{-# LANGUAGE BangPatterns, StandaloneDeriving, FlexibleInstances, ViewPatterns #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE FlexibleContexts #-} {-# OPTIONS_GHC -fno-warn-orphans #-} {-# OPTIONS_GHC -Wno-incomplete-record-updates #-} {-# OPTIONS_HADDOCK hide #-} ----------------------------------------------------------------------------- -- | -- Module : Haddock.GhcUtils -- Copyright : (c) David Waern 2006-2009 -- License : BSD-like -- -- Maintainer : haddock@projects.haskell.org -- Stability : experimental -- Portability : portable -- -- Utils for dealing with types from the GHC API ----------------------------------------------------------------------------- module Haddock.GhcUtils where import Control.Arrow import Data.Char ( isSpace ) import Data.Maybe ( mapMaybe ) import Haddock.Types( DocName, DocNameI ) import BasicTypes ( PromotionFlag(..) ) import Exception import FV import Outputable ( Outputable, panic, showPpr ) import Name import NameSet import Module import HscTypes import GHC import Class import DynFlags import SrcLoc ( advanceSrcLoc ) import Var ( VarBndr(..), TyVarBinder, tyVarKind, updateTyVarKind, isInvisibleArgFlag ) import VarSet ( VarSet, emptyVarSet ) import VarEnv ( TyVarEnv, extendVarEnv, elemVarEnv, emptyVarEnv ) import TyCoRep ( Type(..) ) import Type ( isRuntimeRepVar ) import TysWiredIn( liftedRepDataConTyCon ) import StringBuffer ( StringBuffer ) import qualified StringBuffer as S import Data.ByteString ( ByteString ) import qualified Data.ByteString as BS import qualified Data.ByteString.Internal as BS moduleString :: Module -> String moduleString = moduleNameString . moduleName isNameSym :: Name -> Bool isNameSym = isSymOcc . nameOccName getMainDeclBinder :: (SrcSpanLess (LPat p) ~ Pat p , HasSrcSpan (LPat p)) => HsDecl p -> [IdP p] getMainDeclBinder (TyClD _ d) = [tcdName d] getMainDeclBinder (ValD _ d) = case collectHsBindBinders d of [] -> [] (name:_) -> [name] getMainDeclBinder (SigD _ d) = sigNameNoLoc d getMainDeclBinder (ForD _ (ForeignImport _ name _ _)) = [unLoc name] getMainDeclBinder (ForD _ (ForeignExport _ _ _ _)) = [] getMainDeclBinder _ = [] -- Extract the source location where an instance is defined. This is used -- to correlate InstDecls with their Instance/CoAxiom Names, via the -- instanceMap. getInstLoc :: InstDecl (GhcPass p) -> SrcSpan getInstLoc (ClsInstD _ (ClsInstDecl { cid_poly_ty = ty })) = getLoc (hsSigType ty) getInstLoc (DataFamInstD _ (DataFamInstDecl { dfid_eqn = HsIB { hsib_body = FamEqn { feqn_tycon = L l _ }}})) = l getInstLoc (TyFamInstD _ (TyFamInstDecl -- Since CoAxioms' Names refer to the whole line for type family instances -- in particular, we need to dig a bit deeper to pull out the entire -- equation. This does not happen for data family instances, for some reason. { tfid_eqn = HsIB { hsib_body = FamEqn { feqn_rhs = L l _ }}})) = l getInstLoc (ClsInstD _ (XClsInstDecl nec)) = noExtCon nec getInstLoc (DataFamInstD _ (DataFamInstDecl (HsIB _ (XFamEqn nec)))) = noExtCon nec getInstLoc (TyFamInstD _ (TyFamInstDecl (HsIB _ (XFamEqn nec)))) = noExtCon nec getInstLoc (XInstDecl nec) = noExtCon nec getInstLoc (DataFamInstD _ (DataFamInstDecl (XHsImplicitBndrs nec))) = noExtCon nec getInstLoc (TyFamInstD _ (TyFamInstDecl (XHsImplicitBndrs nec))) = noExtCon nec -- Useful when there is a signature with multiple names, e.g. -- foo, bar :: Types.. -- but only one of the names is exported and we have to