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|
{-# LANGUAGE CPP #-}
{- | "GHC.Syb.Utils" provides common utilities for the Ghc Api,
either based on Data\/Typeable or for use with Data.Generics
over Ghc Api types.
example output of 'showData' on 'parsedSource', 'renamedSource', and
'typecheckedSource' for a trivial @HelloWorld@ module, compared with
'ppr' output:
@
------------------------- pretty-printed parsedSource
module HelloWorld where
main = putStrLn "Hello, World!"
------------------------- pretty-printed renamedSource
Just (HelloWorld.main = System.IO.putStrLn "Hello, World!",
[import Prelude],
Nothing,
Nothing,
(HaddockModInfo
(Nothing)
(Nothing)
(Nothing)
(Nothing)))
------------------------- pretty-printed typecheckedSource
Just <AbsBinds [] [] [HelloWorld.main <= [] main]
HelloWorld.main :: GHC.IOBase.IO ()
[]
{ main = System.IO.putStrLn "Hello, World!" }>
------------------------- shown parsedSource
(L {HelloWorld.hs:1:0}
(HsModule
(Just
(L {HelloWorld.hs:1:7-16} {ModuleName: HelloWorld}))
(Nothing)
[]
[
(L {HelloWorld.hs:2:0-30}
(ValD
(FunBind
(L {HelloWorld.hs:2:0-3}
(Unqual {OccName: main}))
(False)
(MatchGroup
[
(L {HelloWorld.hs:2:0-30}
(Match
[]
(Nothing)
(GRHSs
[
(L {HelloWorld.hs:2:7-30}
(GRHS
[]
(L {HelloWorld.hs:2:7-30}
(HsApp
(L {HelloWorld.hs:2:7-14}
(HsVar
(Unqual {OccName: putStrLn})))
(L {HelloWorld.hs:2:16-30}
(HsLit
(HsString {FastString: "Hello, World!"})))))))]
(EmptyLocalBinds))))] {!type placeholder here?!})
(WpHole) {!NameSet placeholder here!}
(Nothing))))]
(Nothing)
(HaddockModInfo
(Nothing)
(Nothing)
(Nothing)
(Nothing))
(Nothing)))
------------------------- shown renamedSource
((,,,,)
(HsGroup
(ValBindsOut
[
((,)
(NonRecursive) {Bag(Located (HsBind Name)):
[
(L {HelloWorld.hs:2:0-30}
(FunBind
(L {HelloWorld.hs:2:0-3} {Name: HelloWorld.main})
(False)
(MatchGroup
[
(L {HelloWorld.hs:2:0-30}
(Match
[]
(Nothing)
(GRHSs
[
(L {HelloWorld.hs:2:7-30}
(GRHS
[]
(L {HelloWorld.hs:2:7-30}
(HsApp
(L {HelloWorld.hs:2:7-14}
(HsVar {Name: System.IO.putStrLn}))
(L {HelloWorld.hs:2:16-30}
(HsLit
(HsString {FastString: "Hello, World!"})))))))]
(EmptyLocalBinds))))] {!type placeholder here?!})
(WpHole) {NameSet:
[{Name: System.IO.putStrLn}]}
(Nothing)))]})]
[])
[]
[]
[]
[]
[]
[]
[]
[]
[])
[
(L {Implicit import declaration}
(ImportDecl
(L {Implicit import declaration} {ModuleName: Prelude})
(False)
(False)
(Nothing)
(Nothing)))]
(Nothing)
(Nothing)
(HaddockModInfo
(Nothing)
(Nothing)
(Nothing)
(Nothing)))
------------------------- shown typecheckedSource
{Bag(Located (HsBind Var)):
[
(L {HelloWorld.hs:2:0-30}
(AbsBinds
[]
[]
[
((,,,)
[] {Var: HelloWorld.main} {Var: main}
[])] {Bag(Located (HsBind Var)):
[
(L {HelloWorld.hs:2:0-30}
(FunBind
(L {HelloWorld.hs:2:0-3} {Var: main})
(False)
(MatchGroup
[
(L {HelloWorld.hs:2:0-30}
(Match
[]
(Nothing)
(GRHSs
[
(L {HelloWorld.hs:2:7-30}
(GRHS
[]
(L {HelloWorld.hs:2:7-30}
(HsApp
(L {HelloWorld.hs:2:7-14}
(HsVar {Var: System.IO.putStrLn}))
(L {HelloWorld.hs:2:16-30}
(HsLit
(HsString {FastString: "Hello, World!"})))))))]
(EmptyLocalBinds))))] GHC.IOBase.IO ())
(WpHole) {!NameSet placeholder here!}
(Nothing)))]}))]}
@
-}
module GHC.SYB.Utils where
import Data.Generics
-- import qualified GHC.Paths
import PprTyThing
import DynFlags
import GHC
import Outputable
import SrcLoc
import qualified OccName(occNameString)
import Bag(Bag,bagToList)
import Var(Var)
import FastString(FastString)
import NameSet(NameSet,nameSetToList)
#if __GLASGOW_HASKELL__ < 700
import GHC.SYB.Instances
#endif
import Data.List
showSDoc_ :: SDoc -> String
#if __GLASGOW_HASKELL__ >= 707
showSDoc_ = showSDoc unsafeGlobalDynFlags
#elif __GLASGOW_HASKELL__ < 706
showSDoc_ = showSDoc
#else
showSDoc_ = showSDoc tracingDynFlags
#endif
-- | Ghc Ast types tend to have undefined holes, to be filled
-- by later compiler phases. We tag Asts with their source,
-- so that we can avoid such holes based on who generated the Asts.
