Switch to hslua-2.1

This allows for some code simplification and improves stability.

14 files changed, 118 insertions, 230 deletions

diff --git a/src/Text/Pandoc/Lua/ErrorConversion.hs b/src/Text/Pandoc/Lua/ErrorConversion.hs
index 232061514..2083f99dd 100644
--- a/src/Text/Pandoc/Lua/ErrorConversion.hs
+++ b/src/Text/Pandoc/Lua/ErrorConversion.hs
@@ -1,5 +1,4 @@
 {-# OPTIONS_GHC -fno-warn-orphans #-}
-{-# LANGUAGE LambdaCase #-}
 {- |
    Module      : Text.Pandoc.Lua.ErrorConversion
    Copyright   : © 2020-2022 Albert Krewinkel
@@ -17,7 +16,6 @@ module Text.Pandoc.Lua.ErrorConversion
 
 import HsLua (LuaError, LuaE, top)
 import HsLua.Marshalling (resultToEither, runPeek)
-import HsLua.Class.Peekable (PeekError (..))
 import Text.Pandoc.Error (PandocError (PandocLuaError))
 import Text.Pandoc.Lua.Marshal.PandocError (pushPandocError, peekPandocError)
 
@@ -41,8 +39,3 @@ instance LuaError PandocError where
   popException = popPandocError
   pushException = pushPandocError
   luaException = PandocLuaError . T.pack
-
-instance PeekError PandocError where
-  messageFromException = \case
-    PandocLuaError m -> T.unpack m
-    err -> show err
diff --git a/src/Text/Pandoc/Lua/Filter.hs b/src/Text/Pandoc/Lua/Filter.hs
index 9796c4baa..da8af9a26 100644
--- a/src/Text/Pandoc/Lua/Filter.hs
+++ b/src/Text/Pandoc/Lua/Filter.hs
@@ -23,13 +23,12 @@ import Text.Pandoc.Lua.ErrorConversion ()
 import Text.Pandoc.Lua.Marshal.AST
 import Text.Pandoc.Lua.Marshal.Filter
 
-import qualified Text.Pandoc.Lua.Util as LuaUtil
 
 -- | Transform document using the filter defined in the given file.
 runFilterFile :: FilePath -> Pandoc -> LuaE PandocError Pandoc
 runFilterFile filterPath doc = do
   oldtop <- gettop
-  stat <- LuaUtil.dofileWithTraceback filterPath
+  stat <- dofileTrace filterPath
   if stat /= Lua.OK
     then throwErrorAsException
     else do
diff --git a/src/Text/Pandoc/Lua/Marshal/ReaderOptions.hs b/src/Text/Pandoc/Lua/Marshal/ReaderOptions.hs
index 51bd38356..1b3acc076 100644
--- a/src/Text/Pandoc/Lua/Marshal/ReaderOptions.hs
+++ b/src/Text/Pandoc/Lua/Marshal/ReaderOptions.hs
@@ -21,8 +21,8 @@ module Text.Pandoc.Lua.Marshal.ReaderOptions
 
 import Data.Default (def)
 import HsLua as Lua
+import HsLua.Aeson (peekViaJSON, pushViaJSON)
 import Text.Pandoc.Lua.Marshal.List (pushPandocList)
-import Text.Pandoc.Lua.Util (peekViaJSON, pushViaJSON)
 import Text.Pandoc.Options (ReaderOptions (..))
 
 --
diff --git a/src/Text/Pandoc/Lua/Marshal/Reference.hs b/src/Text/Pandoc/Lua/Marshal/Reference.hs
index d7b9fdf5c..3bbc4082c 100644
--- a/src/Text/Pandoc/Lua/Marshal/Reference.hs
+++ b/src/Text/Pandoc/Lua/Marshal/Reference.hs
@@ -28,7 +28,6 @@ import Text.Pandoc.Lua.Marshal.Inline (pushInlines)
 import Text.Pandoc.Lua.Marshal.List (pushPandocList)
 