change the -- type signature to only include the exported names. filterLSigNames :: (IdP (GhcPass p) -> Bool) -> LSig (GhcPass p) -> Maybe (LSig (GhcPass p)) filterLSigNames p (L loc sig) = L loc <$> (filterSigNames p sig) filterSigNames :: (IdP (GhcPass p) -> Bool) -> Sig (GhcPass p) -> Maybe (Sig (GhcPass p)) filterSigNames p orig@(SpecSig _ n _ _) = ifTrueJust (p $ unLoc n) orig filterSigNames p orig@(InlineSig _ n _) = ifTrueJust (p $ unLoc n) orig filterSigNames p (FixSig _ (FixitySig _ ns ty)) = case filter (p . unLoc) ns of [] -> Nothing filtered -> Just (FixSig noExtField (FixitySig noExtField filtered ty)) filterSigNames _ orig@(MinimalSig _ _ _) = Just orig filterSigNames p (TypeSig _ ns ty) = case filter (p . unLoc) ns of [] -> Nothing filtered -> Just (TypeSig noExtField filtered ty) filterSigNames p (ClassOpSig _ is_default ns ty) = case filter (p . unLoc) ns of [] -> Nothing filtered -> Just (ClassOpSig noExtField is_default filtered ty) filterSigNames p (PatSynSig _ ns ty) = case filter (p . unLoc) ns of [] -> Nothing filtered -> Just (PatSynSig noExtField filtered ty) filterSigNames _ _ = Nothing ifTrueJust :: Bool -> name -> Maybe name ifTrueJust True = Just ifTrueJust False = const Nothing sigName :: LSig name -> [IdP name] sigName (L _ sig) = sigNameNoLoc sig sigNameNoLoc :: Sig name -> [IdP name] sigNameNoLoc (TypeSig _ ns _) = map unLoc ns sigNameNoLoc (ClassOpSig _ _ ns _) = map unLoc ns sigNameNoLoc (PatSynSig _ ns _) = map unLoc ns sigNameNoLoc (SpecSig _ n _ _) = [unLoc n] sigNameNoLoc (InlineSig _ n _) = [unLoc n] sigNameNoLoc (FixSig _ (FixitySig _ ns _)) = map unLoc ns sigNameNoLoc _ = [] -- | Was this signature given by the user? isUserLSig :: LSig name -> Bool isUserLSig (L _ (TypeSig {})) = True isUserLSig (L _ (ClassOpSig {})) = True isUserLSig (L _ (PatSynSig {})) = True isUserLSig _ = False isClassD :: HsDecl a -> Bool isClassD (TyClD _ d) = isClassDecl d isClassD _ = False isValD :: HsDecl a -> Bool isValD (ValD _ _) = True isValD _ = False pretty :: Outputable a => DynFlags -> a -> String pretty = showPpr nubByName :: (a -> Name) -> [a] -> [a] nubByName f ns = go emptyNameSet ns where go !_ [] = [] go !s (x:xs) | y `elemNameSet` s = go s xs | otherwise = let !s' = extendNameSet s y in x : go s' xs where y = f x -- --------------------------------------------------------------------- -- These functions are duplicated from the GHC API, as they must be -- instantiated at DocNameI instead of (GhcPass _). -- | Like 'hsTyVarName' from GHC API, but not instantiated at (GhcPass _) hsTyVarBndrName :: (XXTyVarBndr n ~ NoExtCon) => HsTyVarBndr n -> IdP n hsTyVarBndrName (UserTyVar _ name) = unLoc name hsTyVarBndrName (KindedTyVar _ (L _ name) _) = name hsTyVarBndrName (XTyVarBndr nec) = noExtCon nec getConNamesI :: ConDecl DocNameI -> [Located DocName] getConNamesI ConDeclH98 {con_name = name} = [name] getConNamesI ConDeclGADT {con_names = names} = names getConNamesI (XConDecl nec) = noExtCon nec hsImplicitBodyI :: HsImplicitBndrs DocNameI thing -> thing hsImplicitBodyI (HsIB { hsib_body = body }) = body hsImplicitBodyI (XHsImplicitBndrs nec) = noExtCon nec hsSigTypeI :: LHsSigType DocNameI -> LHsType DocNameI hsSigTypeI = hsImplicitBodyI getGADTConType :: ConDecl DocNameI -> LHsType DocNameI -- The full type of a GADT data constructor We really only get this in -- order to pretty-print it, and currently only in Haddock's code. So -- we are cavalier about