module TcTyDecls (
tcTyDecl,
- tcConDecl
+ tcConDecl,
+ mkDataBinds
) where
import Ubiq{-uitous-}
-import HsSyn ( TyDecl(..), ConDecl(..), BangType(..), MonoType )
-import RnHsSyn ( RenamedTyDecl(..), RenamedConDecl(..) )
-
-import TcMonoType ( tcMonoTypeKind, tcMonoType, tcContext )
-import TcEnv ( tcLookupTyCon, tcLookupTyVar, tcLookupClass )
+import HsSyn ( TyDecl(..), ConDecl(..), BangType(..), HsExpr(..),
+ Match(..), GRHSsAndBinds(..), GRHS(..), OutPat(..),
+ HsBinds(..), HsLit, Stmt, Qual, ArithSeqInfo,
+ PolyType, Fake, InPat,
+ Bind(..), MonoBinds(..), Sig,
+ MonoType )
+import RnHsSyn ( RenamedTyDecl(..), RenamedConDecl(..),
+ RnName{-instance Outputable-}
+ )
+import TcHsSyn ( mkHsTyLam, mkHsDictLam, tcIdType, zonkId,
+ TcHsBinds(..), TcIdOcc(..)
+ )
+import Inst ( newDicts, InstOrigin(..), Inst )
+import TcMonoType ( tcMonoTypeKind, tcMonoType, tcPolyType, tcContext )
+import TcType ( tcInstTyVars, tcInstType, tcInstId )
+import TcEnv ( tcLookupTyCon, tcLookupTyVar, tcLookupClass,
+ newLocalId, newLocalIds
+ )
import TcMonad
import TcKind ( TcKind, unifyKind, mkTcArrowKind, mkTcTypeKind )
-import Id ( mkDataCon, StrictnessMark(..) )
+import Class ( GenClass{-instance Eq-} )
+import Id ( mkDataCon, dataConSig, mkRecordSelId,
+ dataConFieldLabels, dataConStrictMarks,
+ StrictnessMark(..),
+ GenId{-instance NamedThing-}
+ )
+import FieldLabel
import Kind ( Kind, mkArrowKind, mkBoxedTypeKind )
import SpecEnv ( SpecEnv(..), nullSpecEnv )
-import Name ( getNameFullName, Name(..) )
+import Name ( nameSrcLoc, isLocallyDefinedName, getSrcLoc,
+ Name{-instance Ord3-}
+ )
import Pretty
-import TyCon ( TyCon, ConsVisible(..), NewOrData(..), mkSynTyCon, mkDataTyCon )
-import Type ( getTypeKind )
-import TyVar ( getTyVarKind )
-import Util ( panic )
-
+import TyCon ( TyCon, NewOrData(..), mkSynTyCon, mkDataTyCon, isDataTyCon,
+ tyConDataCons )
+import Type ( typeKind, getTyVar, tyVarsOfTypes, eqTy,
+ applyTyCon, mkTyVarTys, mkForAllTys, mkFunTy,
+ splitFunTy, mkTyVarTy, getTyVar_maybe
+ )
+import TyVar ( tyVarKind, elementOfTyVarSet, GenTyVar{-instance Eq-} )
+import Unique ( Unique {- instance Eq -}, evalClassKey )
+import UniqSet ( emptyUniqSet, mkUniqSet, uniqSetToList, unionManyUniqSets, UniqSet(..) )
+import Util ( equivClasses, zipEqual, panic, assertPanic )
\end{code}
\begin{code}
(foldr mkTcArrowKind rhs_kind tyvar_kinds)
`thenTc_`
let
- -- Construct the tycon
+ -- Getting the TyCon's kind is a bit of a nuisance. We can't use the tycon_kind,
+ -- because that's a TcKind and may not yet be fully unified with other kinds.
+ -- We could have augmented the tycon environment with a knot-tied kind,
+ -- but the simplest thing to do seems to be to get the Kind by (lazily)
+ -- looking at the tyvars and rhs_ty.
result_kind, final_tycon_kind :: Kind -- NB not TcKind!
