nicer json output which leaks less haskell names

1 files changed, 6 insertions, 3 deletions

diff --git a/lib/Tiled2.hs b/lib/Tiled2.hs
index a729083..7e462cc 100644
--- a/lib/Tiled2.hs
+++ b/lib/Tiled2.hs
@@ -441,11 +441,14 @@ instance ToJSON Tiledmap where
                                , "nextobjectid"    .= tiledmapNextobjectid
                                ]
 
+data LoadResult = Loaded Tiledmap | IOErr String | DecodeErr String
 
 -- | Load a Tiled map from the given 'FilePath'.
-loadTiledmap :: FilePath -> IO (Either String Tiledmap)
+loadTiledmap :: FilePath -> IO LoadResult
 loadTiledmap path = do
   res <- try (BS.readFile path)
   pure $ case res of
-    Right file -> mapLeft ("Json decode error or not a Tiled map: " <>) . eitherDecode . LB.fromStrict $ file
-    Left (err :: SomeException) -> Left $ "IO Error: " <> show err
+    Right file ->  case eitherDecode . LB.fromStrict $ file of
+      Left err  -> DecodeErr err
+      Right map -> Loaded map
+    Left (err :: SomeException) -> IOErr $ show err