data Stage = Parser | Renamer | TypeChecker deriving (Eq,Ord,Show)
-- | Generic Data-based show, with special cases for GHC Ast types,
-- and simplistic indentation-based layout (the 'Int' parameter);
-- showing abstract types abstractly and avoiding known potholes
-- (based on the 'Stage' that generated the Ast)
showData :: Data a => Stage -> Int -> a -> String
showData stage n =
generic `ext1Q` list `extQ` string `extQ` fastString `extQ` srcSpan
`extQ` name `extQ` occName `extQ` moduleName `extQ` var `extQ` dataCon
`extQ` bagName `extQ` bagRdrName `extQ` bagVar `extQ` nameSet
`extQ` postTcType `extQ` fixity
where generic :: Data a => a -> String
generic t = indent n ++ "(" ++ showConstr (toConstr t)
++ space (concat (intersperse " " (gmapQ (showData stage (n+1)) t))) ++ ")"
space "" = ""
space s = ' ':s
indent n = "\n" ++ replicate n ' '
string = show :: String -> String
fastString = ("{FastString: "++) . (++"}") . show :: FastString -> String
list l = indent n ++ "["
++ concat (intersperse "," (map (showData stage (n+1)) l)) ++ "]"
name = ("{Name: "++) . (++"}") . showSDoc_ . ppr :: Name -> String
occName = ("{OccName: "++) . (++"}") . OccName.occNameString
moduleName = ("{ModuleName: "++) . (++"}") . showSDoc_ . ppr :: ModuleName -> String
srcSpan = ("{"++) . (++"}") . showSDoc_ . ppr :: SrcSpan -> String
var = ("{Var: "++) . (++"}") . showSDoc_ . ppr :: Var -> String
dataCon = ("{DataCon: "++) . (++"}") . showSDoc_ . ppr :: DataCon -> String
bagRdrName:: Bag (Located (HsBind RdrName)) -> String
bagRdrName = ("{Bag(Located (HsBind RdrName)): "++) . (++"}") . list . bagToList
bagName :: Bag (Located (HsBind Name)) -> String
bagName = ("{Bag(Located (HsBind Name)): "++) . (++"}") . list . bagToList
bagVar :: Bag (Located (HsBind Var)) -> String
bagVar = ("{Bag(Located (HsBind Var)): "++) . (++"}") . list . bagToList
nameSet | stage `elem` [Parser,TypeChecker]
= const ("{!NameSet placeholder here!}") :: NameSet -> String
| otherwise
= ("{NameSet: "++) . (++"}") . list . nameSetToList
postTcType | stage<TypeChecker = const "{!type placeholder here?!}" :: PostTcType -> String
| otherwise = showSDoc_ . ppr :: Type -> String
fixity | stage<Renamer = const "{!fixity placeholder here?!}" :: GHC.Fixity -> String
| otherwise = ("{Fixity: "++) . (++"}") . showSDoc_ . ppr :: GHC.Fixity -> String
-- | Like 'everything', but avoid known potholes, based on the 'Stage' that
-- generated the Ast.
everythingStaged :: Stage -> (r -> r -> r) -> r -> GenericQ r -> GenericQ r
everythingStaged stage k z f x
| (const False `extQ` postTcType `extQ` fixity `extQ` nameSet) x = z
| otherwise = foldl k (f x) (gmapQ (everythingStaged stage k z f) x)
where nameSet = const (stage `elem` [Parser,TypeChecker]) :: NameSet -> Bool
postTcType = const (stage<TypeChecker) :: PostTcType -> Bool
fixity = const (stage<Renamer) :: GHC.Fixity -> Bool
-- | A variation of 'everything', using a 'GenericQ Bool' to skip
-- parts of the input 'Data'.
--everythingBut :: GenericQ Bool -> (r -> r -> r) -> r -> GenericQ r -> GenericQ r
--everythingBut q k z f x
-- | q x = z
-- | otherwise = foldl k (f x) (gmapQ (everythingBut q k z f) x)
|