 import qualified Data.Map as Map
-import qualified HsLua
 
 -- | Pushes a ReaderOptions value as userdata object.
 pushReference :: LuaError e => Pusher e (Reference Inlines)
@@ -94,14 +93,3 @@ pushDate = pushAsTable
  where
    -- date parts are lists of Int values
    pushDateParts (DateParts dp) = pushPandocList pushIntegral dp
-
--- | Helper funtion to push an object as a table.
-pushAsTable :: LuaError e
-            => [(HsLua.Name, a -> LuaE e ())]
-            -> a -> LuaE e ()
-pushAsTable props obj = do
-  createtable 0 (length props)
-  forM_ props $ \(name, pushValue) -> do
-    HsLua.pushName name
-    pushValue obj
-    rawset (nth 3)
diff --git a/src/Text/Pandoc/Lua/Marshal/WriterOptions.hs b/src/Text/Pandoc/Lua/Marshal/WriterOptions.hs
index a04e0bd94..639b85422 100644
--- a/src/Text/Pandoc/Lua/Marshal/WriterOptions.hs
+++ b/src/Text/Pandoc/Lua/Marshal/WriterOptions.hs
@@ -20,9 +20,9 @@ module Text.Pandoc.Lua.Marshal.WriterOptions
 import Control.Applicative (optional)
 import Data.Default (def)
 import HsLua as Lua
+import HsLua.Aeson (peekViaJSON, pushViaJSON)
 import Text.Pandoc.Lua.Marshal.List (pushPandocList)
 import Text.Pandoc.Lua.Marshal.Template (peekTemplate, pushTemplate)
-import Text.Pandoc.Lua.Util (peekViaJSON, pushViaJSON)
 import Text.Pandoc.Options (WriterOptions (..))
 
 --
diff --git a/src/Text/Pandoc/Lua/Module/MediaBag.hs b/src/Text/Pandoc/Lua/Module/MediaBag.hs
index 51d813517..8be668089 100644
--- a/src/Text/Pandoc/Lua/Module/MediaBag.hs
+++ b/src/Text/Pandoc/Lua/Module/MediaBag.hs
@@ -16,7 +16,7 @@ import Prelude hiding (lookup)
 import Data.Maybe (fromMaybe)
 import HsLua ( LuaE, DocumentedFunction, Module (..)
              , (<#>), (###), (=#>), (=?>), defun, functionResult
-             , optionalParameter , parameter)
+             , opt, parameter, stringParam, textParam)
 import Text.Pandoc.Class.CommonState (CommonState (..))
 import Text.Pandoc.Class.PandocMonad (fetchItem, getMediaBag, modifyCommonState,
                                       setMediaBag)
@@ -55,7 +55,7 @@ delete :: DocumentedFunction PandocError
 delete = defun "delete"
   ### (\fp -> unPandocLua $ modifyCommonState
               (\st -> st { stMediaBag = MB.deleteMedia fp (stMediaBag st) }))
-  <#> parameter Lua.peekString "string" "filepath" "filename of item to delete"
+  <#> stringParam "filepath" "filename of item to delete"
   =#> []
 
 
@@ -72,10 +72,10 @@ insert = defun "insert"
           mb <- getMediaBag
           setMediaBag $ MB.insertMedia fp mmime contents mb
           return (Lua.NumResults 0))
-  <#> parameter Lua.peekString "string" "filepath" "item file path"
-  <#> optionalParameter Lua.peekText "string" "mimetype" "the item's MIME type"
+  <#> stringParam "filepath" "item file path"
+  <#> opt (textParam "mimetype" "the item's MIME type")
   <#> parameter Lua.peekLazyByteString "string" "contents" "binary contents"
-  =?> "Nothing"
+  =#> []
 
 -- | Returns iterator values to be used with a Lua @for@ loop.
 items :: DocumentedFunction PandocError
@@ -98,7 +98,7 @@ lookup = defun "lookup"
           Just item -> 2 <$ do
             Lua.pushText $ MB.mediaMimeType item
             Lua.pushLazyByteString $ MB.mediaContents item)
-  <#> parameter Lua.peekString "string" "filepath" "path of item to lookup"
+  <#> stringParam "filepath" "path of item to lookup"
   =?> "MIME type and contents"
 
 -- | Function listing all mediabag items.
@@ -122,5 +122,5 @@ fetch = defun "fetch"
           Lua.pushText $ fromMaybe "" mimeType
           Lua.pushByteString bs
           return 2)
-  <#> parameter Lua.peekText "string" "src" "URI to fetch"
+  <#> textParam "src" "URI to fetch"
   =?> "Returns two string values: the fetched contents and the mimetype."
diff --git a/src/Text/Pandoc/Lua/Module/Pandoc.hs b/src/Text/Pandoc/Lua/Module/Pandoc.hs
index 9864da0db..7d8a98bb1 100644
--- a/src/Text/Pandoc/Lua/Module/Pandoc.hs
+++ b/src/Text/Pandoc/Lua/Module/Pandoc.hs
@@ -26,7 +26,6 @@ import Data.Default (Default (..))
 import Data.Maybe (fromMaybe)
 import Data.Proxy (Proxy (Proxy))
 import HsLua hiding (pushModule)
-import HsLua.Class.Peekable (PeekError)
 import System.Exit (ExitCode (..))
 import Text.Pandoc.Definition
 import Text.Pandoc.Error (PandocError (..))
@@ -49,7 +48,6 @@ import qualified HsLua as Lua
 import qualified Data.ByteString.Lazy as BL
 import qualified Data.ByteString.Lazy.Char8 as BSL
 import qualified Data.Text as T
-import qualified Text.Pandoc.Lua.Util as LuaUtil
 import qualified Text.Pandoc.UTF8 as UTF8
 
