{-# LANGUAGE TemplateHaskell, CPP #-} -- TH.Ppr contains a prettyprinter for the -- Template Haskell datatypes module Language.Haskell.TH.FixedPpr where -- All of the exports from this module should -- be "public" functions. The main module TH -- re-exports them all. import Text.PrettyPrint.HughesPJ (render) import Language.Haskell.TH.PprLib import Language.Haskell.TH.Syntax import Language.Haskell.TH.Data(isTupleT) import Data.Char ( toLower, isAlpha ) nestDepth :: Int nestDepth = 4 type Precedence = Int appPrec, opPrec, noPrec :: Precedence appPrec = 2 -- Argument of a function application opPrec = 1 -- Argument of an infix operator noPrec = 0 -- Others parensIf :: Bool -> Doc -> Doc parensIf True d = parens d parensIf False d = d ------------------------------ -- Show name with `` and () stripped, so that behaviour is the same -- with fixed and broken syntax-libs showNameRaw :: Name -> String showNameRaw = clean . show where clean ('(':xs) = init xs clean ('`':xs) = init xs clean xs = xs isPrefixName :: Name -> Bool isPrefixName = classify . showNameRaw where classify xs = case break (=='.') xs of (_,(_:xs')) -> classify xs' ((x:xs),[]) -> isAlpha x || x == '_' _ -> False -- operators ending with . pprName_ :: Bool -> Name -> Doc pprName_ True nm | isPrefixName nm = text (showNameRaw nm) | otherwise = text ("(" ++ showNameRaw nm ++ ")") pprName_ False nm | isPrefixName nm = text ("`" ++ showNameRaw nm ++ "`") | otherwise = text (showNameRaw nm) ------------------------------ pprint :: Ppr a => a -> String pprint x = render $ to_HPJ_Doc $ ppr x class Ppr a where ppr :: a -> Doc ppr_list :: [a] -> Doc ppr_list = vcat . map ppr instance Ppr a => Ppr [a] where ppr x = ppr_list x ------------------------------ instance Ppr Name where ppr v = pprName_ True v -- text (show v) ------------------------------ instance Ppr Info where #if __GLASGOW_HASKELL__ >= 700 ppr (ClassI d _) = ppr d #else ppr (ClassI d) = ppr d #endif ppr (TyConI d) = ppr d ppr (PrimTyConI name arity is_unlifted) = text "Primitive" <+> (if is_unlifted then text "unlifted" else empty) <+> text "type construtor" <+> quotes (ppr name) <+> parens (text "arity" <+> int arity) ppr (ClassOpI v ty cls fix) = text "Class op from" <+> ppr cls <> colon <+> vcat [ppr_sig v ty, pprFixity v fix] ppr (DataConI v ty tc fix) = text "Constructor from" <+> ppr tc <> colon <+> vcat [ppr_sig v ty, pprFixity v fix] ppr (TyVarI v ty) = text "Type variable" <+> ppr v <+> equals <+> ppr ty ppr (VarI v ty mb_d fix) = vcat [ppr_sig v ty, pprFixity v fix, case mb_d of { Nothing -> empty; Just d -> ppr d }] ppr_sig v ty = ppr v <+> text "::" <+> ppr ty pprFixity :: Name -> Fixity -> Doc pprFixity v f | f == defaultFixity = empty pprFixity v (Fixity i d) = ppr_fix d <+> int i <+> ppr v where ppr_fix InfixR = text "infixr" ppr_fix InfixL = text "infixl" ppr_fix InfixN = text "infix" ------------------------------ instance Ppr Exp where ppr = pprExp noPrec pprExpInfix :: Exp -> Doc pprExpInfix (VarE v) = pprName_ False v pprExpInfix (ConE c) = pprName_ False c pprExp :: Precedence -> Exp -> Doc pprExp _ (VarE v) = ppr v pprExp _ (ConE c) | isTupleT (ConT c) = text (nameBase c) | c == '[] = text ("[]") | c == '(:) = text ("(:)") | otherwise = ppr c pprExp i (LitE l) = pprLit i l pprExp i (AppE e1 e2) = parensIf (i >= appPrec) $ pprExp opPrec e1 <+> pprExp appPrec e2 pprExp i (InfixE (Just e1) op (Just e2)) = parensIf (i >= opPrec) $ pprExp opPrec e1 <+> pprExpInfix op <+> pprExp opPrec e2 pprExp _ (InfixE me1 op me2) = parens $ pprMaybeExp noPrec me1 <+> pprExpInfix op <+> pprMaybeExp noPrec me2 pprExp i (LamE ps e) = parensIf (i > noPrec) $ char '\\' <> hsep (map (pprPat appPrec) ps) <+> text "->" <+> ppr e pprExp _ (TupE es) = parens $ sep $ punctuate comma $ map ppr es -- Nesting in Cond is to avoid potential problems in do statments pprExp i (CondE guard true false) = parensIf (i > noPrec) $ sep [text "if" <+> ppr guard, nest 1 $ text "then" <+> ppr true, nest 1 $ text "else" <+> ppr false] pprExp i (LetE ds e) = parensIf (i > noPrec) $ text "let" <+> ppr ds $$ text " in" <+> ppr e pprExp i (CaseE e ms) = parensIf (i > noPrec) $ text "case" <+> ppr e <+> text "of" $$ nest nestDepth (ppr ms) pprExp i (DoE ss) = parensIf (i > noPrec) $ text "do" <+> ppr ss pprExp _ (CompE []) = error "Can't happen: pprExp (CompExp [])" -- This will probably break with fixity declarations - would need a ';' pprExp _ (CompE ss) = text "[" <> ppr s <+> text "|" <+> (sep $ punctuate comma $ map ppr ss') <> text "]" where s = last ss ss' = init ss pprExp _ (ArithSeqE d) = ppr d pprExp _ (ListE es) = brackets $ sep $ punctuate comma $ map ppr es pprExp i (SigE e t) = parensIf (i > noPrec) $ ppr e <+> text "::" <+> ppr t pprExp _ (RecConE nm fs) = ppr nm <> braces (pprFields fs) pprExp _ (RecUpdE e fs) = pprExp appPrec e <> braces (pprFields fs) pprFields :: [(Name,Exp)] -> Doc pprFields = sep . punctuate comma . map (\(s,e) -> ppr s <+> equals <+> ppr e) pprMaybeExp :: Precedence -> Maybe Exp -> Doc pprMaybeExp _ Nothing = empty pprMaybeExp i (Just e) = pprExp i e ------------------------------ instance Ppr Stmt where ppr (BindS p e) = ppr p <+> text "<-" <+> ppr e ppr (LetS ds) = text "let" <+> ppr ds ppr (NoBindS e) = ppr e ppr (ParS sss) = sep $ punctuate (text "|") $ map (sep . punctuate comma . map ppr) sss ------------------------------ instance Ppr Match where ppr (Match p rhs ds) = ppr p <+> pprBody False rhs $$ where_clause ds ------------------------------ pprBody :: Bool -> Body -> Doc pprBody eq (GuardedB xs) = nest nestDepth $ vcat $ map do_guard xs where eqd = if eq then text "=" else text "->" do_guard (NormalG g, e) = text "|" <+> ppr g <+> eqd <+> ppr e do_guard (PatG ss, e) = text "|" <+> vcat (map ppr ss) $$ nest nestDepth (eqd <+> ppr e) pprBody eq (NormalB e) = (if eq then text "=" else text "->") <+> ppr e instance Ppr Body where ppr = pprBody True ------------------------------ pprLit :: Precedence -> Lit -> Doc pprLit i (IntPrimL x) = parensIf (i > noPrec && x < 0) (integer x <> char '#') pprLit i (FloatPrimL x) = parensIf (i > noPrec && x < 0) (float (fromRational x) <> char '#') pprLit i (DoublePrimL x) = parensIf (i > noPrec && x < 0) (double (fromRational x) <> text "##") pprLit i (IntegerL x) = parensIf (i > noPrec && x < 0) (integer x) pprLit _ (CharL c) = text (show c) pprLit _ (StringL s) = text (show