi, [GenType flexi])
+splitAppTys :: Type -> (Type, [Type])
splitAppTys ty = split ty ty []
where
split orig_ty (AppTy ty arg) args = split ty ty (arg:args)
~~~~~
\begin{code}
-mkFunTy :: GenType flexi -> GenType flexi -> GenType flexi
+mkFunTy :: Type -> Type -> Type
mkFunTy arg res = FunTy arg res
-mkFunTys :: [GenType flexi] -> GenType flexi -> GenType flexi
+mkFunTys :: [Type] -> Type -> Type
mkFunTys tys ty = foldr FunTy ty tys
-splitFunTy_maybe :: GenType flexi -> Maybe (GenType flexi, GenType flexi)
+splitFunTy_maybe :: Type -> Maybe (Type, Type)
splitFunTy_maybe (FunTy arg res) = Just (arg, res)
splitFunTy_maybe (NoteTy _ ty) = splitFunTy_maybe ty
splitFunTy_maybe other = Nothing
-splitFunTys :: GenType flexi -> ([GenType flexi], GenType flexi)
+splitFunTys :: Type -> ([Type], Type)
splitFunTys ty = split [] ty ty
where
split args orig_ty (FunTy arg res) = split (arg:args) res res
split args orig_ty (NoteTy _ ty) = split args orig_ty ty
split args orig_ty ty = (reverse args, orig_ty)
-funResultTy :: GenType flexi -> GenType flexi
+zipFunTys :: Outputable a => [a] -> Type -> ([(a,Type)], Type)
+zipFunTys orig_xs orig_ty = split [] orig_xs orig_ty orig_ty
+ where
+ split acc [] nty ty = (reverse acc, nty)
+ split acc (x:xs) nty (FunTy arg res) = split ((x,arg):acc) xs res res
+ split acc xs nty (NoteTy _ ty) = split acc xs nty ty
+ split acc (x:xs) nty ty = pprPanic "zipFunTys" (ppr orig_xs <+> pprType orig_ty)
+
+funResultTy :: Type -> Type
funResultTy (FunTy arg res) = res
funResultTy (NoteTy _ ty) = funResultTy ty
-funResultTy ty = ty
+funResultTy ty = pprPanic "funResultTy" (pprType ty)
\end{code}
~~~~~~~~
\begin{code}
-mkTyConApp :: TyCon -> [GenType flexi] -> GenType flexi
+mkTyConApp :: TyCon -> [Type] -> Type
mkTyConApp tycon tys
| isFunTyCon tycon && length tys == 2
= case tys of
= ASSERT(not (isSynTyCon tycon))
TyConApp tycon tys
-mkTyConTy :: TyCon -> GenType flexi
+mkTyConTy :: TyCon -> Type
mkTyConTy tycon = ASSERT( not (isSynTyCon tycon) )
TyConApp tycon []
-- mean a distinct type, but all other type-constructor applications
-- including functions are returned as Just ..
-splitTyConApp_maybe :: GenType flexi -> Maybe (TyCon, [GenType flexi])
+splitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
splitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
splitTyConApp_maybe (FunTy arg res) = Just (funTyCon, [arg,res])
splitTyConApp_maybe (NoteTy _ ty) = splitTyConApp_maybe ty
-- "Algebraic" => newtype, data type, or dictionary (not function types)
-- We return the constructors too.
-splitAlgTyConApp_maybe :: GenType flexi -> Maybe (TyCon, [GenType flexi], [DataCon])
+splitAlgTyConApp_maybe :: Type -> Maybe (TyCon, [Type], [DataCon])
splitAlgTyConApp_maybe (TyConApp tc tys)
| isAlgTyCon tc &&
tyConArity tc == length tys = Just (tc, tys, tyConDataCons tc)
splitAlgTyConApp_maybe (NoteTy _ ty) = splitAlgTyConApp_maybe ty
splitAlgTyConApp_maybe other = Nothing
-splitAlgTyConApp :: GenType flexi -> (TyCon, [GenType flexi], [DataCon])
+splitAlgTyConApp :: Type -> (TyCon, [Type], [DataCon])
-- Here the "algebraic" property is an *assertion*
splitAlgTyConApp (TyConApp tc tys) = ASSERT( isAlgTyCon tc && tyConArity tc == length tys )
(tc, tys, tyConDataCons tc)
tell from the type constructor whether it's a dictionary or not.
