%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[HsTypes]{Abstract syntax: user-defined types}
you get part of GHC.
\begin{code}
-#include "HsVersions.h"
-
module HsTypes (
- PolyType(..), MonoType(..),
- Context(..), ClassAssertion(..)
-
-#ifdef COMPILING_GHC
- , pprParendMonoType, pprContext
- , extractMonoTyNames, extractCtxtTyNames
- , cmpPolyType, cmpMonoType, cmpContext
-#endif
+ HsType(..), HsTyVar(..),
+ Context, ClassAssertion
+
+ , mkHsForAllTy
+ , getTyVarName, replaceTyVarName
+ , pprParendHsType
+ , pprForAll, pprContext, pprClassAssertion
+ , cmpHsType, cmpHsTypes, cmpContext
) where
-#ifdef COMPILING_GHC
-import Ubiq
+#include "HsVersions.h"
-import Outputable ( interppSP, ifnotPprForUser )
-import Pretty
import Type ( Kind )
-import Util ( thenCmp, cmpList, isIn, panic# )
-
-#endif {- COMPILING_GHC -}
+import PprType ( {- instance Outputable Kind -} )
+import Outputable
+import Util ( thenCmp, cmpList, panic )
\end{code}
This is the syntax for types as seen in type signatures.
\begin{code}
-data PolyType name
- = HsPreForAllTy (Context name)
- (MonoType name)
+type Context name = [ClassAssertion name]
- -- The renamer turns HsPreForAllTys into HsForAllTys when they
- -- occur in signatures, to make the binding of variables
- -- explicit. This distinction is made visible for
- -- non-COMPILING_GHC code, because you probably want to do the
- -- same thing.
+type ClassAssertion name = (name, [HsType name])
+ -- The type is usually a type variable, but it
+ -- doesn't have to be when reading interface files
- | HsForAllTy [name]
+data HsType name
+ = HsForAllTy [HsTyVar name]
(Context name)
- (MonoType name)
+ (HsType name)
-type Context name = [ClassAssertion name]
-
-type ClassAssertion name = (name, name)
+ | MonoTyVar name -- Type variable
-data MonoType name
- = MonoTyVar name -- Type variable
+ | MonoTyApp (HsType name)
+ (HsType name)
- | MonoTyApp name -- Type constructor or variable
- [MonoType name]
+ | MonoFunTy (HsType name) -- function type
+ (HsType name)
- -- We *could* have a "MonoTyCon name" equiv to "MonoTyApp name []"
- -- (for efficiency, what?) WDP 96/02/18
+ | MonoListTy (HsType name) -- Element type
- | MonoFunTy (MonoType name) -- function type
- (MonoType name)
+ | MonoTupleTy [HsType name] -- Element types (length gives arity)
+ Bool -- boxed?
- | MonoListTy (MonoType name) -- list type
- | MonoTupleTy [MonoType name] -- tuple type (length gives arity)
-
-#ifdef COMPILING_GHC
-- these next two are only used in unfoldings in interfaces
| MonoDictTy name -- Class
- (MonoType name)
+ [HsType name]
+
+mkHsForAllTy [] [] ty = ty
+mkHsForAllTy tvs ctxt ty = HsForAllTy tvs ctxt ty
- | MonoForAllTy [(name, Kind)]
- (MonoType name)
+data HsTyVar name
+ = UserTyVar name
+ | IfaceTyVar 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.