s) pprLit i (RationalL rat) = parensIf (i > noPrec) $ rational rat instance Ppr Lit where ppr = pprLit 10 ------------------------------ instance Ppr Pat where ppr = pprPat noPrec pprPat :: Precedence -> Pat -> Doc pprPat i (LitP l) = pprLit i l pprPat _ (VarP v) = ppr v pprPat _ (TupP ps) = parens $ sep $ punctuate comma $ map ppr ps pprPat i (ConP s ps) = parensIf (i > noPrec) $ x <+> sep (map (pprPat appPrec) ps) where x | isTupleT (ConT s) = text (nameBase s) | s == '[] = text "[]" | s == '(:) = text "(:)" | otherwise = ppr s pprPat i (InfixP p1 n p2) = parensIf (i > noPrec) $ pprPat opPrec p1 <+> pprName_ False n <+> pprPat opPrec p2 pprPat i (TildeP p) = parensIf (i > noPrec) $ text "~" <> pprPat appPrec p pprPat i (AsP v p) = parensIf (i > noPrec) $ ppr v <> text "@" <> pprPat appPrec p pprPat _ WildP = text "_" pprPat _ (RecP nm fs) = parens $ ppr nm <+> braces (sep $ punctuate comma $ map (\(s,p) -> ppr s <+> equals <+> ppr p) fs) pprPat _ (ListP ps) = brackets $ sep $ punctuate comma $ map ppr ps pprPat i (SigP p t) = parensIf (i > noPrec) $ ppr p <+> text "::" <+> ppr t ------------------------------ instance Ppr Dec where ppr (FunD f cs) = vcat $ map (\c -> ppr f <+> ppr c) cs ppr (ValD p r ds) = ppr p <+> pprBody True r $$ where_clause ds ppr (TySynD t xs rhs) = text "type" <+> ppr t <+> hsep (map ppr xs) <+> text "=" <+> ppr rhs ppr (DataD ctxt t xs cs decs) = text "data" <+> pprCxt ctxt <+> ppr t <+> hsep (map ppr xs) <+> sep (pref $ map ppr cs) $$ if null decs then empty else nest nestDepth $ text "deriving" <+> parens (hsep $ punctuate comma $ map ppr decs) where pref :: [Doc] -> [Doc] pref [] = [] -- Can't happen in H98 pref (d:ds) = (char '=' <+> d):map (char '|' <+>) ds ppr (NewtypeD ctxt t xs c decs) = text "newtype" <+> pprCxt ctxt <+> ppr t <+> hsep (map ppr xs) <+> char '=' <+> ppr c $$ if null decs then empty else nest nestDepth $ text "deriving" <+> parens (hsep $ punctuate comma $ map ppr decs) ppr (ClassD ctxt c xs fds ds) = text "class" <+> pprCxt ctxt <+> ppr c <+> hsep (map ppr xs) <+> ppr fds $$ where_clause ds ppr (InstanceD ctxt i ds) = text "instance" <+> pprCxt ctxt <+> ppr i $$ where_clause (map deQualLhsHead ds) ppr (SigD f t) = ppr f <+> text "::" <+> ppr t ppr (ForeignD f) = ppr f deQualLhsHead :: Dec -> Dec deQualLhsHead (FunD n cs) = FunD (deQualName n) cs deQualLhsHead (ValD p b ds) = ValD (go p) b ds where go (VarP n) = VarP (deQualName n) go (InfixP p1 n p2) = InfixP p1 (deQualName n) p2 go x = x deQualLhsHead x = x deQualName :: Name -> Name deQualName = mkName . nameBase ------------------------------ instance Ppr FunDep where ppr (FunDep xs ys) = hsep (map ppr xs) <+> text "->" <+> hsep (map ppr ys) ppr_list xs = char '|' <+> sep (punctuate (text ", ") (map ppr xs)) ------------------------------ instance Ppr Foreign where ppr (ImportF callconv safety impent as typ) = text "foreign import" <+> showtextl callconv <+> showtextl safety <+> text (show impent) <+> ppr as <+> text "::" <+> ppr typ ppr (ExportF callconv expent as typ) = text "foreign export" <+> showtextl callconv <+> text (show expent) <+> ppr as <+> text "::" <+> ppr typ ------------------------------ instance Ppr Clause