- result_kind = getTypeKind rhs_ty
- final_tycon_kind = foldr (mkArrowKind . getTyVarKind) result_kind rec_tyvars
+ result_kind = typeKind rhs_ty
+ final_tycon_kind = foldr (mkArrowKind . tyVarKind) result_kind rec_tyvars
- tycon = mkSynTyCon (getItsUnique tycon_name)
- (getNameFullName tycon_name)
+ -- Construct the tycon
+ tycon = mkSynTyCon (getName tycon_name)
final_tycon_kind
(length tyvar_names)
rec_tyvars
unifyKind tycon_kind
(foldr mkTcArrowKind mkTcTypeKind tyvar_kinds)
`thenTc_`
+
-- Walk the condecls
mapTc (tcConDecl rec_tycon rec_tyvars ctxt) con_decls
`thenTc` \ con_ids ->
let
-- Construct the tycon
final_tycon_kind :: Kind -- NB not TcKind!
- final_tycon_kind = foldr (mkArrowKind . getTyVarKind) mkBoxedTypeKind rec_tyvars
+ final_tycon_kind = foldr (mkArrowKind . tyVarKind) mkBoxedTypeKind rec_tyvars
- tycon = mkDataTyCon (getItsUnique tycon_name)
+ tycon = mkDataTyCon (getName tycon_name)
final_tycon_kind
- (getNameFullName tycon_name)
rec_tyvars
ctxt
con_ids
derived_classes
- ConsVisible -- For now; if constrs are from pragma we are *abstract*
data_or_new
in
returnTc tycon
+
+tc_derivs Nothing = returnNF_Tc []
+tc_derivs (Just ds) = mapNF_Tc tc_deriv ds
+
+tc_deriv name
+ = tcLookupClass name `thenNF_Tc` \ (_, clas) ->
+ returnNF_Tc clas
+\end{code}
+
+Generating constructor/selector bindings for data declarations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+\begin{code}
+mkDataBinds :: TyCon -> TcM s ([Id], TcHsBinds s)
+mkDataBinds tycon
+ = ASSERT( isDataTyCon tycon )
+ mapAndUnzipTc mkConstructor data_cons `thenTc` \ (con_ids, con_binds) ->
+ mapAndUnzipTc (mkRecordSelector tycon) groups `thenTc` \ (sel_ids, sel_binds) ->
+ returnTc (con_ids ++ sel_ids,
+ SingleBind $ NonRecBind $
+ foldr AndMonoBinds
+ (foldr AndMonoBinds EmptyMonoBinds sel_binds)
+ con_binds
+ )
where
- tc_derivs Nothing = returnNF_Tc []
- tc_derivs (Just ds) = mapNF_Tc tc_deriv ds
+ data_cons = tyConDataCons tycon
+ fields = [ (con, field) | con <- data_cons,
+ field <- dataConFieldLabels con
+ ]
+
+ -- groups is list of fields that share a common name
+ groups = equivClasses cmp_name fields
+ cmp_name (_, field1) (_, field2)
+ = fieldLabelName field1 `cmp` fieldLabelName field2
+\end{code}
+
+We're going to build a constructor that looks like:
+
+ data (Data a, C b) => T a b = T1 !a !Int b
+
+ T1 = /\ a b ->
+ \d1::Data a, d2::C b ->
+ \p q r -> case p of { p ->
+ case q of { q ->
+ HsCon T1 [a,b] [p,q,r]}}
- tc_deriv name
- = tcLookupClass name `thenNF_Tc` \ (_, clas) ->
- returnNF_Tc clas
+Notice that
+
+* d2 is thrown away --- a context in a data decl is used to make sure
+ one *could* construct dictionaries at the site the constructor
+ is used, but the dictionary isn't actually used.
+
+* We have to check that we can construct Data dictionaries for
+ the types a and Int. Once we've done that we can throw d1 away too.
+
+* We use (case p of ...) to evaluate p, rather than "seq" because
+ all that matters is that the arguments are evaluated. "seq" is
+ very careful to preserve evaluation order, which we don't need
+ to be here.
+
+\begin{code}
+mkConstructor con_id
+ | not (isLocallyDefinedName (getName con_id))
+ = returnTc (con_id, EmptyMonoBinds)
+
+ | otherwise -- It is locally defined
+ = tcInstId con_id `thenNF_Tc` \ (tyvars, theta, tau) ->
+ newDicts DataDeclOrigin theta `thenNF_Tc` \ (_, dicts) ->
+ let
+ (arg_tys, result_ty) = splitFunTy tau
+ n_args = length arg_tys
+ in
+ newLocalIds (take n_args (repeat SLIT("con"))) arg_tys
+ `thenNF_Tc` \ args ->
+
+ -- Check that all the types of all the strict arguments are in Data.
+ -- This is trivially true of everything except type variables, for
+ -- which we must check the context.