-#endif {- COMPILING_GHC -}
-\end{code}
+getTyVarName (UserTyVar n) = n
+getTyVarName (IfaceTyVar n _) = n
-This is used in various places:
-\begin{code}
-#ifdef COMPILING_GHC
-pprContext :: (Outputable name) => PprStyle -> (Context name) -> Pretty
-
-pprContext sty [] = ppNil
-pprContext sty [(clas, ty)] = ppCat [ppr sty clas, ppr sty ty, ppStr "=>"]
-pprContext sty context
- = ppBesides [ppLparen,
- ppInterleave ppComma (map pp_assert context),
- ppRparen, ppStr " =>"]
- where
- pp_assert (clas, ty)
- = ppCat [ppr sty clas, ppr sty ty]
+replaceTyVarName :: HsTyVar name1 -> name2 -> HsTyVar name2
+replaceTyVarName (UserTyVar n) n' = UserTyVar n'
+replaceTyVarName (IfaceTyVar n k) n' = IfaceTyVar n' k
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Pretty printing}
+%* *
+%************************************************************************
+
\begin{code}
-instance (Outputable name) => Outputable (PolyType name) where
- ppr sty (HsPreForAllTy ctxt ty)
- = print_it sty ppNil ctxt ty
- ppr sty (HsForAllTy tvs ctxt ty)
- = print_it sty
- (ppBesides [ppStr "_forall_ ", interppSP sty tvs, ppStr " => "])
- ctxt ty
-print_it sty pp_forall ctxt ty
- = ppCat [ifnotPprForUser sty pp_forall, -- print foralls unless PprForUser
- pprContext sty ctxt, ppr sty ty]
+instance (Outputable name) => Outputable (HsType name) where
+ ppr ty = pprHsType ty
+
+instance (Outputable name) => Outputable (HsTyVar name) where
+ ppr (UserTyVar name) = ppr name
+ ppr (IfaceTyVar name kind) = hsep [ppr name, ptext SLIT("::"), ppr kind]
-instance (Outputable name) => Outputable (MonoType name) where
- ppr = pprMonoType
+pprForAll [] = empty
+pprForAll tvs = ptext SLIT("forall") <+> interppSP tvs <> ptext SLIT(".")
+pprContext :: (Outputable name) => Context name -> SDoc
+pprContext [] = empty
+pprContext context = parens (hsep (punctuate comma (map pprClassAssertion context))) <+> ptext SLIT("=>")
+
+pprClassAssertion :: (Outputable name) => ClassAssertion name -> SDoc
+pprClassAssertion (clas, tys)
+ = ppr clas <+> hsep (map ppr tys)
+\end{code}
+
+\begin{code}
pREC_TOP = (0 :: Int)
pREC_FUN = (1 :: Int)
pREC_CON = (2 :: Int)
+maybeParen :: Bool -> SDoc -> SDoc
+maybeParen True p = parens p
+maybeParen False p = p
+
-- printing works more-or-less as for Types
-pprMonoType, pprParendMonoType :: (Outputable name) => PprStyle -> MonoType name -> Pretty
+pprHsType, pprParendHsType :: (Outputable name) => HsType name -> SDoc
-pprMonoType sty ty = ppr_mono_ty sty pREC_TOP ty
-pprParendMonoType sty ty = ppr_mono_ty sty pREC_CON ty
+pprHsType ty = ppr_mono_ty pREC_TOP ty
+pprParendHsType ty = ppr_mono_ty pREC_CON ty
-ppr_mono_ty sty ctxt_prec (MonoTyVar name) = ppr sty name
+ppr_mono_ty ctxt_prec (HsForAllTy tvs ctxt ty)
+ = maybeParen (ctxt_prec >= pREC_FUN) $
+ sep [pprForAll tvs, pprContext ctxt, pprHsType ty]
-ppr_mono_ty sty ctxt_prec (MonoFunTy ty1 ty2)
- = let p1 = ppr_mono_ty sty pREC_FUN ty1
- p2 = ppr_mono_ty sty pREC_TOP ty2
- in
- if ctxt_prec < pREC_FUN then -- no parens needed
