Switch to hslua-2.0

The new HsLua version takes a somewhat different approach to marshalling
and unmarshalling, relying less on typeclasses and more on specialized
types. This allows for better performance and improved error messages.

Furthermore, new abstractions allow to document the code and exposed
functions.

1 files changed, 20 insertions, 14 deletions

diff --git a/src/Text/Pandoc/Lua/Packages.hs b/src/Text/Pandoc/Lua/Packages.hs
index 2f1c139db..f9bd7abe8 100644
--- a/src/Text/Pandoc/Lua/Packages.hs
+++ b/src/Text/Pandoc/Lua/Packages.hs
@@ -1,3 +1,6 @@
+{-# LANGUAGE FlexibleContexts  #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeApplications  #-}
 {- |
    Module      : Text.Pandoc.Lua.Packages
    Copyright   : Copyright © 2017-2021 Albert Krewinkel
@@ -13,12 +16,13 @@ module Text.Pandoc.Lua.Packages
   ) where
 
 import Control.Monad (forM_)
-import Foreign.Lua (NumResults)
+import HsLua (NumResults)
+import Text.Pandoc.Error (PandocError)
 import Text.Pandoc.Lua.PandocLua (PandocLua, liftPandocLua, loadDefaultModule)
 
-import qualified Foreign.Lua as Lua
-import qualified Foreign.Lua.Module.Path as Path
-import qualified Foreign.Lua.Module.Text as Text
+import qualified HsLua as Lua
+import qualified HsLua.Module.Path as Path
+import qualified HsLua.Module.Text as Text
 import qualified Text.Pandoc.Lua.Module.Pandoc as Pandoc
 import qualified Text.Pandoc.Lua.Module.MediaBag as MediaBag
 import qualified Text.Pandoc.Lua.Module.System as System
@@ -30,8 +34,8 @@ installPandocPackageSearcher :: PandocLua ()
 installPandocPackageSearcher = liftPandocLua $ do
   Lua.getglobal' "package.searchers"
   shiftArray
-  Lua.pushHaskellFunction pandocPackageSearcher
-  Lua.rawseti (Lua.nthFromTop 2) 1
+  Lua.pushHaskellFunction $ Lua.toHaskellFunction pandocPackageSearcher
+  Lua.rawseti (Lua.nth 2) 1
   Lua.pop 1           -- remove 'package.searchers' from stack
  where
   shiftArray = forM_ [4, 3, 2, 1] $ \i -> do
@@ -42,14 +46,16 @@ installPandocPackageSearcher = liftPandocLua $ do
 pandocPackageSearcher :: String -> PandocLua NumResults
 pandocPackageSearcher pkgName =
   case pkgName of
-    "pandoc"          -> pushWrappedHsFun Pandoc.pushModule
-    "pandoc.mediabag" -> pushWrappedHsFun MediaBag.pushModule
-    "pandoc.path"     -> pushWrappedHsFun Path.pushModule
-    "pandoc.system"   -> pushWrappedHsFun System.pushModule
-    "pandoc.types"    -> pushWrappedHsFun Types.pushModule
-    "pandoc.utils"    -> pushWrappedHsFun Utils.pushModule
-    "text"            -> pushWrappedHsFun Text.pushModule
-    "pandoc.List"     -> pushWrappedHsFun (loadDefaultModule pkgName)
+    "pandoc"          -> pushWrappedHsFun $ Lua.toHaskellFunction @PandocError Pandoc.pushModule
+    "pandoc.mediabag" -> pushWrappedHsFun $ Lua.toHaskellFunction @PandocError MediaBag.pushModule
+    "pandoc.path"     -> pushWrappedHsFun
+      (Lua.NumResults 1 <$ Lua.pushModule @PandocError Path.documentedModule)
+    "pandoc.system"   -> pushWrappedHsFun $ Lua.toHaskellFunction System.pushModule
+    "pandoc.types"    -> pushWrappedHsFun $ Lua.toHaskellFunction @PandocError Types.pushModule
+    "pandoc.utils"    -> pushWrappedHsFun $ Lua.toHaskellFunction @PandocError Utils.pushModule
+    "text"            -> pushWrappedHsFun
+      (Lua.NumResults 1 <$ Lua.pushModule @PandocError Text.documentedModule)
+    "pandoc.List"     -> pushWrappedHsFun $ Lua.toHaskellFunction @PandocError (loadDefaultModule pkgName)
     _                 -> reportPandocSearcherFailure
  where
   pushWrappedHsFun f = liftPandocLua $ do