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, TyThing(..),
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, tyConArity
34 import Maybes ( maybeToBool )
35 import Name ( getOccString, getOccName )
36 import OccName ( occNameUserString )
38 import Unique ( Uniquable(..) )
39 import Util ( lengthIs )
40 import BasicTypes ( IPName(..), tupleParens, ipNameName )
41 import PrelNames -- quite a few *Keys
44 %************************************************************************
46 \subsection{The external interface}
48 %************************************************************************
50 @pprType@ is the standard @Type@ printer; the overloaded @ppr@ function is
51 defined to use this. @pprParendType@ is the same, except it puts
52 parens around the type, except for the atomic cases. @pprParendType@
53 works just by setting the initial context precedence very high.
56 pprType, pprParendType :: Type -> SDoc
57 pprType ty = ppr_ty tOP_PREC ty
58 pprParendType ty = ppr_ty tYCON_PREC ty
60 pprKind, pprParendKind :: Kind -> SDoc
62 pprParendKind = pprParendType
64 pprPred :: PredType -> SDoc
65 pprPred = pprSourceType
67 pprSourceType :: SourceType -> SDoc
68 pprSourceType (ClassP clas tys) = pprClassPred clas tys
69 pprSourceType (IParam n ty) = hsep [ppr n, dcolon, ppr ty]
70 pprSourceType (NType tc tys) = ppr tc <+> sep (map pprParendType tys)
72 pprClassPred :: Class -> [Type] -> SDoc
73 pprClassPred clas tys = ppr clas <+> sep (map pprParendType tys)
75 pprTheta :: ThetaType -> SDoc
76 pprTheta theta = parens (sep (punctuate comma (map pprPred theta)))
78 instance Outputable Type where
81 instance Outputable SourceType where
84 instance Outputable name => Outputable (IPName name) where
85 ppr (Dupable n) = char '?' <> ppr n -- Ordinary implicit parameters
86 ppr (Linear n) = char '%' <> ppr n -- Splittable implicit parameters
88 instance Outputable name => OutputableBndr (IPName name) where
89 pprBndr _ n = ppr n -- Simple for now
91 instance Outputable TyThing where
92 ppr (AnId id) = ptext SLIT("AnId") <+> ppr id
93 ppr (ATyCon tc) = ptext SLIT("ATyCon") <+> ppr tc
94 ppr (AClass cl) = ptext SLIT("AClass") <+> ppr cl
95 ppr (ADataCon dc) = ptext SLIT("ADataCon") <+> ppr dc
99 %************************************************************************
101 \subsection{Pretty printing}
103 %************************************************************************
107 @ppr_ty@ takes an @Int@ that is the precedence of the context.
108 The precedence levels are:
110 \item[tOP_PREC] No parens required.
111 \item[fUN_PREC] Left hand argument of a function arrow.
112 \item[tYCON_PREC] Argument of a type constructor.
117 tOP_PREC = (0 :: Int) -- type in ParseIface.y
118 fUN_PREC = (1 :: Int) -- btype in ParseIface.y
119 tYCON_PREC = (2 :: Int) -- atype in ParseIface.y
121 maybeParen ctxt_prec inner_prec pretty
122 | ctxt_prec < inner_prec = pretty
123 | otherwise = parens pretty
127 ppr_ty :: Int -> Type -> SDoc
128 ppr_ty ctxt_prec (TyVarTy tyvar)
131 ppr_ty ctxt_prec ty@(TyConApp tycon tys)
132 -- KIND CASE; it's of the form (Type x)
133 | tycon `hasKey` typeConKey,
135 = -- For kinds, print (Type x) as just x if x is a
136 -- type constructor (must be Boxed, Unboxed, AnyBox)
137 -- Otherwise print as (Type x)
139 TyConApp bx [] -> ppr (getOccName bx) -- Always unqualified
140 other -> maybeParen ctxt_prec tYCON_PREC
141 (ppr tycon <+> ppr_ty tYCON_PREC ty)
143 -- TUPLE CASE (boxed and unboxed)
144 | isTupleTyCon tycon,
145 tys `lengthIs` tyConArity tycon -- No magic if partially applied
146 = tupleParens (tupleTyConBoxity tycon)
147 (sep (punctuate comma (map (ppr_ty tOP_PREC) tys)))
150 | tycon `hasKey` listTyConKey,
152 = brackets (ppr_ty tOP_PREC ty)
154 -- PARALLEL ARRAY CASE
155 | tycon `hasKey` parrTyConKey,
157 = pabrackets (ppr_ty tOP_PREC ty)
161 = ppr_tc_app ctxt_prec tycon tys
164 pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]")
167 ppr_ty ctxt_prec ty@(ForAllTy _ _)
168 = getPprStyle $ \ sty ->
169 maybeParen ctxt_prec fUN_PREC $
170 sep [ ptext SLIT("forall") <+> pp_tyvars sty <> ptext SLIT("."),
175 (tyvars, theta, tau) = tcSplitSigmaTy ty
176 pp_tyvars sty = sep (map pprTyVarBndr tyvars)
179 ppr_theta theta = pprTheta theta <+> ptext SLIT("=>")
182 ppr_ty ctxt_prec (FunTy ty1 ty2)
183 -- we don't want to lose usage annotations or synonyms,
184 -- so we mustn't use splitFunTys here.
