-----------------------------------------------------------------------------
module PprTyThing (
+ PrintExplicitForalls,
pprTyThing,
pprTyThingInContext,
pprTyThingLoc,
pprTyThingInContextLoc,
- pprTyThingHdr
+ pprTyThingHdr,
+ pprTypeForUser
) where
-#include "HsVersions.h"
-
import qualified GHC
-import GHC ( TyThing(..), SrcLoc )
-import DataCon ( dataConResTys )
+import GHC ( TyThing(..) )
+import TyCon
+import TcType
+import Var
+import Name
import Outputable
+import FastString
-- -----------------------------------------------------------------------------
-- Pretty-printing entities that we get from the GHC API
-- This should be a good source of sample code for using the GHC API to
-- inspect source code entities.
+type PrintExplicitForalls = Bool
+
-- | Pretty-prints a 'TyThing' with its defining location.
-pprTyThingLoc :: Bool -> TyThing -> SDoc
-pprTyThingLoc exts tyThing
- = showWithLoc loc (pprTyThing exts tyThing)
- where loc = GHC.nameSrcLoc (GHC.getName tyThing)
+pprTyThingLoc :: PrintExplicitForalls -> TyThing -> SDoc
+pprTyThingLoc pefas tyThing
+ = showWithLoc loc (pprTyThing pefas tyThing)
+ where loc = pprNameLoc (GHC.getName tyThing)
-- | Pretty-prints a 'TyThing'.
-pprTyThing :: Bool -> TyThing -> SDoc
-pprTyThing exts (AnId id) = pprId exts id
-pprTyThing exts (ADataCon dataCon) = pprDataConSig exts dataCon
-pprTyThing exts (ATyCon tyCon) = pprTyCon exts tyCon
-pprTyThing exts (AClass cls) = pprClass exts cls
-
+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
+
-- | Like 'pprTyThingInContext', but adds the defining location.
-pprTyThingInContextLoc :: Bool -> TyThing -> SDoc
-pprTyThingInContextLoc exts tyThing
- = showWithLoc loc (pprTyThingInContext exts tyThing)
- where loc = GHC.nameSrcLoc (GHC.getName tyThing)
+pprTyThingInContextLoc :: PrintExplicitForalls -> TyThing -> SDoc
+pprTyThingInContextLoc pefas tyThing
+ = showWithLoc loc (pprTyThingInContext pefas tyThing)
+ where loc = pprNameLoc (GHC.getName tyThing)
-- | Pretty-prints a 'TyThing' in context: that is, if the entity
-- is a data constructor, record selector, or class method, then
-- the entity's parent declaration is pretty-printed with irrelevant
-- parts omitted.
-pprTyThingInContext :: Bool -> TyThing -> SDoc
-pprTyThingInContext exts (AnId id) = pprIdInContext exts id
-pprTyThingInContext exts (ADataCon dataCon) = pprDataCon exts dataCon
-pprTyThingInContext exts (ATyCon tyCon) = pprTyCon exts tyCon
-pprTyThingInContext exts (AClass cls) = pprClass exts cls
+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
-- | Pretty-prints the 'TyThing' header. For functions and data constructors
-- the function is equivalent to 'pprTyThing' but for type constructors
-- and classes it prints only the header part of the declaration.