 -- | Push the "pandoc" package to the Lua stack. Requires the `List`
@@ -198,9 +196,9 @@ functions =
               Left e ->
                 throwM e)
     <#> parameter peekByteString "string" "content" "text to parse"
-    <#> optionalParameter peekText "string" "formatspec" "format and extensions"
-    <#> optionalParameter peekReaderOptions "ReaderOptions" "reader_options"
-          "reader options"
+    <#> opt (textParam "formatspec" "format and extensions")
+    <#> opt (parameter peekReaderOptions "ReaderOptions" "reader_options"
+             "reader options")
     =#> functionResult pushPandoc "Pandoc" "result document"
 
   , sha1
@@ -227,10 +225,9 @@ functions =
               (ByteStringWriter w, es) -> Left <$>
                 w writerOpts{ writerExtensions = es } doc)
     <#> parameter peekPandoc "Pandoc" "doc" "document to convert"
-    <#> optionalParameter peekText "string" "formatspec"
-          "format and extensions"
-    <#> optionalParameter peekWriterOptions "WriterOptions" "writer_options"
-          "writer options"
+    <#> opt (textParam "formatspec" "format and extensions")
+    <#> opt (parameter peekWriterOptions "WriterOptions" "writer_options"
+              "writer options")
     =#> functionResult (either pushLazyByteString pushText) "string"
           "result document"
   ]
@@ -247,23 +244,23 @@ data PipeError = PipeError
   , pipeErrorOutput :: BL.ByteString
   }
 
-peekPipeError :: PeekError e => StackIndex -> LuaE e PipeError
+peekPipeError :: LuaError e => StackIndex -> LuaE e PipeError
 peekPipeError idx =
   PipeError
   <$> (Lua.getfield idx "command"    *> Lua.peek (-1) <* Lua.pop 1)
   <*> (Lua.getfield idx "error_code" *> Lua.peek (-1) <* Lua.pop 1)
   <*> (Lua.getfield idx "output"     *> Lua.peek (-1) <* Lua.pop 1)
 
-pushPipeError :: PeekError e => Pusher e PipeError
+pushPipeError :: LuaError e => Pusher e PipeError
 pushPipeError pipeErr = do
-  Lua.newtable
-  LuaUtil.addField "command" (pipeErrorCommand pipeErr)
-  LuaUtil.addField "error_code" (pipeErrorCode pipeErr)
-  LuaUtil.addField "output" (pipeErrorOutput pipeErr)
+  pushAsTable [ ("command"    , pushText . pipeErrorCommand)
+              , ("error_code" , pushIntegral . pipeErrorCode)
+              , ("output"     , pushLazyByteString . pipeErrorOutput)
+              ] pipeErr
   pushPipeErrorMetaTable
-  Lua.setmetatable (-2)
+  Lua.setmetatable (nth 2)
     where
-      pushPipeErrorMetaTable :: PeekError e => LuaE e ()
+      pushPipeErrorMetaTable :: LuaError e => LuaE e ()
       pushPipeErrorMetaTable = do
         v <- Lua.newmetatable "pandoc pipe error"
         when v $ do
@@ -271,7 +268,7 @@ pushPipeError pipeErr = do
           pushHaskellFunction pipeErrorMessage
           rawset (nth 3)
 
-      pipeErrorMessage :: PeekError e => LuaE e NumResults
+      pipeErrorMessage :: LuaError e => LuaE e NumResults
       pipeErrorMessage = do
         (PipeError cmd errorCode output) <- peekPipeError (nthBottom 1)
         pushByteString . BSL.toStrict . BSL.concat $
diff --git a/src/Text/Pandoc/Lua/Module/Template.hs b/src/Text/Pandoc/Lua/Module/Template.hs
index cd66ce1c1..967fe31a8 100644
--- a/src/Text/Pandoc/Lua/Module/Template.hs
+++ b/src/Text/Pandoc/Lua/Module/Template.hs
@@ -42,7 +42,7 @@ functions =
              Nothing -> runWithDefaultPartials
                         (compileTemplate "templates/default" template))
      <#> parameter peekText "string" "template" "template string"
-     <#> optionalParameter peekString "string" "templ_path" "template path"
+     <#> opt (stringParam "templ_path" "template path")
      =#> functionResult (either failLua pushTemplate) "pandoc Template"
            "compiled template"
 
