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)))]}))]}