+ let
+ strict_marks = dataConStrictMarks con_id
+ strict_args = [arg | (arg, MarkedStrict) <- args `zipEqual` strict_marks]
+
+ data_tyvars = -- The tyvars in the constructor's context that are arguments
+ -- to the Data class
+ [getTyVar "mkConstructor" ty
+ | (clas,ty) <- theta, uniqueOf clas == evalClassKey]
+
+ check_data arg = case getTyVar_maybe (tcIdType arg) of
+ Nothing -> returnTc () -- Not a tyvar, so OK
+ Just tyvar -> checkTc (tyvar `elem` data_tyvars) (missingDataErr tyvar)
+ in
+ mapTc check_data strict_args `thenTc_`
+
+ -- Build the data constructor
+ let
+ con_rhs = mkHsTyLam tyvars $
+ mkHsDictLam dicts $
+ mk_pat_match args $
+ mk_case strict_args $
+ HsCon con_id (mkTyVarTys tyvars) (map HsVar args)
+
+ mk_pat_match [] body = body
+ mk_pat_match (arg:args) body = HsLam (PatMatch (VarPat arg) (SimpleMatch (mk_pat_match args body)))
+
+ mk_case [] body = body
+ mk_case (arg:args) body = HsCase (HsVar arg)
+ [PatMatch (VarPat arg) (SimpleMatch (mk_case args body))]
+ src_loc
+
+ src_loc = nameSrcLoc (getName con_id)
+ in
+
+ returnTc (con_id, VarMonoBind (RealId con_id) con_rhs)
\end{code}
+We're going to build a record selector that looks like this:
+
+ data T a b c = T1 { op :: a, ...}
+ | T2 { op :: a, ...}
+ | T3
+
+ sel :: forall a b c. T a b c -> a
+ sel = /\ a b c -> \ T1 { sel = x } -> x
+ T2 { sel = 2 } -> x
+
+Note that the selector Id itself is used as the field
+label; it has to be an Id, you see!
+
+\begin{code}
+mkRecordSelector tycon fields@((first_con, first_field_label) : other_fields)
+ = let
+ field_ty = fieldLabelType first_field_label
+ field_name = fieldLabelName first_field_label
+ other_tys = [fieldLabelType fl | (_, fl) <- other_fields]
+ (tyvars, _, _, _) = dataConSig first_con
+ data_ty = applyTyCon tycon (mkTyVarTys tyvars)
+ -- tyvars of first_con may be free in field_ty
+ in
+
+ -- Check that all the fields in the group have the same type
+ -- This check assumes that all the constructors of a given
+ -- data type use the same type variables
+ checkTc (all (eqTy field_ty) other_tys)
+ (fieldTypeMisMatch field_name) `thenTc_`
+
+ -- Create an Id for the field itself
+ tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', tyvar_tys, tenv) ->
+ tcInstType tenv field_ty `thenNF_Tc` \ field_ty' ->
+ let
+ data_ty' = applyTyCon tycon tyvar_tys
+ in
+ newLocalId SLIT("x") field_ty' `thenNF_Tc` \ field_id ->
+ newLocalId SLIT("r") data_ty' `thenNF_Tc` \ record_id ->
+
+ -- Now build the selector
+ let
+ selector_ty :: Type
+ selector_ty = mkForAllTys tyvars $
+ mkFunTy data_ty $
+ field_ty
+
+ selector_id :: Id
+ selector_id = mkRecordSelId first_field_label selector_ty
+
+ -- HsSyn is dreadfully verbose for defining the selector!
