ENH clean up errors in import

lib/Internal/Statement.hs

@@ -2,6 +2,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE TupleSections #-}
+{-# LANGUAGE NoImplicitPrelude #-}
 
 module Internal.Statement
   ( readImport
@@ -24,9 +25,9 @@ import qualified RIO.Vector as V
 -- TODO this probably won't scale well (pipes?)
 
 readImport :: MonadUnliftIO m => Import -> MappingT m (EitherErrs [BalTx])
-readImport Import {..} =
+readImport Import {..} = do
-  matchRecords impMatches . L.sort . concat
+  res <- mapM (readImport_ impSkipLines impDelim impTxOpts) impPaths
-    <$> mapM (readImport_ impSkipLines impDelim impTxOpts) impPaths
+  return $ (matchRecords impMatches . L.sort . concat) =<< concatEitherL res
 
 readImport_
   :: MonadUnliftIO m
@@ -34,13 +35,13 @@ readImport_
   -> Word
   -> TxOpts
   -> FilePath
-  -> MappingT m [TxRecord]
+  -> MappingT m (EitherErr [TxRecord])
 readImport_ n delim tns p = do
   dir <- asks kmConfigDir
   bs <- liftIO $ BL.readFile $ dir </> p
   case decodeByNameWithP (parseTxRecord p tns) opts $ skip bs of
-    Left m -> liftIO $ putStrLn m >> return []
+    Left m -> return $ Left $ ParseError $ T.pack m
-    Right (_, v) -> return $ catMaybes $ V.toList v
+    Right (_, v) -> return $ Right $ catMaybes $ V.toList v
   where
     opts = defaultDecodeOptions {decDelimiter = fromIntegral delim}
     skip = BL.intercalate "\n" . L.drop (fromIntegral n) . BL.split 10
@@ -145,10 +146,10 @@ zipperMatch' z x = go z
     go z' = Right (z', MatchFail)
 
 matchDec :: Match -> Maybe Match
-matchDec m@Match {mTimes = t} =
+matchDec m = case mTimes m of
-  if t' == Just 0 then Nothing else Just $ m {mTimes = t'}
+  Just 0 -> Nothing
-  where
+  Just n -> Just $ m {mTimes = Just $ n - 1}
-    t' = fmap pred t
+  Nothing -> Just m
 
 matchAll :: [MatchGroup] -> [TxRecord] -> EitherErrs ([RawTx], [TxRecord], [Match])
 matchAll = go ([], [])