% % (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \begin{code} {-# LANGUAGE DeriveDataTypeable, DeriveFunctor, DeriveFoldable, DeriveTraversable #-} -- | Abstract syntax of global declarations. -- -- Definitions for: @SynDecl@ and @ConDecl@, @ClassDecl@, -- @InstDecl@, @DefaultDecl@ and @ForeignDecl@. module HsDecls ( -- * Toplevel declarations HsDecl(..), LHsDecl, HsDataDefn(..), -- ** Class or type declarations TyClDecl(..), LTyClDecl, TyClGroup, isClassDecl, isDataDecl, isSynDecl, tcdName, isFamilyDecl, isTypeFamilyDecl, isDataFamilyDecl, tyFamInstDeclName, tyFamInstDeclLName, countTyClDecls, pprTyClDeclFlavour, tyClDeclLName, tyClDeclTyVars, FamilyDecl(..), LFamilyDecl, -- ** Instance declarations InstDecl(..), LInstDecl, NewOrData(..), FamilyFlavour(..), TyFamInstDecl(..), LTyFamInstDecl, instDeclDataFamInsts, DataFamInstDecl(..), LDataFamInstDecl, pprDataFamInstFlavour, TyFamInstEqn(..), LTyFamInstEqn, LClsInstDecl, ClsInstDecl(..), -- ** Standalone deriving declarations DerivDecl(..), LDerivDecl, -- ** @RULE@ declarations RuleDecl(..), LRuleDecl, RuleBndr(..), collectRuleBndrSigTys, -- ** @VECTORISE@ declarations VectDecl(..), LVectDecl, lvectDeclName, lvectInstDecl, -- ** @default@ declarations DefaultDecl(..), LDefaultDecl, -- ** Top-level template haskell splice SpliceDecl(..), -- ** Foreign function interface declarations ForeignDecl(..), LForeignDecl, ForeignImport(..), ForeignExport(..), noForeignImportCoercionYet, noForeignExportCoercionYet, CImportSpec(..), -- ** Data-constructor declarations ConDecl(..), LConDecl, ResType(..), HsConDeclDetails, hsConDeclArgTys, -- ** Document comments DocDecl(..), LDocDecl, docDeclDoc, -- ** Deprecations WarnDecl(..), LWarnDecl, -- ** Annotations AnnDecl(..), LAnnDecl, AnnProvenance(..), annProvenanceName_maybe, -- * Grouping HsGroup(..), emptyRdrGroup, emptyRnGroup, appendGroups ) where -- friends: import {-# SOURCE #-} HsExpr( LHsExpr, HsExpr, pprExpr ) -- Because Expr imports Decls via HsBracket import HsBinds import HsPat import HsTypes import HsDoc import TyCon import NameSet import Name import BasicTypes import Coercion import ForeignCall -- others: import InstEnv import Class import Outputable import Util import SrcLoc import FastString import Bag import Data.Data hiding (TyCon) import Data.Foldable (Foldable) import Data.Traversable \end{code} %************************************************************************ %* * \subsection[HsDecl]{Declarations} %* * %************************************************************************ \begin{code} type LHsDecl id = Located (HsDecl id) -- | A Haskell Declaration data HsDecl id = TyClD (TyClDecl id) -- ^ A type or class declaration. | InstD (InstDecl id) -- ^ An instance declaration. | DerivD (DerivDecl id) | ValD (HsBind id) | SigD (Sig id) | DefD (DefaultDecl id) | ForD (ForeignDecl id) | WarningD (WarnDecl id) | AnnD (AnnDecl id) | RuleD (RuleDecl id) | VectD (VectDecl id) | SpliceD (SpliceDecl id) | DocD (DocDecl) | QuasiQuoteD (HsQuasiQuote id) deriving (Data, Typeable) -- NB: all top-level fixity decls are contained EITHER -- EITHER SigDs -- OR in the ClassDecls in TyClDs -- -- The former covers -- a) data constructors -- b) class methods (but they can be also done in the -- signatures of class decls) -- c) imported functions (that have an IfacSig) -- d) top level decls -- -- The latter is for class methods only -- | A 'HsDecl' is categorised into a 'HsGroup' before being -- fed to the renamer. data HsGroup id = HsGroup { hs_valds :: HsValBinds id, hs_tyclds :: [[LTyClDecl id]], -- A list of mutually-recursive groups -- No family-instances here; they are in hs_instds -- Parser generates a singleton list; -- renamer does dependency analysis hs_instds :: [LInstDecl id], -- Both class and family instance declarations in here hs_derivds :: [LDerivDecl id], hs_fixds :: [LFixitySig id], -- Snaffled out of both top-level fixity signatures, -- and those in class declarations hs_defds :: [LDefaultDecl id], hs_fords :: [LForeignDecl id], hs_warnds :: [LWarnDecl id], hs_annds :: [LAnnDecl id], hs_ruleds :: [LRuleDecl id], hs_vects :: [LVectDecl id], hs_docs :: [LDocDecl] } deriving (Data, Typeable) emptyGroup, emptyRdrGroup, emptyRnGroup :: HsGroup a emptyRdrGroup = emptyGroup { hs_valds = emptyValBindsIn } emptyRnGroup = emptyGroup { hs_valds = emptyValBindsOut } emptyGroup = HsGroup { hs_tyclds = [], hs_instds = [], hs_derivds = [], hs_fixds = [], hs_defds = [], hs_annds = [], hs_fords = [], hs_warnds = [], hs_ruleds = [], hs_vects = [], hs_valds = error "emptyGroup hs_valds: Can't happen", hs_docs = [] } appendGroups :: HsGroup a -> HsGroup a -> HsGroup a appendGroups HsGroup { hs_valds = val_groups1, hs_tyclds = tyclds1, hs_instds = instds1, hs_derivds = derivds1, hs_fixds = fixds1, hs_defds = defds1, hs_annds = annds1, hs_fords = fords1, hs_warnds = warnds1, hs_ruleds = rulds1, hs_vects = vects1, hs_docs = docs1 } HsGroup { hs_valds = val_groups2, hs_tyclds = tyclds2, hs_instds = instds2, hs_derivds = derivds2, hs_fixds = fixds2, hs_defds = defds2, hs_annds = annds2, hs_fords = fords2, hs_warnds = warnds2, hs_ruleds = rulds2, hs_vects = vects2, hs_docs = docs2 } = HsGroup { hs_valds = val_groups1 `plusHsValBinds` val_groups2, hs_tyclds = tyclds1 ++ tyclds2, hs_instds = instds1 ++ instds2, hs_derivds = derivds1 ++ derivds2, hs_fixds = fixds1 ++ fixds2, hs_annds = annds1 ++ annds2, hs_defds = defds1 ++ defds2, hs_fords = fords1 ++ fords2, hs_warnds = warnds1 ++ warnds2, hs_ruleds = rulds1 ++ rulds2, hs_vects = vects1 ++ vects2, hs_docs = docs1 ++ docs2 } \end{code} \begin{code} instance OutputableBndr name => Outputable (HsDecl name) where ppr (TyClD dcl) = ppr dcl ppr (ValD binds) = ppr binds ppr (DefD def) = ppr def ppr (InstD inst) = ppr inst ppr (DerivD deriv) = ppr deriv ppr (ForD fd) = ppr fd ppr (SigD sd) = ppr sd ppr (RuleD rd) = ppr rd ppr (VectD vect) = ppr vect ppr (WarningD wd) = ppr wd ppr (AnnD ad) = ppr ad ppr (SpliceD dd) = ppr dd ppr (DocD doc) = ppr doc ppr (QuasiQuoteD qq) = ppr qq instance OutputableBndr name => Outputable (HsGroup name) where ppr (HsGroup { hs_valds = val_decls, hs_tyclds = tycl_decls, hs_instds = inst_decls, hs_derivds = deriv_decls, hs_fixds = fix_decls, hs_warnds = deprec_decls, hs_annds = ann_decls, hs_fords = foreign_decls, hs_defds = default_decls, hs_ruleds = rule_decls, hs_vects = vect_decls }) = vcat_mb empty [ppr_ds fix_decls, ppr_ds default_decls, ppr_ds deprec_decls, ppr_ds ann_decls, ppr_ds rule_decls, ppr_ds vect_decls, if isEmptyValBinds val_decls then Nothing else Just (ppr val_decls), ppr_ds (concat tycl_decls), ppr_ds inst_decls, ppr_ds deriv_decls, ppr_ds foreign_decls] where ppr_ds :: Outputable a => [a] -> Maybe SDoc ppr_ds [] = Nothing ppr_ds ds = Just (vcat (map ppr ds)) vcat_mb :: SDoc -> [Maybe SDoc] -> SDoc -- Concatenate vertically with white-space between non-blanks vcat_mb _ [] = empty vcat_mb gap (Nothing : ds) = vcat_mb gap ds vcat_mb gap (Just d : ds) = gap $$ d $$ vcat_mb blankLine ds data SpliceDecl id = SpliceDecl -- Top level splice (Located (HsExpr id)) HsExplicitFlag -- Explicit <=> $(f x y) -- Implicit <=> f x y, i.e. a naked top level expression deriving (Data, Typeable) instance OutputableBndr name => Outputable (SpliceDecl name) where ppr (SpliceDecl e _) = ptext (sLit "$") <> parens (pprExpr (unLoc e)) \end{code} %************************************************************************ %* * \subsection[SynDecl]{@data@, @newtype@ or @type@ (synonym) type declaration} %* * %************************************************************************ -------------------------------- THE NAMING STORY -------------------------------- Here is the story about the implicit names that go with type, class, and instance decls. It's a bit tricky, so pay attention! "Implicit" (or "system") binders ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Each data type decl defines a worker name for each constructor to-T and from-T convertors Each class decl defines a tycon for the class a data constructor for that tycon the worker for that constructor a selector for each superclass All have occurrence names that are derived uniquely from their parent declaration. None of these get separate definitions in an interface file; they are fully defined by the data or class decl. But they may *occur* in interface files, of course. Any such occurrence must haul in the relevant type or class decl. Plan of attack: - Ensure they "point to" the parent data/class decl when loading that decl from an interface file (See RnHiFiles.getSysBinders) - When typechecking the decl, we build the implicit TyCons and Ids. When doing so we look them up in the name cache (RnEnv.lookupSysName), to ensure correct module and provenance is set These are the two places that we have to conjure up the magic derived names. (The actual magic is in OccName.mkWorkerOcc, etc.) Default methods ~~~~~~~~~~~~~~~ - Occurrence name is derived uniquely from the method name E.g. $dmmax - If there is a default method name at all, it's recorded in the ClassOpSig (in HsBinds), in the DefMeth field. (DefMeth is defined in Class.lhs) Source-code class decls and interface-code class decls are treated subtly differently, which has given me a great deal of confusion over the years. Here's the deal. (We distinguish the two cases because source-code decls have (Just binds) in the tcdMeths field, whereas interface decls have Nothing. In *source-code* class declarations: - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName This is done by RdrHsSyn.mkClassOpSigDM - The renamer renames it to a Name - During typechecking, we generate a binding for each $dm for which there's a programmer-supplied default method: class Foo a where op1 :: op2 :: op1 = ... We generate a binding for $dmop1 but not for $dmop2. The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1. The Name for $dmop2 is simply discarded. In *interface-file* class declarations: - When parsing, we see if there's an explicit programmer-supplied default method because there's an '=' sign to indicate it: class Foo a where op1 = :: -- NB the '=' op2 :: We use this info to generate a DefMeth with a suitable RdrName for op1, and a NoDefMeth for op2 - The interface file has a separate definition for $dmop1, with unfolding etc. - The renamer renames it to a Name. - The renamer treats $dmop1 as a free variable of the declaration, so that the binding for $dmop1 will be sucked in. (See RnHsSyn.tyClDeclFVs) This doesn't happen for source code class decls, because they *bind* the default method. Dictionary functions ~~~~~~~~~~~~~~~~~~~~ Each instance declaration gives rise to one dictionary function binding. The type checker makes up new source-code instance declarations (e.g. from 'deriving' or generic default methods --- see TcInstDcls.tcInstDecls1). So we can't generate the names for dictionary functions in advance (we don't know how many we need). On the other hand for interface-file instance declarations, the decl specifies the name of the dictionary function, and it has a binding elsewhere in the interface file: instance {Eq Int} = dEqInt dEqInt :: {Eq Int} So again we treat source code and interface file code slightly differently. Source code: - Source code instance decls have a Nothing in the (Maybe name) field (see data InstDecl below) - The typechecker makes up a Local name for the dict fun for any source-code instance decl, whether it comes from a source-code instance decl, or whether the instance decl is derived from some other construct (e.g. 