+++ /dev/null
------------------------------------------------------------------------------
---
--- Pretty-printing TyThings
---
--- (c) The GHC Team 2005
---
------------------------------------------------------------------------------
-
-module PprTyThing (
- pprTyThing,
- pprTyThingInContext,
- pprTyThingLoc,
- pprTyThingInContextLoc,
- pprTyThingHdr
- ) where
-
-#include "HsVersions.h"
-
-import qualified GHC
-import GHC ( TyThing(..), SrcLoc )
-import Outputable
-
--- -----------------------------------------------------------------------------
--- 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.
-
--- | 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)
-
--- | 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
-
--- | 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)
-
--- | 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
-
--- | 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 =
- ptext keyword <+> 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")
-
-pprDataConSig exts dataCon =
- ppr_bndr dataCon <+> dcolon <+> pprType exts (GHC.dataConType dataCon)
-
-pprClassHdr exts 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 exts id
- | GHC.isRecordSelector id = pprRecordSelector exts id
- | Just cls <- GHC.isClassOpId_maybe id = pprClassOneMethod exts cls id
- | otherwise = pprId exts id
-
-pprRecordSelector exts id
- = pprAlgTyCon exts 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)
-
-pprTyCon exts tyCon
- | GHC.isSynTyCon tyCon
- = let rhs_type = GHC.synTyConRhs tyCon
- in hang (pprTyConHdr exts tyCon <+> equals) 2 (pprType exts rhs_type)
- | otherwise
- = pprAlgTyCon exts tyCon (const True) (const True)
-
-pprAlgTyCon exts tyCon ok_con ok_label
- | gadt = pprTyConHdr exts tyCon <+> ptext SLIT("where") $$
- nest 2 (vcat (ppr_trim show_con datacons))
- | otherwise = hang (pprTyConHdr exts 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)
- | otherwise = Nothing
-
-pprDataCon exts dataCon = pprAlgTyCon exts tyCon (== dataCon) (const True)
- where tyCon = GHC.dataConTyCon dataCon
-
-pprDataConDecl exts 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, tyCon, res_tys) = GHC.dataConSig 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
- 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
-
- 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, ppr 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 exts cls
- | null methods =
- pprClassHdr exts cls
- | otherwise =
- hang (pprClassHdr exts cls <+> ptext SLIT("where"))
- 2 (vcat (map (pprClassMethod exts) 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))
- where
- methods = GHC.classMethods cls
- show_meth id | id == this_one = Just (pprClassMethod exts id)
- | otherwise = Nothing
-
-pprClassMethod exts id =
- hang (ppr_bndr id <+> dcolon) 2 (pprType exts (classOpType id))
- 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)
-
-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 [] = empty
-add_bars [c] = equals <+> c
-add_bars (c:cs) = sep ((equals <+> c) : map (char '|' <+>) cs)
-
--- Wrap operators in ()
-ppr_bndr :: GHC.NamedThing a => a -> SDoc
-ppr_bndr a = GHC.pprParenSymName a
-
-showWithLoc :: SrcLoc -> SDoc -> SDoc
-showWithLoc loc doc
- = hang doc 2 (char '\t' <> comment <+> GHC.pprDefnLoc loc)
- -- The tab tries to make them line up a bit
- where
- comment = ptext SLIT("--")
-