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(..), Kind ) -- friend
22 import Type ( SourceType(..) )
23 import TcType ( ThetaType, PredType,
24 tcSplitSigmaTy, isPredTy, isDictTy,
25 tcSplitTyConApp_maybe, tcSplitFunTy_maybe
27 import Var ( TyVar, tyVarKind )
28 import Class ( Class )
29 import TyCon ( TyCon, isPrimTyCon, isTupleTyCon, tupleTyConBoxity,
30 maybeTyConSingleCon, isEnumerationTyCon,
35 import Maybes ( maybeToBool )
36 import Name ( getOccString, getOccName )
37 import OccName ( occNameUserString )
39 import Unique ( Uniquable(..) )
40 import Util ( lengthIs )
41 import BasicTypes ( IPName(..), tupleParens, ipNameName )
42 import PrelNames -- quite a few *Keys
45 %************************************************************************
47 \subsection{The external interface}
49 %************************************************************************
51 @pprType@ is the standard @Type@ printer; the overloaded @ppr@ function is
52 defined to use this. @pprParendType@ is the same, except it puts
53 parens around the type, except for the atomic cases. @pprParendType@
54 works just by setting the initial context precedence very high.
57 pprType, pprParendType :: Type -> SDoc
58 pprType ty = ppr_ty tOP_PREC ty
59 pprParendType ty = ppr_ty tYCON_PREC ty
61 pprKind, pprParendKind :: Kind -> SDoc
63 pprParendKind = pprParendType
65 pprPred :: PredType -> SDoc
66 pprPred = pprSourceType
68 pprSourceType :: SourceType -> SDoc
69 pprSourceType (ClassP clas tys) = pprClassPred clas tys
70 pprSourceType (IParam n ty) = hsep [ppr n, dcolon, ppr ty]
71 pprSourceType (NType tc tys) = ppr tc <+> sep (map pprParendType tys)
73 pprClassPred :: Class -> [Type] -> SDoc
74 pprClassPred clas tys = ppr clas <+> sep (map pprParendType tys)
76 pprTheta :: ThetaType -> SDoc
77 pprTheta theta = parens (sep (punctuate comma (map pprPred theta)))
79 instance Outputable Type where
82 instance Outputable SourceType where
85 instance Outputable name => Outputable (IPName name) where
86 ppr (Dupable n) = char '?' <> ppr n -- Ordinary implicit parameters
87 ppr (Linear n) = char '%' <> ppr n -- Splittable implicit parameters
89 instance Outputable name => OutputableBndr (IPName name) where
90 pprBndr _ n = ppr n -- Simple for now
94 %************************************************************************
96 \subsection{Pretty printing}
98 %************************************************************************
102 @ppr_ty@ takes an @Int@ that is the precedence of the context.
103 The precedence levels are:
105 \item[tOP_PREC] No parens required.
106 \item[fUN_PREC] Left hand argument of a function arrow.
107 \item[tYCON_PREC] Argument of a type constructor.
112 tOP_PREC = (0 :: Int) -- type in ParseIface.y
113 fUN_PREC = (1 :: Int) -- btype in ParseIface.y
114 tYCON_PREC = (2 :: Int) -- atype in ParseIface.y
116 maybeParen ctxt_prec inner_prec pretty
117 | ctxt_prec < inner_prec = pretty
118 | otherwise = parens pretty
122 ppr_ty :: Int -> Type -> SDoc
123 ppr_ty ctxt_prec (TyVarTy tyvar)
126 ppr_ty ctxt_prec ty@(TyConApp tycon tys)
127 -- KIND CASE; it's of the form (Type x)
128 | tycon `hasKey` typeConKey,
130 = -- For kinds, print (Type x) as just x if x is a
131 -- type constructor (must be Boxed, Unboxed, AnyBox)
132 -- Otherwise print as (Type x)
134 TyConApp bx [] -> ppr (getOccName bx) -- Always unqualified
135 other -> maybeParen ctxt_prec tYCON_PREC
136 (ppr tycon <+> ppr_ty tYCON_PREC ty)
139 | (tycon `hasKey` usOnceTyConKey || tycon `hasKey` usManyTyConKey),
141 = -- For usages (! and .), always print bare OccName, without pkg/mod/uniq
142 ppr (getOccName (tyConName tycon))
144 -- TUPLE CASE (boxed and unboxed)
145 | isTupleTyCon tycon,
146 tys `lengthIs` tyConArity tycon -- No magic if partially applied
147 = tupleParens (tupleTyConBoxity tycon)
148 (sep (punctuate comma (map (ppr_ty tOP_PREC) tys)))
151 | tycon `hasKey` listTyConKey,
153 = brackets (ppr_ty tOP_PREC ty)
155 -- PARALLEL ARRAY CASE
156 | tycon `hasKey` parrTyConKey,
158 = pabrackets (ppr_ty tOP_PREC ty)
162 = ppr_tc_app ctxt_prec tycon tys
165 pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]")
168 ppr_ty ctxt_prec ty@(ForAllTy _ _)
169 = getPprStyle $ \ sty ->
170 maybeParen ctxt_prec fUN_PREC $
171 sep [ ptext SLIT("forall") <+> pp_tyvars sty <> ptext SLIT("."),
176 (tyvars, theta, tau) = tcSplitSigmaTy ty
177 pp_tyvars sty = sep (map pprTyVarBndr tyvars)
180 ppr_theta theta = pprTheta theta <+> ptext SLIT("=>")
183 ppr_ty ctxt_prec (FunTy ty1 ty2)
184 -- we don't want to lose usage annotations or synonyms,
185 -- so we mustn't use splitFunTys here.