- ppSep [p1, ppBeside (ppStr "-> ") p2]
- else
- ppSep [ppBeside ppLparen p1, ppBesides [ppStr "-> ", p2, ppRparen]]
-
-ppr_mono_ty sty ctxt_prec (MonoTupleTy tys)
- = ppBesides [ppLparen, ppInterleave ppComma (map (ppr sty) tys), ppRparen]
-
-ppr_mono_ty sty ctxt_prec (MonoListTy ty)
- = ppBesides [ppLbrack, ppr_mono_ty sty pREC_TOP ty, ppRbrack]
-
-ppr_mono_ty sty ctxt_prec (MonoTyApp tycon tys)
- = let pp_tycon = ppr sty tycon in
- if null tys then
- pp_tycon
- else if ctxt_prec < pREC_CON then -- no parens needed
- ppCat [pp_tycon, ppInterleave ppNil (map (ppr_mono_ty sty pREC_CON) tys)]
- else
- ppBesides [ ppLparen, pp_tycon, ppSP,
- ppInterleave ppNil (map (ppr_mono_ty sty pREC_CON) tys), ppRparen ]
-
--- unfoldings only
-ppr_mono_ty sty ctxt_prec (MonoDictTy clas ty)
- = ppBesides [ppStr "{{", ppr sty clas, ppSP, ppr_mono_ty sty ctxt_prec ty, ppStr "}}"]
-
-#endif {- COMPILING_GHC -}
-\end{code}
+ppr_mono_ty ctxt_prec (MonoTyVar name)
+ = ppr name
-\begin{code}
-#ifdef COMPILING_GHC
+ppr_mono_ty ctxt_prec (MonoFunTy 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])
-extractCtxtTyNames :: Eq name => Context name -> [name]
-extractMonoTyNames :: Eq name => (name -> Bool) -> MonoType name -> [name]
+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("#)")
-extractCtxtTyNames ctxt
- = foldr get [] ctxt
- where
- get (clas, tv) acc
- | tv `is_elem` acc = acc
- | otherwise = tv : acc
+ppr_mono_ty ctxt_prec (MonoListTy ty)
+ = brackets (ppr_mono_ty pREC_TOP ty)
- is_elem = isIn "extractCtxtTyNames"
+ppr_mono_ty ctxt_prec (MonoTyApp fun_ty arg_ty)
+ = maybeParen (ctxt_prec >= pREC_CON)
+ (hsep [ppr_mono_ty pREC_FUN fun_ty, ppr_mono_ty pREC_CON arg_ty])
-extractMonoTyNames is_tyvar_name ty
- = get ty []
- where
- get (MonoTyApp con tys) acc = let
- rest = foldr get acc tys
- in
- if is_tyvar_name con && not (con `is_elem` rest)
- then con : rest
- else rest
- get (MonoListTy ty) acc = get ty acc
- get (MonoFunTy ty1 ty2) acc = get ty1 (get ty2 acc)
- get (MonoDictTy _ ty) acc = get ty acc
- get (MonoTupleTy tys) acc = foldr get acc tys
- get (MonoTyVar tv) acc
- | tv `is_elem` acc = acc
- | otherwise = tv : acc
-
- is_elem = isIn "extractMonoTyNames"
-
-#endif {- COMPILING_GHC -}
+ppr_mono_ty ctxt_prec (MonoDictTy clas tys)
+ = ppr clas <+> hsep (map (ppr_mono_ty pREC_CON) tys)
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Comparison}
+%* *
+%************************************************************************
+
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!
+
\begin{code}
-#ifdef COMPILING_GHC
+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
+cmpContext :: (a -> a -> Ordering) -> Context a -> Context a -> Ordering
-cmpPolyType :: (a -> a -> TAG_) -> PolyType a -> PolyType a -> TAG_
-cmpMonoType :: (a -> a -> TAG_) -> MonoType a -> MonoType a -> TAG_
-cmpContext :: (a -> a -> TAG_) -> Context a -> Context a -> TAG_
+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
--- We assume that HsPreForAllTys have been smashed by now.
