-%
+]%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[HsTypes]{Abstract syntax: user-defined types}
\begin{code}
module HsTypes (
- HsType(..), HsTyVarBndr(..), HsTyOp(..),
+ HsType(..), HsTyVarBndr(..),
, HsContext, HsPred(..)
- , HsTupCon(..), hsTupParens, mkHsTupCon,
, mkHsForAllTy, mkHsDictTy, mkHsIParamTy
, hsTyVarName, hsTyVarNames, replaceTyVarName
-- Printing
, pprParendHsType, pprHsForAll, pprHsContext, ppr_hs_context, pprHsTyVarBndr
-
- -- Equality over Hs things
- , EqHsEnv, emptyEqHsEnv, extendEqHsEnv,
- , eqWithHsTyVars, eq_hsVar, eq_hsVars, eq_hsTyVars, eq_hsType, eq_hsContext, eqListBy
-
- -- Converting from Type to HsType
- , toHsType, toHsTyVar, toHsTyVars, toHsContext, toHsFDs
) where
#include "HsVersions.h"
-import Class ( FunDep )
-import TcType ( Type, Kind, ThetaType, SourceType(..),
- tcSplitSigmaTy, liftedTypeKind, eqKind, tcEqType
- )
-import TypeRep ( Type(..), TyNote(..) ) -- toHsType sees the representation
-import TyCon ( isTupleTyCon, tupleTyConBoxity, tyConArity, isNewTyCon, getSynTyConDefn )
-import RdrName ( mkUnqual )
-import Name ( Name, getName, mkInternalName )
-import OccName ( NameSpace, mkVarOcc, tvName )
-import Var ( TyVar, tyVarKind )
-import Subst ( substTyWith )
+import TcType ( Type, Kind, liftedTypeKind, eqKind )
+import TypeRep ( Type )
+import Name ( Name, mkInternalName )
+import OccName ( mkVarOcc )
import PprType ( {- instance Outputable Kind -}, pprParendKind, pprKind )
-import BasicTypes ( Boxity(..), Arity, IPName, tupleParens )
-import PrelNames ( listTyConKey, parrTyConKey,
- hasKey, unboundKey )
+import BasicTypes ( IPName, Boxity, tupleParens )
+import PrelNames ( unboundKey )
import SrcLoc ( noSrcLoc )
-import Util ( eqListBy, lengthIs )
-import FiniteMap
import Outputable
\end{code}
| HsPArrTy (HsType name) -- Elem. type of parallel array: [:t:]
- | HsTupleTy HsTupCon
+ | HsTupleTy Boxity
[HsType name] -- Element types (length gives arity)
- | HsOpTy (HsType name) (HsTyOp name) (HsType name)
+ | HsOpTy (HsType name) name (HsType name)
| HsParTy (HsType name)
-- Parenthesis preserved for the precedence re-arrangement in RnTypes
Kind -- A type with a kind signature
-data HsTyOp name = HsArrow | HsTyOp name
- -- Function arrows from *source* get read in as HsOpTy t1 HsArrow t2
- -- But when we generate or parse interface files, we use HsFunTy.
- -- This keeps interfaces a bit smaller, because there are a lot of arrows
-
------------------------
-data HsTupCon = HsTupCon Boxity Arity
-
-instance Eq HsTupCon where
- (HsTupCon b1 a1) == (HsTupCon b2 a2) = b1==b2 && a1==a2
-
-mkHsTupCon :: NameSpace -> Boxity -> [a] -> HsTupCon
-mkHsTupCon space boxity args = HsTupCon boxity (length args)
-
-hsTupParens :: HsTupCon -> SDoc -> SDoc
-hsTupParens (HsTupCon b _) p = tupleParens b p
-
-----------------------
-- Combine adjacent for-alls.
-- The following awkward situation can happen otherwise:
data HsTyVarBndr name
= UserTyVar name
- | IfaceTyVar name Kind
+ | KindedTyVar name Kind
-- *** NOTA BENE *** A "monotype" in a pragma can have
-- for-alls in it, (mostly to do with dictionaries). These
-- must be explicitly Kinded.
