\begin{code}
module HsTypes (
- HsType(..), MonoUsageAnn(..), HsTyVar(..),
- HsContext, HsClassAssertion, HsPred(..)
+ HsType(..), HsUsageAnn(..), HsTyVarBndr(..),
+ , HsContext, HsPred(..)
+ , HsTupCon(..), hsTupParens, mkHsTupCon,
- , mkHsForAllTy, mkHsUsForAllTy
+ , mkHsForAllTy, mkHsUsForAllTy, mkHsDictTy, mkHsIParamTy
, getTyVarName, replaceTyVarName
- , pprParendHsType
- , pprForAll, pprHsContext, pprHsClassAssertion, pprHsPred
- , cmpHsType, cmpHsTypes, cmpHsContext, cmpHsPred
+
+ -- Printing
+ , pprParendHsType, pprHsForAll, pprHsContext, pprHsTyVarBndr
+
+ -- Equality over Hs things
+ , EqHsEnv, emptyEqHsEnv, extendEqHsEnv,
+ , eqWithHsTyVars, eq_hsVar, eq_hsVars, eq_hsType, eq_hsContext, eqListBy
+
+ -- Converting from Type to HsType
+ , toHsType, toHsTyVar, toHsTyVars, toHsContext, toHsFDs
) where
#include "HsVersions.h"
-import Type ( Kind, UsageAnn(..) )
-import PprType ( {- instance Outputable Kind -} )
+import Class ( FunDep )
+import Type ( Type, Kind, PredType(..), UsageAnn(..), ClassContext,
+ getTyVar_maybe, splitFunTy_maybe, splitAppTy_maybe,
+ splitTyConApp_maybe, splitPredTy_maybe,
+ splitUsgTy, splitSigmaTy, unUsgTy, boxedTypeKind
+ )
+import TypeRep ( Type(..), TyNote(..) ) -- toHsType sees the representation
+import TyCon ( isTupleTyCon, tupleTyConBoxity, tyConArity, tyConClass_maybe )
+import PrelInfo ( mkTupConRdrName )
+import RdrName ( RdrName )
+import Name ( toRdrName )
+import OccName ( NameSpace )
+import Var ( TyVar, tyVarKind )
+import PprType ( {- instance Outputable Kind -}, pprParendKind )
+import BasicTypes ( Arity, Boxity(..), tupleParens )
+import Unique ( hasKey, listTyConKey, Uniquable(..) )
+import Maybes ( maybeToBool )
+import FiniteMap
import Outputable
-import Util ( thenCmp, cmpList )
\end{code}
This is the syntax for types as seen in type signatures.
\begin{code}
type HsContext name = [HsPred name]
-type HsClassAssertion name = (name, [HsType name])
--- The type is usually a type variable, but it
--- doesn't have to be when reading interface files
-data HsPred name =
- HsPClass name [HsType name]
- | HsPIParam name (HsType name)
+
+data HsPred name = HsPClass name [HsType name]
+ | HsPIParam name (HsType name)
data HsType name
- = HsForAllTy (Maybe [HsTyVar name]) -- Nothing for implicitly quantified signatures
- (HsContext name)
- (HsType name)
+ = HsForAllTy (Maybe [HsTyVarBndr name]) -- Nothing for implicitly quantified signatures
+ (HsContext name)
+ (HsType name)
- | MonoTyVar name -- Type variable
+ | HsTyVar name -- Type variable
- | MonoTyApp (HsType name)
+ | HsAppTy (HsType name)
(HsType name)
- | MonoFunTy (HsType name) -- function type
+ | HsFunTy (HsType name) -- function type
(HsType name)
- | MonoListTy (HsType name) -- Element type
-
- | MonoTupleTy [HsType name] -- Element types (length gives arity)
- Bool -- boxed?