\begin{code}
-mkDictTy :: Class -> [GenType flexi] -> GenType flexi
+mkDictTy :: Class -> [Type] -> Type
mkDictTy clas tys = TyConApp (classTyCon clas) tys
-splitDictTy_maybe :: GenType flexi -> Maybe (Class, [GenType flexi])
+splitDictTy_maybe :: Type -> Maybe (Class, [Type])
splitDictTy_maybe (TyConApp tc tys)
| maybeToBool maybe_class
&& tyConArity tc == length tys = Just (clas, tys)
splitDictTy_maybe (NoteTy _ ty) = splitDictTy_maybe ty
splitDictTy_maybe other = Nothing
-isDictTy :: GenType flexi -> Bool
+isDictTy :: Type -> Bool
-- This version is slightly more efficient than (maybeToBool . splitDictTy)
isDictTy (TyConApp tc tys)
| maybeToBool (tyConClass_maybe tc)
mkSynTy syn_tycon tys
= ASSERT(isSynTyCon syn_tycon)
NoteTy (SynNote (TyConApp syn_tycon tys))
- (substFlexiTy (zipVarEnv tyvars tys) body)
- -- The "flexi" is needed so we can get a TcType from a synonym
+ (substTopTy (zipVarEnv tyvars tys) body)
where
(tyvars, body) = getSynTyConDefn syn_tycon
isSynTy (NoteTy (SynNote _) _) = True
isSynTy other = False
+
+deNoteType :: Type -> Type
+ -- Sorry for the cute name
+deNoteType ty@(TyVarTy tyvar) = ty
+deNoteType (TyConApp tycon tys) = TyConApp tycon (map deNoteType tys)
+deNoteType (NoteTy _ ty) = deNoteType ty
+deNoteType (AppTy fun arg) = AppTy (deNoteType fun) (deNoteType arg)
+deNoteType (FunTy fun arg) = FunTy (deNoteType fun) (deNoteType arg)
+deNoteType (ForAllTy tv ty) = ForAllTy tv (deNoteType ty)
\end{code}
Notes on type synonyms
\begin{code}
mkForAllTy = ForAllTy
-mkForAllTys :: [GenTyVar flexi] -> GenType flexi -> GenType flexi
+mkForAllTys :: [TyVar] -> Type -> Type
mkForAllTys tyvars ty = foldr ForAllTy ty tyvars
-splitForAllTy_maybe :: GenType flexi -> Maybe (GenTyVar flexi, GenType flexi)
+splitForAllTy_maybe :: Type -> Maybe (TyVar, Type)
splitForAllTy_maybe (NoteTy _ ty) = splitForAllTy_maybe ty
splitForAllTy_maybe (ForAllTy tyvar ty) = Just(tyvar, ty)
splitForAllTy_maybe _ = Nothing
-isForAllTy :: GenType flexi -> Bool
+isForAllTy :: Type -> Bool
isForAllTy (NoteTy _ ty) = isForAllTy ty
isForAllTy (ForAllTy tyvar ty) = True
isForAllTy _ = False
-splitForAllTys :: GenType flexi -> ([GenTyVar flexi], GenType flexi)
+splitForAllTys :: Type -> ([TyVar], Type)
splitForAllTys ty = split ty ty []
where
split orig_ty (ForAllTy tv ty) tvs = split ty ty (tv:tvs)
\end{code}
\begin{code}
-applyTy :: GenType flexi -> GenType flexi -> GenType flexi
+applyTy :: Type -> Type -> Type
applyTy (NoteTy _ fun) arg = applyTy fun arg
applyTy (ForAllTy tv ty) arg = substTy (mkVarEnv [(tv,arg)]) ty
applyTy other arg = panic "applyTy"
-applyTys :: GenType flexi -> [GenType flexi] -> GenType flexi
+applyTys :: Type -> [Type] -> Type
applyTys fun_ty arg_tys
= go [] fun_ty arg_tys
where
@isTauTy@ tests for nested for-alls.
