% % (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % HsDecls: Abstract syntax: global declarations Definitions for: @TyDecl@ and @oCnDecl@, @ClassDecl@, @InstDecl@, @DefaultDecl@ and @ForeignDecl@. \begin{code} module HsDecls ( HsDecl(..), LHsDecl, TyClDecl(..), LTyClDecl, InstDecl(..), LInstDecl, DerivDecl(..), LDerivDecl, NewOrData(..), FamilyFlavour(..), RuleDecl(..), LRuleDecl, RuleBndr(..), DefaultDecl(..), LDefaultDecl, SpliceDecl(..), ForeignDecl(..), LForeignDecl, ForeignImport(..), ForeignExport(..), CImportSpec(..), FoType(..), ConDecl(..), ResType(..), LConDecl, DocDecl(..), LDocDecl, docDeclDoc, DeprecDecl(..), LDeprecDecl, HsGroup(..), emptyRdrGroup, emptyRnGroup, appendGroups, tcdName, tyClDeclNames, tyClDeclTyVars, isClassDecl, isSynDecl, isDataDecl, isTypeDecl, isFamilyDecl, isFamInstDecl, countTyClDecls, conDetailsTys, instDeclATs, collectRuleBndrSigTys, ) where #include "HsVersions.h" -- friends: import {-# SOURCE #-} HsExpr( HsExpr, pprExpr ) -- Because Expr imports Decls via HsBracket import HsBinds import HsPat import HsImpExp import HsTypes import HsDoc import NameSet import CoreSyn import {- Kind parts of -} Type import BasicTypes import ForeignCall -- others: import Class import Outputable import Util import SrcLoc import FastString import Data.Maybe ( isJust ) \end{code} %************************************************************************ %* * \subsection[HsDecl]{Declarations} %* * %************************************************************************ \begin{code} type LHsDecl id = Located (HsDecl id) data HsDecl id = TyClD (TyClDecl id) | InstD (InstDecl id) | DerivD (DerivDecl id) | ValD (HsBind id) | SigD (Sig id) | DefD (DefaultDecl id) | ForD (ForeignDecl id) | DeprecD (DeprecDecl id) | RuleD (RuleDecl id) | SpliceD (SpliceDecl id) | DocD (DocDecl id) -- 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], hs_instds :: [LInstDecl id], 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_depds :: [LDeprecDecl id], hs_ruleds :: [LRuleDecl id], hs_docs :: [LDocDecl id] } 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_fords = [], hs_depds = [], hs_ruleds = [], 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_fords = fords1, hs_depds = depds1, hs_ruleds = rulds1, hs_docs = docs1 } HsGroup { hs_valds = val_groups2, hs_tyclds = tyclds2, hs_instds = instds2, hs_derivds = derivds2, hs_fixds = fixds2, hs_defds = defds2, hs_fords = fords2, hs_depds = depds2, hs_ruleds = rulds2, 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_defds = defds1 ++ defds2, hs_fords = fords1 ++ fords2, hs_depds = depds1 ++ depds2, hs_ruleds = rulds1 ++ rulds2, 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 (DeprecD dd) = ppr dd ppr (SpliceD dd) = ppr dd ppr (DocD doc) = ppr doc 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_depds = deprec_decls, hs_fords = foreign_decls, hs_defds = default_decls, hs_ruleds = rule_decls }) = vcat [ppr_ds fix_decls, ppr_ds default_decls, ppr_ds deprec_decls, ppr_ds rule_decls, ppr val_decls, ppr_ds tycl_decls, ppr_ds inst_decls, ppr_ds deriv_decls, ppr_ds foreign_decls] where ppr_ds [] = empty ppr_ds ds = text "" $$ vcat (map ppr ds) data SpliceDecl id = SpliceDecl (Located (HsExpr id)) -- Top level splice instance OutputableBndr name => Outputable (SpliceDecl name) where ppr (SpliceDecl e) = ptext SLIT("$") <> parens (pprExpr (unLoc e)) \end{code} %************************************************************************ %* * \subsection[TyDecl]{@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} -- Representation of indexed types -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Family kind signatures are represented by the