--
-----------------------------------------------------------------------------
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
module PprTyThing (
PrintExplicitForalls,
pprTyThing,
- pprTyThingInContext,
+ pprTyThingInContext, pprTyThingParent_maybe,
pprTyThingLoc,
pprTyThingInContextLoc,
- pprTyThingHdr
+ pprTyThingHdr,
+ pprTypeForUser
) where
-#include "HsVersions.h"
-
import qualified GHC
-import TyCon ( tyConFamInst_maybe )
-import Type ( pprTypeApp )
-import GHC ( TyThing(..), SrcSpan )
-import Var
+import GHC ( TyThing(..) )
+import DataCon
+import Id
+import IdInfo
+import TyCon
+import Coercion( pprCoAxiom )
+import TcType
+import Name
import Outputable
+import FastString
-- -----------------------------------------------------------------------------
-- Pretty-printing entities that we get from the GHC API
type PrintExplicitForalls = Bool
+type ShowMe = Name -> Bool
+-- The ShowMe function says which sub-components to print
+-- True <=> print
+-- False <=> elide to "..."
+
+----------------------------
-- | Pretty-prints a 'TyThing' with its defining location.
pprTyThingLoc :: PrintExplicitForalls -> TyThing -> SDoc
-pprTyThingLoc pefas tyThing
+pprTyThingLoc pefas tyThing
= showWithLoc loc (pprTyThing pefas tyThing)
- where loc = GHC.nameSrcSpan (GHC.getName tyThing)
+ where loc = pprNameLoc (GHC.getName tyThing)
-- | Pretty-prints a 'TyThing'.
pprTyThing :: PrintExplicitForalls -> TyThing -> SDoc
-pprTyThing pefas (AnId id) = pprId pefas id
-pprTyThing pefas (ADataCon dataCon) = pprDataConSig pefas dataCon
-pprTyThing pefas (ATyCon tyCon) = pprTyCon pefas tyCon
-pprTyThing pefas (AClass cls) = pprClass pefas cls
+pprTyThing pefas thing = ppr_ty_thing pefas (const True) thing
--- | Like 'pprTyThingInContext', but adds the defining location.
-pprTyThingInContextLoc :: PrintExplicitForalls -> TyThing -> SDoc
-pprTyThingInContextLoc pefas tyThing
- = showWithLoc loc (pprTyThingInContext pefas tyThing)
- where loc = GHC.nameSrcSpan (GHC.getName tyThing)
+ppr_ty_thing :: PrintExplicitForalls -> ShowMe -> TyThing -> SDoc
+ppr_ty_thing pefas _ (AnId id) = pprId pefas id
+ppr_ty_thing pefas _ (ADataCon dataCon) = pprDataConSig pefas dataCon
+ppr_ty_thing pefas show_me (ATyCon tyCon) = pprTyCon pefas show_me tyCon
+ppr_ty_thing _ _ (ACoAxiom ax) = pprCoAxiom ax
+ppr_ty_thing pefas show_me (AClass cls) = pprClass pefas show_me cls
-- | Pretty-prints a 'TyThing' in context: that is, if the entity
--- is a data constructor, record selector, or class method, then
+-- is a data constructor, record selector, or class method, then
-- the entity's parent declaration is pretty-printed with irrelevant
-- parts omitted.
pprTyThingInContext :: PrintExplicitForalls -> TyThing -> SDoc
-pprTyThingInContext pefas (AnId id) = pprIdInContext pefas id
-pprTyThingInContext pefas (ADataCon dataCon) = pprDataCon pefas dataCon
-pprTyThingInContext pefas (ATyCon tyCon) = pprTyCon pefas tyCon
-pprTyThingInContext pefas (AClass cls) = pprClass pefas cls
+pprTyThingInContext pefas thing
+ | Just parent <- pprTyThingParent_maybe thing
+ = ppr_ty_thing pefas (== GHC.getName thing) parent
+ | otherwise
+ = pprTyThing pefas thing
+
+-- | Like 'pprTyThingInContext', but adds the defining location.