+ selector_rhs = mkHsTyLam tyvars' $
+ HsLam $
+ PatMatch (VarPat record_id) $
+ SimpleMatch $
+ selector_body
+
+ selector_body = HsCase (HsVar record_id) (map mk_match fields) (getSrcLoc tycon)
+
+ mk_match (con_id, field_label)
+ = PatMatch (RecPat con_id data_ty' [(selector_id, VarPat field_id, False)]) $
+ SimpleMatch $
+ HsVar field_id
+ in
+ returnTc (selector_id, if isLocallyDefinedName (getName tycon)
+ then VarMonoBind (RealId selector_id) selector_rhs
+ else EmptyMonoBinds)
+\end{code}
Constructors
~~~~~~~~~~~~
tcConDecl :: TyCon -> [TyVar] -> [(Class,Type)] -> RenamedConDecl -> TcM s Id
tcConDecl tycon tyvars ctxt (ConDecl name btys src_loc)
+ = tcDataCon tycon tyvars ctxt name btys src_loc
+
+tcConDecl tycon tyvars ctxt (ConOpDecl bty1 op bty2 src_loc)
+ = tcDataCon tycon tyvars ctxt op [bty1,bty2] src_loc
+
+tcConDecl tycon tyvars ctxt (NewConDecl name ty src_loc)
= tcAddSrcLoc src_loc $
+ tcMonoType ty `thenTc` \ arg_ty ->
let
- (stricts, tys) = sep_bangs btys
- in
- mapTc tcMonoType tys `thenTc` \ arg_tys ->
- let
- data_con = mkDataCon (getItsUnique name)
- (getNameFullName name)
- stricts
+ data_con = mkDataCon (getName name)
+ [NotMarkedStrict]
+ [{- No labelled fields -}]
tyvars
- [] -- ToDo: ctxt; limited to tyvars in arg_tys
- arg_tys
+ ctxt
+ [arg_ty]
tycon
-- nullSpecEnv
in
returnTc data_con
-tcConDecl tycon tyvars ctxt (ConOpDecl bty1 op bty2 src_loc)
+tcConDecl tycon tyvars ctxt (RecConDecl name fields src_loc)
= tcAddSrcLoc src_loc $
+ mapTc tcField fields `thenTc` \ field_label_infos_s ->
let
- (stricts, tys) = sep_bangs [bty1, bty2]
- in
- mapTc tcMonoType tys `thenTc` \ arg_tys ->
- let
- data_con = mkDataCon (getItsUnique op)
- (getNameFullName op)
+ field_label_infos = concat field_label_infos_s
+ stricts = [strict | (_, _, strict) <- field_label_infos]
+ arg_tys = [ty | (_, ty, _) <- field_label_infos]
+
+ field_labels = [ mkFieldLabel (getName name) ty tag
+ | ((name, ty, _), tag) <- field_label_infos `zip` allFieldLabelTags
+ ]
+
+ data_con = mkDataCon (getName name)
stricts
+ field_labels
tyvars
- [] -- ToDo: ctxt
+ (thinContext arg_tys ctxt)
arg_tys
tycon
-- nullSpecEnv
in
returnTc data_con
-tcConDecl tycon tyvars ctxt (NewConDecl name ty src_loc)
+tcField (field_label_names, bty)
+ = tcPolyType (get_pty bty) `thenTc` \ field_ty ->
+ returnTc [(name, field_ty, get_strictness bty) | name <- field_label_names]
+
+tcDataCon tycon tyvars ctxt name btys src_loc
= tcAddSrcLoc src_loc $
- tcMonoType ty `thenTc` \ arg_ty ->
let
- data_con = mkDataCon (getItsUnique name)
- (getNameFullName name)
- [NotMarkedStrict]
+ stricts = map get_strictness btys
+ tys = map get_pty btys
+ in
+ mapTc tcPolyType tys `thenTc` \ arg_tys ->
+ let
+ data_con = mkDataCon (getName name)
+ stricts
+ [{- No field labels -}]
tyvars
- [] -- ToDo: ctxt
- [arg_ty]
+ (thinContext arg_tys ctxt)
+ arg_tys
tycon
-- nullSpecEnv
in
returnTc data_con
-tcConDecl tycon tyvars ctxt (RecConDecl con fields src_loc)
- = panic "tcConDecls:RecConDecl"
-
-
-sep_bangs btys
- = unzip (map sep_bang btys)
- where
- sep_bang (Banged ty) = (MarkedStrict, ty)
- sep_bang (Unbanged ty) = (NotMarkedStrict, ty)
+-- The context for a data constructor should be limited to
+-- the type variables mentioned in the arg_tys
+thinContext arg_tys ctxt
+ = filter in_arg_tys ctxt
+ where
+ arg_tyvars = tyVarsOfTypes arg_tys
+ in_arg_tys (clas,ty) = getTyVar "tcDataCon" ty `elementOfTyVarSet` arg_tyvars
+
+get_strictness (Banged _) = MarkedStrict
+get_strictness (Unbanged _) = NotMarkedStrict
+
+get_pty (Banged ty) = ty
+get_pty (Unbanged ty) = ty
\end{code}
tyNewCtxt tycon_name sty
= ppCat [ppStr "In the newtype declaration for", ppr sty tycon_name]
+
+fieldTypeMisMatch field_name sty
+ = ppSep [ppStr "Declared types differ for field", ppr sty field_name]
+
+missingDataErr tyvar sty
+ = ppStr "Missing `data' (???)" -- ToDo: improve
\end{code}
projects / ghc-hetmet.git / blobdiff