variant `TyFamily'. It -- covers "type family", "newtype family", and "data family" declarations, -- distinguished by the value of the field `tcdFlavour'. -- -- Indexed types are represented by 'TyData' and 'TySynonym' using the field -- 'tcdTyPats::Maybe [LHsType name]', with the following meaning: -- -- * If it is 'Nothing', we have a *vanilla* data type declaration or type -- synonym declaration and 'tcdVars' contains the type parameters of the -- type constructor. -- -- * If it is 'Just pats', we have the definition of an indexed type. Then, -- 'pats' are type patterns for the type-indexes of the type constructor -- and 'tcdVars' are the variables in those patterns. Hence, the arity of -- the indexed type (ie, the number of indexes) is 'length tcdTyPats' and -- *not* 'length tcdVars'. -- -- In both cases, 'tcdVars' collects all variables we need to quantify over. type LTyClDecl name = Located (TyClDecl name) data TyClDecl name = ForeignType { tcdLName :: Located name, tcdExtName :: FastString, tcdFoType :: FoType } -- type/data/newtype family T :: *->* | TyFamily { tcdFlavour:: FamilyFlavour, -- type, new, or data tcdLName :: Located name, -- type constructor tcdTyVars :: [LHsTyVarBndr name], -- type variables tcdKind :: Maybe Kind -- result kind } -- Declares a data type or newtype, giving its construcors -- data/newtype T a = -- data/newtype instance T [a] = | TyData { tcdND :: NewOrData, tcdCtxt :: LHsContext name, -- Context tcdLName :: Located name, -- Type constructor tcdTyVars :: [LHsTyVarBndr name], -- Type variables tcdTyPats :: Maybe [LHsType name], -- Type patterns -- Just [t1..tn] for data instance T t1..tn = ... -- in this case tcdTyVars = fv( tcdTyPats ) -- Nothing for everything else tcdKindSig:: Maybe Kind, -- Optional kind sig -- (Just k) for a GADT-style 'data', or 'data -- instance' decl with explicit kind sig tcdCons :: [LConDecl name], -- Data constructors -- For data T a = T1 | T2 a the LConDecls all have ResTyH98 -- For data T a where { T1 :: T a } the LConDecls all have ResTyGADT tcdDerivs :: 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 } | TySynonym { tcdLName :: Located name, -- type constructor tcdTyVars :: [LHsTyVarBndr name], -- type variables tcdTyPats :: Maybe [LHsType name], -- Type patterns -- See comments for tcdTyPats in TyData -- 'Nothing' => vanilla type synonym tcdSynRhs :: LHsType name -- synonym expansion } | ClassDecl { tcdCtxt :: LHsContext name, -- Context... tcdLName :: Located name, -- Name of the class tcdTyVars :: [LHsTyVarBndr name], -- Class type variables tcdFDs :: [Located (FunDep name)], -- Functional deps tcdSigs :: [LSig name], -- Methods' signatures tcdMeths :: LHsBinds name, -- Default methods tcdATs :: [LTyClDecl name], -- Associated types; ie -- only 'TyData', -- 'TyFunction', -- and 'TySynonym' tcdDocs :: [LDocDecl name] -- Haddock docs } data NewOrData = NewType -- "newtype Blah ..." | DataType -- "data Blah ..." deriving( Eq ) -- Needed because Demand derives Eq data FamilyFlavour = TypeFamily -- "type family ..." | DataFamily NewOrData -- "newtype family ..." or "data family ..." \end{code} Simple classifiers \begin{code} isDataDecl, isTypeDecl, isSynDecl, isClassDecl, isFamilyDecl, isFamInstDecl :: TyClDecl name -> Bool -- data/newtype or data/newtype instance declaration isDataDecl (TyData {}) = True isDataDecl _other = False -- type or type instance declaration isTypeDecl (TySynonym {}) = True isTypeDecl _other = False -- vanilla Haskell type synonym (ie, not a type instance) isSynDecl (TySynonym {tcdTyPats = Nothing}) = True isSynDecl _other = False -- type class isClassDecl (ClassDecl {}) = True isClassDecl other = False -- type