@@ -53,8 +53,8 @@ functions =
                  forcePeek $ peekText top `lastly` pop 1
            format <- maybe getFORMAT pure mformat
            getDefaultTemplate format)
-     <#> optionalParameter peekText "string" "writer"
-           "writer for which the template should be returned."
+     <#> opt (textParam "writer"
+              "writer for which the template should be returned.")
      =#> functionResult pushText "string"
            "string representation of the writer's default template"
 
diff --git a/src/Text/Pandoc/Lua/Module/Utils.hs b/src/Text/Pandoc/Lua/Module/Utils.hs
index 0c3969e13..14796b146 100644
--- a/src/Text/Pandoc/Lua/Module/Utils.hs
+++ b/src/Text/Pandoc/Lua/Module/Utils.hs
@@ -56,8 +56,7 @@ documentedModule = Module
               return $ B.toList (Shared.blocksToInlinesWithSep sep blks))
       <#> parameter (peekList peekBlock) "list of blocks"
             "blocks" ""
-      <#> optionalParameter (peekList peekInline) "list of inlines"
-            "inline" ""
+      <#> opt (parameter (peekList peekInline) "list of inlines" "inline" "")
       =#> functionResult pushInlines "list of inlines" ""
 
     , defun "equals"
@@ -121,8 +120,8 @@ documentedModule = Module
           )
       <#> parameter peekPandoc "Pandoc" "doc" "input document"
       <#> parameter peekString "filepath" "filter_path" "path to filter"
-      <#> optionalParameter (peekList peekString) "list of strings"
-            "args" "arguments to pass to the filter"
+      <#> opt (parameter (peekList peekString) "list of strings"
+               "args" "arguments to pass to the filter")
       =#> functionResult pushPandoc "Pandoc" "filtered document"
 
     , defun "stringify"
diff --git a/src/Text/Pandoc/Lua/Orphans.hs b/src/Text/Pandoc/Lua/Orphans.hs
index c8a83fea4..62b54d051 100644
--- a/src/Text/Pandoc/Lua/Orphans.hs
+++ b/src/Text/Pandoc/Lua/Orphans.hs
@@ -65,9 +65,6 @@ instance Pushable QuoteType where
 instance Pushable Cell where
   push = pushCell
 
-instance Peekable Cell where
-  peek = forcePeek . peekCell
-
 instance Pushable Inline where
   push = pushInline
 
@@ -92,25 +89,28 @@ instance Pushable TableHead where
 -- These instances exist only for testing. It's a hack to avoid making
 -- the marshalling modules public.
 instance Peekable Inline where
-  peek = forcePeek . peekInline
+  safepeek = peekInline
 
 instance Peekable Block where
-  peek = forcePeek . peekBlock
+  safepeek = peekBlock
+
+instance Peekable Cell where
+  safepeek = peekCell
 
 instance Peekable Meta where
-  peek = forcePeek . peekMeta
+  safepeek = peekMeta
 
 instance Peekable Pandoc where
-  peek = forcePeek . peekPandoc
+  safepeek = peekPandoc
 
 instance Peekable Row where
-  peek = forcePeek . peekRow
+  safepeek = peekRow
 
 instance Peekable Version where
-  peek = forcePeek . peekVersionFuzzy
+  safepeek = peekVersionFuzzy
 
 instance {-# OVERLAPPING #-} Peekable Attr where
-  peek = forcePeek . peekAttr
+  safepeek = peekAttr
 
 instance Pushable Sources where
   push = pushSources
diff --git a/src/Text/Pandoc/Lua/PandocLua.hs b/src/Text/Pandoc/Lua/PandocLua.hs
index bc5085fdb..52ace5f6b 100644
--- a/src/Text/Pandoc/Lua/PandocLua.hs
+++ b/src/Text/Pandoc/Lua/PandocLua.hs
@@ -68,10 +68,10 @@ runPandocLua pLua = do
   return result
 
 instance {-# OVERLAPPING #-} Exposable PandocError (PandocLua NumResults) where
-  partialApply _narg = unPandocLua
+  partialApply _narg = liftLua . unPandocLua
 
 instance Pushable a => Exposable PandocError (PandocLua a) where
-  partialApply _narg x = 1 <$ (unPandocLua x >>= Lua.push)
+  partialApply _narg x = 1 <$ (liftLua (unPandocLua x >>= Lua.push))
 