where ppr (Clause ps rhs ds) = hsep (map (pprPat appPrec) ps) <+> pprBody True rhs $$ where_clause ds ------------------------------ instance Ppr Con where ppr (NormalC c sts) = ppr c <+> sep (map pprStrictType sts) ppr (RecC c vsts) = ppr c <+> braces (sep (punctuate comma $ map pprVarStrictType vsts)) ppr (InfixC st1 c st2) = pprStrictType st1 <+> pprName_ False c <+> pprStrictType st2 ppr (ForallC ns ctxt con) = text "forall" <+> hsep (map ppr ns) <+> char '.' <+> pprCxt ctxt <+> ppr con ------------------------------ pprVarStrictType :: (Name, Strict, Type) -> Doc -- Slight infelicity: with print non-atomic type with parens pprVarStrictType (v, str, t) = ppr v <+> text "::" <+> pprStrictType (str, t) ------------------------------ pprStrictType :: (Strict, Type) -> Doc -- Prints with parens if not already atomic pprStrictType (IsStrict, t) = char '!' <> pprParendType t pprStrictType (NotStrict, t) = pprParendType t ------------------------------ pprParendType :: Type -> Doc pprParendType (VarT v) = ppr v pprParendType (ConT c) | c == ''[] = pprParendType ListT | c == ''(->) = pprParendType ArrowT | isTupleT (ConT c) = pprParendType (TupleT (length (nameBase c) - 1)) | otherwise = ppr c pprParendType (TupleT 0) = text "()" pprParendType (TupleT n) = parens (hcat (replicate (n-1) comma)) pprParendType ArrowT = parens (text "->") pprParendType ListT = text "[]" pprParendType other = parens (ppr other) instance Ppr Type where ppr (ForallT tvars ctxt ty) = text "forall" <+> hsep (map ppr tvars) <+> text "." <+> pprCxt ctxt <+> ppr ty ppr ty = pprTyApp (split ty) pprTyApp :: (Type, [Type]) -> Doc pprTyApp (ArrowT, [arg1,arg2]) = sep [ppr arg1 <+> text "->", ppr arg2] pprTyApp (ListT, [arg]) = brackets (ppr arg) pprTyApp (TupleT n, args) | length args == n = parens (sep (punctuate comma (map ppr args))) pprTyApp (fun, args) = pprParendType fun <+> sep (map pprParendType args) split :: Type -> (Type, [Type]) -- Split into function and args split t = go t [] where go (AppT t1 t2) args = go t1 (t2:args) go ty args = (ty, args) ------------------------------ pprCxt :: Cxt -> Doc pprCxt [] = empty pprCxt [t] = ppr t <+> text "=>" pprCxt ts = parens (hsep $ punctuate comma $ map ppr ts) <+> text "=>" ------------------------------ instance Ppr Range where ppr = brackets . pprRange where pprRange :: Range -> Doc pprRange (FromR e) = ppr e <> text ".." pprRange (FromThenR e1 e2) = ppr e1 <> text "," <> ppr e2 <> text ".." pprRange (FromToR e1 e2) = ppr e1 <> text ".." <> ppr e2 pprRange (FromThenToR e1 e2 e3) = ppr e1 <> text "," <> ppr e2 <> text ".." <> ppr e3 ------------------------------ where_clause :: [Dec] -> Doc where_clause [] = empty where_clause ds = nest nestDepth $ text "where" <+> vcat (map ppr ds) showtextl :: Show a => a -> Doc showtextl = text . map toLower . show #if __GLASGOW_HASKELL__ >= 612 instance Ppr TyVarBndr where ppr (PlainTV v) = ppr v ppr (KindedTV v k) = parens $ ppr v <+> text "::" <+> ppr k instance Ppr Kind where ppr StarK = text "*" ppr (ArrowK j k) = ppr j <+> text "->" <+> ppr k instance Ppr Pred where ppr (ClassP n ts) = ppr n <+> hsep (map ppr ts) ppr (EqualP t u ) = ppr t <+> text "~" <+> ppr u #endif