'deriving'). - The occurrence name it chooses is derived from the instance decl (just for documentation really) --- e.g. dNumInt. Two dict funs may share a common occurrence name, but will have different uniques. E.g. instance Foo [Int] where ... instance Foo [Bool] where ... These might both be dFooList - The CoreTidy phase externalises the name, and ensures the occurrence name is unique (this isn't special to dict funs). So we'd get dFooList and dFooList1. - We can take this relaxed approach (changing the occurrence name later) because dict fun Ids are not captured in a TyCon or Class (unlike default methods, say). Instead, they are kept separately in the InstEnv. This makes it easy to adjust them after compiling a module. (Once we've finished compiling that module, they don't change any more.) Interface file code: - The instance decl gives the dict fun name, so the InstDecl has a (Just name) in the (Maybe name) field. - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we suck in the dfun binding \begin{code} type LTyClDecl name = Located (TyClDecl name) type TyClGroup name = [LTyClDecl name] -- This is used in TcTyClsDecls to represent -- strongly connected components of decls -- No familiy instances in here -- | A type or class declaration. data TyClDecl name = ForeignType { tcdLName :: Located name, tcdExtName :: Maybe FastString } | -- | @type/data family T :: *->*@ FamDecl { tcdFam :: FamilyDecl name } | -- | @type@ declaration SynDecl { tcdLName :: Located name -- ^ Type constructor , tcdTyVars :: LHsTyVarBndrs name -- ^ Type variables; for an associated type -- these include outer binders , tcdRhs :: LHsType name -- ^ RHS of type declaration , tcdFVs :: NameSet } | -- | @data@ declaration DataDecl { tcdLName :: Located name -- ^ Type constructor , tcdTyVars :: LHsTyVarBndrs name -- ^ Type variables; for an assoicated type -- these include outer binders -- Eg class T a where -- type F a :: * -- type F a = a -> a -- Here the type decl for 'f' includes 'a' -- in its tcdTyVars , tcdDataDefn :: HsDataDefn name , tcdFVs :: NameSet } | ClassDecl { tcdCtxt :: LHsContext name, -- ^ Context... tcdLName :: Located name, -- ^ Name of the class tcdTyVars :: LHsTyVarBndrs name, -- ^ Class type variables tcdFDs :: [Located (FunDep name)], -- ^ Functional deps tcdSigs :: [LSig name], -- ^ Methods' signatures tcdMeths :: LHsBinds name, -- ^ Default methods tcdATs :: [LFamilyDecl name], -- ^ Associated types; ie tcdATDefs :: [LTyFamInstDecl name], -- ^ Associated type defaults tcdDocs :: [LDocDecl], -- ^ Haddock docs tcdFVs :: NameSet } deriving (Data, Typeable) type LFamilyDecl name = Located (FamilyDecl name) data FamilyDecl name = FamilyDecl { fdFlavour :: FamilyFlavour -- type or data , fdLName :: Located name -- type constructor , fdTyVars :: LHsTyVarBndrs name -- type variables , fdKindSig :: Maybe (LHsKind name) } -- result kind deriving( Data, Typeable ) data FamilyFlavour = TypeFamily | DataFamily deriving( Data, Typeable, Eq ) \end{code} ------------------------------ Simple classifiers \begin{code} -- | @True@ <=> argument is a @data@\/@newtype@ -- declaration. isDataDecl :: TyClDecl name -> Bool isDataDecl (DataDecl {}) = True isDataDecl _other = False -- | type or type instance declaration isSynDecl :: TyClDecl name -> Bool isSynDecl (SynDecl {}) = True isSynDecl _other = False -- | type class isClassDecl :: TyClDecl name -> Bool isClassDecl (ClassDecl {}) = True isClassDecl _ = False -- | type/data family declaration isFamilyDecl :: TyClDecl name -> Bool isFamilyDecl (FamDecl {}) = True isFamilyDecl _other = False -- | type family declaration isTypeFamilyDecl :: TyClDecl name -> Bool isTypeFamilyDecl (FamDecl d) = fdFlavour d == TypeFamily isTypeFamilyDecl _other = False -- | data family declaration isDataFamilyDecl :: TyClDecl name -> Bool isDataFamilyDecl (FamDecl d) = fdFlavour d == DataFamily isDataFamilyDecl _other = False \end{code} Dealing with names \begin{code} tyFamInstDeclName :: OutputableBndr name => TyFamInstDecl name -> name tyFamInstDeclName = unLoc . tyFamInstDeclLName tyFamInstDeclLName :: OutputableBndr name => TyFamInstDecl name -> Located name tyFamInstDeclLName (TyFamInstDecl { tfid_eqns = (L _ (TyFamInstEqn { tfie_tycon = ln })) : _ }) -- there may be more than one equation, but grab the name from the first = ln tyFamInstDeclLName decl = pprPanic "tyFamInstDeclLName" (ppr decl) tyClDeclLName :: TyClDecl name -> Located name tyClDeclLName (FamDecl { tcdFam = FamilyDecl { fdLName = ln } }) = ln tyClDeclLName decl = tcdLName decl tcdName :: TyClDecl name -> name tcdName = unLoc . tyClDeclLName tyClDeclTyVars :: OutputableBndr name => TyClDecl name -> LHsTyVarBndrs name tyClDeclTyVars decl@(ForeignType {}) = pprPanic "tyClDeclTyVars" (ppr decl) tyClDeclTyVars (FamDecl { tcdFam = FamilyDecl { fdTyVars = tvs } }) = tvs tyClDeclTyVars d = tcdTyVars d \end{code} \begin{code} countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int, Int) -- class, synonym decls, data, newtype, family decls countTyClDecls decls = (count isClassDecl decls, count isSynDecl decls, -- excluding... count isDataTy decls, -- ...family... count isNewTy decls, -- ...instances count isFamilyDecl decls) where isDataTy DataDecl{ tcdDataDefn = HsDataDefn { dd_ND = DataType } } = True isDataTy _ = False isNewTy DataDecl{ tcdDataDefn = HsDataDefn { dd_ND = NewType } } = True isNewTy _ = False \end{code} \begin{code} instance OutputableBndr name => Outputable (TyClDecl name) where ppr (ForeignType {tcdLName = ltycon}) = hsep [ptext (sLit "foreign import type dotnet"), ppr ltycon] ppr (FamDecl { tcdFam = decl }) = ppr decl ppr (SynDecl { tcdLName = ltycon, tcdTyVars = tyvars, tcdRhs = rhs }) = hang (ptext (sLit "type") <+> pp_vanilla_decl_head ltycon tyvars [] <+> equals) 4 (ppr rhs) ppr (DataDecl { tcdLName = ltycon, tcdTyVars = tyvars, tcdDataDefn = defn }) = pp_data_defn (pp_vanilla_decl_head ltycon tyvars) defn ppr (ClassDecl {tcdCtxt = context, tcdLName = lclas, tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs, tcdMeths = methods, tcdATs = ats, tcdATDefs = at_defs}) | null sigs && isEmptyBag methods && null ats && null at_defs -- No "where" part = top_matter | otherwise -- Laid out = vcat [ top_matter <+> ptext (sLit "where") , nest 2 $ pprDeclList (map ppr ats ++ map ppr at_defs ++ pprLHsBindsForUser methods sigs) ] where top_matter = ptext (sLit "class") <+> pp_vanilla_decl_head lclas tyvars (unLoc context) <+> pprFundeps (map unLoc fds) instance (OutputableBndr name) => Outputable (FamilyDecl name) where ppr (FamilyDecl { fdFlavour = flavour, fdLName = ltycon, fdTyVars = tyvars, fdKindSig = mb_kind}) = ppr flavour <+> pp_vanilla_decl_head ltycon tyvars [] <+> pp_kind where pp_kind = case mb_kind of Nothing -> empty Just kind -> dcolon <+> ppr kind instance Outputable FamilyFlavour where ppr TypeFamily = ptext (sLit "type family") ppr DataFamily = ptext (sLit "data family") pp_vanilla_decl_head :: OutputableBndr name => Located name -> LHsTyVarBndrs name -> HsContext name -> SDoc pp_vanilla_decl_head thing tyvars context = hsep [pprHsContext context, pprPrefixOcc (unLoc thing), ppr tyvars] pp_fam_inst_lhs :: OutputableBndr name => Located name -> HsWithBndrs [LHsType name] -> HsContext name -> SDoc pp_fam_inst_lhs thing (HsWB { hswb_cts = typats }) context -- explicit type patterns = hsep [ pprHsContext context, pprPrefixOcc (unLoc thing) , hsep (map (pprParendHsType.unLoc) typats)] pprTyClDeclFlavour :: TyClDecl a -> SDoc pprTyClDeclFlavour (ClassDecl {}) = ptext (sLit "class") pprTyClDeclFlavour (FamDecl {}) = ptext (sLit "family") pprTyClDeclFlavour (SynDecl {}) = ptext (sLit "type") pprTyClDeclFlavour (DataDecl { tcdDataDefn = (HsDataDefn { dd_ND = nd }) }) = ppr nd pprTyClDeclFlavour (ForeignType {}) = ptext (sLit "foreign type") \end{code} %************************************************************************ %* * \subsection[ConDecl]{A data-constructor declaration} %* * %************************************************************************ \begin{code} data HsDataDefn name -- The payload of a data type defn -- Used *both* for vanilla data declarations, -- *and* for data family instances = -- | Declares a data type or newtype, giving its constructors -- @ -- data/newtype T a = -- data/newtype instance T [a] = -- @ HsDataDefn { dd_ND :: NewOrData, dd_ctxt :: LHsContext name, -- ^ Context dd_cType :: Maybe CType, dd_kindSig:: Maybe (LHsKind name), -- ^ Optional kind signature. -- -- @(Just k)@ for a GADT-style @data@, -- or @data instance@ decl, with explicit kind sig -- -- Always @Nothing@ for H98-syntax decls dd_cons :: [LConDecl name], -- ^ Data constructors -- -- For @data T a = T1 | T2 a@ -- the 'LConDecl's all have 'ResTyH98'. -- For @data T a where { T1 :: T a }@ -- the 'LConDecls' all have 'ResTyGADT'. dd_derivs :: Maybe [LHsType name] -- ^ Derivings; @Nothing@ => not specified, -- @Just []@ => derive exactly what is asked -- -- These "types" must be of form -- @ -- forall ab. C ty1 ty2 -- @ -- Typically the foralls and ty args are empty, but they -- are non-empty for the newtype-deriving case } deriving( Data, Typeable ) data NewOrData = NewType -- ^ @newtype Blah ...@ | DataType -- ^ @data Blah ...@ deriving( Eq, Data, Typeable ) -- Needed because Demand derives Eq type LConDecl name = Located (ConDecl name) -- data T b = forall a. Eq a => MkT a b -- MkT :: forall b a. Eq a => MkT a b -- data T b where -- MkT1 :: Int -> T Int -- data T = Int `MkT` Int -- | MkT2 -- data T a where -- Int `MkT` Int :: T Int data ConDecl name = ConDecl { con_name :: Located name -- ^ Constructor name. This is used for the DataCon itself, and for -- the user-callable wrapper Id. , con_explicit :: HsExplicitFlag -- ^ Is there an user-written forall? (cf. 