 -- | Global variables which should always be set.
 defaultGlobals :: PandocMonad m => m [Global]
diff --git a/src/Text/Pandoc/Lua/Util.hs b/src/Text/Pandoc/Lua/Util.hs
deleted file mode 100644
index 324a1a8e8..000000000
--- a/src/Text/Pandoc/Lua/Util.hs
+++ /dev/null
@@ -1,83 +0,0 @@
-{-# LANGUAGE OverloadedStrings     #-}
-{- |
-   Module      : Text.Pandoc.Lua.Util
-   Copyright   : © 2012-2022 John MacFarlane,
-                 © 2017-2022 Albert Krewinkel
-   License     : GNU GPL, version 2 or above
-
-   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
-   Stability   : alpha
-
-Lua utility functions.
--}
-module Text.Pandoc.Lua.Util
-  ( addField
-  , callWithTraceback
-  , pcallWithTraceback
-  , dofileWithTraceback
-  , peekViaJSON
-  , pushViaJSON
-  ) where
-
-import Control.Monad (when)
-import HsLua
-import HsLua.Aeson (peekValue, pushValue)
-import qualified Data.Aeson as Aeson
-import qualified HsLua as Lua
-import qualified Text.Pandoc.UTF8 as UTF8
-
--- | Add a value to the table at the top of the stack at a string-index.
-addField :: (LuaError e, Pushable a) => String -> a -> LuaE e ()
-addField key value = do
-  Lua.push key
-  Lua.push value
-  Lua.rawset (Lua.nth 3)
-
--- | Like @'Lua.pcall'@, but uses a predefined error handler which adds a
--- traceback on error.
-pcallWithTraceback :: LuaError e => NumArgs -> NumResults -> LuaE e Status
-pcallWithTraceback nargs nresults = do
-  let traceback' :: LuaError e => LuaE e NumResults
-      traceback' = do
-        l <- Lua.state
-        msg <- Lua.tostring' (Lua.nthBottom 1)
-        Lua.traceback l (Just msg) 2
-        return 1
-  tracebackIdx <- Lua.absindex (Lua.nth (Lua.fromNumArgs nargs + 1))
-  Lua.pushHaskellFunction traceback'
-  Lua.insert tracebackIdx
-  result <- Lua.pcall nargs nresults (Just tracebackIdx)
-  Lua.remove tracebackIdx
-  return result
-
--- | Like @'Lua.call'@, but adds a traceback to the error message (if any).
-callWithTraceback :: LuaError e => NumArgs -> NumResults -> LuaE e ()
-callWithTraceback nargs nresults = do
-  result <- pcallWithTraceback nargs nresults
-  when (result /= Lua.OK)
-    Lua.throwErrorAsException
-
--- | Run the given string as a Lua program, while also adding a traceback to the
--- error message if an error occurs.
-dofileWithTraceback :: LuaError e => FilePath -> LuaE e Status
-dofileWithTraceback fp = do
-  loadRes <- Lua.loadfile fp
-  case loadRes of
-    Lua.OK -> pcallWithTraceback 0 Lua.multret
-    _ -> return loadRes
-
-
--- These will become part of hslua-aeson in future versions.
-
--- | Retrieves a value from the Lua stack via JSON.
-peekViaJSON :: (Aeson.FromJSON a, LuaError e) => Peeker e a
-peekViaJSON idx = do
-  value <- peekValue idx
-  case Aeson.fromJSON value of
-    Aeson.Success x -> pure x
-    Aeson.Error msg -> failPeek $ "failed to decode: " <>
-                       UTF8.fromString msg
-
--- | Pushes a value to the Lua stack as a JSON-like value.
-pushViaJSON :: (Aeson.ToJSON a, LuaError e) => Pusher e a
-pushViaJSON = pushValue . Aeson.toJSON
diff --git a/src/Text/Pandoc/Readers/Custom.hs b/src/Text/Pandoc/Readers/Custom.hs
index 031beb679..195ad6cf4 100644
--- a/src/Text/Pandoc/Readers/Custom.hs
+++ b/src/Text/Pandoc/Readers/Custom.hs
@@ -14,7 +14,7 @@ Supports custom parsers written in Lua which produce a Pandoc AST.
 module Text.Pandoc.Readers.Custom ( readCustom ) where
 import Control.Exception
 import Control.Monad (when)
-import HsLua as Lua hiding (Operation (Div), render)
+import HsLua as Lua hiding (Operation (Div))
 import Control.Monad.IO.Class (MonadIO)
 import Text.Pandoc.Definition
 import Text.Pandoc.Class (PandocMonad, report)
@@ -22,8 +22,6 @@ import Text.Pandoc.Logging
 import Text.Pandoc.Lua (Global (..), runLua, setGlobals)
 import Text.Pandoc.Lua.PandocLua
 import Text.Pandoc.Lua.Marshal.Pandoc (peekPandoc)
-import Text.Pandoc.Lua.Util (dofileWithTraceback, callWithTraceback,
-                             pcallWithTraceback)
 import Text.Pandoc.Options
 import Text.Pandoc.Sources (ToSources(..), sourcesToText)
 import qualified Data.Text as T
@@ -35,7 +33,7 @@ readCustom luaFile opts srcs = do
   let globals = [ PANDOC_SCRIPT_FILE luaFile ]
   res <- runLua $ do
     setGlobals globals
-    stat <- dofileWithTraceback luaFile
+    stat <- dofileTrace luaFile
     -- check for error in lua script (later we'll change the return type
     -- to handle this more gracefully):
     when (stat /= Lua.OK)
@@ -50,7 +48,7 @@ readCustom luaFile opts srcs = do
     getglobal "Reader"
     push input
     push opts
-    pcallWithTraceback 2 1 >>= \case
+    pcallTrace 2 1 >>= \case
       OK -> forcePeek $ peekPandoc top
       ErrRun -> do
         -- Caught a runtime error. Check if parsing might work if we
@@ -74,7 +72,7 @@ readCustom luaFile opts srcs = do
                 getglobal "Reader"
                 push $ sourcesToText input  -- push sources as string
                 push opts
-                callWithTraceback 2 1
+                callTrace 2 1
                 forcePeek $ peekPandoc top
               else
                 -- nothing we can do here
diff --git a/src/Text/Pandoc/Writers/Custom.hs b/src/Text/Pandoc/Writers/Custom.hs
index 6ad36468a..70c03a016 100644
--- a/src/Text/Pandoc/Writers/Custom.hs
+++ b/src/Text/Pandoc/Writers/Custom.hs
@@ -25,14 +25,13 @@ import qualified Data.Map as M
 import Data.Maybe (fromMaybe)
 import qualified Data.Text as T
 import Data.Text (Text, pack)
-import HsLua as Lua hiding (Operation (Div), render)
-import HsLua.Class.Peekable (PeekError)
+import HsLua as Lua hiding (Operation (Div))
+import HsLua.Aeson (peekViaJSON)
 import Text.DocLayout (render, literal)
 import Text.DocTemplates (Context)
 import Control.Monad.IO.Class (MonadIO)
 import Text.Pandoc.Definition
 import Text.Pandoc.Lua (Global (..), runLua, setGlobals)
-import Text.Pandoc.Lua.Util (addField, dofileWithTraceback, peekViaJSON)
 import Text.Pandoc.Options
 import Text.Pandoc.Class (PandocMonad)
 import Text.Pandoc.Templates (renderTemplate)
@@ -44,36 +43,34 @@ attrToMap (id',classes,keyvals) = M.fromList
     : ("class", T.unwords classes)
     : keyvals
 