family declaration isFamilyDecl (TyFamily {}) = True isFamilyDecl _other = False -- family instance (types, newtypes, and data types) isFamInstDecl tydecl | isTypeDecl tydecl || isDataDecl tydecl = isJust (tcdTyPats tydecl) | otherwise = False \end{code} Dealing with names \begin{code} tcdName :: TyClDecl name -> name tcdName decl = unLoc (tcdLName decl) tyClDeclNames :: Eq name => TyClDecl name -> [Located name] -- Returns all the *binding* names of the decl, along with their SrcLocs -- The first one is guaranteed to be the name of the decl -- For record fields, the first one counts as the SrcLoc -- We use the equality to filter out duplicate field names tyClDeclNames (TyFamily {tcdLName = name}) = [name] tyClDeclNames (TySynonym {tcdLName = name}) = [name] tyClDeclNames (ForeignType {tcdLName = name}) = [name] tyClDeclNames (ClassDecl {tcdLName = cls_name, tcdSigs = sigs, tcdATs = ats}) = cls_name : concatMap (tyClDeclNames . unLoc) ats ++ [n | L _ (TypeSig n _) <- sigs] tyClDeclNames (TyData {tcdLName = tc_name, tcdCons = cons}) = tc_name : conDeclsNames (map unLoc cons) tyClDeclTyVars (TyFamily {tcdTyVars = tvs}) = tvs tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs tyClDeclTyVars (ForeignType {}) = [] \end{code} \begin{code} countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int, Int, Int) -- class, synonym decls, data, newtype, family decls, family instances countTyClDecls decls = (count isClassDecl decls, count isSynDecl decls, -- excluding... count isDataTy decls, -- ...family... count isNewTy decls, -- ...instances count isFamilyDecl decls, count isFamInstDecl decls) where isDataTy TyData{tcdND = DataType, tcdTyPats = Nothing} = True isDataTy _ = False isNewTy TyData{tcdND = NewType, tcdTyPats = Nothing} = True isNewTy _ = False \end{code} \begin{code} instance OutputableBndr name => Outputable (TyClDecl name) where ppr (ForeignType {tcdLName = ltycon, tcdFoType = fo_type }) = ptext SLIT("foreign import") <+> ppr fo_type <+> ptext SLIT("type") <+> ppr ltycon ppr (TyFamily {tcdFlavour = flavour, tcdLName = ltycon, tcdTyVars = tyvars, tcdKind = mb_kind}) = pp_flavour <+> pp_decl_head [] ltycon tyvars Nothing <+> pp_kind where pp_flavour = case flavour of TypeFamily -> ptext SLIT("type family") DataFamily NewType -> ptext SLIT("newtype family") DataFamily DataType -> ptext SLIT("data family") pp_kind = case mb_kind of Nothing -> empty Just kind -> dcolon <+> pprKind kind ppr (TySynonym {tcdLName = ltycon, tcdTyVars = tyvars, tcdTyPats = typats, tcdSynRhs = mono_ty}) = hang (ptext SLIT("type") <+> (if isJust typats then ptext SLIT("instance") else empty) <+> pp_decl_head [] ltycon tyvars typats <+> equals) 4 (ppr mono_ty) ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = ltycon, tcdTyVars = tyvars, tcdTyPats = typats, tcdKindSig = mb_sig, tcdCons = condecls, tcdDerivs = derivings}) = pp_tydecl (null condecls && isJust mb_sig) (ppr new_or_data <+> (if isJust typats then ptext SLIT("instance") else empty) <+> pp_decl_head (unLoc context) ltycon tyvars typats <+> ppr_sig mb_sig) (pp_condecls condecls) derivings where ppr_sig Nothing = empty ppr_sig (Just kind) = dcolon <+> pprKind kind ppr (ClassDecl {tcdCtxt = context, tcdLName = lclas, tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs, tcdMeths = methods, tcdATs = ats}) | null sigs && null ats -- No "where" part = top_matter | otherwise -- Laid out = sep [hsep [top_matter, ptext SLIT("where {")], nest 4 (sep [ sep (map ppr_semi ats) , sep (map ppr_semi sigs) , pprLHsBinds methods , char '}'])] where top_matter = ptext SLIT("class") <+> pp_decl_head (unLoc context) lclas tyvars Nothing <+> pprFundeps (map unLoc fds) ppr_semi decl = ppr decl <> semi pp_decl_head :: OutputableBndr name => HsContext name -> Located name -> [LHsTyVarBndr name] -> Maybe [LHsType name] -> SDoc pp_decl_head context thing tyvars Nothing -- no explicit type patterns = hsep [pprHsContext context, ppr thing, interppSP tyvars] pp_decl_head context thing _ (Just typats) -- explicit type patterns = hsep [ pprHsContext context, ppr thing , hsep (map (pprParendHsType.unLoc) typats)] 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)) pp_tydecl True pp_head pp_decl_rhs derivings = pp_head pp_tydecl False pp_head pp_decl_rhs derivings = hang pp_head 4 (sep [ pp_decl_rhs, case derivings of Nothing -> empty Just ds -> hsep [ptext SLIT("deriving"), parens (interpp'SP ds)] ]) instance Outputable NewOrData where ppr NewType = ptext SLIT("newtype") ppr DataType = ptext SLIT("data") \end{code} %************************************************************************ %* * \subsection[ConDecl]{A data-constructor declaration} %* * %************************************************************************ \begin{code} 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 :: HsExplicitForAll -- Is there an user-written forall? (cf. HStypes.HsForAllTy) , con_qvars :: [LHsTyVarBndr name] -- ResTyH98: the constructor's existential type variables -- ResTyGADT: all the constructor's quantified type variables , con_cxt :: LHsContext name -- The context. This *does not* include the -- "stupid theta" which lives only in the TyData decl , con_details :: HsConDetails name (LBangType name) -- The main payload , con_res :: ResType name -- Result type of the constructor , con_doc :: Maybe (LHsDoc name) -- A possible Haddock comment } data ResType name = ResTyH98 -- Constructor was declared using Haskell 98 syntax | ResTyGADT (LHsType name) -- Constructor was declared using GADT-style syntax, -- and here is its result type \end{code} \begin{code} conDeclsNames :: Eq name => [ConDecl name] -> [Located name] -- See tyClDeclNames for what this does -- The function is boringly complicated because of the records -- And since we only have equality, we have to be a little careful conDeclsNames cons = snd (foldl do_one ([], []) cons) where do_one (flds_seen, acc) (ConDecl { con_name = lname, con_details = RecCon flds }) = (map unLoc new_flds ++ flds_seen, lname : [f | f <- new_flds] ++ acc) where new_flds = [ f | (HsRecField f _ _) <- flds, not (unLoc f `elem` flds_seen) ] do_one (flds_seen, acc) c = (flds_seen, (con_name c):acc) conDetailsTys details = map getBangType (hsConArgs details) \end{code} \begin{code} instance (OutputableBndr name) => Outputable (ConDecl name) where ppr = pprConDecl pprConDecl (ConDecl con expl tvs cxt details ResTyH98 doc) = sep [ppr_mbDoc doc, pprHsForAll expl tvs cxt, ppr_details con details] where ppr_details con (InfixCon t1 t2) = hsep [ppr t1, pprHsVar con, ppr t2] ppr_details con (PrefixCon tys) = hsep (pprHsVar con : map ppr tys) ppr_details con (RecCon fields) = ppr con <+> ppr_fields fields pprConDecl (ConDecl con expl tvs cxt (PrefixCon arg_tys) (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 expl tvs cxt (RecCon fields) (ResTyGADT res_ty) _) = sep [pprHsForAll expl tvs cxt, ppr con <+> ppr_fields fields <+> dcolon <+> ppr res_ty] ppr_fields fields = braces (sep (punctuate comma (map ppr fields))) \end{code} %************************************************************************ %* * \subsection[InstDecl]{An instance declaration %* * %************************************************************************ \begin{code} type LInstDecl name = Located (InstDecl name) data InstDecl name = InstDecl (LHsType name) -- Context => Class Instance-type -- Using