printAST.hs

#! /usr/bin/env nix-shell
#! nix-shell --pure -i "runghc -- -package --ghc-arg=ghc" -p "haskellPackages.ghcWithPackages (p: with p; [ ghc-exactprint pretty-simple ])"

import GHC.Hs.Dump
import Language.Haskell.GHC.ExactPrint.Parsers
import GHC.Utils.Outputable
import System.Environment
import Text.Pretty.Simple

main :: IO ()
main = do
  args <- getArgs
  case args of
    [file] -> do
      Right (anns, pm) <- parseModule file
      putStrLn . showSDocUnsafe $ showAstData NoBlankSrcSpan pm
      pPrint anns
    _ -> putStrLn "Expect one arg."