2 files changed, 27 insertions, 17 deletions
diff --git a/src/Text/Pandoc/Lua/StackInstances.hs b/src/Text/Pandoc/Lua/StackInstances.hs
index 4eea5bc2f..7d451a16a 100644
--- a/src/Text/Pandoc/Lua/StackInstances.hs
+++ b/src/Text/Pandoc/Lua/StackInstances.hs
@@ -34,11 +34,11 @@ module Text.Pandoc.Lua.StackInstances () where
 
 import Control.Applicative ((<|>))
 import Foreign.Lua (Lua, Type (..), FromLuaStack (peek), ToLuaStack (push),
-                    StackIndex, peekEither, throwLuaError)
-import Foreign.Lua.Api (getfield, ltype, newtable, pop, rawlen)
+                    StackIndex, throwLuaError, tryLua)
+import Foreign.Lua.Api (getmetatable, ltype, newtable, pop, rawget, rawlen)
 import Text.Pandoc.Definition
 import Text.Pandoc.Lua.SharedInstances ()
-import Text.Pandoc.Lua.Util (addValue, getTable, pushViaConstructor)
+import Text.Pandoc.Lua.Util (addValue, adjustIndexBy, getTable, pushViaConstructor)
 import Text.Pandoc.Shared (safeRead)
 
 instance ToLuaStack Pandoc where
@@ -46,6 +46,7 @@ instance ToLuaStack Pandoc where
     newtable
     addValue "blocks" blocks
     addValue "meta"   meta
+
 instance FromLuaStack Pandoc where
   peek idx = do
     blocks <- getTable idx "blocks"
@@ -151,7 +152,7 @@ peekMetaValue idx = do
     TypeBoolean -> MetaBool <$> peek idx
     TypeString  -> MetaString <$> peek idx
     TypeTable   -> do
-      tag <- getfield idx "t" *> peekEither (-1) <* pop 1
+      tag <- tryLua $ getTag idx
       case tag of
         Right "MetaBlocks"  -> MetaBlocks  <$> elementContent
         Right "MetaBool"    -> MetaBool    <$> elementContent
@@ -192,7 +193,7 @@ pushBlock = \case
 -- | Return the value at the given index as block if possible.
 peekBlock :: StackIndex -> Lua Block
 peekBlock idx = do
-  tag <- getTable idx "t"
+  tag <- getTag idx
   case tag of
       "BlockQuote"     -> BlockQuote <$> elementContent
       "BulletList"     -> BulletList <$> elementContent
@@ -243,7 +244,7 @@ pushInline = \case
 -- | Return the value at the given index as inline if possible.
 peekInline :: StackIndex -> Lua Inline
 peekInline idx = do
-  tag <- getTable idx "t"
+  tag <- getTag idx
   case tag of
     "Cite"       -> (uncurry Cite) <$> elementContent
     "Code"       -> (withAttr Code) <$> elementContent
@@ -272,6 +273,19 @@ peekInline idx = do
    elementContent :: FromLuaStack a => Lua a
    elementContent = getTable idx "c"
 
+getTag :: StackIndex -> Lua String
+getTag idx = do
+  hasMT <- getmetatable idx
+  if hasMT
+    then do
+      push "tag"
+      rawget (-2)
+      peek (-1) <* pop 2
+    else do
+      push "tag"
+      rawget (idx `adjustIndexBy` 1)
+      peek (-1) <* pop 1
+
 withAttr :: (Attr -> a -> b) -> (LuaAttr, a) -> b
 withAttr f (attributes, x) = f (fromLuaAttr attributes) x
 
@@ -281,5 +295,6 @@ newtype LuaAttr = LuaAttr { fromLuaAttr :: Attr }
 instance ToLuaStack LuaAttr where
   push (LuaAttr (id', classes, kv)) =
     pushViaConstructor "Attr" id' classes kv
+
 instance FromLuaStack LuaAttr where
   peek idx = LuaAttr <$> peek idx
diff --git a/src/Text/Pandoc/Lua/Util.hs b/src/Text/Pandoc/Lua/Util.hs
index 9e72b652c..1b6338e64 100644
--- a/src/Text/Pandoc/Lua/Util.hs
+++ b/src/Text/Pandoc/Lua/Util.hs
@@ -31,7 +31,6 @@ Lua utility functions.
 module Text.Pandoc.Lua.Util
   ( adjustIndexBy
   , getTable
-  , setTable
   , addValue
   , getRawInt
   , setRawInt
@@ -43,7 +42,7 @@ module Text.Pandoc.Lua.Util
 
 import Foreign.Lua (Lua, FromLuaStack (..), ToLuaStack (..), NumArgs,
                     StackIndex, getglobal')
-import Foreign.Lua.Api (call, gettable, pop, rawgeti, rawseti, settable)
+import Foreign.Lua.Api (call, pop, rawget, rawgeti, rawset, rawseti)
 
 -- | Adjust the stack index, assuming that @n@ new elements have been pushed on
 -- the stack.
@@ -57,19 +56,15 @@ adjustIndexBy idx n =
 getTable :: (ToLuaStack a, FromLuaStack b) => StackIndex -> a -> Lua b
 getTable idx key = do
   push key
-  gettable (idx `adjustIndexBy` 1)
+  rawget (idx `adjustIndexBy` 1)
   peek (-1) <* pop 1
 
--- | Set value for key for table at the given index
-setTable :: (ToLuaStack a, ToLuaStack b) => StackIndex -> a -> b -> Lua ()
-setTable idx key value = do
-  push key
-  push value
-  settable (idx `adjustIndexBy` 2)
-
 -- | Add a key-value pair to the table at the top of the stack
 addValue :: (ToLuaStack a, ToLuaStack b) => a -> b -> Lua ()
-addValue = setTable (-1)
+addValue key value = do
+  push key
+  push value
+  rawset (-3)
 
 -- | Get value behind key from table at given index.
 getRawInt :: FromLuaStack a => StackIndex -> Int -> Lua a