-pprTyThingHdr :: Bool -> TyThing -> SDoc
-pprTyThingHdr exts (AnId id) = pprId exts id
-pprTyThingHdr exts (ADataCon dataCon) = pprDataConSig exts dataCon
-pprTyThingHdr exts (ATyCon tyCon) = pprTyConHdr exts tyCon
-pprTyThingHdr exts (AClass cls) = pprClassHdr exts cls
-
-pprTyConHdr exts tyCon =
- addFamily (ptext keyword) <+> ppr_bndr tyCon <+> hsep (map ppr vars)
+pprTyThingHdr :: PrintExplicitForalls -> TyThing -> SDoc
+pprTyThingHdr pefas (AnId id) = pprId pefas id
+pprTyThingHdr pefas (ADataCon dataCon) = pprDataConSig pefas dataCon
+pprTyThingHdr pefas (ATyCon tyCon) = pprTyConHdr pefas tyCon
+pprTyThingHdr pefas (AClass cls) = pprClassHdr pefas cls
+
+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 <+> opt_stupid <+> ppr_bndr tyCon <+> hsep (map ppr vars)
where
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"
- addFamily keytext
- | GHC.isOpenTyCon tyCon = keytext <> ptext SLIT(" family")
- | otherwise = keytext
+ opt_family
+ | GHC.isOpenTyCon tyCon = ptext (sLit "family")
+ | otherwise = empty
-pprDataConSig exts dataCon =
- ppr_bndr dataCon <+> dcolon <+> pprType exts (GHC.dataConType dataCon)
+ opt_stupid -- The "stupid theta" part of the declaration
+ | isAlgTyCon tyCon = GHC.pprThetaArrow (tyConStupidTheta tyCon)
+ | otherwise = empty -- Returns 'empty' if null theta
-pprClassHdr exts cls =
+pprDataConSig :: PrintExplicitForalls -> GHC.DataCon -> SDoc
+pprDataConSig pefas dataCon =
+ ppr_bndr dataCon <+> dcolon <+> pprTypeForUser pefas (GHC.dataConType dataCon)
+
+pprClassHdr :: PrintExplicitForalls -> GHC.Class -> SDoc
+pprClassHdr _ cls =
let (tyVars, funDeps) = GHC.classTvsFds cls
- in ptext SLIT("class") <+>
+ in ptext (sLit "class") <+>
GHC.pprThetaArrow (GHC.classSCTheta cls) <+>
ppr_bndr cls <+>
hsep (map ppr tyVars) <+>
GHC.pprFundeps funDeps
-pprIdInContext exts id
- | GHC.isRecordSelector id = pprRecordSelector exts id
- | Just cls <- GHC.isClassOpId_maybe id = pprClassOneMethod exts cls id
- | otherwise = pprId exts id
+pprIdInContext :: PrintExplicitForalls -> Var -> SDoc
+pprIdInContext pefas id
+ | GHC.isRecordSelector id = pprRecordSelector pefas id
+ | Just cls <- GHC.isClassOpId_maybe id = pprClassOneMethod pefas cls id
+ | otherwise = pprId pefas id
-pprRecordSelector exts id
- = pprAlgTyCon exts tyCon show_con show_label
+pprRecordSelector :: PrintExplicitForalls -> Id -> SDoc
+pprRecordSelector pefas id
+ = pprAlgTyCon pefas tyCon show_con show_label
where
(tyCon,label) = GHC.recordSelectorFieldLabel id
show_con dataCon = label `elem` GHC.dataConFieldLabels dataCon
show_label label' = label == label'
-pprId exts id
- = hang (ppr_bndr id <+> dcolon) 2
- (pprType exts (GHC.idType id))
-
-pprType True ty = ppr ty
-pprType False ty = ppr (GHC.dropForAlls ty)
+pprId :: PrintExplicitForalls -> Var -> SDoc
+pprId pefas ident
+ = 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 [p | (_tvs, ps) <- ctxt, p <- ps] ty')
+ where
+ tidy_ty = tidyTopType ty
+ (ctxt, ty') = tcMultiSplitSigmaTy tidy_ty
-pprTyCon exts tyCon
+pprTyCon :: PrintExplicitForalls -> TyCon -> SDoc
+pprTyCon pefas tyCon
| GHC.isSynTyCon tyCon
= if GHC.isOpenTyCon tyCon
- then pprTyConHdr exts tyCon <+> dcolon <+>
- pprType exts (GHC.synTyConResKind tyCon)
+ then pprTyConHdr pefas tyCon <+> dcolon <+>
+ pprTypeForUser pefas (GHC.synTyConResKind tyCon)
else
let rhs_type = GHC.synTyConType tyCon
- in hang (pprTyConHdr exts tyCon <+> equals) 2 (pprType exts rhs_type)
+ in hang (pprTyConHdr pefas tyCon <+> equals) 2 (pprTypeForUser pefas rhs_type)