185 = maybeParen ctxt_prec fUN_PREC $
186 sep [ ppr_ty fUN_PREC ty1
187 , ptext arrow <+> ppr_ty tOP_PREC ty2
189 where arrow | isPredTy ty1 = SLIT("=>")
190 | otherwise = SLIT("->")
192 ppr_ty ctxt_prec (AppTy ty1 ty2)
193 = maybeParen ctxt_prec tYCON_PREC $
194 ppr_ty fUN_PREC ty1 <+> ppr_ty tYCON_PREC ty2
196 ppr_ty ctxt_prec (NoteTy (SynNote ty) expansion)
197 = ppr_ty ctxt_prec ty
198 -- = ppr_ty ctxt_prec expansion -- if we don't want to see syntys
200 ppr_ty ctxt_prec (NoteTy (FTVNote _) ty) = ppr_ty ctxt_prec ty
202 ppr_ty ctxt_prec (SourceTy (NType tc tys)) = ppr_tc_app ctxt_prec tc tys
203 ppr_ty ctxt_prec (SourceTy pred) = braces (pprPred pred)
205 ppr_tc_app ctxt_prec tc [] = ppr tc
206 ppr_tc_app ctxt_prec tc tys = maybeParen ctxt_prec tYCON_PREC
207 (sep [ppr tc, nest 4 (sep (map (ppr_ty tYCON_PREC) tys))])
211 %************************************************************************
213 \subsection[TyVar]{@TyVar@}
215 %************************************************************************
217 We print type-variable binders with their kinds in interface files,
218 and when in debug mode.
221 pprTyVarBndr :: TyVar -> SDoc
223 = getPprStyle $ \ sty ->
224 if debugStyle sty then
225 hsep [ppr tyvar, dcolon, pprParendKind kind]
226 -- See comments with ppDcolon in PprCore.lhs
230 kind = tyVarKind tyvar
232 pprTyVarBndrs tyvars = hsep (map pprTyVarBndr tyvars)
236 %************************************************************************
238 \subsection{Mumbo jumbo}
240 %************************************************************************
242 Grab a name for the type. This is used to determine the type
243 description for profiling.
246 getTyDescription :: Type -> String
249 = case (tcSplitSigmaTy ty) of { (_, _, tau_ty) ->
252 AppTy fun _ -> getTyDescription fun
253 FunTy _ res -> '-' : '>' : fun_result res
254 TyConApp tycon _ -> occNameUserString (getOccName tycon)
255 NoteTy (FTVNote _) ty -> getTyDescription ty
256 NoteTy (SynNote ty1) _ -> getTyDescription ty1
257 SourceTy sty -> getSourceTyDescription sty
258 ForAllTy _ ty -> getTyDescription ty
261 fun_result (FunTy _ res) = '>' : fun_result res
262 fun_result other = getTyDescription other
264 getSourceTyDescription (ClassP cl tys) = getOccString cl
265 getSourceTyDescription (NType tc tys) = getOccString tc
266 getSourceTyDescription (IParam ip ty) = getOccString (ipNameName ip)
271 showTypeCategory :: Type -> Char
273 {C,I,F,D} char, int, float, double
275 S other single-constructor type
276 {c,i,f,d} unboxed ditto
278 s *unpacked" single-cons...
284 + dictionary, unless it's a ...
287 M other (multi-constructor) data-con type
289 - reserved for others to mark as "uninteresting"
295 case tcSplitTyConApp_maybe ty of
296 Nothing -> if maybeToBool (tcSplitFunTy_maybe ty)
301 let utc = getUnique tycon in
302 if utc == charDataConKey then 'C'
303 else if utc == intDataConKey then 'I'
304 else if utc == floatDataConKey then 'F'
305 else if utc == doubleDataConKey then 'D'
306 else if utc == smallIntegerDataConKey ||
307 utc == largeIntegerDataConKey then 'J'
308 else if utc == charPrimTyConKey then 'c'
309 else if (utc == intPrimTyConKey || utc == wordPrimTyConKey
310 || utc == addrPrimTyConKey) then 'i'
311 else if utc == floatPrimTyConKey then 'f'
312 else if utc == doublePrimTyConKey then 'd'
313 else if isPrimTyCon tycon {- array, we hope -} then 'A' -- Bogus
314 else if isEnumerationTyCon tycon then 'E'
315 else if isTupleTyCon tycon then 'T'
316 else if maybeToBool (maybeTyConSingleCon tycon) then 'S'
317 else if utc == listTyConKey then 'L'
318 else 'M' -- oh, well...