\begin{code}
-isTauTy :: GenType flexi -> Bool
+isTauTy :: Type -> Bool
isTauTy (TyVarTy v) = True
isTauTy (TyConApp _ tys) = all isTauTy tys
isTauTy (AppTy a b) = isTauTy a && isTauTy b
\end{code}
\begin{code}
-mkRhoTy :: [(Class, [GenType flexi])] -> GenType flexi -> GenType flexi
+mkRhoTy :: [(Class, [Type])] -> Type -> Type
mkRhoTy theta ty = foldr (\(c,t) r -> FunTy (mkDictTy c t) r) ty theta
-splitRhoTy :: GenType flexi -> ([(Class, [GenType flexi])], GenType flexi)
+splitRhoTy :: Type -> ([(Class, [Type])], Type)
splitRhoTy ty = split ty ty []
where
split orig_ty (FunTy arg res) ts = case splitDictTy_maybe arg of
\begin{code}
mkSigmaTy tyvars theta tau = mkForAllTys tyvars (mkRhoTy theta tau)
-splitSigmaTy :: GenType flexi -> ([GenTyVar flexi], [(Class, [GenType flexi])], GenType flexi)
+splitSigmaTy :: Type -> ([TyVar], [(Class, [Type])], Type)
splitSigmaTy ty =
(tyvars, theta, tau)
where
Finding the kind of a type
~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
--- typeKind is only ever used on Types, never Kinds
--- If it were used on Kinds, the typeKind of FunTy would not be boxedTypeKind;
--- yet at the type level functions are boxed even if neither argument nor
--- result are boxed. This seems pretty fishy to me.
-
-typeKind :: GenType flexi -> Kind
+typeKind :: Type -> Kind
-typeKind (TyVarTy tyvar) = tyVarKind tyvar
+typeKind (TyVarTy tyvar) = tyVarKind tyvar
typeKind (TyConApp tycon tys) = foldr (\_ k -> funResultTy k) (tyConKind tycon) tys
typeKind (NoteTy _ ty) = typeKind ty
-typeKind (FunTy fun arg) = boxedTypeKind
typeKind (AppTy fun arg) = funResultTy (typeKind fun)
-typeKind (ForAllTy _ _) = boxedTypeKind
+typeKind (FunTy fun arg) = typeKindF arg
+typeKind (ForAllTy _ ty) = typeKindF ty -- We could make this a new kind polyTypeKind
+ -- to prevent a forall type unifying with a
+ -- boxed type variable, but I didn't think it
+ -- was worth it yet.
+
+-- The complication is that a *function* is boxed even if
+-- its *result* type is unboxed. Seems wierd.
+
+typeKindF :: Type -> Kind
+typeKindF (NoteTy _ ty) = typeKindF ty
+typeKindF (FunTy _ ty) = typeKindF ty
+typeKindF (ForAllTy _ ty) = typeKindF ty
+typeKindF other = fix_up (typeKind other)
+ where
+ fix_up (TyConApp kc _) | kc == typeCon = boxedTypeKind
+ -- Functions at the type level are always boxed
+ fix_up (NoteTy _ kind) = fix_up kind
+ fix_up kind = kind
\end{code}
Free variables of a type
~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tyVarsOfType :: GenType flexi -> GenTyVarSet flexi
+tyVarsOfType :: Type -> TyVarSet
tyVarsOfType (TyVarTy tv) = unitVarSet tv
tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar
-tyVarsOfTypes :: [GenType flexi] -> GenTyVarSet flexi
+tyVarsOfTypes :: [Type] -> TyVarSet
tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
-- Add a Note with the free tyvars to the top of the type
-addFreeTyVars :: GenType flexi -> GenType flexi
+addFreeTyVars :: Type -> Type
addFreeTyVars ty@(NoteTy (FTVNote _) _) = ty
addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
-- Find the free names of a type, including the type constructors and classes it mentions
-namesOfType :: GenType flexi -> NameSet
+namesOfType :: Type -> NameSet
namesOfType (TyVarTy tv) = unitNameSet (getName tv)
namesOfType (TyConApp tycon tys) = unitNameSet (getName tycon) `unionNameSets`
namesOfTypes tys
@substTy@ applies a substitution to a type. It deals correctly with name capture.