+ | HsListTy (HsType name) -- Element type
- | MonoIParamTy name (HsType name)
+ | HsTupleTy (HsTupCon name)
+ [HsType name] -- Element types (length gives arity)
-- these next two are only used in interfaces
- | MonoDictTy name -- Class
- [HsType name]
+ | HsPredTy (HsPred name)
- | MonoUsgTy (MonoUsageAnn name)
+ | HsUsgTy (HsUsageAnn name)
(HsType name)
- | MonoUsgForAllTy name
+ | HsUsgForAllTy name
(HsType name)
-data MonoUsageAnn name
- = MonoUsOnce
- | MonoUsMany
- | MonoUsVar name
+data HsUsageAnn name
+ = HsUsOnce
+ | HsUsMany
+ | HsUsVar name
+-----------------------
+data HsTupCon name = HsTupCon name Boxity
+
+instance Eq name => Eq (HsTupCon name) where
+ (HsTupCon _ b1) == (HsTupCon _ b2) = b1==b2
+
+mkHsTupCon :: NameSpace -> Boxity -> [a] -> HsTupCon RdrName
+mkHsTupCon space boxity args = HsTupCon (mkTupConRdrName space boxity (length args)) boxity
+
+hsTupParens :: HsTupCon name -> SDoc -> SDoc
+hsTupParens (HsTupCon _ b) p = tupleParens b p
+
+-----------------------
-- Combine adjacent for-alls.
-- The following awkward situation can happen otherwise:
-- f :: forall a. ((Num a) => Int)
(Just tvs1) `plus` (Just tvs2) = Just (tvs1 ++ tvs2)
mkHsForAllTy tvs ctxt ty = HsForAllTy tvs ctxt ty
-mkHsUsForAllTy uvs ty = foldr (\ uv ty -> MonoUsgForAllTy uv ty)
+mkHsUsForAllTy uvs ty = foldr (\ uv ty -> HsUsgForAllTy uv ty)
ty uvs
-data HsTyVar name
+mkHsDictTy cls tys = HsPredTy (HsPClass cls tys)
+mkHsIParamTy v ty = HsPredTy (HsPIParam v ty)
+
+data HsTyVarBndr name
= UserTyVar name
| IfaceTyVar name Kind
-- *** NOTA BENE *** A "monotype" in a pragma can have
getTyVarName (UserTyVar n) = n
getTyVarName (IfaceTyVar n _) = n
-replaceTyVarName :: HsTyVar name1 -> name2 -> HsTyVar name2
+replaceTyVarName :: HsTyVarBndr name1 -> name2 -> HsTyVarBndr name2
replaceTyVarName (UserTyVar n) n' = UserTyVar n'
replaceTyVarName (IfaceTyVar n k) n' = IfaceTyVar n' k
\end{code}
%************************************************************************
\begin{code}
-
instance (Outputable name) => Outputable (HsType name) where
ppr ty = pprHsType ty
-instance (Outputable name) => Outputable (HsTyVar name) where
+instance (Outputable name) => Outputable (HsTyVarBndr name) where
ppr (UserTyVar name) = ppr name
- ppr (IfaceTyVar name kind) = hsep [ppr name, dcolon, ppr kind]
+ ppr (IfaceTyVar name kind) = pprHsTyVarBndr name kind
+
+instance Outputable name => Outputable (HsPred name) where
+ ppr (HsPClass clas tys) = ppr clas <+> hsep (map pprParendHsType tys)
+ ppr (HsPIParam n ty) = hsep [{- char '?' <> -} ppr n, text "::", ppr ty]
--- Better to see those for-alls
--- pprForAll [] = empty
-pprForAll tvs = ptext SLIT("forall") <+> interppSP tvs <> ptext SLIT(".")