| otherwise
- = pprAlgTyCon exts tyCon (const True) (const True)
+ = pprAlgTyCon pefas tyCon (const True) (const True)
-pprAlgTyCon exts tyCon ok_con ok_label
- | gadt = pprTyConHdr exts tyCon <+> ptext SLIT("where") $$
+pprAlgTyCon :: PrintExplicitForalls -> TyCon -> (GHC.DataCon -> Bool)
+ -> (FieldLabel -> Bool) -> SDoc
+pprAlgTyCon pefas tyCon ok_con ok_label
+ | gadt = pprTyConHdr pefas tyCon <+> ptext (sLit "where") $$
nest 2 (vcat (ppr_trim show_con datacons))
- | otherwise = hang (pprTyConHdr exts tyCon)
+ | otherwise = hang (pprTyConHdr pefas tyCon)
2 (add_bars (ppr_trim show_con datacons))
where
datacons = GHC.tyConDataCons tyCon
gadt = any (not . GHC.isVanillaDataCon) datacons
show_con dataCon
- | ok_con dataCon = Just (pprDataConDecl exts gadt ok_label dataCon)
+ | ok_con dataCon = Just (pprDataConDecl pefas gadt ok_label dataCon)
| otherwise = Nothing
-pprDataCon exts dataCon = pprAlgTyCon exts tyCon (== dataCon) (const True)
+pprDataCon :: PrintExplicitForalls -> GHC.DataCon -> SDoc
+pprDataCon pefas dataCon = pprAlgTyCon pefas tyCon (== dataCon) (const True)
where tyCon = GHC.dataConTyCon dataCon
-pprDataConDecl exts gadt_style show_label dataCon
+pprDataConDecl :: PrintExplicitForalls -> Bool -> (FieldLabel -> Bool)
+ -> GHC.DataCon -> SDoc
+pprDataConDecl _ gadt_style show_label dataCon
| not gadt_style = ppr_fields tys_w_strs
| otherwise = ppr_bndr dataCon <+> dcolon <+>
sep [ ppr_tvs, GHC.pprThetaArrow theta, pp_tau ]
where
- (tyvars, theta, argTypes) = GHC.dataConSig dataCon
+ (tyvars, theta, argTypes, res_ty) = GHC.dataConSig dataCon
tyCon = GHC.dataConTyCon dataCon
labels = GHC.dataConFieldLabels dataCon
- res_tys = dataConResTys 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") <+>
+ | otherwise = ptext (sLit "forall") <+>
hsep (map ppr qualVars) <> dot
-- printing out the dataCon as a type signature, in GADT style
- pp_tau = foldr add pp_res_ty tys_w_strs
- pp_res_ty = ppr_bndr tyCon <+> hsep (map GHC.pprParendType res_tys)
- add (str,ty) pp_ty = pprBangTy str ty <+> arrow <+> pp_ty
+ pp_tau = foldr add (ppr res_ty) tys_w_strs
+ 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)
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)
braces (sep (punctuate comma (ppr_trim maybe_show_label
(zip labels fields))))
-pprClass exts cls
+pprClass :: PrintExplicitForalls -> GHC.Class -> SDoc
+pprClass pefas cls
| null methods =
- pprClassHdr exts cls
+ pprClassHdr pefas cls
| otherwise =
- hang (pprClassHdr exts cls <+> ptext SLIT("where"))
- 2 (vcat (map (pprClassMethod exts) methods))
+ hang (pprClassHdr pefas cls <+> ptext (sLit "where"))
+ 2 (vcat (map (pprClassMethod pefas) methods))
where
methods = GHC.classMethods cls
-pprClassOneMethod exts cls this_one =
- hang (pprClassHdr exts cls <+> ptext SLIT("where"))
- 2 (vcat (ppr_trim show_meth methods))
+pprClassOneMethod :: PrintExplicitForalls -> GHC.Class -> Id -> SDoc
+pprClassOneMethod pefas cls this_one
+ = 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 exts id)
+ show_meth id | id == this_one = Just (pprClassMethod pefas id)
| otherwise = Nothing
-pprClassMethod exts id =
- hang (ppr_bndr id <+> dcolon) 2 (pprType exts (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 :: SrcLoc -> SDoc -> SDoc
+showWithLoc :: SDoc -> SDoc -> SDoc
showWithLoc loc doc
- = hang doc 2 (char '\t' <> comment <+> GHC.pprDefnLoc loc)
+ = 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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