a polytype means that the renamer conveniently -- figures out the quantified type variables for us. (LHsBinds name) [LSig name] -- User-supplied pragmatic info [LTyClDecl name]-- Associated types (ie, 'TyData' and -- 'TySynonym' only) instance (OutputableBndr name) => Outputable (InstDecl name) where ppr (InstDecl inst_ty binds uprags ats) = vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")], nest 4 (ppr ats), nest 4 (ppr uprags), nest 4 (pprLHsBinds binds) ] -- Extract the declarations of associated types from an instance -- instDeclATs :: InstDecl name -> [LTyClDecl name] instDeclATs (InstDecl _ _ _ ats) = ats \end{code} %************************************************************************ %* * \subsection[DerivDecl]{A stand-alone instance deriving declaration %* * %************************************************************************ \begin{code} type LDerivDecl name = Located (DerivDecl name) data DerivDecl name = DerivDecl (LHsType name) instance (OutputableBndr name) => Outputable (DerivDecl name) where ppr (DerivDecl ty) = hsep [ptext SLIT("derived 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] 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) (LHsType name) ForeignImport -- defines name | ForeignExport (Located name) (LHsType name) ForeignExport -- uses name -- 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 -- safe or unsafe FastString -- name of C header FastString -- name of library object CImportSpec -- details of the C entity -- import of a .NET function -- | DNImport DNCallSpec | JVMImport JVMCallSpec -- 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.) -- pretty printing of foreign declarations -- instance OutputableBndr name => Outputable (ForeignDecl name) where ppr (ForeignImport n ty fimport) = ptext SLIT("foreign import") <+> ppr fimport <+> ppr n <+> dcolon <+> ppr ty ppr (ForeignExport n ty fexport) = ptext SLIT("foreign export") <+> ppr fexport <+> ppr n <+> dcolon <+> ppr ty instance Outputable ForeignImport where ppr (JVMImport spec) = ptext SLIT("jvm") <+> ppr spec ppr (DNImport spec) = ptext SLIT("dotnet") <+> ppr spec ppr (CImport cconv safety header lib spec) = ppr cconv <+> ppr safety <+> char '"' <> pprCEntity header lib spec <> char '"' where pprCEntity header lib (CLabel lbl) = ptext SLIT("static") <+> ftext header <+> char '&' <> pprLib lib <> ppr lbl pprCEntity header lib (CFunction (StaticTarget lbl)) = ptext SLIT("static") <+> ftext header <+> char '&' <> pprLib lib <> ppr lbl pprCEntity header lib (CFunction (DynamicTarget)) = ptext SLIT("dynamic") pprCEntity _ _ (CWrapper) = ptext SLIT("wrapper") -- pprLib lib | nullFS lib = empty | otherwise = char '[' <> ppr lib <> 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 data RuleBndr name = RuleBndr (Located name) | RuleBndrSig (Located name) (LHsType name) collectRuleBndrSigTys :: [RuleBndr name] -> [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[DocDecl]{Document comments} %* * %************************************************************************ \begin{code} type LDocDecl name = Located (DocDecl name) data DocDecl name = DocCommentNext (HsDoc name) | DocCommentPrev (HsDoc name) | DocCommentNamed String (HsDoc name) | DocGroup Int (HsDoc name) -- Okay, I need to reconstruct the document comments, but for now: instance Outputable (DocDecl name) where ppr _ = text "" 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 LDeprecDecl name = Located (DeprecDecl name) data DeprecDecl name = Deprecation name DeprecTxt instance OutputableBndr name => Outputable (DeprecDecl name) where ppr (Deprecation thing txt) = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"] \end{code}