+pprHsTyVarBndr :: Outputable name => name -> Kind -> SDoc
+pprHsTyVarBndr name kind | kind == boxedTypeKind = ppr name
+ | otherwise = hsep [ppr name, dcolon, pprParendKind kind]
+
+pprHsForAll [] [] = empty
+pprHsForAll tvs cxt = ptext SLIT("__forall") <+> interppSP tvs <+> ppr_context cxt <+> ptext SLIT("=>")
pprHsContext :: (Outputable name) => HsContext name -> SDoc
-pprHsContext [] = empty
-pprHsContext context = parens (hsep (punctuate comma (map pprHsPred context))) <+> ptext SLIT("=>")
-
-pprHsClassAssertion :: (Outputable name) => HsClassAssertion name -> SDoc
-pprHsClassAssertion (clas, tys)
- = ppr clas <+> hsep (map pprParendHsType tys)
-
-pprHsPred :: (Outputable name) => HsPred name -> SDoc
-pprHsPred (HsPClass clas tys)
- = ppr clas <+> hsep (map pprParendHsType tys)
-pprHsPred (HsPIParam n ty)
- = hsep [{- char '?' <> -} ppr n, text "::", ppr ty]
+pprHsContext [] = empty
+pprHsContext cxt = ppr_context cxt <+> ptext SLIT("=>")
+
+ppr_context [] = empty
+ppr_context cxt = parens (interpp'SP cxt)
\end{code}
\begin{code}
ppr_mono_ty ctxt_prec (HsForAllTy maybe_tvs ctxt ty)
= maybeParen (ctxt_prec >= pREC_FUN) $
- sep [pp_tvs, pprHsContext ctxt, pprHsType ty]
+ sep [pp_header, pprHsType ty]
where
- pp_tvs = case maybe_tvs of
- Just tvs -> pprForAll tvs
- Nothing -> text "{- implicit forall -}"
+ pp_header = case maybe_tvs of
+ Just tvs -> pprHsForAll tvs ctxt
+ Nothing -> pprHsContext ctxt
-ppr_mono_ty ctxt_prec (MonoTyVar name)
+ppr_mono_ty ctxt_prec (HsTyVar name)
= ppr name
-ppr_mono_ty ctxt_prec (MonoFunTy ty1 ty2)
+ppr_mono_ty ctxt_prec (HsFunTy ty1 ty2)
= let p1 = ppr_mono_ty pREC_FUN ty1
p2 = ppr_mono_ty pREC_TOP ty2
in
maybeParen (ctxt_prec >= pREC_FUN)
(sep [p1, (<>) (ptext SLIT("-> ")) p2])
-ppr_mono_ty ctxt_prec (MonoTupleTy tys True)
- = parens (sep (punctuate comma (map ppr tys)))
-ppr_mono_ty ctxt_prec (MonoTupleTy tys False)
- = ptext SLIT("(#") <> sep (punctuate comma (map ppr tys)) <> ptext SLIT("#)")
+ppr_mono_ty ctxt_prec (HsTupleTy con tys) = hsTupParens con (interpp'SP tys)
+ppr_mono_ty ctxt_prec (HsListTy ty) = brackets (ppr_mono_ty pREC_TOP ty)
-ppr_mono_ty ctxt_prec (MonoListTy ty)
- = brackets (ppr_mono_ty pREC_TOP ty)
-
-ppr_mono_ty ctxt_prec (MonoTyApp fun_ty arg_ty)
+ppr_mono_ty ctxt_prec (HsAppTy fun_ty arg_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 (MonoIParamTy n ty)
- = hsep [{- char '?' <> -} ppr n, text "::", ppr_mono_ty pREC_TOP ty]
-
-ppr_mono_ty ctxt_prec (MonoDictTy clas tys)
- = ppr clas <+> hsep (map (ppr_mono_ty pREC_CON) tys)
-
-ppr_mono_ty ctxt_prec ty@(MonoUsgForAllTy _ _)
+ppr_mono_ty ctxt_prec (HsPredTy pred)
= maybeParen (ctxt_prec >= pREC_FUN) $
+ braces (ppr pred)
+
+ppr_mono_ty ctxt_prec ty@(HsUsgForAllTy _ _)
+ =
sep [ ptext SLIT("__fuall") <+> brackets pp_uvars <+> ptext SLIT("=>"),
ppr_mono_ty pREC_TOP sigma
]
(uvars,sigma) = split [] ty
pp_uvars = interppSP uvars
- split uvs (MonoUsgForAllTy uv ty') = split (uv:uvs) ty'
+ split uvs (HsUsgForAllTy uv ty') = split (uv:uvs) ty'
split uvs ty' = (reverse uvs,ty')
-ppr_mono_ty ctxt_prec (MonoUsgTy u ty)
+ppr_mono_ty ctxt_prec (HsUsgTy u ty)
= maybeParen (ctxt_prec >= pREC_CON) $
ptext SLIT("__u") <+> pp_ua <+> ppr_mono_ty pREC_CON ty
where
pp_ua = case u of
- MonoUsOnce -> ptext SLIT("-")
- MonoUsMany -> ptext SLIT("!")