locations and extensions, hence the -- 'undefined's getGADTConType (ConDeclGADT { con_forall = L _ has_forall , con_qvars = qtvs , con_mb_cxt = mcxt, con_args = args , con_res_ty = res_ty }) | has_forall = noLoc (HsForAllTy { hst_fvf = ForallInvis , hst_xforall = noExtField , hst_bndrs = hsQTvExplicit qtvs , hst_body = theta_ty }) | otherwise = theta_ty where theta_ty | Just theta <- mcxt = noLoc (HsQualTy { hst_xqual = noExtField, hst_ctxt = theta, hst_body = tau_ty }) | otherwise = tau_ty tau_ty = case args of RecCon flds -> noLoc (HsFunTy noExtField (noLoc (HsRecTy noExtField (unLoc flds))) res_ty) PrefixCon pos_args -> foldr mkFunTy res_ty pos_args InfixCon arg1 arg2 -> arg1 `mkFunTy` (arg2 `mkFunTy` res_ty) mkFunTy a b = noLoc (HsFunTy noExtField a b) getGADTConType (ConDeclH98 {}) = panic "getGADTConType" -- Should only be called on ConDeclGADT getGADTConType (XConDecl nec) = noExtCon nec -- ------------------------------------- getGADTConTypeG :: ConDecl (GhcPass p) -> LHsType (GhcPass p) -- The full type of a GADT data constructor We really only get this in -- order to pretty-print it, and currently only in Haddock's code. So -- we are cavalier about locations and extensions, hence the -- 'undefined's getGADTConTypeG (ConDeclGADT { con_forall = L _ has_forall , con_qvars = qtvs , con_mb_cxt = mcxt, con_args = args , con_res_ty = res_ty }) | has_forall = noLoc (HsForAllTy { hst_fvf = ForallInvis , hst_xforall = noExtField , hst_bndrs = hsQTvExplicit qtvs , hst_body = theta_ty }) | otherwise = theta_ty where theta_ty | Just theta <- mcxt = noLoc (HsQualTy { hst_xqual = noExtField, hst_ctxt = theta, hst_body = tau_ty }) | otherwise = tau_ty tau_ty = case args of RecCon flds -> noLoc (HsFunTy noExtField (noLoc (HsRecTy noExtField (unLoc flds))) res_ty) PrefixCon pos_args -> foldr mkFunTy res_ty pos_args InfixCon arg1 arg2 -> arg1 `mkFunTy` (arg2 `mkFunTy` res_ty) mkFunTy a b = noLoc (HsFunTy noExtField a b) getGADTConTypeG (ConDeclH98 {}) = panic "getGADTConTypeG" -- Should only be called on ConDeclGADT getGADTConTypeG (XConDecl nec) = noExtCon nec mkEmptySigWcType :: LHsType GhcRn -> LHsSigWcType GhcRn -- Dubious, because the implicit binders are empty even -- though the type might have free varaiables mkEmptySigWcType ty = mkEmptyWildCardBndrs (mkEmptyImplicitBndrs ty) addClassContext :: Name -> LHsQTyVars GhcRn -> LSig GhcRn -> LSig GhcRn -- Add the class context to a class-op signature addClassContext cls tvs0 (L pos (ClassOpSig _ _ lname ltype)) = L pos (TypeSig noExtField lname (mkEmptySigWcType (go (hsSigType ltype)))) -- The mkEmptySigWcType is suspicious where go (L loc (HsForAllTy { hst_fvf = fvf, hst_bndrs = tvs, hst_body = ty })) = L loc (HsForAllTy { hst_fvf = fvf, hst_xforall = noExtField , hst_bndrs = tvs, hst_body = go ty }) go (L loc (HsQualTy { hst_ctxt = ctxt, hst_body = ty })) = L loc (HsQualTy { hst_xqual = noExtField , hst_ctxt = add_ctxt ctxt, hst_body = ty }) go (L loc ty) = L loc (HsQualTy { hst_xqual = noExtField , hst_ctxt = add_ctxt (L loc []), hst_body = L loc ty }) extra_pred = nlHsTyConApp cls (lHsQTyVarsToTypes tvs0) add_ctxt (L loc preds) = L loc (extra_pred : preds) addClassContext _ _ sig = sig -- E.g. a MinimalSig is fine lHsQTyVarsToTypes :: LHsQTyVars GhcRn -> [LHsType GhcRn] lHsQTyVarsToTypes tvs = [ noLoc (HsTyVar noExtField NotPromoted (noLoc (hsLTyVarName tv))) | tv <- hsQTvExplicit tvs ] -------------------------------------------------------------------------------- -- * Making abstract declarations -------------------------------------------------------------------------------- restrictTo :: [Name] -> LHsDecl GhcRn -> LHsDecl GhcRn restrictTo names (L loc decl) = L loc $ case decl of TyClD x d | isDataDecl d -> TyClD x (d { tcdDataDefn = restrictDataDefn names (tcdDataDefn d) }) TyClD x d | isClassDecl d -> TyClD x (d { tcdSigs = restrictDecls names (tcdSigs d), tcdATs = restrictATs names (tcdATs d) }) _ -> decl restrictDataDefn :: [Name] -> HsDataDefn GhcRn -> HsDataDefn GhcRn restrictDataDefn names defn@(HsDataDefn { dd_ND = new_or_data, dd_cons = cons }) | DataType <- new_or_data = defn { dd_cons = restrictCons names cons } | otherwise -- Newtype = case restrictCons names cons of [] -> defn { dd_ND = DataType, dd_cons = [] } [con] -> defn { dd_cons = [con] } _ -> error "Should not happen" restrictDataDefn _ (XHsDataDefn nec) = noExtCon nec restrictCons :: [Name] -> [LConDecl GhcRn] -> [LConDecl GhcRn] restrictCons names decls = [ L p d | L p (Just d) <- map (fmap keep) decls ] where keep d | any (\n -> n `elem` names) (map unLoc $ getConNames d) = case con_args d of PrefixCon _ -> Just d RecCon fields | all field_avail (unLoc fields) -> Just d | otherwise -> Just (d { con_args = PrefixCon (field_types (map unLoc (unLoc fields))) }) -- if we have *all* the field names available, then -- keep the record declaration. Otherwise degrade to -- a constructor declaration. This isn't quite right, but -- it's the best we can do. InfixCon _ _ -> Just d where field_avail :: LConDeclField GhcRn -> Bool field_avail (L _ (ConDeclField _ fs _ _)) = all (\f -> extFieldOcc (unLoc f) `elem` names) fs field_avail (L _ (XConDeclField nec)) = noExtCon nec field_types flds = [ t | ConDeclField _ _ t _ <- flds ] keep _ = Nothing restrictDecls :: [Name] -> [LSig GhcRn] -> [LSig GhcRn] restrictDecls names = mapMaybe (filterLSigNames (`elem` names)) restrictATs :: [Name] -> [LFamilyDecl GhcRn] -> [LFamilyDecl GhcRn] restrictATs names ats = [ at | at <- ats , unLoc (fdLName (unLoc at)) `elem` names ] ------------------------------------------------------------------------------- -- * Parenthesization ------------------------------------------------------------------------------- -- | Precedence level (inside the 'HsType' AST). data Precedence = PREC_TOP -- ^ precedence of 'type' production in GHC's parser | PREC_SIG -- ^ explicit type signature | PREC_CTX -- ^ Used for single contexts, eg. ctx => type -- (as opposed to (ctx1, ctx2) => type) | PREC_FUN -- ^ precedence of 'btype' production in GHC's parser -- (used for LH arg of (->)) | PREC_OP -- ^ arg of any infix operator -- (we don't keep have fixity info) | PREC_CON -- ^ arg of type application: always parenthesize unless atomic deriving (Eq, Ord) -- | Add in extra 'HsParTy' where needed to ensure that what would be printed -- out using 'ppr' has enough parentheses to be re-parsed properly. -- -- We cannot add parens that may be required by fixities because we do not have -- any fixity information to work with in the first place :(. reparenTypePrec :: (XParTy a ~ NoExtField) => Precedence -> HsType a -> HsType a reparenTypePrec = go where -- Shorter name for 'reparenType' go :: (XParTy a ~ NoExtField) => Precedence -> HsType a -> HsType a go _ (HsBangTy x b ty) = HsBangTy x b (reparenLType ty) go _ (HsTupleTy x con tys) = HsTupleTy x con (map reparenLType tys) go _ (HsSumTy x tys) = HsSumTy x (map reparenLType tys) go _ (HsListTy x ty) = HsListTy x (reparenLType ty) go _ (HsRecTy x flds) = HsRecTy x (map (fmap reparenConDeclField) flds) go p (HsDocTy x ty d) = HsDocTy x (goL p ty) d go _ (HsExplicitListTy x p tys) = HsExplicitListTy x p (map reparenLType tys) go _ (HsExplicitTupleTy x tys) = HsExplicitTupleTy x (map reparenLType tys) go p (HsKindSig x ty kind) = paren p PREC_SIG $ HsKindSig x (goL PREC_SIG ty) (goL PREC_SIG kind) go p (HsIParamTy x n ty) = paren p PREC_SIG $ HsIParamTy x n (reparenLType ty) go p (HsForAllTy x fvf tvs ty) = paren p PREC_CTX $ HsForAllTy x fvf (map (fmap reparenTyVar) tvs) (reparenLType ty) go p (HsQualTy x ctxt ty) = let p' [_] = PREC_CTX p' _ = PREC_TOP -- parens will get added anyways later... in paren p PREC_CTX $ HsQualTy x (fmap (\xs -> map (goL (p' xs)) xs) ctxt) (goL PREC_TOP ty) go p (HsFunTy x ty1 ty2) = paren p PREC_FUN $ HsFunTy x (goL PREC_FUN ty1) (goL PREC_TOP ty2) go p (HsAppTy x fun_ty arg_ty) = paren p PREC_CON $ HsAppTy x (goL PREC_FUN fun_ty) (goL PREC_CON arg_ty) go p (HsAppKindTy x fun_ty arg_ki) = paren p PREC_CON $ HsAppKindTy x (goL PREC_FUN fun_ty) (goL PREC_CON arg_ki) go p (HsOpTy x ty1 op ty2) = paren p PREC_FUN $ HsOpTy x (goL PREC_OP ty1) op (goL PREC_OP ty2) go p (HsParTy _ t) = unLoc $ goL p t -- pretend the paren doesn't exist - it will be added back if needed go _ t@HsTyVar{} = t go _ t@HsStarTy{} = t go _ t@HsSpliceTy{} = t go _ t@HsTyLit{} = t go _ t@HsWildCardTy{} = t go _ t@XHsType{} = t -- Located variant of 'go' goL :: (XParTy a ~ NoExtField) => Precedence -> LHsType a -> LHsType a goL ctxt_prec = fmap (go ctxt_prec) -- Optionally wrap a type in parens paren :: (XParTy a ~ NoExtField) => Precedence -- Precedence of context -> Precedence -- Precedence of top-level operator -> HsType a -> HsType a -- Wrap in parens if (ctxt >= op) paren ctxt_prec op_prec | ctxt_prec >= op_prec = HsParTy noExtField . noLoc | otherwise = id -- | Add parenthesis around the types in a 'HsType' (see 'reparenTypePrec') reparenType :: (XParTy a ~ NoExtField) => HsType a -> HsType a reparenType = reparenTypePrec PREC_TOP -- | Add parenthesis around the types in a 'LHsType' (see 'reparenTypePrec') reparenLType :: (XParTy a ~ NoExtField) => LHsType a -> LHsType a reparenLType = fmap reparenType -- | Add parenthesis around the types in a 'HsTyVarBndr' (see 'reparenTypePrec') reparenTyVar :: (XParTy a ~ NoExtField) => HsTyVarBndr a -> HsTyVarBndr a reparenTyVar (UserTyVar x n) = UserTyVar x n reparenTyVar (KindedTyVar x n kind) = KindedTyVar x n (reparenLType kind) reparenTyVar v@XTyVarBndr{} = v -- | Add parenthesis around the types in a 'ConDeclField' (see 'reparenTypePrec') reparenConDeclField :: (XParTy a ~ NoExtField) => ConDeclField a -> ConDeclField a reparenConDeclField (ConDeclField x n t d) = ConDeclField x n (reparenLType t) d reparenConDeclField c@XConDeclField{} = c ------------------------------------------------------------------------------- -- * NamedThing instances ------------------------------------------------------------------------------- instance NamedThing (TyClDecl GhcRn) where getName = tcdName ------------------------------------------------------------------------------- -- * Subordinates ------------------------------------------------------------------------------- class Parent a where children :: a -> [Name] instance Parent (ConDecl GhcRn) where children con = case