Script.hs

import Prelude
import Control.Monad
import Data.Foldable
import Language.PureScript.CST.Types as CST
import Language.PureScript.CST.Parser as CST
import Language.PureScript.CST.Print as CST
import Data.Text (Text)
import Data.Text.IO as Text
import System.Directory
import System.FilePath
import System.IO (hSetEncoding, stdout, stderr, utf8)

readModule :: FilePath -> IO (Text, Maybe (CST.Module ()))
readModule path = do
  contents <- BS.fromStrict . Text.encodeUtf8 path
  module_ <- case snd $ CST.parse contents of
    Left err -> print (show err) *> pure Nothing
    Right module_ -> pure $ Just module_
  pure (contents, module_)

roundtripParser :: IO ()
roundtripParser = do
  hSetEncoding stdout utf8
  hSetEncoding stderr utf8
  let dir = "lib/purescript-cst/tests/purs/layout"
  -- let dir = "tests/purs/passing"
  files <- listDirectory dir
  for_ files $ \path -> when (isExtensionOf "purs" path) $ do
    print path
    (content, module_) <- readModule (dir </> path)
    for_ module_ $ \module_ -> if content == CST.printModule module_ then pure () else error path
  pure ()

main = roundtripParser