-hsTyVarName (UserTyVar n) = n
-hsTyVarName (IfaceTyVar n _) = n
+hsTyVarName (UserTyVar n) = n
+hsTyVarName (KindedTyVar n _) = n
hsTyVarNames tvs = map hsTyVarName tvs
replaceTyVarName :: HsTyVarBndr name1 -> name2 -> HsTyVarBndr name2
-replaceTyVarName (UserTyVar n) n' = UserTyVar n'
-replaceTyVarName (IfaceTyVar n k) n' = IfaceTyVar n' k
+replaceTyVarName (UserTyVar n) n' = UserTyVar n'
+replaceTyVarName (KindedTyVar n k) n' = KindedTyVar n' k
\end{code}
instance (Outputable name) => Outputable (HsType name) where
ppr ty = pprHsType ty
-instance (Outputable name) => Outputable (HsTyOp name) where
- ppr HsArrow = ftext FSLIT("->")
- ppr (HsTyOp n) = ppr n
-
instance (Outputable name) => Outputable (HsTyVarBndr name) where
- ppr (UserTyVar name) = ppr name
- ppr (IfaceTyVar name kind) = pprHsTyVarBndr name kind
+ ppr (UserTyVar name) = ppr name
+ ppr (KindedTyVar name kind) = pprHsTyVarBndr name kind
instance Outputable name => Outputable (HsPred name) where
ppr (HsClassP clas tys) = ppr clas <+> hsep (map pprParendHsType tys)
ppr_mono_ty ctxt_prec (HsTyVar name) = ppr name
ppr_mono_ty ctxt_prec (HsFunTy ty1 ty2) = ppr_fun_ty ctxt_prec ty1 ty2
-ppr_mono_ty ctxt_prec (HsTupleTy con tys) = hsTupParens con (interpp'SP tys)
+ppr_mono_ty ctxt_prec (HsTupleTy con tys) = tupleParens con (interpp'SP tys)
ppr_mono_ty ctxt_prec (HsKindSig ty kind) = parens (ppr_mono_ty pREC_TOP ty <+> dcolon <+> pprKind kind)
ppr_mono_ty ctxt_prec (HsListTy ty) = brackets (ppr_mono_ty pREC_TOP ty)
ppr_mono_ty ctxt_prec (HsPArrTy ty) = pabrackets (ppr_mono_ty pREC_TOP ty)
= maybeParen ctxt_prec pREC_CON $
hsep [ppr_mono_ty pREC_FUN fun_ty, ppr_mono_ty pREC_CON arg_ty]
-ppr_mono_ty ctxt_prec (HsOpTy ty1 HsArrow ty2)
- = ppr_fun_ty ctxt_prec ty1 ty2
-
ppr_mono_ty ctxt_prec (HsOpTy ty1 op ty2)
= maybeParen ctxt_prec pREC_OP $
ppr_mono_ty pREC_OP ty1 <+> ppr op <+> ppr_mono_ty pREC_OP ty2
\end{code}
-%************************************************************************
-%* *
-\subsection{Converting from Type to HsType}
-%* *
-%************************************************************************
-
-@toHsType@ converts from a Type to a HsType, making the latter look as
-user-friendly as possible. Notably, it uses synonyms where possible, and
-expresses overloaded functions using the '=>' context part of a HsForAllTy.
-
-\begin{code}
-toHsTyVar :: TyVar -> HsTyVarBndr Name
-toHsTyVar tv = IfaceTyVar (getName tv) (tyVarKind tv)
-
-toHsTyVars tvs = map toHsTyVar tvs
-
-toHsType :: Type -> HsType Name
--- This function knows the representation of types
-toHsType (TyVarTy tv) = HsTyVar (getName tv)
-toHsType (FunTy arg res) = HsFunTy (toHsType arg) (toHsType res)
-toHsType (AppTy fun arg) = HsAppTy (toHsType fun) (toHsType arg)
-
-toHsType (NoteTy (SynNote ty@(TyConApp tycon tyargs)) real_ty)
- | isNewTyCon tycon = toHsType ty
- | syn_matches = toHsType ty -- Use synonyms if possible!!
