2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
7 buildSynTyCon, buildAlgTyCon, buildDataCon,
9 mkAbstractTyConRhs, mkNewTyConRhs, mkDataTyConRhs
12 #include "HsVersions.h"
14 import IfaceEnv ( newImplicitBinder )
17 import DataCon ( DataCon, isNullarySrcDataCon,
18 mkDataCon, dataConFieldLabels, dataConOrigArgTys )
19 import Var ( tyVarKind, TyVar, Id )
20 import VarSet ( isEmptyVarSet, intersectVarSet )
21 import TysWiredIn ( unitTy )
22 import BasicTypes ( RecFlag, StrictnessMark(..) )
24 import OccName ( mkDataConWrapperOcc, mkDataConWorkerOcc, mkClassTyConOcc,
25 mkClassDataConOcc, mkSuperDictSelOcc )
26 import MkId ( mkDataConIds, mkRecordSelId, mkDictSelId )
27 import Class ( mkClass, Class( classTyCon), FunDep, DefMeth(..) )
28 import TyCon ( mkSynTyCon, mkAlgTyCon, visibleDataCons, tyConStupidTheta,
29 tyConDataCons, isNewTyCon, mkClassTyCon, TyCon( tyConTyVars ),
30 ArgVrcs, AlgTyConRhs(..), newTyConRhs )
31 import Type ( mkArrowKinds, liftedTypeKind, typeKind, tyVarsOfTypes, tyVarsOfPred,
32 splitTyConApp_maybe, mkPredTys, mkTyVarTys, ThetaType, Type,
33 substTyWith, zipTopTvSubst, substTheta )
41 ------------------------------------------------------
42 buildSynTyCon name tvs rhs_ty arg_vrcs
43 = mkSynTyCon name kind tvs rhs_ty arg_vrcs
45 kind = mkArrowKinds (map tyVarKind tvs) (typeKind rhs_ty)
48 ------------------------------------------------------
49 buildAlgTyCon :: Name -> [TyVar]
50 -> ThetaType -- Stupid theta
53 -> Bool -- True <=> want generics functions
56 buildAlgTyCon tc_name tvs stupid_theta rhs arg_vrcs is_rec want_generics
57 = do { let { tycon = mkAlgTyCon tc_name kind tvs arg_vrcs stupid_theta
58 rhs fields is_rec want_generics
59 ; kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
60 ; fields = mkTyConSelIds tycon rhs
64 ------------------------------------------------------
65 mkAbstractTyConRhs :: AlgTyConRhs
66 mkAbstractTyConRhs = AbstractTyCon
68 mkDataTyConRhs :: [DataCon] -> AlgTyConRhs
70 = DataTyCon cons (all isNullarySrcDataCon cons)
72 mkNewTyConRhs :: TyCon -> DataCon -> AlgTyConRhs
73 mkNewTyConRhs tycon con
74 = NewTyCon con rhs_ty (mkNewTyConRep tycon)
76 rhs_ty = head (dataConOrigArgTys con)
77 -- Newtypes are guaranteed vanilla, so OrigArgTys will do
79 mkNewTyConRep :: TyCon -- The original type constructor
80 -> Type -- Chosen representation type
81 -- (guaranteed not to be another newtype)
82 -- Free vars of rep = tyConTyVars tc
84 -- Find the representation type for this newtype TyCon
85 -- Remember that the representation type is the *ultimate* representation
86 -- type, looking through other newtypes.
88 -- The non-recursive newtypes are easy, because they look transparent
89 -- to splitTyConApp_maybe, but recursive ones really are represented as
90 -- TyConApps (see TypeRep).