'HsTypes.HsForAllTy') , con_qvars :: LHsTyVarBndrs name -- ^ Type variables. Depending on 'con_res' this describes the -- following entities -- -- - ResTyH98: the constructor's *existential* type variables -- - ResTyGADT: *all* the constructor's quantified type variables -- -- If con_explicit is Implicit, then con_qvars is irrelevant -- until after renaming. , con_cxt :: LHsContext name -- ^ The context. This /does not/ include the \"stupid theta\" which -- lives only in the 'TyData' decl. , con_details :: HsConDeclDetails name -- ^ The main payload , con_res :: ResType (LHsType name) -- ^ Result type of the constructor , con_doc :: Maybe LHsDocString -- ^ A possible Haddock comment. , con_old_rec :: Bool -- ^ TEMPORARY field; True <=> user has employed now-deprecated syntax for -- GADT-style record decl C { blah } :: T a b -- Remove this when we no longer parse this stuff, and hence do not -- need to report decprecated use } deriving (Data, Typeable) type HsConDeclDetails name = HsConDetails (LBangType name) [ConDeclField name] hsConDeclArgTys :: HsConDeclDetails name -> [LBangType name] hsConDeclArgTys (PrefixCon tys) = tys hsConDeclArgTys (InfixCon ty1 ty2) = [ty1,ty2] hsConDeclArgTys (RecCon flds) = map cd_fld_type flds data ResType ty = ResTyH98 -- Constructor was declared using Haskell 98 syntax | ResTyGADT ty -- Constructor was declared using GADT-style syntax, -- and here is its result type deriving (Data, Typeable) instance Outputable ty => Outputable (ResType ty) where -- Debugging only ppr ResTyH98 = ptext (sLit "ResTyH98") ppr (ResTyGADT ty) = ptext (sLit "ResTyGADT") <+> ppr ty \end{code} \begin{code} pp_data_defn :: OutputableBndr name => (HsContext name -> SDoc) -- Printing the header -> HsDataDefn name -> SDoc pp_data_defn pp_hdr (HsDataDefn { dd_ND = new_or_data, dd_ctxt = L _ context , dd_kindSig = mb_sig , dd_cons = condecls, dd_derivs = derivings }) | null condecls = ppr new_or_data <+> pp_hdr context <+> pp_sig | otherwise = hang (ppr new_or_data <+> pp_hdr context <+> pp_sig) 2 (pp_condecls condecls $$ pp_derivings) where pp_sig = case mb_sig of Nothing -> empty Just kind -> dcolon <+> ppr kind pp_derivings = case derivings of Nothing -> empty Just ds -> hsep [ptext (sLit "deriving"), parens (interpp'SP ds)] instance OutputableBndr name => Outputable (HsDataDefn name) where ppr d = pp_data_defn (\_ -> ptext (sLit "Naked HsDataDefn")) d instance Outputable NewOrData where ppr NewType = ptext (sLit "newtype") ppr DataType = ptext (sLit "data") pp_condecls :: OutputableBndr name => [LConDecl name] -> SDoc pp_condecls cs@(L _ ConDecl{ con_res = ResTyGADT _ } : _) -- In GADT syntax = hang (ptext (sLit "where")) 2 (vcat (map ppr cs)) pp_condecls cs -- In H98 syntax = equals <+> sep (punctuate (ptext (sLit " |")) (map ppr cs)) instance (OutputableBndr name) => Outputable (ConDecl name) where ppr = pprConDecl pprConDecl :: OutputableBndr name => ConDecl name -> SDoc pprConDecl (ConDecl { con_name = con, con_explicit = expl, con_qvars = tvs , con_cxt = cxt, con_details = details , con_res = ResTyH98, con_doc = doc }) = sep [ppr_mbDoc doc, pprHsForAll expl tvs cxt, ppr_details details] where ppr_details (InfixCon t1 t2) = hsep [ppr t1, pprInfixOcc (unLoc con), ppr t2] ppr_details (PrefixCon tys) = hsep (pprPrefixOcc (unLoc con) : map (pprParendHsType . unLoc) tys) ppr_details (RecCon fields) = ppr con <+> pprConDeclFields fields pprConDecl (ConDecl { con_name = con, con_explicit = expl, con_qvars = tvs , con_cxt = cxt, con_details = PrefixCon arg_tys , con_res = ResTyGADT res_ty }) = ppr con <+> dcolon <+> sep [pprHsForAll expl tvs cxt, ppr (foldr mk_fun_ty res_ty arg_tys)] where mk_fun_ty a b = noLoc (HsFunTy a b) pprConDecl (ConDecl { con_name = con, con_explicit = expl, con_qvars = tvs , con_cxt = cxt, con_details = RecCon fields, con_res = ResTyGADT res_ty }) = sep [ppr con <+> dcolon <+> pprHsForAll expl tvs cxt, pprConDeclFields fields <+> arrow <+> ppr res_ty] pprConDecl decl@(ConDecl { con_details = InfixCon ty1 ty2, con_res = ResTyGADT {} }) = pprConDecl (decl { con_details = PrefixCon [ty1,ty2] }) -- In GADT syntax we don't allow infix constructors -- but the renamer puts them in this form (Note [Infix GADT constructors] in RnSource) \end{code} %************************************************************************ %* * Instance declarations %* * %************************************************************************ \begin{code} ----------------- Type synonym family instances ------------- -- See note [Family instance equation groups] type LTyFamInstEqn name = Located (TyFamInstEqn name) -- | One equation in a family instance declaration data TyFamInstEqn name = TyFamInstEqn { tfie_tycon :: Located name , tfie_pats :: HsWithBndrs [LHsType name] -- ^ Type patterns (with kind and type bndrs) -- See Note [Family instance declaration binders] , tfie_rhs :: LHsType name } deriving( Typeable, Data ) type LTyFamInstDecl name = Located (TyFamInstDecl name) data TyFamInstDecl name = TyFamInstDecl { tfid_eqns :: [LTyFamInstEqn name] -- ^ list of (possibly-overlapping) eqns -- Always non-empty , tfid_group :: Bool -- Was this declared with the "where" syntax? , tfid_fvs :: NameSet } -- The group is type-checked as one, -- so one NameSet will do -- INVARIANT: tfid_group == False --> length tfid_eqns == 1 deriving( Typeable, Data ) ----------------- Data family instances ------------- type LDataFamInstDecl name = Located (DataFamInstDecl name) data DataFamInstDecl name = DataFamInstDecl { dfid_tycon :: Located name , dfid_pats :: HsWithBndrs [LHsType name] -- lhs -- ^ Type patterns (with kind and type bndrs) -- See Note [Family instance declaration binders] , dfid_defn :: HsDataDefn name -- rhs , dfid_fvs :: NameSet } -- free vars for dependency analysis deriving( Typeable, Data ) ----------------- Class instances ------------- type LClsInstDecl name = Located (ClsInstDecl name) data ClsInstDecl name = ClsInstDecl { cid_poly_ty :: LHsType name -- Context => Class Instance-type -- Using a polytype means that the renamer conveniently -- figures out the quantified type variables for us. , cid_binds :: LHsBinds name , cid_sigs :: [LSig name] -- User-supplied pragmatic info , cid_tyfam_insts :: [LTyFamInstDecl name] -- type family instances , cid_datafam_insts :: [LDataFamInstDecl name] -- data family instances } deriving (Data, Typeable) ----------------- Instances of all kinds ------------- type LInstDecl name = Located (InstDecl name) data InstDecl name -- Both class and family instances = ClsInstD { cid_inst :: ClsInstDecl name } | DataFamInstD -- data family instance { dfid_inst :: DataFamInstDecl name } | TyFamInstD -- type family instance { tfid_inst :: TyFamInstDecl name } deriving (Data, Typeable) \end{code} Note [Family instance declaration binders] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A {Ty|Data}FamInstDecl is a data/type family instance declaration the pats field is LHS patterns, and the tvs of the HsBSig tvs are fv(pat_tys), *including* ones that are already in scope Eg class C s t where type F t p :: * instance C w (a,b) where type F (a,b) x = x->a The tcdTyVars of the F decl are {a,b,x}, even though the F decl is nested inside the 'instance' decl. However after the renamer, the uniques will match up: instance C w7 (a8,b9) where type F (a8,b9) x10 = x10->a8 so that we can compare the type patter in the 'instance' decl and in the associated 'type' decl Note [Family instance equation groups] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A TyFamInstDecl contains a list of FamInstEqn's, one for each equation defined in the instance group. For a standalone instance declaration, this list contains exactly one element. It is not possible for this list to have 0 elements -- 'type instance where' without anything else is not allowed. \begin{code} instance (OutputableBndr name) => Outputable (TyFamInstDecl name) where ppr = pprTyFamInstDecl TopLevel pprTyFamInstDecl :: OutputableBndr name => TopLevelFlag -> TyFamInstDecl name -> SDoc pprTyFamInstDecl top_lvl (TyFamInstDecl { tfid_group = False, tfid_eqns = [eqn] }) = ptext (sLit "type") <+> ppr_instance_keyword top_lvl <+> (ppr eqn) pprTyFamInstDecl top_lvl (TyFamInstDecl { tfid_eqns = eqns }) = hang (ptext (sLit "type") <+> ppr_instance_keyword top_lvl <+> ptext (sLit "where")) 2 (vcat (map ppr eqns)) ppr_instance_keyword :: TopLevelFlag -> SDoc ppr_instance_keyword TopLevel = ptext (sLit "instance") ppr_instance_keyword NotTopLevel = empty instance (OutputableBndr name) => Outputable (TyFamInstEqn name) where ppr (TyFamInstEqn { tfie_tycon = tycon , tfie_pats = pats , tfie_rhs = rhs }) = (pp_fam_inst_lhs tycon pats []) <+> equals <+> (ppr rhs) instance (OutputableBndr name) => Outputable (DataFamInstDecl name) where ppr = pprDataFamInstDecl TopLevel pprDataFamInstDecl :: OutputableBndr name => TopLevelFlag -> DataFamInstDecl name -> SDoc pprDataFamInstDecl top_lvl (DataFamInstDecl { dfid_tycon = tycon , dfid_pats = pats , dfid_defn = defn }) = pp_data_defn pp_hdr defn where pp_hdr ctxt = ppr_instance_keyword top_lvl <+> pp_fam_inst_lhs tycon pats ctxt pprDataFamInstFlavour :: DataFamInstDecl name -> SDoc pprDataFamInstFlavour (DataFamInstDecl { dfid_defn = (HsDataDefn { dd_ND = nd }) }) = ppr nd instance (OutputableBndr name) => Outputable (ClsInstDecl name) where ppr (ClsInstDecl { cid_poly_ty = inst_ty, cid_binds = binds , cid_sigs = sigs, cid_tyfam_insts = ats , cid_datafam_insts = adts }) | null sigs, null ats, null adts, isEmptyBag binds -- No "where" part = top_matter | otherwise -- Laid out = vcat [ top_matter <+> ptext (sLit "where") , nest 2 $ pprDeclList $ map (pprTyFamInstDecl NotTopLevel . unLoc) ats ++ map (pprDataFamInstDecl NotTopLevel . unLoc) adts ++ pprLHsBindsForUser binds sigs ] where top_matter = ptext (sLit "instance") <+> ppr inst_ty instance (OutputableBndr name) => Outputable (InstDecl name) where ppr (ClsInstD { cid_inst = decl }) = ppr decl ppr (TyFamInstD { tfid_inst = decl }) = ppr decl ppr (DataFamInstD { dfid_inst = decl }) = ppr decl -- Extract the declarations of associated data types from an instance instDeclDataFamInsts :: [LInstDecl name] -> [DataFamInstDecl name] instDeclDataFamInsts inst_decls = concatMap do_one inst_decls where do_one (L _ (ClsInstD { cid_inst = ClsInstDecl { cid_datafam_insts = fam_insts } })) = map unLoc fam_insts do_one (L _ (DataFamInstD { dfid_inst = fam_inst })) = [fam_inst] do_one (L _ (TyFamInstD {})) = [] \end{code} %************************************************************************ %* * \subsection[DerivDecl]{A stand-alone instance deriving declaration} %* * %************************************************************************ \begin{code} type LDerivDecl name = Located (DerivDecl name) data DerivDecl name = DerivDecl { deriv_type :: LHsType name } deriving (Data, Typeable) instance (OutputableBndr name) => Outputable (DerivDecl name) where ppr (DerivDecl ty) = hsep [ptext (sLit "deriving instance"), ppr ty] \end{code} %************************************************************************ %* * \subsection[DefaultDecl]{A @default@ declaration} %* * %************************************************************************ There can only be one default declaration per module, but it is hard for the parser to check that; we pass them all through in the abstract syntax, and that restriction must be checked in the front end. \begin{code} type LDefaultDecl name = Located (DefaultDecl name) data DefaultDecl name = DefaultDecl [LHsType name] deriving (Data, Typeable) instance (OutputableBndr name) => Outputable (DefaultDecl name) where ppr (DefaultDecl tys) = ptext (sLit "default") <+> parens (interpp'SP tys) \end{code} %************************************************************************ %* * \subsection{Foreign function interface declaration} %* * %************************************************************************ \begin{code} -- foreign declarations are distinguished as to whether they define or use a -- Haskell name -- -- * the Boolean value indicates whether the pre-standard deprecated syntax -- has been used -- type LForeignDecl name = Located (ForeignDecl name) data ForeignDecl name = ForeignImport (Located name) -- defines this name (LHsType name) -- sig_ty Coercion -- rep_ty ~ sig_ty ForeignImport | ForeignExport (Located name) -- uses this name (LHsType name) -- sig_ty Coercion -- sig_ty ~ rep_ty ForeignExport deriving (Data, Typeable) {- In both ForeignImport and ForeignExport: sig_ty is the type given in the Haskell code rep_ty is the representation for this type, i.e. with newtypes coerced away and type functions evaluated. Thus if the declaration is valid, then rep_ty will only use types such as Int and IO that we know how to make foreign calls with. -} noForeignImportCoercionYet :: Coercion noForeignImportCoercionYet = panic "ForeignImport coercion evaluated before typechecking" noForeignExportCoercionYet :: Coercion noForeignExportCoercionYet = panic "ForeignExport coercion evaluated before typechecking" -- Specification Of an imported external entity in dependence on the calling -- convention -- data ForeignImport = -- import of a C entity -- -- * the two strings specifying a header file or library -- may be empty, which indicates the absence of a -- header or object specification (both are not used -- in the case of `CWrapper' and when `CFunction' -- has a dynamic target) -- -- * the calling convention is irrelevant for code -- generation in the case of `CLabel', but is needed -- for pretty printing -- -- * `Safety' is irrelevant for `CLabel' and `CWrapper' -- CImport CCallConv -- ccall or stdcall Safety -- interruptible, safe or unsafe (Maybe Header) -- name of C header CImportSpec -- details of the C entity deriving (Data, Typeable) -- details of an external C entity -- data CImportSpec = CLabel CLabelString -- import address of a C label | CFunction CCallTarget -- static or dynamic function | CWrapper -- wrapper to expose closures -- (former f.e.d.) deriving (Data, Typeable) -- specification of an externally exported entity in dependence on the calling -- convention -- data ForeignExport = CExport CExportSpec -- contains the calling convention deriving (Data, Typeable) -- pretty printing of foreign declarations -- instance OutputableBndr name => Outputable (ForeignDecl name) where ppr (ForeignImport n ty _ fimport) = hang (ptext (sLit "foreign import") <+> ppr fimport <+> ppr n) 2 (dcolon <+> ppr ty) ppr (ForeignExport n ty _ fexport) = hang (ptext (sLit "foreign export") <+> ppr fexport <+> ppr n) 2 (dcolon <+> ppr ty) instance Outputable ForeignImport where ppr (CImport cconv safety mHeader spec) = ppr cconv <+> ppr safety <+> char '"' <> pprCEntity spec <> char '"' where pp_hdr = case mHeader of Nothing -> empty Just (Header header) -> ftext header pprCEntity (CLabel lbl) = ptext (sLit "static") <+> pp_hdr <+> char '&' <> ppr lbl pprCEntity (CFunction (StaticTarget lbl _ isFun)) = ptext (sLit "static") <+> pp_hdr <+> (if isFun then empty else ptext (sLit "value")) <+> ppr lbl pprCEntity (CFunction (DynamicTarget)) = ptext (sLit "dynamic") pprCEntity (CWrapper) = ptext (sLit "wrapper") instance Outputable ForeignExport where ppr (CExport (CExportStatic lbl cconv)) = ppr cconv <+> char '"' <> ppr lbl <> char '"' \end{code} %************************************************************************ %* * \subsection{Transformation rules} %* * %************************************************************************ \begin{code} type LRuleDecl name = Located (RuleDecl name) data RuleDecl name = HsRule -- Source rule RuleName -- Rule name Activation [RuleBndr name] -- Forall'd vars; after typechecking this includes tyvars (Located (HsExpr name)) -- LHS NameSet -- Free-vars from the LHS (Located (HsExpr name)) -- RHS NameSet -- Free-vars from the RHS deriving (Data, Typeable) data RuleBndr name = RuleBndr (Located name) | RuleBndrSig (Located name) (HsWithBndrs (LHsType name)) deriving (Data, Typeable) collectRuleBndrSigTys :: [RuleBndr name] -> [HsWithBndrs (LHsType name)] collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs] instance OutputableBndr name => Outputable (RuleDecl name) where ppr (HsRule name act ns lhs _fv_lhs rhs _fv_rhs) = sep [text "{-# RULES" <+> doubleQuotes (ftext name) <+> ppr act, nest 4 (pp_forall <+> pprExpr (unLoc lhs)), nest 4 (equals <+> pprExpr (unLoc rhs) <+> text "#-}") ] where pp_forall | null ns = empty | otherwise = text "forall" <+> fsep (map ppr ns) <> dot instance OutputableBndr name => Outputable (RuleBndr name) where ppr (RuleBndr name) = ppr name ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty \end{code} %************************************************************************ %* * \subsection{Vectorisation declarations} %* * %************************************************************************ A vectorisation pragma, one of {-# VECTORISE f = closure1 g (scalar_map g) #-} {-# VECTORISE SCALAR f #-} {-# NOVECTORISE f #-} {-# VECTORISE