+pprTyThingInContextLoc :: PrintExplicitForalls -> TyThing -> SDoc
+pprTyThingInContextLoc pefas tyThing
+ = showWithLoc (pprNameLoc (GHC.getName tyThing))
+ (pprTyThingInContext pefas tyThing)
+
+pprTyThingParent_maybe :: TyThing -> Maybe TyThing
+-- (pprTyThingParent_maybe x) returns (Just p)
+-- when pprTyThingInContext sould print a declaration for p
+-- (albeit with some "..." in it) when asked to show x
+pprTyThingParent_maybe (ADataCon dc) = Just (ATyCon (dataConTyCon dc))
+pprTyThingParent_maybe (AnId id) = case idDetails id of
+ RecSelId { sel_tycon = tc } -> Just (ATyCon tc)
+ ClassOpId cls -> Just (AClass cls)
+ _other -> Nothing
+pprTyThingParent_maybe _other = Nothing
-- | Pretty-prints the 'TyThing' header. For functions and data constructors
-- the function is equivalent to 'pprTyThing' but for type constructors
pprTyThingHdr pefas (AnId id) = pprId pefas id
pprTyThingHdr pefas (ADataCon dataCon) = pprDataConSig pefas dataCon
pprTyThingHdr pefas (ATyCon tyCon) = pprTyConHdr pefas tyCon
+pprTyThingHdr _ (ACoAxiom ax) = pprCoAxiom ax
pprTyThingHdr pefas (AClass cls) = pprClassHdr pefas cls
-
-pprTyConHdr pefas tyCon
- | Just (fam_tc, tys) <- tyConFamInst_maybe tyCon
- = ptext keyword <+> ptext SLIT("instance") <+> pprTypeApp tyCon (ppr_bndr tyCon) tys
+
+pprTyConHdr :: PrintExplicitForalls -> TyCon -> SDoc
+pprTyConHdr _ tyCon
+ | Just (_fam_tc, tys) <- tyConFamInst_maybe tyCon
+ = ptext keyword <+> ptext (sLit "instance") <+> pprTypeApp tyCon tys
| otherwise
- = ptext keyword <+> opt_family <+> ppr_bndr tyCon <+> hsep (map ppr vars)
+ = ptext keyword <+> opt_family <+> opt_stupid <+> ppr_bndr tyCon <+> hsep (map ppr vars)
where
- vars | GHC.isPrimTyCon tyCon ||
+ vars | GHC.isPrimTyCon tyCon ||
GHC.isFunTyCon tyCon = take (GHC.tyConArity tyCon) GHC.alphaTyVars
| otherwise = GHC.tyConTyVars tyCon
- keyword | GHC.isSynTyCon tyCon = SLIT("type")
- | GHC.isNewTyCon tyCon = SLIT("newtype")
- | otherwise = SLIT("data")
+ keyword | GHC.isSynTyCon tyCon = sLit "type"
+ | GHC.isNewTyCon tyCon = sLit "newtype"
+ | otherwise = sLit "data"
opt_family
- | GHC.isOpenTyCon tyCon = ptext SLIT("family")
+ | GHC.isFamilyTyCon tyCon = ptext (sLit "family")
| otherwise = empty
-pprDataConSig pefas dataCon =
- ppr_bndr dataCon <+> dcolon <+> pprType pefas (GHC.dataConType dataCon)
-
-pprClassHdr pefas cls =
- let (tyVars, funDeps) = GHC.classTvsFds cls
- in ptext SLIT("class") <+>
- GHC.pprThetaArrow (GHC.classSCTheta cls) <+>
- ppr_bndr cls <+>
- hsep (map ppr tyVars) <+>
- GHC.pprFundeps funDeps
-
-pprIdInContext pefas id
- | GHC.isRecordSelector id = pprRecordSelector pefas id
- | Just cls <- GHC.isClassOpId_maybe id = pprClassOneMethod pefas cls id
- | otherwise = pprId pefas id
-
-pprRecordSelector pefas id