- MonoUsVar uv -> ppr uv
+ HsUsOnce -> ptext SLIT("-")
+ HsUsMany -> ptext SLIT("!")
+ HsUsVar uv -> ppr uv
+\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 RdrName
+toHsTyVar tv = IfaceTyVar (toRdrName tv) (tyVarKind tv)
+
+toHsTyVars tvs = map toHsTyVar tvs
+
+toHsType :: Type -> HsType RdrName
+toHsType ty = toHsType' (unUsgTy ty)
+ -- For now we just discard the usage
+-- = case splitUsgTy ty of
+-- (usg, tau) -> HsUsgTy (toHsUsg usg) (toHsType' tau)
+
+toHsType' :: Type -> HsType RdrName
+-- Called after the usage is stripped off
+-- This function knows the representation of types
+toHsType' (TyVarTy tv) = HsTyVar (toRdrName tv)
+toHsType' (FunTy arg res) = HsFunTy (toHsType arg) (toHsType res)
+toHsType' (AppTy fun arg) = HsAppTy (toHsType fun) (toHsType arg)
+
+toHsType' (NoteTy (SynNote ty) _) = toHsType ty -- Use synonyms if possible!!
+toHsType' (NoteTy _ ty) = toHsType ty
+
+toHsType' ty@(TyConApp tc tys) -- Must be saturated because toHsType's arg is of kind *
+ | not saturated = generic_case
+ | isTupleTyCon tc = HsTupleTy (HsTupCon (toRdrName tc) (tupleTyConBoxity tc)) tys'
+ | tc `hasKey` listTyConKey = HsListTy (head tys')
+ | maybeToBool maybe_class = HsPredTy (HsPClass (toRdrName clas) tys')
+ | otherwise = generic_case
+ where
+ generic_case = foldl HsAppTy (HsTyVar (toRdrName tc)) tys'
+ maybe_class = tyConClass_maybe tc
+ Just clas = maybe_class
+ tys' = map toHsType tys
+ saturated = length tys == tyConArity tc
+
+toHsType' ty@(ForAllTy _ _) = case splitSigmaTy ty of
+ (tvs, preds, tau) -> HsForAllTy (Just (map toHsTyVar tvs))
+ (map toHsPred preds)
+ (toHsType tau)
+
+
+toHsPred (Class cls tys) = HsPClass (toRdrName cls) (map toHsType tys)
+toHsPred (IParam n ty) = HsPIParam (toRdrName n) (toHsType ty)
+
+toHsContext :: ClassContext -> HsContext RdrName
+toHsContext cxt = [HsPClass (toRdrName cls) (map toHsType tys) | (cls,tys) <- cxt]
+
+toHsUsg UsOnce = HsUsOnce
+toHsUsg UsMany = HsUsMany
+toHsUsg (UsVar v) = HsUsVar (toRdrName v)
+
+toHsFDs :: [FunDep TyVar] -> [FunDep RdrName]
+toHsFDs fds = [(map toRdrName ns, map toRdrName ms) | (ns,ms) <- fds]
\end{code}
%* *
%************************************************************************
+\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. Most any other use is likely to be {\em
-wrong}, so be careful!