type T = ty #-} {-# VECTORISE SCALAR type T #-} \begin{code} type LVectDecl name = Located (VectDecl name) data VectDecl name = HsVect (Located name) (LHsExpr name) | HsNoVect (Located name) | HsVectTypeIn -- pre type-checking Bool -- 'TRUE' => SCALAR declaration (Located name) (Maybe (Located name)) -- 'Nothing' => no right-hand side | HsVectTypeOut -- post type-checking Bool -- 'TRUE' => SCALAR declaration TyCon (Maybe TyCon) -- 'Nothing' => no right-hand side | HsVectClassIn -- pre type-checking (Located name) | HsVectClassOut -- post type-checking Class | HsVectInstIn -- pre type-checking (always SCALAR) !!!FIXME: should be superfluous now (LHsType name) | HsVectInstOut -- post type-checking (always SCALAR) !!!FIXME: should be superfluous now ClsInst deriving (Data, Typeable) lvectDeclName :: NamedThing name => LVectDecl name -> Name lvectDeclName (L _ (HsVect (L _ name) _)) = getName name lvectDeclName (L _ (HsNoVect (L _ name))) = getName name lvectDeclName (L _ (HsVectTypeIn _ (L _ name) _)) = getName name lvectDeclName (L _ (HsVectTypeOut _ tycon _)) = getName tycon lvectDeclName (L _ (HsVectClassIn (L _ name))) = getName name lvectDeclName (L _ (HsVectClassOut cls)) = getName cls lvectDeclName (L _ (HsVectInstIn _)) = panic "HsDecls.lvectDeclName: HsVectInstIn" lvectDeclName (L _ (HsVectInstOut _)) = panic "HsDecls.lvectDeclName: HsVectInstOut" lvectInstDecl :: LVectDecl name -> Bool lvectInstDecl (L _ (HsVectInstIn _)) = True lvectInstDecl (L _ (HsVectInstOut _)) = True lvectInstDecl _ = False instance OutputableBndr name => Outputable (VectDecl name) where ppr (HsVect v rhs) = sep [text "{-# VECTORISE" <+> ppr v, nest 4 $ pprExpr (unLoc rhs) <+> text "#-}" ] ppr (HsNoVect v) = sep [text "{-# NOVECTORISE" <+> ppr v <+> text "#-}" ] ppr (HsVectTypeIn False t Nothing) = sep [text "{-# VECTORISE type" <+> ppr t <+> text "#-}" ] ppr (HsVectTypeIn False t (Just t')) = sep [text "{-# VECTORISE type" <+> ppr t, text "=", ppr t', text "#-}" ] ppr (HsVectTypeIn True t Nothing) = sep [text "{-# VECTORISE SCALAR type" <+> ppr t <+> text "#-}" ] ppr (HsVectTypeIn True t (Just t')) = sep [text "{-# VECTORISE SCALAR type" <+> ppr t, text "=", ppr t', text "#-}" ] ppr (HsVectTypeOut False t Nothing) = sep [text "{-# VECTORISE type" <+> ppr t <+> text "#-}" ] ppr (HsVectTypeOut False t (Just t')) = sep [text "{-# VECTORISE type" <+> ppr t, text "=", ppr t', text "#-}" ] ppr (HsVectTypeOut True t Nothing) = sep [text "{-# VECTORISE SCALAR type" <+> ppr t <+> text "#-}" ] ppr (HsVectTypeOut True t (Just t')) = sep [text "{-# VECTORISE SCALAR type" <+> ppr t, text "=", ppr t', text "#-}" ] ppr (HsVectClassIn c) = sep [text "{-# VECTORISE class" <+> ppr c <+> text "#-}" ] ppr (HsVectClassOut c) = sep [text "{-# VECTORISE class" <+> ppr c <+> text "#-}" ] ppr (HsVectInstIn ty) = sep [text "{-# VECTORISE SCALAR instance" <+> ppr ty <+> text "#-}" ] ppr (HsVectInstOut i) = sep [text "{-# VECTORISE SCALAR instance" <+> ppr i <+> text "#-}" ] \end{code} %************************************************************************ %* * \subsection[DocDecl]{Document comments} %* * %************************************************************************ \begin{code} type LDocDecl = Located (DocDecl) data DocDecl = DocCommentNext HsDocString | DocCommentPrev HsDocString | DocCommentNamed String HsDocString | DocGroup Int HsDocString deriving (Data, Typeable) -- Okay, I need to reconstruct the document comments, but for now: instance Outputable DocDecl where ppr _ = text "" docDeclDoc :: DocDecl -> HsDocString docDeclDoc (DocCommentNext d) = d docDeclDoc (DocCommentPrev d) = d docDeclDoc (DocCommentNamed _ d) = d docDeclDoc (DocGroup _ d) = d \end{code} %************************************************************************ %* * \subsection[DeprecDecl]{Deprecations} %* * %************************************************************************ We use exported entities for things to deprecate. \begin{code} type LWarnDecl name = Located (WarnDecl name) data WarnDecl name = Warning name WarningTxt deriving (Data, Typeable) instance OutputableBndr name => Outputable (WarnDecl name) where ppr (Warning thing txt) = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"] \end{code} %************************************************************************ %* * \subsection[AnnDecl]{Annotations} %* * %************************************************************************ \begin{code} type LAnnDecl name = Located (AnnDecl name) data AnnDecl name = HsAnnotation (AnnProvenance name) (Located (HsExpr name)) deriving (Data, Typeable) instance (OutputableBndr name) => Outputable (AnnDecl name) where ppr (HsAnnotation provenance expr) = hsep [text "{-#", pprAnnProvenance provenance, pprExpr (unLoc expr), text "#-}"] data AnnProvenance name = ValueAnnProvenance name | TypeAnnProvenance name | ModuleAnnProvenance deriving (Data, Typeable, Functor, Foldable, Traversable) annProvenanceName_maybe :: AnnProvenance name -> Maybe name annProvenanceName_maybe (ValueAnnProvenance name) = Just name annProvenanceName_maybe (TypeAnnProvenance name) = Just name annProvenanceName_maybe ModuleAnnProvenance = Nothing pprAnnProvenance :: OutputableBndr name => AnnProvenance name -> SDoc pprAnnProvenance ModuleAnnProvenance = ptext (sLit "ANN module") pprAnnProvenance (ValueAnnProvenance name) = ptext (sLit "ANN") <+> ppr name pprAnnProvenance (TypeAnnProvenance name) = ptext (sLit "ANN type") <+> ppr name \end{code}