- | otherwise =
-#ifdef DEBUG
- pprTrace "WARNING: synonym info lost in .hi file for " (ppr syn_ty) $
-#endif
- toHsType real_ty -- but drop it if not.
- where
- syn_matches = ty_from_syn `tcEqType` real_ty
- (tyvars,syn_ty) = getSynTyConDefn tycon
- ty_from_syn = substTyWith tyvars tyargs syn_ty
-
- -- We only use the type synonym in the file if this doesn't cause
- -- us to lose important information. This matters for usage
- -- annotations. It's an issue if some of the args to the synonym
- -- have arrows in them, or if the synonym's RHS has an arrow; for
- -- example, with nofib/real/ebnf2ps/ in Parsers.using.
-
- -- **! It would be nice if when this test fails we could still
- -- write the synonym in as a Note, so we don't lose the info for
- -- error messages, but it's too much work for right now.
- -- KSW 2000-07.
-
-toHsType (NoteTy _ ty) = toHsType ty
-
-toHsType (SourceTy (NType tc tys)) = foldl HsAppTy (HsTyVar (getName tc)) (map toHsType tys)
-toHsType (SourceTy pred) = HsPredTy (toHsPred pred)
-
-toHsType ty@(TyConApp tc tys) -- Must be saturated because toHsType's arg is of kind *
- | not saturated = generic_case
- | isTupleTyCon tc = HsTupleTy (HsTupCon (tupleTyConBoxity tc) (tyConArity tc)) tys'
- | tc `hasKey` listTyConKey = HsListTy (head tys')
- | tc `hasKey` parrTyConKey = HsPArrTy (head tys')
- | otherwise = generic_case
- where
- generic_case = foldl HsAppTy (HsTyVar (getName tc)) tys'
- tys' = map toHsType tys
- saturated = tys `lengthIs` tyConArity tc
-
-toHsType ty@(ForAllTy _ _) = case tcSplitSigmaTy ty of
- (tvs, preds, tau) -> HsForAllTy (Just (map toHsTyVar tvs))
- (map toHsPred preds)
- (toHsType tau)
-
-toHsPred (ClassP cls tys) = HsClassP (getName cls) (map toHsType tys)
-toHsPred (IParam n ty) = HsIParam n (toHsType ty)
-
-toHsContext :: ThetaType -> HsContext Name
-toHsContext theta = map toHsPred theta
-
-toHsFDs :: [FunDep TyVar] -> [FunDep Name]
-toHsFDs fds = [(map getName ns, map getName ms) | (ns,ms) <- fds]
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Comparison}
-%* *
-%************************************************************************
-
-\begin{code}
-instance Ord a => Eq (HsType a) where
- -- The Ord is needed because we keep a
- -- finite map of variables to variables
- (==) a b = eq_hsType emptyEqHsEnv a b
-
-instance Ord a => Eq (HsPred a) where
- (==) a b = eq_hsPred emptyEqHsEnv a b
-
-eqWithHsTyVars :: Ord name =>
- [HsTyVarBndr name] -> [HsTyVarBndr name]
- -> (EqHsEnv name -> Bool) -> Bool
-eqWithHsTyVars = eq_hsTyVars emptyEqHsEnv
-\end{code}
-
-\begin{code}
-type EqHsEnv n = FiniteMap n n
--- Tracks the mapping from L-variables to R-variables
-
-eq_hsVar :: Ord n => EqHsEnv n -> n -> n -> Bool
-eq_hsVar env n1 n2 = case lookupFM env n1 of
- Just n1 -> n1 == n2
- Nothing -> n1 == n2
-
-extendEqHsEnv env n1 n2
- | n1 == n2 = env
- | otherwise = addToFM env n1 n2
-
-emptyEqHsEnv :: EqHsEnv n
-emptyEqHsEnv = emptyFM
-\end{code}
-
-We do define a specialised equality for these \tr{*Type} types; used
-in checking interfaces.