- = pprAlgTyCon pefas tyCon show_con show_label
+ opt_stupid -- The "stupid theta" part of the declaration
+ | isAlgTyCon tyCon = GHC.pprThetaArrowTy (tyConStupidTheta tyCon)
+ | otherwise = empty -- Returns 'empty' if null theta
+
+pprDataConSig :: PrintExplicitForalls -> GHC.DataCon -> SDoc
+pprDataConSig pefas dataCon
+ = ppr_bndr dataCon <+> dcolon <+> pprTypeForUser pefas (GHC.dataConType dataCon)
+
+pprClassHdr :: PrintExplicitForalls -> GHC.Class -> SDoc
+pprClassHdr _ cls
+ = ptext (sLit "class") <+>
+ GHC.pprThetaArrowTy (GHC.classSCTheta cls) <+>
+ ppr_bndr cls <+>
+ hsep (map ppr tyVars) <+>
+ GHC.pprFundeps funDeps
where
- (tyCon,label) = GHC.recordSelectorFieldLabel id
- show_con dataCon = label `elem` GHC.dataConFieldLabels dataCon
- show_label label' = label == label'
+ (tyVars, funDeps) = GHC.classTvsFds cls
pprId :: PrintExplicitForalls -> Var -> SDoc
pprId pefas ident
- = hang (ppr_bndr ident <+> dcolon) 2
- (pprType pefas (GHC.idType ident))
-
-pprType :: PrintExplicitForalls -> GHC.Type -> SDoc
-pprType True ty = ppr ty
-pprType False ty = ppr (GHC.dropForAlls ty)
+ = hang (ppr_bndr ident <+> dcolon)
+ 2 (pprTypeForUser pefas (GHC.idType ident))
+
+pprTypeForUser :: PrintExplicitForalls -> GHC.Type -> SDoc
+-- We do two things here.
+-- a) We tidy the type, regardless
+-- b) If PrintExplicitForAlls is True, we discard the foralls
+-- but we do so `deeply'
+-- Prime example: a class op might have type
+-- forall a. C a => forall b. Ord b => stuff
+-- Then we want to display
+-- (C a, Ord b) => stuff
+pprTypeForUser print_foralls ty
+ | print_foralls = ppr tidy_ty
+ | otherwise = ppr (mkPhiTy ctxt ty')
+ where
+ tidy_ty = tidyTopType ty
+ (_, ctxt, ty') = tcSplitSigmaTy tidy_ty
-pprTyCon pefas tyCon
+pprTyCon :: PrintExplicitForalls -> ShowMe -> TyCon -> SDoc
+pprTyCon pefas show_me tyCon
| GHC.isSynTyCon tyCon
- = if GHC.isOpenTyCon tyCon
+ = if GHC.isFamilyTyCon tyCon
then pprTyConHdr pefas tyCon <+> dcolon <+>
- pprType pefas (GHC.synTyConResKind tyCon)
- else
+ pprTypeForUser pefas (GHC.synTyConResKind tyCon)
+ else
let rhs_type = GHC.synTyConType tyCon
- in hang (pprTyConHdr pefas tyCon <+> equals) 2 (pprType pefas rhs_type)
+ in hang (pprTyConHdr pefas tyCon <+> equals) 2 (pprTypeForUser pefas rhs_type)
| otherwise
- = pprAlgTyCon pefas tyCon (const True) (const True)
+ = pprAlgTyCon pefas show_me tyCon
-pprAlgTyCon pefas tyCon ok_con ok_label
- | gadt = pprTyConHdr pefas tyCon <+> ptext SLIT("where") $$
+pprAlgTyCon :: PrintExplicitForalls -> ShowMe -> TyCon -> SDoc
+pprAlgTyCon pefas show_me tyCon
+ | gadt = pprTyConHdr pefas tyCon <+> ptext (sLit "where") $$
nest 2 (vcat (ppr_trim show_con datacons))
| otherwise = hang (pprTyConHdr pefas tyCon)
2 (add_bars (ppr_trim show_con datacons))
datacons = GHC.tyConDataCons tyCon
