-%************************************************************************
-%* *
-\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}