1 files changed, 17 insertions, 100 deletions

diff --git a/src/Text/Pandoc/Lua/Util.hs b/src/Text/Pandoc/Lua/Util.hs
index 70a8a6d47..9c6f42b2b 100644
--- a/src/Text/Pandoc/Lua/Util.hs
+++ b/src/Text/Pandoc/Lua/Util.hs
@@ -1,6 +1,4 @@
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE LambdaCase #-}
-{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE OverloadedStrings     #-}
 {- |
    Module      : Text.Pandoc.Lua.Util
    Copyright   : © 2012-2021 John MacFarlane,
@@ -13,115 +11,34 @@
 Lua utility functions.
 -}
 module Text.Pandoc.Lua.Util
-  ( getTag
-  , rawField
-  , addField
-  , addFunction
-  , addValue
-  , pushViaConstructor
-  , defineHowTo
-  , throwTopMessageAsError'
+  ( addField
   , callWithTraceback
+  , pcallWithTraceback
   , dofileWithTraceback
   ) where
 
-import Control.Monad (unless, when)
-import Data.Text (Text)
-import Foreign.Lua ( Lua, NumArgs, NumResults, Peekable, Pushable, StackIndex
-                   , Status, ToHaskellFunction )
-import qualified Foreign.Lua as Lua
-import qualified Text.Pandoc.UTF8 as UTF8
-
--- | Get value behind key from table at given index.
-rawField :: Peekable a => StackIndex -> String -> Lua a
-rawField idx key = do
-  absidx <- Lua.absindex idx
-  Lua.push key
-  Lua.rawget absidx
-  Lua.popValue
+import Control.Monad (when)
+import HsLua
+import qualified HsLua as Lua
 
 -- | Add a value to the table at the top of the stack at a string-index.
-addField :: Pushable a => String -> a -> Lua ()
-addField = addValue
-
--- | Add a key-value pair to the table at the top of the stack.
-addValue :: (Pushable a, Pushable b) => a -> b -> Lua ()
-addValue key value = do
+addField :: (LuaError e, Pushable a) => String -> a -> LuaE e ()
+addField key value = do
   Lua.push key
   Lua.push value
-  Lua.rawset (Lua.nthFromTop 3)
-
--- | Add a function to the table at the top of the stack, using the given name.
-addFunction :: ToHaskellFunction a => String -> a -> Lua ()
-addFunction name fn = do
-  Lua.push name
-  Lua.pushHaskellFunction fn
-  Lua.rawset (-3)
-
--- | Helper class for pushing a single value to the stack via a lua function.
--- See @pushViaCall@.
-class PushViaCall a where
-  pushViaCall' :: String -> Lua () -> NumArgs -> a
-
-instance PushViaCall (Lua ()) where
-  pushViaCall' fn pushArgs num = do
-    Lua.push fn
-    Lua.rawget Lua.registryindex
-    pushArgs
-    Lua.call num 1
-
-instance (Pushable a, PushViaCall b) => PushViaCall (a -> b) where
-  pushViaCall' fn pushArgs num x =
-    pushViaCall' fn (pushArgs *> Lua.push x) (num + 1)
-
--- | Push an value to the stack via a lua function. The lua function is called
--- with all arguments that are passed to this function and is expected to return
--- a single value.
-pushViaCall :: PushViaCall a => String -> a
-pushViaCall fn = pushViaCall' fn (return ()) 0
-
--- | Call a pandoc element constructor within Lua, passing all given arguments.
-pushViaConstructor :: PushViaCall a => String -> a
-pushViaConstructor pandocFn = pushViaCall ("pandoc." ++ pandocFn)
-
--- | Get the tag of a value. This is an optimized and specialized version of
--- @Lua.getfield idx "tag"@. It only checks for the field on the table at index
--- @idx@ and on its metatable, also ignoring any @__index@ value on the
--- metatable.
-getTag :: StackIndex -> Lua String
-getTag idx = do
-  -- push metatable or just the table
-  Lua.getmetatable idx >>= \hasMT -> unless hasMT (Lua.pushvalue idx)
-  Lua.push ("tag" :: Text)
-  Lua.rawget (Lua.nthFromTop 2)
-  Lua.tostring Lua.stackTop <* Lua.pop 2 >>= \case
-    Nothing -> Lua.throwMessage "untagged value"
-    Just x -> return (UTF8.toString x)
-
--- | Modify the message at the top of the stack before throwing it as an
--- Exception.
-throwTopMessageAsError' :: (String -> String) -> Lua a
-throwTopMessageAsError' modifier = do
-  msg <- Lua.tostring' Lua.stackTop
-  Lua.pop 2 -- remove error and error string pushed by tostring'
-  Lua.throwMessage (modifier (UTF8.toString msg))
-
--- | Mark the context of a Lua computation for better error reporting.
-defineHowTo :: String -> Lua a -> Lua a
-defineHowTo ctx op = Lua.errorConversion >>= \ec ->
-  Lua.addContextToException ec ("Could not " <> ctx <> ": ") op
+  Lua.rawset (Lua.nth 3)
 
 -- | Like @'Lua.pcall'@, but uses a predefined error handler which adds a
 -- traceback on error.
-pcallWithTraceback :: NumArgs -> NumResults -> Lua Status
+pcallWithTraceback :: LuaError e => NumArgs -> NumResults -> LuaE e Status
 pcallWithTraceback nargs nresults = do
-  let traceback' :: Lua NumResults
+  let traceback' :: LuaError e => LuaE e NumResults
       traceback' = do
         l <- Lua.state
-        msg <- Lua.tostring' (Lua.nthFromBottom 1)
-        Lua.traceback l (Just (UTF8.toString msg)) 2
+        msg <- Lua.tostring' (Lua.nthBottom 1)
+        Lua.traceback l (Just msg) 2
         return 1
-  tracebackIdx <- Lua.absindex (Lua.nthFromTop (Lua.fromNumArgs nargs + 1))
+  tracebackIdx <- Lua.absindex (Lua.nth (Lua.fromNumArgs nargs + 1))
   Lua.pushHaskellFunction traceback'
   Lua.insert tracebackIdx
   result <- Lua.pcall nargs nresults (Just tracebackIdx)
@@ -129,15 +46,15 @@ pcallWithTraceback nargs nresults = do
   return result
 
 -- | Like @'Lua.call'@, but adds a traceback to the error message (if any).
-callWithTraceback :: NumArgs -> NumResults -> Lua ()
+callWithTraceback :: LuaError e => NumArgs -> NumResults -> LuaE e ()
 callWithTraceback nargs nresults = do
   result <- pcallWithTraceback nargs nresults
   when (result /= Lua.OK)
-    Lua.throwTopMessage
+    Lua.throwErrorAsException
 
 -- | Run the given string as a Lua program, while also adding a traceback to the
 -- error message if an error occurs.
-dofileWithTraceback :: FilePath -> Lua Status
+dofileWithTraceback :: LuaError e => FilePath -> LuaE e Status
 dofileWithTraceback fp = do
   loadRes <- Lua.loadfile fp
   case loadRes of