\begin{code}
-substTy :: GenTyVarSubst flexi -> GenType flexi -> GenType flexi
-substTy tenv ty = subst_ty tenv tset ty
- where
- tset = foldVarEnv (unionVarSet . tyVarsOfType) emptyVarSet tenv
- -- If ty doesn't have any for-alls, then this thunk
- -- will never be evaluated
+substTy :: TyVarSubst -> Type -> Type
+substTy tenv ty
+ | isEmptyVarEnv tenv = ty
+ | otherwise = subst_ty tenv tset ty
+ where
+ tset = foldVarEnv (unionVarSet . tyVarsOfType) emptyVarSet tenv
+ -- If ty doesn't have any for-alls, then this thunk
+ -- will never be evaluated
+
+substTheta :: TyVarSubst -> ThetaType -> ThetaType
+substTheta tenv theta
+ | isEmptyVarEnv tenv = theta
+ | otherwise = [(clas, map (subst_ty tenv tset) tys) | (clas, tys) <- theta]
+ where
+ tset = foldVarEnv (unionVarSet . tyVarsOfType) emptyVarSet tenv
+ -- If ty doesn't have any for-alls, then this thunk
+ -- will never be evaluated
+
+substTopTy :: TyVarSubst -> Type -> Type
+substTopTy = substTy -- Called when doing top-level substitutions.
+ -- Here we expect that the free vars of the range of the
+ -- substitution will be empty; but during typechecking I'm
+ -- a bit dubious about that (mutable tyvars bouund to Int, say)
+ -- So I've left it as substTy for the moment. SLPJ Nov 98
+substTopTheta = substTheta
\end{code}
@fullSubstTy@ is like @substTy@ except that it needs to be given a set
if you happen to have that set lying around.
\begin{code}
-fullSubstTy :: GenTyVarSubst flexi -- Substitution to apply
- -> GenTyVarSet flexi -- Superset of the free tyvars of
- -- the range of the tyvar env
- -> GenType flexi -> GenType flexi
+fullSubstTy :: TyVarSubst -- Substitution to apply
+ -> TyVarSet -- Superset of the free tyvars of
+ -- the range of the tyvar env
+ -> Type -> Type
-- ASSUMPTION: The substitution is idempotent.
-- Equivalently: No tyvar is both in scope, and in the domain of the substitution.
fullSubstTy tenv tset ty | isEmptyVarEnv tenv = ty
go (ForAllTy tv ty) = case substTyVar tenv tset tv of
(tenv', tset', tv') -> ForAllTy tv' (subst_ty tenv' tset' ty)
-substTyVar :: GenTyVarSubst flexi -> GenTyVarSet flexi -> GenTyVar flexi
- -> (GenTyVarSubst flexi, GenTyVarSet flexi, GenTyVar flexi)
+substTyVar :: TyVarSubst -> TyVarSet -> TyVar
+ -> (TyVarSubst, TyVarSet, TyVar)
substTyVar tenv tset tv
| not (tv `elemVarSet` tset) -- No need to clone
\end{code}
-@substFlexiTy@ applies a substitution to a (GenType flexi1) returning
-a (GenType flexi2). Note that we convert from one flexi status to another.
+%************************************************************************
+%* *
+\subsection{TidyType}
+%* *
+%************************************************************************
+
+tidyTy tidies up a type for printing in an error message, or in
+an interface file.
+
+It doesn't change the uniques at all, just the print names.