con_args con of RecCon fields -> map (extFieldOcc . unLoc) $ concatMap (cd_fld_names . unLoc) (unLoc fields) _ -> [] instance Parent (TyClDecl GhcRn) where children d | isDataDecl d = map unLoc $ concatMap (getConNames . unLoc) $ (dd_cons . tcdDataDefn) $ d | isClassDecl d = map (unLoc . fdLName . unLoc) (tcdATs d) ++ [ unLoc n | L _ (TypeSig _ ns _) <- tcdSigs d, n <- ns ] | otherwise = [] -- | A parent and its children family :: (NamedThing a, Parent a) => a -> (Name, [Name]) family = getName &&& children familyConDecl :: ConDecl GHC.GhcRn -> [(Name, [Name])] familyConDecl d = zip (map unLoc (getConNames d)) (repeat $ children d) -- | A mapping from the parent (main-binder) to its children and from each -- child to its grand-children, recursively. families :: TyClDecl GhcRn -> [(Name, [Name])] families d | isDataDecl d = family d : concatMap (familyConDecl . unLoc) (dd_cons (tcdDataDefn d)) | isClassDecl d = [family d] | otherwise = [] -- | A mapping from child to parent parentMap :: TyClDecl GhcRn -> [(Name, Name)] parentMap d = [ (c, p) | (p, cs) <- families d, c <- cs ] -- | The parents of a subordinate in a declaration parents :: Name -> HsDecl GhcRn -> [Name] parents n (TyClD _ d) = [ p | (c, p) <- parentMap d, c == n ] parents _ _ = [] ------------------------------------------------------------------------------- -- * Utils that work in monads defined by GHC ------------------------------------------------------------------------------- modifySessionDynFlags :: (DynFlags -> DynFlags) -> Ghc () modifySessionDynFlags f = do dflags <- getSessionDynFlags _ <- setSessionDynFlags (f dflags) return () -- | A variant of 'gbracket' where the return value from the first computation -- is not required. gbracket_ :: ExceptionMonad m => m a -> m b -> m c -> m c gbracket_ before_ after thing = gbracket before_ (const after) (const thing) -- Extract the minimal complete definition of a Name, if one exists minimalDef :: GhcMonad m => Name -> m (Maybe ClassMinimalDef) minimalDef n = do mty <- lookupGlobalName n case mty of Just (ATyCon (tyConClass_maybe -> Just c)) -> return . Just $ classMinimalDef c _ -> return Nothing ------------------------------------------------------------------------------- -- * DynFlags ------------------------------------------------------------------------------- -- TODO: use `setOutputDir` from GHC setOutputDir :: FilePath -> DynFlags -> DynFlags setOutputDir dir dynFlags = dynFlags { objectDir = Just dir , hiDir = Just dir , hieDir = Just dir , stubDir = Just dir , includePaths = addGlobalInclude (includePaths dynFlags) [dir] , dumpDir = Just dir } ------------------------------------------------------------------------------- -- * 'StringBuffer' and 'ByteString' ------------------------------------------------------------------------------- -- We get away with a bunch of these functions because 'StringBuffer' and -- 'ByteString' have almost exactly the same structure. -- | Convert a UTF-8 encoded 'ByteString' into a 'StringBuffer. This really -- relies on the internals of both 'ByteString' and 'StringBuffer'. -- -- /O(n)/ (but optimized into a @memcpy@ by @bytestring@ under the hood) stringBufferFromByteString :: ByteString -> StringBuffer stringBufferFromByteString bs = let BS.PS fp off len = bs <> BS.pack [0,0,0] in S.StringBuffer { S.buf = fp, S.len = len - 3, S.cur = off } -- | Take the first @n@ /bytes/ of the 'StringBuffer' and put them in a -- 'ByteString'. -- -- /O(1)/ takeStringBuffer :: Int -> StringBuffer -> ByteString takeStringBuffer !n !