-newtype Stringify e a = Stringify a
+newtype Stringify a = Stringify a
 
-instance Pushable (Stringify e Format) where
+instance Pushable (Stringify Format) where
   push (Stringify (Format f)) = Lua.push (T.toLower f)
 
-instance PeekError e => Pushable (Stringify e [Inline]) where
-  push (Stringify ils) = Lua.push =<<
-    changeErrorType ((inlineListToCustom @e) ils)
+instance Pushable (Stringify [Inline]) where
+  push (Stringify ils) = Lua.push =<< inlineListToCustom ils
 
-instance PeekError e => Pushable (Stringify e [Block]) where
-  push (Stringify blks) = Lua.push =<<
-    changeErrorType ((blockListToCustom @e) blks)
+instance Pushable (Stringify [Block]) where
+  push (Stringify blks) = Lua.push =<< blockListToCustom blks
 
-instance PeekError e => Pushable (Stringify e MetaValue) where
-  push (Stringify (MetaMap m))       = Lua.push (fmap (Stringify @e) m)
-  push (Stringify (MetaList xs))     = Lua.push (map (Stringify @e) xs)
+instance Pushable (Stringify MetaValue) where
+  push (Stringify (MetaMap m))       = Lua.push (fmap Stringify m)
+  push (Stringify (MetaList xs))     = Lua.push (map Stringify xs)
   push (Stringify (MetaBool x))      = Lua.push x
   push (Stringify (MetaString s))    = Lua.push s
-  push (Stringify (MetaInlines ils)) = Lua.push (Stringify @e ils)
-  push (Stringify (MetaBlocks bs))   = Lua.push (Stringify @e bs)
-
-instance PeekError e => Pushable (Stringify e Citation) where
-  push (Stringify cit) = do
-    Lua.createtable 6 0
-    addField "citationId" $ citationId cit
-    addField "citationPrefix" . Stringify @e $ citationPrefix cit
-    addField "citationSuffix" . Stringify @e $ citationSuffix cit
-    addField "citationMode" $ show (citationMode cit)
-    addField "citationNoteNum" $ citationNoteNum cit
-    addField "citationHash" $ citationHash cit
+  push (Stringify (MetaInlines ils)) = Lua.push (Stringify ils)
+  push (Stringify (MetaBlocks bs))   = Lua.push (Stringify bs)
+
+instance Pushable (Stringify Citation) where
+  push (Stringify cit) = flip pushAsTable cit
+    [ ("citationId", push . citationId)
+    , ("citationPrefix",  push . Stringify . citationPrefix)
+    , ("citationSuffix",  push . Stringify . citationSuffix)
+    , ("citationMode",    push . citationMode)
+    , ("citationNoteNum", push . citationNoteNum)
+    , ("citationHash",    push . citationHash)
+    ]
 