+
+\begin{code}
+tidyTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
+tidyTyVar env@(tidy_env, subst) tyvar
+ = case lookupVarEnv subst tyvar of
+
+ Just tyvar' -> -- Already substituted
+ (env, tyvar')
+
+ Nothing -> -- Make a new nice name for it
+
+ case tidyOccName tidy_env (getOccName name) of
+ (tidy', occ') -> -- New occname reqd
+ ((tidy', subst'), tyvar')
+ where
+ subst' = extendVarEnv subst tyvar tyvar'
+ tyvar' = setTyVarName tyvar name'
+ name' = mkLocalName (getUnique name) occ' noSrcLoc
+ -- Note: make a *user* tyvar, so it printes nicely
+ -- Could extract src loc, but no need.
+ where
+ name = tyVarName tyvar
+
+tidyTyVars env tyvars = mapAccumL tidyTyVar env tyvars
+
+tidyType :: TidyEnv -> Type -> Type
+tidyType env@(tidy_env, subst) ty
+ = go ty
+ where
+ go (TyVarTy tv) = case lookupVarEnv subst tv of
+ Nothing -> TyVarTy tv
+ Just tv' -> TyVarTy tv'
+ go (TyConApp tycon tys) = TyConApp tycon (map go tys)
+ go (NoteTy note ty) = NoteTy (go_note note) (go ty)
+ go (AppTy fun arg) = AppTy (go fun) (go arg)
+ go (FunTy fun arg) = FunTy (go fun) (go arg)
+ go (ForAllTy tv ty) = ForAllTy tv' (tidyType env' ty)
+ where
+ (env', tv') = tidyTyVar env tv
+
+ go_note (SynNote ty) = SynNote (go ty)
+ go_note note@(FTVNote ftvs) = note -- No need to tidy the free tyvars
+
+tidyTypes env tys = map (tidyType env) tys
+\end{code}
-Two assumptions, for (substFlexiTy env ty)
- (a) the substitution, env, must cover all free tyvars of the type, ty
- (b) the free vars of the range of the substitution must be
- different than any of the forall'd variables in the type, ty
-The latter assumption is reasonable because, after all, ty has a different
-type to the range of the substitution.
+@tidyOpenType@ grabs the free type varibles, tidies them
+and then uses @tidyType@ to work over the type itself
\begin{code}
-substFlexiTy :: GenTyVarSubst flexi2 -> GenType flexi1 -> GenType flexi2
-substFlexiTy env ty = go ty
+tidyOpenType :: TidyEnv -> Type -> (TidyEnv, Type)
+tidyOpenType env ty
+ = (env', tidyType env' ty)
where
- go (TyVarTy tv) = case lookupVarEnv env tv of
- Just ty -> ty
- Nothing -> pprPanic "substFlexiTy" (ppr tv)
- go (TyConApp tc tys) = TyConApp tc (map go tys)
- go (NoteTy (SynNote ty1) ty2) = NoteTy (SynNote (go ty1)) (go ty2)
- go (NoteTy (FTVNote _) ty2) = go ty2 -- Discard free tyvar note
- go (FunTy arg res) = FunTy (go arg) (go res)
- go (AppTy fun arg) = mkAppTy (go fun) (go arg)
- go (ForAllTy tv ty) = ForAllTy tv' (substFlexiTy env' ty)
- where
- tv' = removeTyVarFlexi tv
- env' = extendVarEnv env tv (TyVarTy tv')
-
-substFlexiTheta :: GenTyVarSubst flexi2 -> [(Class, [GenType flexi1])]
- -> [(Class, [GenType flexi2])]
-substFlexiTheta env theta = [(clas, map (substFlexiTy env) tys) | (clas,tys) <- theta]
+ env' = foldl go env (varSetElems (tyVarsOfType ty))
+ go env tyvar = fst (tidyTyVar env tyvar)
+
+tidyOpenTypes :: TidyEnv -> [Type] -> (TidyEnv, [Type])
+tidyOpenTypes env tys = mapAccumL tidyOpenType env tys
+
+tidyTopType :: Type -> Type
+tidyTopType ty = tidyType emptyTidyEnv ty
\end{code}
%************************************************************************
\begin{code}