gadt = any (not . GHC.isVanillaDataCon) datacons
- show_con dataCon
- | ok_con dataCon = Just (pprDataConDecl pefas gadt ok_label dataCon)
- | otherwise = Nothing
+ ok_con dc = show_me (dataConName dc) || any show_me (dataConFieldLabels dc)
+ show_con dc
+ | ok_con dc = Just (pprDataConDecl pefas show_me gadt dc)
+ | otherwise = Nothing
-pprDataCon pefas dataCon = pprAlgTyCon pefas tyCon (== dataCon) (const True)
- where tyCon = GHC.dataConTyCon dataCon
-
-pprDataConDecl pefas gadt_style show_label dataCon
+pprDataConDecl :: PrintExplicitForalls -> ShowMe -> Bool -> GHC.DataCon -> SDoc
+pprDataConDecl pefas show_me gadt_style dataCon
| not gadt_style = ppr_fields tys_w_strs
- | otherwise = ppr_bndr dataCon <+> dcolon <+>
- sep [ ppr_tvs, GHC.pprThetaArrow theta, pp_tau ]
+ | otherwise = ppr_bndr dataCon <+> dcolon <+>
+ sep [ pp_foralls, GHC.pprThetaArrowTy theta, pp_tau ]
+ -- Printing out the dataCon as a type signature, in GADT style
where
- (tyvars, theta, argTypes, res_ty) = GHC.dataConSig dataCon
- tyCon = GHC.dataConTyCon dataCon
- labels = GHC.dataConFieldLabels dataCon
- qualVars = filter (flip notElem (GHC.tyConTyVars tyCon)) tyvars
- stricts = GHC.dataConStrictMarks dataCon
- tys_w_strs = zip stricts argTypes
-
- ppr_tvs
- | null qualVars = empty
- | otherwise = ptext SLIT("forall") <+>
- hsep (map ppr qualVars) <> dot
-
- -- printing out the dataCon as a type signature, in GADT style
+ (forall_tvs, theta, tau) = tcSplitSigmaTy (GHC.dataConUserType dataCon)
+ (arg_tys, res_ty) = tcSplitFunTys tau
+ labels = GHC.dataConFieldLabels dataCon
+ stricts = GHC.dataConStrictMarks dataCon
+ tys_w_strs = zip stricts arg_tys
+ pp_foralls | pefas = GHC.pprForAll forall_tvs
+ | otherwise = empty
+
pp_tau = foldr add (ppr res_ty) tys_w_strs
- add (str,ty) pp_ty = pprBangTy str ty <+> arrow <+> pp_ty
+ add str_ty pp_ty = pprParendBangTy str_ty <+> arrow <+> pp_ty
- pprParendBangTy (strict,ty)
- | GHC.isMarkedStrict strict = char '!' <> GHC.pprParendType ty
- | otherwise = GHC.pprParendType ty
+ pprParendBangTy (bang,ty) = ppr bang <> GHC.pprParendType ty
- pprBangTy strict ty
- | GHC.isMarkedStrict strict = char '!' <> ppr ty
- | otherwise = ppr ty
+ pprBangTy bang ty = ppr bang <> ppr ty
maybe_show_label (lbl,(strict,tp))
- | show_label lbl = Just (ppr lbl <+> dcolon <+> pprBangTy strict tp)
- | otherwise = Nothing
+ | show_me lbl = Just (ppr lbl <+> dcolon <+> pprBangTy strict tp)
+ | otherwise = Nothing
ppr_fields [ty1, ty2]
| GHC.dataConIsInfix dataCon && null labels
- = sep [pprParendBangTy ty1, ppr dataCon, pprParendBangTy ty2]
+ = sep [pprParendBangTy ty1, pprInfixName dataCon, pprParendBangTy ty2]
ppr_fields fields
| null labels
= ppr_bndr dataCon <+> sep (map pprParendBangTy fields)
| otherwise
- = ppr_bndr dataCon <+>
