2 % (c) The AQUA Project, Glasgow University, 1996-1998
4 \section[PprType]{Printing Types, TyVars, Classes, TyCons}
8 pprKind, pprParendKind,
9 pprType, pprParendType,
10 pprSourceType, pprPred, pprTheta, pprClassPred,
11 pprTyVarBndr, pprTyVarBndrs,
14 getTyDescription, showTypeCategory
17 #include "HsVersions.h"
20 -- (PprType can see all the representations it's trying to print)
21 import TypeRep ( Type(..), TyNote(..), IPName(..),
22 Kind, liftedTypeKind ) -- friend
23 import Type ( SourceType(..), isUTyVar, eqKind )
24 import TcType ( ThetaType, PredType, ipNameName,
25 tcSplitSigmaTy, isPredTy, isDictTy,
26 tcSplitTyConApp_maybe, tcSplitFunTy_maybe
28 import Var ( TyVar, tyVarKind )
29 import Class ( Class )
30 import TyCon ( TyCon, isPrimTyCon, isTupleTyCon, tupleTyConBoxity,
31 maybeTyConSingleCon, isEnumerationTyCon,
36 import CmdLineOpts ( opt_PprStyle_RawTypes )
37 import Maybes ( maybeToBool )
38 import Name ( getOccString, getOccName )
40 import Unique ( Uniquable(..) )
41 import Util ( lengthIs )
42 import BasicTypes ( tupleParens )
43 import PrelNames -- quite a few *Keys
46 %************************************************************************
48 \subsection{The external interface}
50 %************************************************************************
52 @pprType@ is the standard @Type@ printer; the overloaded @ppr@ function is
53 defined to use this. @pprParendType@ is the same, except it puts
54 parens around the type, except for the atomic cases. @pprParendType@
55 works just by setting the initial context precedence very high.
58 pprType, pprParendType :: Type -> SDoc
59 pprType ty = ppr_ty tOP_PREC ty
60 pprParendType ty = ppr_ty tYCON_PREC ty
62 pprKind, pprParendKind :: Kind -> SDoc
64 pprParendKind = pprParendType
66 pprPred :: PredType -> SDoc
67 pprPred = pprSourceType
69 pprSourceType :: SourceType -> SDoc
70 pprSourceType (ClassP clas tys) = pprClassPred clas tys
71 pprSourceType (IParam n ty) = hsep [ppr n, dcolon, ppr ty]
72 pprSourceType (NType tc tys) = ppr tc <+> hsep (map pprParendType tys)
74 pprClassPred :: Class -> [Type] -> SDoc
75 pprClassPred clas tys = ppr clas <+> hsep (map pprParendType tys)
77 pprTheta :: ThetaType -> SDoc
78 pprTheta theta = parens (hsep (punctuate comma (map pprPred theta)))
80 instance Outputable Type where
83 instance Outputable SourceType where
86 instance Outputable name => Outputable (IPName name) where
87 ppr (Dupable n) = char '?' <> ppr n -- Ordinary implicit parameters
88 ppr (MustSplit n) = char '%' <> ppr n -- Splittable implicit parameters
92 %************************************************************************
94 \subsection{Pretty printing}
96 %************************************************************************
100 @ppr_ty@ takes an @Int@ that is the precedence of the context.
101 The precedence levels are:
103 \item[tOP_PREC] No parens required.
104 \item[fUN_PREC] Left hand argument of a function arrow.
105 \item[tYCON_PREC] Argument of a type constructor.
110 tOP_PREC = (0 :: Int) -- type in ParseIface.y
111 fUN_PREC = (1 :: Int) -- btype in ParseIface.y
112 tYCON_PREC = (2 :: Int) -- atype in ParseIface.y
114 maybeParen ctxt_prec inner_prec pretty
115 | ctxt_prec < inner_prec = pretty
116 | otherwise = parens pretty
120 ppr_ty :: Int -> Type -> SDoc
121 ppr_ty ctxt_prec (TyVarTy tyvar)
124 ppr_ty ctxt_prec ty@(TyConApp tycon tys)
125 -- KIND CASE; it's of the form (Type x)
126 | tycon `hasKey` typeConKey,
128 = -- For kinds, print (Type x) as just x if x is a
129 -- type constructor (must be Boxed, Unboxed, AnyBox)
130 -- Otherwise print as (Type x)
132 TyConApp bx [] -> ppr (getOccName bx) -- Always unqualified
133 other -> maybeParen ctxt_prec tYCON_PREC
134 (ppr tycon <+> ppr_ty tYCON_PREC ty)
137 | (tycon `hasKey` usOnceTyConKey || tycon `hasKey` usManyTyConKey),
139 = -- For usages (! and .), always print bare OccName, without pkg/mod/uniq
140 ppr (getOccName (tyConName tycon))
142 -- TUPLE CASE (boxed and unboxed)
143 | isTupleTyCon tycon,
144 tys `lengthIs` tyConArity tycon -- No magic if partially applied
145 = tupleParens (tupleTyConBoxity tycon)
146 (sep (punctuate comma (map (ppr_ty tOP_PREC) tys)))
149 | tycon `hasKey` listTyConKey,
151 = brackets (ppr_ty tOP_PREC ty)
155 = ppr_tc_app ctxt_prec tycon tys
158 ppr_ty ctxt_prec ty@(ForAllTy _ _)
159 = getPprStyle $ \ sty ->
160 maybeParen ctxt_prec fUN_PREC $
161 sep [ ptext SLIT("forall") <+> pp_tyvars sty <> ptext SLIT("."),
166 (tyvars, theta, tau) = tcSplitSigmaTy ty
168 pp_tyvars sty = sep (map pprTyVarBndr some_tyvars)
170 some_tyvars | userStyle sty && not opt_PprStyle_RawTypes
171 = filter (not . isUTyVar) tyvars -- hide uvars from user
176 ppr_theta theta = pprTheta theta <+> ptext SLIT("=>")
179 ppr_ty ctxt_prec (FunTy ty1 ty2)
180 -- we don't want to lose usage annotations or synonyms,
181 -- so we mustn't use splitFunTys here.