+in checking interfaces.
\begin{code}
-cmpHsTyVar :: (a -> a -> Ordering) -> HsTyVar a -> HsTyVar a -> Ordering
-cmpHsType :: (a -> a -> Ordering) -> HsType a -> HsType a -> Ordering
-cmpHsTypes :: (a -> a -> Ordering) -> [HsType a] -> [HsType a] -> Ordering
-cmpHsContext :: (a -> a -> Ordering) -> HsContext a -> HsContext a -> Ordering
-cmpHsPred :: (a -> a -> Ordering) -> HsPred a -> HsPred a -> Ordering
+-------------------
+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 == 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}
-cmpHsTyVar cmp (UserTyVar v1) (UserTyVar v2) = v1 `cmp` v2
-cmpHsTyVar cmp (IfaceTyVar v1 _) (IfaceTyVar v2 _) = v1 `cmp` v2
-cmpHsTyVar cmp (UserTyVar _) other = LT
-cmpHsTyVar cmp other1 other2 = GT
+\begin{code}
+-------------------
+eq_hsTypes env = eqListBy (eq_hsType env)
-cmpHsTypes cmp [] [] = EQ
-cmpHsTypes cmp [] tys2 = LT
-cmpHsTypes cmp tys1 [] = GT
-cmpHsTypes cmp (ty1:tys1) (ty2:tys2) = cmpHsType cmp ty1 ty2 `thenCmp` cmpHsTypes cmp tys1 tys2
+-------------------
+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
-cmpHsType cmp (HsForAllTy tvs1 c1 t1) (HsForAllTy tvs2 c2 t2)
- = cmpMaybe (cmpList (cmpHsTyVar cmp)) tvs1 tvs2 `thenCmp`
- cmpHsContext cmp c1 c2 `thenCmp`
- cmpHsType cmp t1 t2
+eq_hsType env (HsTyVar n1) (HsTyVar n2)
+ = eq_hsVar env n1 n2
-cmpHsType cmp (MonoTyVar n1) (MonoTyVar n2)
- = cmp n1 n2
+eq_hsType env (HsTupleTy c1 tys1) (HsTupleTy c2 tys2)
+ = (c1 == c2) && eq_hsTypes env tys1 tys2
-cmpHsType cmp (MonoTupleTy tys1 b1) (MonoTupleTy tys2 b2)
- = (b1 `compare` b2) `thenCmp` cmpHsTypes cmp tys1 tys2
+eq_hsType env (HsListTy ty1) (HsListTy ty2)
+ = eq_hsType env ty1 ty2
-cmpHsType cmp (MonoListTy ty1) (MonoListTy ty2)
- = cmpHsType cmp 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
-cmpHsType cmp (MonoTyApp fun_ty1 arg_ty1) (MonoTyApp fun_ty2 arg_ty2)
- = cmpHsType cmp fun_ty1 fun_ty2 `thenCmp` cmpHsType cmp arg_ty1 arg_ty2
+eq_hsType env (HsFunTy a1 b1) (HsFunTy a2 b2)
+ = eq_hsType env a1 a2 && eq_hsType env b1 b2
-cmpHsType cmp (MonoFunTy a1 b1) (MonoFunTy a2 b2)
- = cmpHsType cmp a1 a2 `thenCmp` cmpHsType cmp b1 b2
+eq_hsType env (HsPredTy p1) (HsPredTy p2)
+ = eq_hsPred env p1 p2
-cmpHsType cmp (MonoDictTy c1 tys1) (MonoDictTy c2 tys2)
- = cmp c1 c2 `thenCmp` cmpHsTypes cmp tys1 tys2
