module PprTyThing (
PrintExplicitForalls,
pprTyThing,
pprTyThingInContext,
pprTyThingLoc,
pprTyThingInContextLoc,
pprTyThingHdr,
pprTypeForUser
) where
import qualified GHC
import GHC ( TyThing(..) )
import TyCon
import TcType
import Var
import Name
import Outputable
import FastString
type PrintExplicitForalls = Bool
pprTyThingLoc :: PrintExplicitForalls -> TyThing -> SDoc
pprTyThingLoc pefas tyThing
= showWithLoc loc (pprTyThing pefas tyThing)
where loc = pprNameLoc (GHC.getName 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
pprTyThingInContextLoc :: PrintExplicitForalls -> TyThing -> SDoc
pprTyThingInContextLoc pefas tyThing
= showWithLoc loc (pprTyThingInContext pefas tyThing)
where loc = pprNameLoc (GHC.getName tyThing)
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
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"
opt_family
| GHC.isOpenTyCon tyCon = ptext (sLit "family")
| otherwise = empty
opt_stupid
| isAlgTyCon tyCon = GHC.pprThetaArrow (tyConStupidTheta tyCon)
| otherwise = empty
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") <+>
GHC.pprThetaArrow (GHC.classSCTheta cls) <+>
ppr_bndr cls <+>
hsep (map ppr tyVars) <+>
GHC.pprFundeps funDeps
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 :: 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 :: PrintExplicitForalls -> Var -> SDoc
pprId pefas ident
= hang (ppr_bndr ident <+> dcolon)
2 (pprTypeForUser pefas (GHC.idType ident))
pprTypeForUser :: PrintExplicitForalls -> GHC.Type -> SDoc
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 :: PrintExplicitForalls -> TyCon -> SDoc
pprTyCon pefas tyCon
| GHC.isSynTyCon tyCon
= if GHC.isOpenTyCon tyCon
then pprTyConHdr pefas tyCon <+> dcolon <+>
pprTypeForUser pefas (GHC.synTyConResKind tyCon)
else
let rhs_type = GHC.synTyConType tyCon
in hang (pprTyConHdr pefas tyCon <+> equals) 2 (pprTypeForUser pefas rhs_type)
| otherwise
= pprAlgTyCon pefas tyCon (const True) (const True)
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 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 pefas gadt ok_label dataCon)
| otherwise = Nothing
pprDataCon :: PrintExplicitForalls -> GHC.DataCon -> SDoc
pprDataCon pefas dataCon = pprAlgTyCon pefas tyCon (== dataCon) (const True)
where tyCon = GHC.dataConTyCon 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, 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
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
pprBangTy strict ty
| GHC.isMarkedStrict strict = char '!' <> ppr ty
| otherwise = ppr ty
maybe_show_label (lbl,(strict,tp))
| show_label lbl = Just (ppr lbl <+> dcolon <+> pprBangTy strict tp)
| otherwise = Nothing
ppr_fields [ty1, ty2]
| GHC.dataConIsInfix dataCon && null labels
= 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
(zip labels fields))))
pprClass :: PrintExplicitForalls -> GHC.Class -> SDoc
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 :: 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 pefas id)
| otherwise = Nothing
pprClassMethod :: PrintExplicitForalls -> Id -> SDoc
pprClassMethod pefas id
= hang (ppr_bndr id <+> dcolon) 2 (pprTypeForUser pefas op_ty)
where
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
= snd (foldr go (False, []) xs)
where
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)
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 :: SDoc -> SDoc -> SDoc
showWithLoc loc doc
= hang doc 2 (char '\t' <> comment <+> loc)
where
comment = ptext (sLit "--")