project-m36-1.0.0: src/bin/TutorialD/Interpreter/Export/CSV.hs

module TutorialD.Interpreter.Export.CSV where
import ProjectM36.Relation.Show.CSV
import ProjectM36.Interpreter
import TutorialD.Interpreter.Export.Base
import TutorialD.Interpreter.RelationalExpr
import TutorialD.Interpreter.Base hiding (try)
import ProjectM36.Base
import ProjectM36.Error
import qualified Data.ByteString.Lazy as BS
import Control.Exception (try)
import qualified Data.Text as T

exportCSVP :: Parser RelVarDataExportOperator
exportCSVP = do
  reserved ":exportcsv"
  exportExpr <- relExprP
  path <- quotedString
  return $ RelVarDataExportOperator exportExpr (T.unpack path) exportRelationCSV 
                               
exportRelationCSV :: RelVarDataExportOperator -> Relation -> IO (Maybe RelationalError)
exportRelationCSV (RelVarDataExportOperator _  pathOut _) rel =
  case relationAsCSV rel of
    Left err -> return $ Just err
    Right csvData -> do
      writeResult <- try (BS.writeFile pathOut csvData) :: IO (Either IOError ())
      case writeResult of
        Left err -> return $ Just (ExportError $ T.pack (show err))
        Right _ -> return Nothing