-# ifdef DEBUG
-cmpPolyType _ (HsPreForAllTy _ _) _ = panic# "cmpPolyType:HsPreForAllTy:1st arg"
-cmpPolyType _ _ (HsPreForAllTy _ _) = panic# "cmpPolyType:HsPreForAllTy:2nd arg"
-# endif
-cmpPolyType cmp (HsForAllTy tvs1 c1 t1) (HsForAllTy tvs2 c2 t2)
- = thenCmp (cmp_tvs tvs1 tvs2)
- (thenCmp (cmpContext cmp c1 c2) (cmpMonoType cmp t1 t2))
- where
- cmp_tvs [] [] = EQ_
- cmp_tvs [] _ = LT_
- cmp_tvs _ [] = GT_
- cmp_tvs (a:as) (b:bs)
- = thenCmp (cmp a b) (cmp_tvs as bs)
- cmp_tvs _ _ = panic# "cmp_tvs"
-
------------
-cmpMonoType cmp (MonoTyVar n1) (MonoTyVar n2)
+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
+
+cmpHsType cmp (HsForAllTy tvs1 c1 t1) (HsForAllTy tvs2 c2 t2)
+ = cmpList (cmpHsTyVar cmp) tvs1 tvs2 `thenCmp`
+ cmpContext cmp c1 c2 `thenCmp`
+ cmpHsType cmp t1 t2
+
+cmpHsType cmp (MonoTyVar n1) (MonoTyVar n2)
= cmp n1 n2
-cmpMonoType cmp (MonoTupleTy tys1) (MonoTupleTy tys2)
- = cmpList (cmpMonoType cmp) tys1 tys2
-cmpMonoType cmp (MonoListTy ty1) (MonoListTy ty2)
- = cmpMonoType cmp ty1 ty2
+cmpHsType cmp (MonoTupleTy tys1 b1) (MonoTupleTy tys2 b2)
+ = (b1 `compare` b2) `thenCmp` cmpHsTypes cmp tys1 tys2
-cmpMonoType cmp (MonoTyApp tc1 tys1) (MonoTyApp tc2 tys2)
- = thenCmp (cmp tc1 tc2) (cmpList (cmpMonoType cmp) tys1 tys2)
+cmpHsType cmp (MonoListTy ty1) (MonoListTy ty2)
+ = cmpHsType cmp ty1 ty2
-cmpMonoType cmp (MonoFunTy a1 b1) (MonoFunTy a2 b2)
- = thenCmp (cmpMonoType cmp a1 a2) (cmpMonoType cmp b1 b2)
+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
-cmpMonoType cmp (MonoDictTy c1 ty1) (MonoDictTy c2 ty2)
- = thenCmp (cmp c1 c2) (cmpMonoType cmp ty1 ty2)
+cmpHsType cmp (MonoFunTy a1 b1) (MonoFunTy a2 b2)
+ = cmpHsType cmp a1 a2 `thenCmp` cmpHsType cmp b1 b2
-cmpMonoType cmp ty1 ty2 -- tags must be different
+cmpHsType cmp (MonoDictTy c1 tys1) (MonoDictTy c2 tys2)
+ = cmp c1 c2 `thenCmp` cmpHsTypes cmp tys1 tys2
+
+cmpHsType cmp ty1 ty2 -- tags must be different
= let tag1 = tag ty1
tag2 = tag ty2
in
- if tag1 _LT_ tag2 then LT_ else GT_
+ 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 ty1) = ILIT(7)
+ 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(7)
+ tag (HsForAllTy _ _ _) = ILIT(8)
-------------------
cmpContext cmp a b
= cmpList cmp_ctxt a b
where
- cmp_ctxt (c1, tv1) (c2, tv2)
- = thenCmp (cmp c1 c2) (cmp tv1 tv2)
-
-#endif {- COMPILING_GHC -}
+ cmp_ctxt (c1, tys1) (c2, tys2)
+ = cmp c1 c2 `thenCmp` cmpHsTypes cmp tys1 tys2
\end{code}
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