(S.StringBuffer fp _ cur) = BS.PS fp cur n -- | Return the prefix of the first 'StringBuffer' that /isn't/ in the second -- 'StringBuffer'. **The behavior is undefined if the 'StringBuffers' use -- separate buffers.** -- -- /O(1)/ splitStringBuffer :: StringBuffer -> StringBuffer -> ByteString splitStringBuffer buf1 buf2 = takeStringBuffer n buf1 where n = S.byteDiff buf1 buf2 -- | Split the 'StringBuffer' at the next newline (or the end of the buffer). -- Also: initial position is passed in and the updated position is returned. -- -- /O(n)/ (but /O(1)/ space) spanLine :: RealSrcLoc -> StringBuffer -> (ByteString, RealSrcLoc, StringBuffer) spanLine !loc !buf = go loc buf where go !l !b | not (S.atEnd b) = case S.nextChar b of ('\n', b') -> (splitStringBuffer buf b', advanceSrcLoc l '\n', b') (c, b') -> go (advanceSrcLoc l c) b' | otherwise = (splitStringBuffer buf b, advanceSrcLoc l '\n', b) -- | Given a start position and a buffer with that start position, split the -- buffer at an end position. -- -- /O(n)/ (but /O(1)/ space) spanPosition :: RealSrcLoc -- ^ start of buffeer -> RealSrcLoc -- ^ position until which to take -> StringBuffer -- ^ buffer from which to take -> (ByteString, StringBuffer) spanPosition !start !end !buf = go start buf where go !l !b | l < end , not (S.atEnd b) , (c, b') <- S.nextChar b = go (advanceSrcLoc l c) b' | otherwise = (splitStringBuffer buf b, b) -- | Try to parse a line of CPP from the from of the buffer. A \"line\" of CPP -- consists of -- -- * at most 10 whitespace characters, including at least one newline -- * a @#@ character -- * keep parsing lines until you find a line not ending in @\\@. -- -- This is chock full of heuristics about what a line of CPP is. -- -- /O(n)/ (but /O(1)/ space) tryCppLine :: RealSrcLoc -> StringBuffer -> Maybe (ByteString, RealSrcLoc, StringBuffer) tryCppLine !loc !buf = spanSpace (S.prevChar buf '\n' == '\n') loc buf where -- Keep consuming space characters until we hit either a @#@ or something -- else. If we hit a @#@, start parsing CPP spanSpace !seenNl !l !b | S.atEnd b = Nothing | otherwise = case S.nextChar b of ('#' , b') | not (S.atEnd b') , ('-', b'') <- S.nextChar b' , ('}', _) <- S.nextChar b'' -> Nothing -- Edge case exception for @#-}@ | seenNl -> Just (spanCppLine (advanceSrcLoc l '#') b') -- parse CPP | otherwise -> Nothing -- We didn't see a newline, so this can't be CPP! (c , b') | isSpace c -> spanSpace (seenNl || c == '\n') (advanceSrcLoc l c) b' | otherwise -> Nothing -- Consume a CPP line to its "end" (basically the first line that ends not -- with a @\@ character) spanCppLine !l !b | S.atEnd b = (splitStringBuffer buf b, l, b) | otherwise = case S.nextChar b of ('\\', b') | not (S.atEnd b') , ('\n', b'') <- S.nextChar b' -> spanCppLine (advanceSrcLoc (advanceSrcLoc l '\\') '\n') b'' ('\n', b') -> (splitStringBuffer buf b', advanceSrcLoc l '\n', b') (c , b') -> spanCppLine (advanceSrcLoc l c) b' ------------------------------------------------------------------------------- -- * Free variables of a 'Type' ------------------------------------------------------------------------------- -- | Get free type variables in a 'Type' in their order of appearance. -- See [Ordering of implicit variables]. orderedFVs :: VarSet -- ^ free variables to ignore -> [Type] -- ^ types to traverse (in order) looking