module TcTyDecls (
tcTyDecl,
tcConDecl,
- tcRecordSelectors
+ mkDataBinds
) where
import Ubiq{-uitous-}
import HsSyn ( TyDecl(..), ConDecl(..), BangType(..), HsExpr(..),
Match(..), GRHSsAndBinds(..), GRHS(..), OutPat(..),
- HsBinds(..), HsLit, Stmt, Qual, ArithSeqInfo, PolyType,
+ HsBinds(..), HsLit, Stmt, Qual, ArithSeqInfo,
+ PolyType, Fake, InPat,
Bind(..), MonoBinds(..), Sig,
MonoType )
import RnHsSyn ( RenamedTyDecl(..), RenamedConDecl(..),
RnName{-instance Outputable-}
)
-import TcHsSyn ( TcHsBinds(..), TcIdOcc(..), mkHsTyLam )
+import TcHsSyn ( mkHsTyLam, tcIdType, zonkId, TcHsBinds(..), TcIdOcc(..) )
+import Inst ( newDicts, InstOrigin(..), Inst )
import TcMonoType ( tcMonoTypeKind, tcMonoType, tcContext )
-import TcType ( tcInstTyVars, tcInstType )
+import TcType ( tcInstTyVars, tcInstType, tcInstId )
import TcEnv ( tcLookupTyCon, tcLookupTyVar, tcLookupClass,
- newLocalId
+ tcLookupClassByKey,
+ newLocalId, newLocalIds
)
import TcMonad
import TcKind ( TcKind, unifyKind, mkTcArrowKind, mkTcTypeKind )
+import Class ( GenClass{-instance Eq-} )
import Id ( mkDataCon, dataConSig, mkRecordSelId,
- dataConFieldLabels, StrictnessMark(..)
+ dataConFieldLabels, dataConStrictMarks,
+ StrictnessMark(..),
+ GenId{-instance NamedThing-}
)
import FieldLabel
import Kind ( Kind, mkArrowKind, mkBoxedTypeKind )
import SpecEnv ( SpecEnv(..), nullSpecEnv )
-import Name ( Name{-instance Ord3-} )
+import Name ( nameSrcLoc, isLocallyDefinedName, getSrcLoc,
+ Name{-instance Ord3-}
+ )
import Pretty
-import TyCon ( TyCon, NewOrData(..), mkSynTyCon, mkDataTyCon, tyConDataCons )
-import Type ( getTypeKind, getTyVar, tyVarsOfTypes, eqTy, applyTyCon,
- mkForAllTys, mkFunTy )
-import TyVar ( getTyVarKind, elementOfTyVarSet )
+import TyCon ( TyCon, NewOrData(..), mkSynTyCon, mkDataTyCon, isDataTyCon,
+ tyConDataCons )
+import Type ( getTypeKind, getTyVar, tyVarsOfTypes, eqTy,
+ applyTyCon, mkTyVarTys, mkForAllTys, mkFunTy,
+ splitFunTy, mkTyVarTy, getTyVar_maybe
+ )
+import TyVar ( getTyVarKind, elementOfTyVarSet, GenTyVar{-instance Eq-} )
+import Unique ( Unique {- instance Eq -}, dataClassKey )
import UniqSet ( emptyUniqSet, mkUniqSet, uniqSetToList, unionManyUniqSets, UniqSet(..) )
-import Util ( panic, equivClasses )
+import Util ( equivClasses, zipEqual, panic, assertPanic )
\end{code}
\begin{code}
returnNF_Tc clas
\end{code}
-Generating selector bindings for record delarations
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Generating constructor/selector bindings for data declarations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tcRecordSelectors :: TyCon -> TcM s ([Id], TcHsBinds s)
-tcRecordSelectors tycon
- = mapAndUnzipTc (tcRecordSelector tycon) groups `thenTc` \ (ids, binds) ->
- returnTc (ids, SingleBind (NonRecBind (foldr AndMonoBinds EmptyMonoBinds binds)))
+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 con_binds)
+ con_binds
+ )
where
data_cons = tyConDataCons tycon
fields = [ (con, field) | con <- data_cons,
= 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 [a,b,c] [p,q,r]}}
+
+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` {- \ pre_zonk_args ->
+ mapNF_Tc zonkId pre_zonk_args `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 == dataClassKey]
+
+ 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 $
+ DictLam dicts $
+ mk_pat_match args $
+ mk_case strict_args $
+ HsCon con_id arg_tys (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, ...}
label; it has to be an Id, you see!
\begin{code}
-tcRecordSelector tycon fields@((first_con, first_field_label) : other_fields)
- = panic "tcRecordSelector: don't typecheck"
-{-
+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) <- fields]
+ other_tys = [fieldLabelType fl | (_, fl) <- other_fields]
(tyvars, _, _, _) = dataConSig first_con
- -- tyvars of first_con may be free in first_ty
+ 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
tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', tyvar_tys, tenv) ->
tcInstType tenv field_ty `thenNF_Tc` \ field_ty' ->
let
- data_ty' = applyTyCon tycon tyvar_tys
+ 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
- tycon_src_loc = getSrcLoc tycon
-
- selector_ty = mkForAllTys tyvars' $
- mkFunTy data_ty' $
- field_ty'
+ 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) $
- GRHSMatch $
- GRHSsAndBindsOut [OtherwiseGRHS selector_body tycon_src_loc]
- EmptyBinds field_ty'
+ SimpleMatch $
+ selector_body
- selector_body = HsCase (HsVar record_id) (map mk_match fields) tycon_src_loc
+ 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)]) $
- GRHSMatch $
- GRHSsAndBindsOut [OtherwiseGRHS (HsVar field_id)
- (getSrcLoc (fieldLabelName field_label))]
- EmptyBinds
- field_ty'
+ = PatMatch (RecPat con_id data_ty' [(RealId selector_id, VarPat field_id, False)]) $
+ SimpleMatch $
+ HsVar field_id
in
- returnTc (selector_id, VarMonoBind selector_id selector_rhs)
--}
+ returnTc (selector_id, if isLocallyDefinedName (getName tycon)
+ then VarMonoBind (RealId selector_id) selector_rhs
+ else EmptyMonoBinds)
\end{code}
Constructors
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