 -- | Key-value pair, pushed as a table with @a@ as the only key and @v@ as the
 -- associated value.
@@ -96,7 +93,7 @@ writeCustom luaFile opts doc@(Pandoc meta _) = do
                 ]
   res <- runLua $ do
     setGlobals globals
-    stat <- dofileWithTraceback luaFile
+    stat <- dofileTrace luaFile
     -- check for error in lua script (later we'll change the return type
     -- to handle this more gracefully):
     when (stat /= Lua.OK)
@@ -115,7 +112,7 @@ writeCustom luaFile opts doc@(Pandoc meta _) = do
         Just tpl -> render Nothing $
                     renderTemplate tpl $ setField "body" body context
 
-docToCustom :: forall e. PeekError e
+docToCustom :: forall e. LuaError e
             => WriterOptions -> Pandoc -> LuaE e (String, Context Text)
 docToCustom opts (Pandoc (Meta metamap) blocks) = do
   body <- blockListToCustom blocks
@@ -123,7 +120,7 @@ docToCustom opts (Pandoc (Meta metamap) blocks) = do
   -- `Doc` manually.
   Lua.getglobal "Doc"                 -- function
   push body                           -- argument 1
-  push (fmap (Stringify @e) metamap)  -- argument 2
+  push (fmap Stringify  metamap)      -- argument 2
   push (writerVariables opts)         -- argument 3
   call 3 2
   rendered  <- peek (nth 2)           -- first return value
@@ -131,125 +128,125 @@ docToCustom opts (Pandoc (Meta metamap) blocks) = do
   return (rendered, fromMaybe mempty context)
 
 -- | Convert Pandoc block element to Custom.
-blockToCustom :: forall e. PeekError e
+blockToCustom :: forall e. LuaError e
               => Block         -- ^ Block element
               -> LuaE e String
 
 blockToCustom Null = return ""
 
-blockToCustom (Plain inlines) = invoke @e "Plain" (Stringify @e inlines)
+blockToCustom (Plain inlines) = invoke "Plain" (Stringify inlines)
 
 blockToCustom (Para [Image attr txt (src,tit)]) =
-  invoke @e "CaptionedImage" src tit (Stringify @e txt) (attrToMap attr)
+  invoke "CaptionedImage" src tit (Stringify txt) (attrToMap attr)
 
-blockToCustom (Para inlines) = invoke @e "Para" (Stringify @e inlines)
+blockToCustom (Para inlines) = invoke "Para" (Stringify inlines)
 
 blockToCustom (LineBlock linesList) =
-  invoke @e "LineBlock" (map (Stringify @e) linesList)
+  invoke "LineBlock" (map (Stringify) linesList)
 
 blockToCustom (RawBlock format str) =
-  invoke @e "RawBlock" (Stringify @e format) str
+  invoke "RawBlock" (Stringify format) str
 
-blockToCustom HorizontalRule = invoke @e "HorizontalRule"
+blockToCustom HorizontalRule = invoke "HorizontalRule"
 
 blockToCustom (Header level attr inlines) =
-  invoke @e "Header" level (Stringify @e inlines) (attrToMap attr)
+  invoke "Header" level (Stringify inlines) (attrToMap attr)
 
 blockToCustom (CodeBlock attr str) =
-  invoke @e "CodeBlock" str (attrToMap attr)
+  invoke "CodeBlock" str (attrToMap attr)
 
 blockToCustom (BlockQuote blocks) =
-  invoke @e "BlockQuote" (Stringify @e blocks)
+  invoke "BlockQuote" (Stringify blocks)
 
 blockToCustom (Table _ blkCapt specs thead tbody tfoot) =
   let (capt, aligns, widths, headers, rows) = toLegacyTable blkCapt specs thead tbody tfoot
       aligns' = map show aligns
-      capt' = Stringify @e capt
-      headers' = map (Stringify @e) headers
-      rows' = map (map (Stringify @e)) rows
-  in invoke @e "Table" capt' aligns' widths headers' rows'
+      capt' = Stringify capt
+      headers' = map (Stringify) headers
+      rows' = map (map (Stringify)) rows
+  in invoke "Table" capt' aligns' widths headers' rows'
 
 blockToCustom (BulletList items) =
-  invoke @e "BulletList" (map (Stringify @e) items)
+  invoke "BulletList" (map (Stringify) items)
 
 blockToCustom (OrderedList (num,sty,delim) items) =
-  invoke @e "OrderedList" (map (Stringify @e) items) num (show sty) (show delim)
+  invoke "OrderedList" (map (Stringify) items) num (show sty) (show delim)
 
 blockToCustom (DefinitionList items) =
-  invoke @e "DefinitionList"
-               (map (KeyValue . (Stringify @e *** map (Stringify @e))) items)
+  invoke "DefinitionList"
+               (map (KeyValue . (Stringify *** map (Stringify))) items)
 
 blockToCustom (Div attr items) =
-  invoke @e "Div" (Stringify @e items) (attrToMap attr)
+  invoke "Div" (Stringify items) (attrToMap attr)
 