for free variables -> [TyVar] -- ^ free type variables, in the order they appear in orderedFVs vs tys = reverse . fst $ tyCoFVsOfTypes' tys (const True) vs ([], emptyVarSet) -- See the "Free variables of types and coercions" section in 'TyCoRep', or -- check out Note [Free variables of types]. The functions in this section -- don't output type variables in the order they first appear in in the 'Type'. -- -- For example, 'tyCoVarsOfTypeList' reports an incorrect order for the type -- of 'const :: a -> b -> a': -- -- >>> import Name -- >>> import TyCoRep -- >>> import TysPrim -- >>> import Var -- >>> a = TyVarTy alphaTyVar -- >>> b = TyVarTy betaTyVar -- >>> constTy = mkFunTys [a, b] a -- >>> map (getOccString . tyVarName) (tyCoVarsOfTypeList constTy) -- ["b","a"] -- -- However, we want to reuse the very optimized traversal machinery there, so -- so we make our own `tyCoFVsOfType'`, `tyCoFVsBndr'`, and `tyCoVarsOfTypes'`. -- All these do differently is traverse in a different order and ignore -- coercion variables. -- | Just like 'tyCoFVsOfType', but traverses type variables in reverse order -- of appearance. tyCoFVsOfType' :: Type -> FV tyCoFVsOfType' (TyVarTy v) a b c = (FV.unitFV v `unionFV` tyCoFVsOfType' (tyVarKind v)) a b c tyCoFVsOfType' (TyConApp _ tys) a b c = tyCoFVsOfTypes' tys a b c tyCoFVsOfType' (LitTy {}) a b c = emptyFV a b c tyCoFVsOfType' (AppTy fun arg) a b c = (tyCoFVsOfType' arg `unionFV` tyCoFVsOfType' fun) a b c tyCoFVsOfType' (FunTy _ arg res) a b c = (tyCoFVsOfType' res `unionFV` tyCoFVsOfType' arg) a b c tyCoFVsOfType' (ForAllTy bndr ty) a b c = tyCoFVsBndr' bndr (tyCoFVsOfType' ty) a b c tyCoFVsOfType' (CastTy ty _) a b c = (tyCoFVsOfType' ty) a b c tyCoFVsOfType' (CoercionTy _ ) a b c = emptyFV a b c -- | Just like 'tyCoFVsOfTypes', but traverses type variables in reverse order -- of appearance. tyCoFVsOfTypes' :: [Type] -> FV tyCoFVsOfTypes' (ty:tys) fv_cand in_scope acc = (tyCoFVsOfTypes' tys `unionFV` tyCoFVsOfType' ty) fv_cand in_scope acc tyCoFVsOfTypes' [] fv_cand in_scope acc = emptyFV fv_cand in_scope acc -- | Just like 'tyCoFVsBndr', but traverses type variables in reverse order of -- appearance. tyCoFVsBndr' :: TyVarBinder -> FV -> FV tyCoFVsBndr' (Bndr tv _) fvs = FV.delFV tv fvs `unionFV` tyCoFVsOfType' (tyVarKind tv) ------------------------------------------------------------------------------- -- * Defaulting RuntimeRep variables ------------------------------------------------------------------------------- -- | Traverses the type, defaulting type variables of kind 'RuntimeRep' to -- 'LiftedType'. See 'defaultRuntimeRepVars' in IfaceType.hs the original such -- function working over `IfaceType`'s. defaultRuntimeRepVars :: Type -> Type defaultRuntimeRepVars = go emptyVarEnv where go :: TyVarEnv () -> Type -> Type go subs (ForAllTy (Bndr var flg) ty) | isRuntimeRepVar var , isInvisibleArgFlag flg = let subs' = extendVarEnv subs var () in go subs' ty | otherwise = ForAllTy (Bndr (updateTyVarKind (go subs) var) flg) (go subs ty) go subs (TyVarTy tv) | tv `elemVarEnv` subs = TyConApp liftedRepDataConTyCon [] | otherwise = TyVarTy (updateTyVarKind (go subs) tv) go subs (TyConApp tc tc_args) = TyConApp tc (map (go subs) tc_args) go subs (FunTy af arg res) = FunTy af (go subs arg) (go subs res) go subs (AppTy t u) = AppTy (go subs t) (go subs u) go subs (CastTy x co) = CastTy (go subs x) co go _ ty@(LitTy {}) = ty go _ ty@(CoercionTy {}) = ty