186 = maybeParen ctxt_prec fUN_PREC $
187 sep [ ppr_ty fUN_PREC ty1
188 , ptext arrow <+> ppr_ty tOP_PREC ty2
190 where arrow | isPredTy ty1 = SLIT("=>")
191 | otherwise = SLIT("->")
193 ppr_ty ctxt_prec (AppTy ty1 ty2)
194 = maybeParen ctxt_prec tYCON_PREC $
195 ppr_ty fUN_PREC ty1 <+> ppr_ty tYCON_PREC ty2
197 ppr_ty ctxt_prec (NoteTy (SynNote ty) expansion)
198 = ppr_ty ctxt_prec ty
199 -- = ppr_ty ctxt_prec expansion -- if we don't want to see syntys
201 ppr_ty ctxt_prec (NoteTy (FTVNote _) ty) = ppr_ty ctxt_prec ty
203 ppr_ty ctxt_prec (SourceTy (NType tc tys)) = ppr_tc_app ctxt_prec tc tys
204 ppr_ty ctxt_prec (SourceTy pred) = braces (pprPred pred)
206 ppr_tc_app ctxt_prec tc [] = ppr tc
207 ppr_tc_app ctxt_prec tc tys = maybeParen ctxt_prec tYCON_PREC
208 (sep [ppr tc, nest 4 (sep (map (ppr_ty tYCON_PREC) tys))])
212 %************************************************************************
214 \subsection[TyVar]{@TyVar@}
216 %************************************************************************
218 We print type-variable binders with their kinds in interface files,
219 and when in debug mode.
222 pprTyVarBndr :: TyVar -> SDoc
224 = getPprStyle $ \ sty ->
225 if debugStyle sty then
226 hsep [ppr tyvar, dcolon, pprParendKind kind]
227 -- See comments with ppDcolon in PprCore.lhs
231 kind = tyVarKind tyvar
233 pprTyVarBndrs tyvars = hsep (map pprTyVarBndr tyvars)
237 %************************************************************************
239 \subsection{Mumbo jumbo}
241 %************************************************************************
243 Grab a name for the type. This is used to determine the type
244 description for profiling.
247 getTyDescription :: Type -> String
250 = case (tcSplitSigmaTy ty) of { (_, _, tau_ty) ->
253 AppTy fun _ -> getTyDescription fun
254 FunTy _ res -> '-' : '>' : fun_result res
255 TyConApp tycon _ -> occNameUserString (getOccName tycon)
256 NoteTy (FTVNote _) ty -> getTyDescription ty
257 NoteTy (SynNote ty1) _ -> getTyDescription ty1
258 SourceTy sty -> getSourceTyDescription sty
259 ForAllTy _ ty -> getTyDescription ty
262 fun_result (FunTy _ res) = '>' : fun_result res
263 fun_result other = getTyDescription other
265 getSourceTyDescription (ClassP cl tys) = getOccString cl
266 getSourceTyDescription (NType tc tys) = getOccString tc
267 getSourceTyDescription (IParam ip ty) = getOccString (ipNameName ip)
272 showTypeCategory :: Type -> Char
274 {C,I,F,D} char, int, float, double
276 S other single-constructor type
277 {c,i,f,d} unboxed ditto
279 s *unpacked" single-cons...
285 + dictionary, unless it's a ...
288 M other (multi-constructor) data-con type
290 - reserved for others to mark as "uninteresting"
296 case tcSplitTyConApp_maybe ty of
297 Nothing -> if maybeToBool (tcSplitFunTy_maybe ty)
302 let utc = getUnique tycon in
303 if utc == charDataConKey then 'C'
304 else if utc == intDataConKey then 'I'
305 else if utc == floatDataConKey then 'F'
306 else if utc == doubleDataConKey then 'D'
307 else if utc == smallIntegerDataConKey ||
308 utc == largeIntegerDataConKey then 'J'
309 else if utc == charPrimTyConKey then 'c'
310 else if (utc == intPrimTyConKey || utc == wordPrimTyConKey
311 || utc == addrPrimTyConKey) then 'i'
312 else if utc == floatPrimTyConKey then 'f'
313 else if utc == doublePrimTyConKey then 'd'
314 else if isPrimTyCon tycon {- array, we hope -} then 'A' -- Bogus
315 else if isEnumerationTyCon tycon then 'E'
316 else if isTupleTyCon tycon then 'T'
317 else if maybeToBool (maybeTyConSingleCon tycon) then 'S'
318 else if utc == listTyConKey then 'L'
319 else 'M' -- oh, well...