92 -- The trick is to to deal correctly with recursive newtypes
93 -- such as newtype T = MkT T
96 | null (tyConDataCons tc) = unitTy
97 -- External Core programs can have newtypes with no data constructors
98 | otherwise = go [] tc
100 -- Invariant: tc is a NewTyCon
101 -- tcs have been seen before
103 | tc `elem` tcs = unitTy
105 = case splitTyConApp_maybe rhs_ty of
106 Just (tc1, tys) | isNewTyCon tc1
107 -> ASSERT( length (tyConTyVars tc1) == length tys )
108 substTyWith (tyConTyVars tc1) tys (go (tc:tcs) tc1)
111 (_tc_tvs, rhs_ty) = newTyConRhs tc
114 ------------------------------------------------------
115 buildDataCon :: Name -> Bool -> Bool
117 -> [Name] -- Field labels
119 -> ThetaType -- Does not include the "stupid theta"
120 -> [Type] -> TyCon -> [Type]
121 -> TcRnIf m n DataCon
122 -- A wrapper for DataCon.mkDataCon that
123 -- a) makes the worker Id
124 -- b) makes the wrapper Id if necessary, including
125 -- allocating its unique (hence monadic)
126 buildDataCon src_name declared_infix vanilla arg_stricts field_lbls
127 tyvars ctxt arg_tys tycon res_tys
128 = do { wrap_name <- newImplicitBinder src_name mkDataConWrapperOcc
129 ; work_name <- newImplicitBinder src_name mkDataConWorkerOcc
130 -- This last one takes the name of the data constructor in the source
131 -- code, which (for Haskell source anyway) will be in the DataName name
132 -- space, and puts it into the VarName name space
135 stupid_ctxt = mkDataConStupidTheta tycon arg_tys res_tys
136 data_con = mkDataCon src_name declared_infix vanilla
137 arg_stricts field_lbls
138 tyvars stupid_ctxt ctxt
139 arg_tys tycon res_tys dc_ids
140 dc_ids = mkDataConIds wrap_name work_name data_con
145 -- The stupid context for a data constructor should be limited to
146 -- the type variables mentioned in the arg_tys
147 mkDataConStupidTheta tycon arg_tys res_tys
148 | null stupid_theta = [] -- The common case
149 | otherwise = filter in_arg_tys stupid_theta
151 tc_subst = zipTopTvSubst (tyConTyVars tycon) res_tys
152 stupid_theta = substTheta tc_subst (tyConStupidTheta tycon)
153 -- Start by instantiating the master copy of the
154 -- stupid theta, taken from the TyCon
156 arg_tyvars = tyVarsOfTypes arg_tys
157 in_arg_tys pred = not $ isEmptyVarSet $
158 tyVarsOfPred pred `intersectVarSet` arg_tyvars
160 ------------------------------------------------------
161 mkTyConSelIds :: TyCon -> AlgTyConRhs -> [Id]
162 mkTyConSelIds tycon rhs
163 = [ mkRecordSelId tycon fld
164 | fld <- nub (concatMap dataConFieldLabels (visibleDataCons rhs)) ]
165 -- We'll check later that fields with the same name
166 -- from different constructors have the same type.
170 ------------------------------------------------------
172 buildClass :: Name -> [TyVar] -> ThetaType
173 -> [FunDep TyVar] -- Functional dependencies
174 -> [(Name, DefMeth, Type)] -- Method info
175 -> RecFlag -> ArgVrcs -- Info for type constructor
178 buildClass class_name tvs sc_theta fds sig_stuff tc_isrec tc_vrcs
179 = do { tycon_name <- newImplicitBinder class_name mkClassTyConOcc
180 ; datacon_name <- newImplicitBinder class_name mkClassDataConOcc
181 -- The class name is the 'parent' for this datacon, not its tycon,
182 -- because one should import the class to get the binding for
184 ; sc_sel_names <- mapM (newImplicitBinder class_name . mkSuperDictSelOcc)
186 -- We number off the superclass selectors, 1, 2, 3 etc so that we
187 -- can construct names for the selectors. Thus
188 -- class (C a, C b) => D a b where ...
189 -- gives superclass selectors
191 -- (We used to call them D_C, but now we can have two different
192 -- superclasses both called C!)
194 ; fixM (\ clas -> do { -- Only name generation inside loop
196 let { op_tys = [ty | (_,_,ty) <- sig_stuff]
197 ; sc_tys = mkPredTys sc_theta
198 ; dict_component_tys = sc_tys ++ op_tys
199 ; sc_sel_ids = [mkDictSelId sc_name clas | sc_name <- sc_sel_names]
200 ; op_items = [ (mkDictSelId op_name clas, dm_info)
201 | (op_name, dm_info, _) <- sig_stuff ] }
202 -- Build the selector id and default method id
204 ; dict_con <- buildDataCon datacon_name
205 False -- Not declared infix
206 True -- Is vanilla; tyvars same as tycon
207 (map (const NotMarkedStrict) dict_component_tys)
208 [{- No labelled fields -}]
209 tvs [{-No context-}] dict_component_tys
210 (classTyCon clas) (mkTyVarTys tvs)
212 ; let { clas = mkClass class_name tvs fds
213 sc_theta sc_sel_ids op_items
216 ; tycon = mkClassTyCon tycon_name clas_kind tvs
217 tc_vrcs rhs clas tc_isrec
218 -- A class can be recursive, and in the case of newtypes
219 -- this matters. For example
220 -- class C a where { op :: C b => a -> b -> Int }
221 -- Because C has only one operation, it is represented by
222 -- a newtype, and it should be a *recursive* newtype.
223 -- [If we don't make it a recursive newtype, we'll expand the
224 -- newtype like a synonym, but that will lead to an infinite type]
226 ; clas_kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind
228 ; rhs = case dict_component_tys of
229 [rep_ty] -> mkNewTyConRhs tycon dict_con
230 other -> mkDataTyConRhs [dict_con]