1 files changed, 24 insertions, 38 deletions

diff --git a/src/Text/Pandoc/Lua/Marshaling/PandocError.hs b/src/Text/Pandoc/Lua/Marshaling/PandocError.hs
index f698704e0..6f29a5c89 100644
--- a/src/Text/Pandoc/Lua/Marshaling/PandocError.hs
+++ b/src/Text/Pandoc/Lua/Marshaling/PandocError.hs
@@ -1,7 +1,7 @@
-{-# OPTIONS_GHC -fno-warn-orphans #-}
 {-# LANGUAGE LambdaCase           #-}
 {-# LANGUAGE OverloadedStrings    #-}
 {-# LANGUAGE ScopedTypeVariables  #-}
+{-# LANGUAGE TypeApplications     #-}
 {- |
    Module      : Text.Pandoc.Lua.Marshaling.PandocError
    Copyright   : © 2020-2021 Albert Krewinkel
@@ -15,51 +15,37 @@ Marshaling of @'PandocError'@ values.
 module Text.Pandoc.Lua.Marshaling.PandocError
   ( peekPandocError
   , pushPandocError
+  , typePandocError
   )
   where
 
-import Foreign.Lua (Lua, Peekable, Pushable, StackIndex)
+import HsLua.Core (LuaError)
+import HsLua.Marshalling (Peeker, Pusher, pushString, liftLua)
+import HsLua.Packaging
 import Text.Pandoc.Error (PandocError (PandocLuaError))
 
-import qualified Foreign.Lua as Lua
-import qualified Foreign.Lua.Userdata as Lua
-import qualified Text.Pandoc.Lua.Util as LuaUtil
+import qualified HsLua as Lua
 import qualified Text.Pandoc.UTF8 as UTF8
 
--- | Userdata name used by Lua for the @PandocError@ type.
-pandocErrorName :: String
-pandocErrorName = "pandoc error"
+-- | Lua userdata type definition for PandocError.
+typePandocError :: LuaError e => DocumentedType e PandocError
+typePandocError = deftype "PandocError"
+  [ operation Tostring $ defun "__tostring"
+    ### liftPure (show @PandocError)
+    <#> udparam typePandocError "obj" "PandocError object"
+    =#> functionResult pushString "string" "string representation of error."
+  ]
+  mempty -- no members
 
 -- | Peek a @'PandocError'@ element to the Lua stack.
-pushPandocError :: PandocError -> Lua ()
-pushPandocError = Lua.pushAnyWithMetatable pushPandocErrorMT
-  where
-    pushPandocErrorMT = Lua.ensureUserdataMetatable pandocErrorName $
-      LuaUtil.addFunction "__tostring" __tostring
+pushPandocError :: LuaError e => Pusher e PandocError
+pushPandocError = pushUD typePandocError
 
 -- | Retrieve a @'PandocError'@ from the Lua stack.
-peekPandocError :: StackIndex -> Lua PandocError
-peekPandocError idx = Lua.ltype idx >>= \case
-  Lua.TypeUserdata -> do
-    errMb <- Lua.toAnyWithName idx pandocErrorName
-    return $ case errMb of
-      Just err -> err
-      Nothing  -> PandocLuaError "could not retrieve original error"
-  _ -> do
-    Lua.pushvalue idx
-    msg <- Lua.state >>= \l -> Lua.liftIO (Lua.errorMessage l)
-    return $ PandocLuaError (UTF8.toText msg)
-
--- | Convert to string.
-__tostring :: PandocError -> Lua String
-__tostring = return . show
-
---
--- Instances
---
-
-instance Pushable PandocError where
-  push = pushPandocError
-
-instance Peekable PandocError where
-  peek = peekPandocError
+peekPandocError :: LuaError e => Peeker e PandocError
+peekPandocError idx = Lua.retrieving "PandocError" $
+  liftLua (Lua.ltype idx) >>= \case
+    Lua.TypeUserdata -> peekUD typePandocError idx
+    _ -> do
+      msg <- liftLua $ Lua.state >>= \l -> Lua.liftIO (Lua.popErrorMessage l)
+      return $ PandocLuaError (UTF8.toText msg)