-
-\begin{code}
--------------------
-eq_hsTyVars env [] [] k = k env
-eq_hsTyVars env (tv1:tvs1) (tv2:tvs2) k = eq_hsTyVar env tv1 tv2 $ \ env ->
- eq_hsTyVars env tvs1 tvs2 k
-eq_hsTyVars env _ _ _ = False
-
-eq_hsTyVar env (UserTyVar v1) (UserTyVar v2) k = k (extendEqHsEnv env v1 v2)
-eq_hsTyVar env (IfaceTyVar v1 k1) (IfaceTyVar v2 k2) k = k1 `eqKind` k2 && k (extendEqHsEnv env v1 v2)
-eq_hsTyVar env _ _ _ = False
-
-eq_hsVars env [] [] k = k env
-eq_hsVars env (v1:bs1) (v2:bs2) k = eq_hsVars (extendEqHsEnv env v1 v2) bs1 bs2 k
-eq_hsVars env _ _ _ = False
-\end{code}
-
-\begin{code}
--------------------
-eq_hsTypes env = eqListBy (eq_hsType env)
-
--------------------
-eq_hsType env (HsForAllTy tvs1 c1 t1) (HsForAllTy tvs2 c2 t2)
- = eq_tvs tvs1 tvs2 $ \env ->
- eq_hsContext env c1 c2 &&
- eq_hsType env t1 t2
- where
- eq_tvs Nothing (Just _) k = False
- eq_tvs Nothing Nothing k = k env
- eq_tvs (Just _) Nothing k = False
- eq_tvs (Just tvs1) (Just tvs2) k = eq_hsTyVars env tvs1 tvs2 k
-
-eq_hsType env (HsTyVar n1) (HsTyVar n2)
- = eq_hsVar env n1 n2
-
-eq_hsType env (HsTupleTy c1 tys1) (HsTupleTy c2 tys2)
- = (c1 == c2) && eq_hsTypes env tys1 tys2
-
-eq_hsType env (HsListTy ty1) (HsListTy ty2)
- = eq_hsType env ty1 ty2
-
-eq_hsType env (HsKindSig ty1 k1) (HsKindSig ty2 k2)
- = eq_hsType env ty1 ty2 && k1 `eqKind` k2
-
-eq_hsType env (HsPArrTy ty1) (HsPArrTy ty2)
- = eq_hsType env ty1 ty2
-
-eq_hsType env (HsAppTy fun_ty1 arg_ty1) (HsAppTy fun_ty2 arg_ty2)
- = eq_hsType env fun_ty1 fun_ty2 && eq_hsType env arg_ty1 arg_ty2
-
-eq_hsType env (HsFunTy a1 b1) (HsFunTy a2 b2)
- = eq_hsType env a1 a2 && eq_hsType env b1 b2
-
-eq_hsType env (HsPredTy p1) (HsPredTy p2)
- = eq_hsPred env p1 p2
-
-eq_hsType env (HsOpTy lty1 op1 rty1) (HsOpTy lty2 op2 rty2)
- = eq_hsOp env op1 op2 && eq_hsType env lty1 lty2 && eq_hsType env rty1 rty2
-
-eq_hsType env ty1 ty2 = False
-
-
-eq_hsOp env (HsTyOp n1) (HsTyOp n2) = eq_hsVar env n1 n2
-eq_hsOp env HsArrow HsArrow = True
-eq_hsOp env op1 op2 = False
-
--------------------
-eq_hsContext env a b = eqListBy (eq_hsPred env) a b
-
--------------------
-eq_hsPred env (HsClassP c1 tys1) (HsClassP c2 tys2)
- = c1 == c2 && eq_hsTypes env tys1 tys2
-eq_hsPred env (HsIParam n1 ty1) (HsIParam n2 ty2)
- = n1 == n2 && eq_hsType env ty1 ty2
-eq_hsPred env _ _ = False
-\end{code}
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