-isUnboxedType :: GenType flexi -> Bool
+isUnboxedType :: Type -> Bool
isUnboxedType ty = not (isFollowableRep (typePrimRep ty))
-isUnLiftedType :: GenType flexi -> Bool
+isUnLiftedType :: Type -> Bool
isUnLiftedType ty = case splitTyConApp_maybe ty of
Just (tc, ty_args) -> isUnLiftedTyCon tc
other -> False
-isUnboxedTupleType :: GenType flexi -> Bool
+isUnboxedTupleType :: Type -> Bool
isUnboxedTupleType ty = case splitTyConApp_maybe ty of
Just (tc, ty_args) -> isUnboxedTupleTyCon tc
other -> False
-isAlgType :: GenType flexi -> Bool
+-- Should only be applied to *types*; hence the assert
+isAlgType :: Type -> Bool
isAlgType ty = case splitTyConApp_maybe ty of
- Just (tc, ty_args) -> isAlgTyCon tc
+ Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
+ isAlgTyCon tc
+ other -> False
+
+-- Should only be applied to *types*; hence the assert
+isDataType :: Type -> Bool
+isDataType ty = case splitTyConApp_maybe ty of
+ Just (tc, ty_args) -> ASSERT( length ty_args == tyConArity tc )
+ isDataTyCon tc
other -> False
-typePrimRep :: GenType flexi -> PrimRep
+typePrimRep :: Type -> PrimRep
typePrimRep ty = case splitTyConApp_maybe ty of
Just (tc, ty_args) -> tyConPrimRep tc
other -> PtrRep
there are embedded for-alls.
\begin{code}
-instance Eq (GenType flexi) where
+instance Eq Type where
ty1 == ty2 = case ty1 `cmpTy` ty2 of { EQ -> True; other -> False }
-instance Ord (GenType flexi) where
+instance Ord Type where
compare ty1 ty2 = cmpTy ty1 ty2
-cmpTy :: GenType flexi -> GenType flexi -> Ordering
+cmpTy :: Type -> Type -> Ordering
cmpTy ty1 ty2
= cmp emptyVarEnv ty1 ty2
where
\end{code}
-
-%************************************************************************
-%* *
-\subsection{Grime}
-%* *
-%************************************************************************
-
-
-
-\begin{code}
-showTypeCategory :: Type -> Char
- {-
- {C,I,F,D} char, int, float, double
- T tuple
- S other single-constructor type
- {c,i,f,d} unboxed ditto
- t *unpacked* tuple
- s *unpacked" single-cons...
-
- v void#
- a primitive array
-
- E enumeration type
- + dictionary, unless it's a ...
- L List
- > function
- M other (multi-constructor) data-con type
- . other type
- - reserved for others to mark as "uninteresting"
- -}
-showTypeCategory ty
- = if isDictTy ty
- then '+'
- else
- case splitTyConApp_maybe ty of
- Nothing -> if maybeToBool (splitFunTy_maybe ty)
- then '>'
- else '.'
-
- Just (tycon, _) ->
- let utc = getUnique tycon in
- if utc == charDataConKey then 'C'
- else if utc == intDataConKey then 'I'
- else if utc == floatDataConKey then 'F'
- else if utc == doubleDataConKey then 'D'
- else if utc == integerDataConKey then 'J'
- else if utc == charPrimTyConKey then 'c'
- else if (utc == intPrimTyConKey || utc == wordPrimTyConKey
- || utc == addrPrimTyConKey) then 'i'
- else if utc == floatPrimTyConKey then 'f'
- else if utc == doublePrimTyConKey then 'd'
- else if isPrimTyCon tycon {- array, we hope -} then 'A'
- else if isEnumerationTyCon tycon then 'E'
- else if isTupleTyCon tycon then 'T'
- else if maybeToBool (maybeTyConSingleCon tycon) then 'S'
- else if utc == listTyConKey then 'L'
- else 'M' -- oh, well...
-\end{code}
projects / ghc-hetmet.git / blobdiff