182 = maybeParen ctxt_prec fUN_PREC $
183 sep [ ppr_ty fUN_PREC ty1
184 , ptext arrow <+> ppr_ty tOP_PREC ty2
186 where arrow | isPredTy ty1 = SLIT("=>")
187 | otherwise = SLIT("->")
189 ppr_ty ctxt_prec (AppTy ty1 ty2)
190 = maybeParen ctxt_prec tYCON_PREC $
191 ppr_ty fUN_PREC ty1 <+> ppr_ty tYCON_PREC ty2
193 ppr_ty ctxt_prec (UsageTy u ty)
194 = maybeParen ctxt_prec tYCON_PREC $
195 ptext SLIT("__u") <+> ppr_ty tYCON_PREC u
196 <+> ppr_ty tYCON_PREC ty
197 -- fUN_PREC would be logical for u, but it yields a reduce/reduce conflict with AppTy
199 ppr_ty ctxt_prec (NoteTy (SynNote ty) expansion)
200 = ppr_ty ctxt_prec ty
201 -- = ppr_ty ctxt_prec expansion -- if we don't want to see syntys
203 ppr_ty ctxt_prec (NoteTy (FTVNote _) ty) = ppr_ty ctxt_prec ty
205 ppr_ty ctxt_prec (SourceTy (NType tc tys)) = ppr_tc_app ctxt_prec tc tys
206 ppr_ty ctxt_prec (SourceTy pred) = braces (pprPred pred)
208 ppr_tc_app ctxt_prec tc [] = ppr tc
209 ppr_tc_app ctxt_prec tc tys = maybeParen ctxt_prec tYCON_PREC
210 (sep [ppr tc, nest 4 (sep (map (ppr_ty tYCON_PREC) tys))])
214 %************************************************************************
216 \subsection[TyVar]{@TyVar@}
218 %************************************************************************
220 We print type-variable binders with their kinds in interface files,
221 and when in debug mode.
224 pprTyVarBndr :: TyVar -> SDoc
226 = getPprStyle $ \ sty ->
227 if (ifaceStyle sty && not (kind `eqKind` liftedTypeKind)) || debugStyle sty then
228 hsep [ppr tyvar, dcolon, pprParendKind kind]
229 -- See comments with ppDcolon in PprCore.lhs
233 kind = tyVarKind tyvar
235 pprTyVarBndrs tyvars = hsep (map pprTyVarBndr tyvars)
239 %************************************************************************
241 \subsection{Mumbo jumbo}
243 %************************************************************************
245 Grab a name for the type. This is used to determine the type
246 description for profiling.
249 getTyDescription :: Type -> String
252 = case (tcSplitSigmaTy ty) of { (_, _, tau_ty) ->
255 AppTy fun _ -> getTyDescription fun
256 FunTy _ res -> '-' : '>' : fun_result res
257 TyConApp tycon _ -> getOccString tycon
258 NoteTy (FTVNote _) ty -> getTyDescription ty
259 NoteTy (SynNote ty1) _ -> getTyDescription ty1
260 SourceTy sty -> getSourceTyDescription sty
261 ForAllTy _ ty -> getTyDescription ty
264 fun_result (FunTy _ res) = '>' : fun_result res
265 fun_result other = getTyDescription other
267 getSourceTyDescription (ClassP cl tys) = getOccString cl
268 getSourceTyDescription (NType tc tys) = getOccString tc
269 getSourceTyDescription (IParam ip ty) = getOccString (ipNameName ip)
274 showTypeCategory :: Type -> Char
276 {C,I,F,D} char, int, float, double
278 S other single-constructor type
279 {c,i,f,d} unboxed ditto
281 s *unpacked" single-cons...
287 + dictionary, unless it's a ...
290 M other (multi-constructor) data-con type
292 - reserved for others to mark as "uninteresting"
298 case tcSplitTyConApp_maybe ty of
299 Nothing -> if maybeToBool (tcSplitFunTy_maybe ty)
304 let utc = getUnique tycon in
305 if utc == charDataConKey then 'C'
306 else if utc == intDataConKey then 'I'
307 else if utc == floatDataConKey then 'F'
308 else if utc == doubleDataConKey then 'D'
309 else if utc == smallIntegerDataConKey ||
310 utc == largeIntegerDataConKey then 'J'
311 else if utc == charPrimTyConKey then 'c'
312 else if (utc == intPrimTyConKey || utc == wordPrimTyConKey
313 || utc == addrPrimTyConKey) then 'i'
314 else if utc == floatPrimTyConKey then 'f'
315 else if utc == doublePrimTyConKey then 'd'
316 else if isPrimTyCon tycon {- array, we hope -} then 'A' -- Bogus
317 else if isEnumerationTyCon tycon then 'E'
318 else if isTupleTyCon tycon then 'T'
319 else if maybeToBool (maybeTyConSingleCon tycon) then 'S'
320 else if utc == listTyConKey then 'L'
321 else 'M' -- oh, well...