+eq_hsType env (HsUsgTy u1 ty1) (HsUsgTy u2 ty2)
+ = eqUsg u1 u2 && eq_hsType env ty1 ty2
-cmpHsType cmp (MonoUsgTy u1 ty1) (MonoUsgTy u2 ty2)
- = cmpUsg cmp u1 u2 `thenCmp` cmpHsType cmp ty1 ty2
+eq_hsType env ty1 ty2 = False
-cmpHsType cmp ty1 ty2 -- tags must be different
- = let tag1 = tag ty1
- tag2 = tag ty2
- in
- if tag1 _LT_ tag2 then LT else GT
- where
- tag (MonoTyVar n1) = (ILIT(1) :: FAST_INT)
- tag (MonoTupleTy tys1 _) = ILIT(2)
- tag (MonoListTy ty1) = ILIT(3)
- tag (MonoTyApp tc1 tys1) = ILIT(4)
- tag (MonoFunTy a1 b1) = ILIT(5)
- tag (MonoDictTy c1 tys1) = ILIT(6)
- tag (MonoUsgTy c1 ty1) = ILIT(7)
- tag (MonoUsgForAllTy uv1 ty1) = ILIT(8)
- tag (HsForAllTy _ _ _) = ILIT(9)
-------------------
-cmpHsContext cmp a b
- = cmpList (cmpHsPred cmp) a b
-
-cmpHsPred cmp (HsPClass c1 tys1) (HsPClass c2 tys2)
- = cmp c1 c2 `thenCmp` cmpHsTypes cmp tys1 tys2
-cmpHsPred cmp (HsPIParam n1 ty1) (HsPIParam n2 ty2)
- = cmp n1 n2 `thenCmp` cmpHsType cmp ty1 ty2
-cmpHsPred cmp (HsPClass _ _) (HsPIParam _ _) = LT
-cmpHsPred cmp _ _ = GT
-
-cmpUsg cmp MonoUsOnce MonoUsOnce = EQ
-cmpUsg cmp MonoUsMany MonoUsMany = EQ
-cmpUsg cmp (MonoUsVar u1) (MonoUsVar u2) = cmp u1 u2
-
-cmpUsg cmp ua1 ua2 -- tags must be different
- = let tag1 = tag ua1
- tag2 = tag ua2
- in
- if tag1 _LT_ tag2 then LT else GT
- where
- tag MonoUsOnce = (ILIT(1) :: FAST_INT)
- tag MonoUsMany = ILIT(2)
- tag (MonoUsVar _) = ILIT(3)
-
--- Should be in Maybes, I guess
-cmpMaybe cmp Nothing Nothing = EQ
-cmpMaybe cmp Nothing (Just x) = LT
-cmpMaybe cmp (Just x) Nothing = GT
-cmpMaybe cmp (Just x) (Just y) = x `cmp` y
+eq_hsContext env a b = eqListBy (eq_hsPred env) a b
+
+-------------------
+eq_hsPred env (HsPClass c1 tys1) (HsPClass c2 tys2)
+ = c1 == c2 && eq_hsTypes env tys1 tys2
+eq_hsPred env (HsPIParam n1 ty1) (HsPIParam n2 ty2)
+ = n1 == n2 && eq_hsType env ty1 ty2
+eq_hsPred env _ _ = False
+
+-------------------
+eqUsg HsUsOnce HsUsOnce = True
+eqUsg HsUsMany HsUsMany = True
+eqUsg (HsUsVar u1) (HsUsVar u2) = u1 == u2
+eqUsg _ _ = False
+
+-------------------
+eqListBy :: (a->a->Bool) -> [a] -> [a] -> Bool
+eqListBy eq [] [] = True
+eqListBy eq (x:xs) (y:ys) = eq x y && eqListBy eq xs ys
+eqListBy eq xs ys = False
\end{code}
projects / ghc-hetmet.git / blobdiff