 -- | Convert list of Pandoc block elements to Custom.
-blockListToCustom :: forall e. PeekError e
+blockListToCustom :: forall e. LuaError e
                   => [Block]       -- ^ List of block elements
                   -> LuaE e String
 blockListToCustom xs = do
-  blocksep <- invoke @e "Blocksep"
+  blocksep <- invoke "Blocksep"
   bs <- mapM blockToCustom xs
   return $ mconcat $ intersperse blocksep bs
 
 -- | Convert list of Pandoc inline elements to Custom.
-inlineListToCustom :: forall e. PeekError e => [Inline] -> LuaE e String
+inlineListToCustom :: forall e. LuaError e => [Inline] -> LuaE e String
 inlineListToCustom lst = do
   xs <- mapM (inlineToCustom @e) lst
   return $ mconcat xs
 
 -- | Convert Pandoc inline element to Custom.
-inlineToCustom :: forall e. PeekError e => Inline -> LuaE e String
+inlineToCustom :: forall e. LuaError e => Inline -> LuaE e String
 
-inlineToCustom (Str str) = invoke @e "Str" str
+inlineToCustom (Str str) = invoke "Str" str
 
-inlineToCustom Space = invoke @e "Space"
+inlineToCustom Space = invoke "Space"
 
-inlineToCustom SoftBreak = invoke @e "SoftBreak"
+inlineToCustom SoftBreak = invoke "SoftBreak"
 
-inlineToCustom (Emph lst) = invoke @e "Emph" (Stringify @e lst)
+inlineToCustom (Emph lst) = invoke "Emph" (Stringify lst)
 
-inlineToCustom (Underline lst) = invoke @e "Underline" (Stringify @e lst)
+inlineToCustom (Underline lst) = invoke "Underline" (Stringify lst)
 
-inlineToCustom (Strong lst) = invoke @e "Strong" (Stringify @e lst)
+inlineToCustom (Strong lst) = invoke "Strong" (Stringify lst)
 
-inlineToCustom (Strikeout lst) = invoke @e "Strikeout" (Stringify @e lst)
+inlineToCustom (Strikeout lst) = invoke "Strikeout" (Stringify lst)
 
-inlineToCustom (Superscript lst) = invoke @e "Superscript" (Stringify @e lst)
+inlineToCustom (Superscript lst) = invoke "Superscript" (Stringify lst)
 
-inlineToCustom (Subscript lst) = invoke @e "Subscript" (Stringify @e lst)
+inlineToCustom (Subscript lst) = invoke "Subscript" (Stringify lst)
 
-inlineToCustom (SmallCaps lst) = invoke @e "SmallCaps" (Stringify @e lst)
+inlineToCustom (SmallCaps lst) = invoke "SmallCaps" (Stringify lst)
 
 inlineToCustom (Quoted SingleQuote lst) =
-  invoke @e "SingleQuoted" (Stringify @e lst)
+  invoke "SingleQuoted" (Stringify lst)
 
 inlineToCustom (Quoted DoubleQuote lst) =
-  invoke @e "DoubleQuoted" (Stringify @e lst)
+  invoke "DoubleQuoted" (Stringify lst)
 
 inlineToCustom (Cite cs lst) =
-  invoke @e "Cite" (Stringify @e lst) (map (Stringify @e) cs)
+  invoke "Cite" (Stringify lst) (map (Stringify) cs)
 
 inlineToCustom (Code attr str) =
-  invoke @e "Code" str (attrToMap attr)
+  invoke "Code" str (attrToMap attr)
 
 inlineToCustom (Math DisplayMath str) =
-  invoke @e "DisplayMath" str
+  invoke "DisplayMath" str
 
 inlineToCustom (Math InlineMath str) =
-  invoke @e "InlineMath" str
+  invoke "InlineMath" str
 
 inlineToCustom (RawInline format str) =
-  invoke @e "RawInline" (Stringify @e format) str
+  invoke "RawInline" (Stringify format) str
 
-inlineToCustom LineBreak = invoke @e "LineBreak"
+inlineToCustom LineBreak = invoke "LineBreak"
 
 inlineToCustom (Link attr txt (src,tit)) =
-  invoke @e "Link" (Stringify @e txt) src tit (attrToMap attr)
+  invoke "Link" (Stringify txt) src tit (attrToMap attr)
 
 inlineToCustom (Image attr alt (src,tit)) =
-  invoke @e "Image" (Stringify @e alt) src tit (attrToMap attr)
+  invoke "Image" (Stringify alt) src tit (attrToMap attr)
 
-inlineToCustom (Note contents) = invoke @e "Note" (Stringify @e contents)
+inlineToCustom (Note contents) = invoke "Note" (Stringify contents)
 
 inlineToCustom (Span attr items) =
-  invoke @e "Span" (Stringify @e items) (attrToMap attr)
+  invoke "Span" (Stringify items) (attrToMap attr)