Type, PredType, ThetaType,
Kind, TyVarSubst,
- TyThing(..), isTyClThing,
-
superKind, superBoxity, -- KX and BX respectively
liftedBoxity, unliftedBoxity, -- :: BX
openKindCon, -- :: KX
isTypeKind, isAnyTypeKind,
funTyCon,
- usageKindCon, -- :: KX
- usageTypeKind, -- :: KX
- usOnceTyCon, usManyTyCon, -- :: $
- usOnce, usMany, -- :: $
-
-- exports from this module:
hasMoreBoxityInfo, defaultKind,
tidyTopType, tidyPred,
-- Comparison
- eqType, eqKind, eqUsage,
+ eqType, eqKind,
-- Seq
seqType, seqTypes
import SrcLoc ( noSrcLoc )
import PrimRep ( PrimRep(..) )
import Unique ( Uniquable(..) )
-import Util ( mapAccumL, seqList, lengthIs )
+import Util ( mapAccumL, seqList, lengthIs, snocView )
import Outputable
import UniqSet ( sizeUniqSet ) -- Should come via VarSet
import Maybe ( isJust )
%************************************************************************
%* *
- TyThing
-%* *
-%************************************************************************
-
-\begin{code}
-data TyThing = AnId Id
- | ATyCon TyCon
- | AClass Class
-
-isTyClThing :: TyThing -> Bool
-isTyClThing (ATyCon _) = True
-isTyClThing (AClass _) = True
-isTyClThing (AnId _) = False
-
-instance NamedThing TyThing where
- getName (AnId id) = getName id
- getName (ATyCon tc) = getName tc
- getName (AClass cl) = getName cl
-\end{code}
-
-
-%************************************************************************
-%* *
\subsection{Stuff to do with kinds.}
%* *
%************************************************************************
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 (SourceTy p) = splitAppTy_maybe (sourceTypeRep p)
-splitAppTy_maybe (TyConApp tc []) = Nothing
-splitAppTy_maybe (TyConApp tc tys) = split tys []
- where
- split [ty2] acc = Just (TyConApp tc (reverse acc), ty2)
- split (ty:tys) acc = split tys (ty:acc)
-
-splitAppTy_maybe other = Nothing
+splitAppTy_maybe (SourceTy p) = splitAppTy_maybe (sourceTypeRep p)
+splitAppTy_maybe (TyConApp tc tys) = case snocView tys of
+ Nothing -> Nothing
+ Just (tys',ty') -> Just (TyConApp tc tys', ty')
+splitAppTy_maybe other = Nothing
splitAppTy :: Type -> (Type, Type)
splitAppTy ty = case splitAppTy_maybe ty of
where
split orig_ty (AppTy ty arg) args = split ty ty (arg:args)
split orig_ty (NoteTy _ ty) args = split orig_ty ty args
- split orig_ty (SourceTy p) args = split orig_ty (sourceTypeRep p) args
+ split orig_ty (SourceTy p) args = split orig_ty (sourceTypeRep p) args
split orig_ty (FunTy ty1 ty2) args = ASSERT( null args )
(TyConApp funTyCon [], [ty1,ty2])
split orig_ty (TyConApp tc tc_args) args = (TyConApp tc [], tc_args ++ args)
-- (mkPiType now in CoreUtils)
-Applying a for-all to its arguments. Lift usage annotation as required.
+applyTy, applyTys
+~~~~~~~~~~~~~~~~~
+Instantiate a for-all type with one or more type arguments.
+Used when we have a polymorphic function applied to type args:
+ f t1 t2
+Then we use (applyTys type-of-f [t1,t2]) to compute the type of
+the expression.
\begin{code}
applyTy :: Type -> Type -> Type
applyTy other arg = panic "applyTy"
applyTys :: Type -> [Type] -> Type
-applyTys orig_fun_ty arg_tys
- = substTyWith tvs arg_tys ty
- where
- (tvs, ty) = split orig_fun_ty arg_tys
-
- split fun_ty [] = ([], fun_ty)
- split (NoteTy _ fun_ty) args = split fun_ty args
- split (SourceTy p) args = split (sourceTypeRep p) args
- split (ForAllTy tv fun_ty) (arg:args) = case split fun_ty args of
- (tvs, ty) -> (tv:tvs, ty)
- split other_ty args = panic "applyTys"
- -- No show instance for Type yet
+-- This function is interesting because
+-- a) the function may have more for-alls than there are args
+-- b) less obviously, it may have fewer for-alls
+-- For case (b) think of
+-- applyTys (forall a.a) [forall b.b, Int]
+-- This really can happen, via dressing up polymorphic types with newtype
+-- clothing. Here's an example:
+-- newtype R = R (forall a. a->a)
+-- foo = case undefined :: R of
+-- R f -> f ()
+
+applyTys orig_fun_ty [] = orig_fun_ty
+applyTys orig_fun_ty arg_tys
+ | n_tvs == n_args -- The vastly common case
+ = substTyWith tvs arg_tys rho_ty
+ | n_tvs > n_args -- Too many for-alls
+ = substTyWith (take n_args tvs) arg_tys
+ (mkForAllTys (drop n_args tvs) rho_ty)
+ | otherwise -- Too many type args
+ = ASSERT2( n_tvs > 0, pprType orig_fun_ty ) -- Zero case gives infnite loop!
+ applyTys (substTyWith tvs (take n_tvs arg_tys) rho_ty)
+ (drop n_tvs arg_tys)
+ where
+ (tvs, rho_ty) = splitForAllTys orig_fun_ty
+ n_tvs = length tvs
+ n_args = length arg_tys
\end{code}
\begin{code}
eqType t1 t2 = eq_ty emptyVarEnv t1 t2
eqKind = eqType -- No worries about looking
-eqUsage = eqType -- through source types for these two
-- Look through Notes
eq_ty env (NoteTy _ t1) t2 = eq_ty env t1 t2
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