- braces (sep (punctuate comma (ppr_trim maybe_show_label
+ = ppr_bndr dataCon <+>
+ braces (sep (punctuate comma (ppr_trim maybe_show_label
(zip labels fields))))
-pprClass pefas cls
- | null methods =
- pprClassHdr pefas cls
- | otherwise =
- hang (pprClassHdr pefas cls <+> ptext SLIT("where"))
- 2 (vcat (map (pprClassMethod pefas) methods))
- where
- methods = GHC.classMethods cls
-
-pprClassOneMethod pefas cls this_one =
- hang (pprClassHdr pefas cls <+> ptext SLIT("where"))
- 2 (vcat (ppr_trim show_meth methods))
+pprClass :: PrintExplicitForalls -> ShowMe -> GHC.Class -> SDoc
+pprClass pefas show_me cls
+ | null methods
+ = pprClassHdr pefas cls
+ | otherwise
+ = hang (pprClassHdr pefas cls <+> ptext (sLit "where"))
+ 2 (vcat (ppr_trim show_meth methods))
where
- methods = GHC.classMethods cls
- show_meth id | id == this_one = Just (pprClassMethod pefas id)
- | otherwise = Nothing
+ methods = GHC.classMethods cls
+ show_meth id | show_me (idName id) = Just (pprClassMethod pefas id)
+ | otherwise = Nothing
-pprClassMethod pefas id =
- hang (ppr_bndr id <+> dcolon) 2 (pprType pefas (classOpType id))
+pprClassMethod :: PrintExplicitForalls -> Id -> SDoc
+pprClassMethod pefas id
+ = hang (ppr_bndr id <+> dcolon) 2 (pprTypeForUser pefas op_ty)
where
-- Here's the magic incantation to strip off the dictionary
-- from the class op type. Stolen from IfaceSyn.tyThingToIfaceDecl.
- classOpType id = GHC.funResultTy rho_ty
- where (_sel_tyvars, rho_ty) = GHC.splitForAllTys (GHC.idType id)
+ --
+ -- It's important to tidy it *before* splitting it up, so that if
+ -- we have class C a b where
+ -- op :: forall a. a -> b
+ -- then the inner forall on op gets renamed to a1, and we print
+ -- (when dropping foralls)
+ -- class C a b where
+ -- op :: a1 -> b
+
+ tidy_sel_ty = tidyTopType (GHC.idType id)
+ (_sel_tyvars, rho_ty) = GHC.splitForAllTys tidy_sel_ty
+ op_ty = GHC.funResultTy rho_ty
ppr_trim :: (a -> Maybe SDoc) -> [a] -> [SDoc]
ppr_trim show xs
go x (eliding, so_far)
| Just doc <- show x = (False, doc : so_far)
| otherwise = if eliding then (True, so_far)
- else (True, ptext SLIT("...") : so_far)
+ else (True, ptext (sLit "...") : so_far)
+add_bars :: [SDoc] -> SDoc
add_bars [] = empty
add_bars [c] = equals <+> c
add_bars (c:cs) = sep ((equals <+> c) : map (char '|' <+>) cs)
ppr_bndr :: GHC.NamedThing a => a -> SDoc
ppr_bndr a = GHC.pprParenSymName a
-showWithLoc :: SrcSpan -> SDoc -> SDoc
-showWithLoc loc doc
- = hang doc 2 (char '\t' <> comment <+> GHC.pprDefnLoc loc)
+showWithLoc :: SDoc -> SDoc -> SDoc
+showWithLoc loc doc
+ = hang doc 2 (char '\t' <> comment <+> loc)
-- The tab tries to make them line up a bit
where
- comment = ptext SLIT("--")
+ comment = ptext (sLit "--")
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