Lua subsystem and custom writers: generalize types from PandocIO...

to any instance of PandocMonad and MonadIO.

This involves an API change, since the type of
runLua is now

    (PandocMonad m, MonadIO m) => Lua a -> m (Either PandocError a)

src/Text/Pandoc/Lua/Init.hs

@@ -18,8 +18,7 @@ import Control.Monad.Trans (MonadIO (..))
 import Data.Data (Data, dataTypeConstrs, dataTypeOf, showConstr)
 import Foreign.Lua (Lua)
 import GHC.IO.Encoding (getForeignEncoding, setForeignEncoding, utf8)
-import Text.Pandoc.Class.PandocMonad (readDataFile)
-import Text.Pandoc.Class.PandocIO (PandocIO)
+import Text.Pandoc.Class.PandocMonad (readDataFile, PandocMonad)
 import Text.Pandoc.Error (PandocError)
 import Text.Pandoc.Lua.Packages (installPandocPackageSearcher)
 import Text.Pandoc.Lua.PandocLua (PandocLua, liftPandocLua, runPandocLua)
@@ -30,7 +29,7 @@ import qualified Text.Pandoc.Lua.Module.Pandoc as ModulePandoc
 
 -- | Run the lua interpreter, using pandoc's default way of environment
 -- initialization.
-runLua :: Lua a -> PandocIO (Either PandocError a)
+runLua :: (PandocMonad m, MonadIO m) => Lua a -> m (Either PandocError a)
 runLua luaOp = do
   enc <- liftIO $ getForeignEncoding <* setForeignEncoding utf8
   res <- runPandocLua . try $ do

src/Text/Pandoc/Lua/PandocLua.hs

@@ -30,7 +30,6 @@ import Control.Monad.Catch (MonadCatch, MonadMask, MonadThrow)
 import Control.Monad.Except (MonadError (catchError, throwError))
 import Control.Monad.IO.Class (MonadIO (liftIO))
 import Foreign.Lua (Lua (..), NumResults, Pushable, ToHaskellFunction)
-import Text.Pandoc.Class.PandocIO (PandocIO)
 import Text.Pandoc.Class.PandocMonad (PandocMonad (..), readDefaultDataFile)
 import Text.Pandoc.Error (PandocError (PandocLuaError))
 import Text.Pandoc.Lua.Global (Global (..), setGlobals)
@@ -59,7 +58,7 @@ liftPandocLua = PandocLua
 
 -- | Evaluate a @'PandocLua'@ computation, running all contained Lua
 -- operations..
-runPandocLua :: PandocLua a -> PandocIO a
+runPandocLua :: (PandocMonad m, MonadIO m) => PandocLua a -> m a
 runPandocLua pLua = do
   origState <- getCommonState
   globals <- defaultGlobals
@@ -103,7 +102,7 @@ loadDefaultModule name = do
       throwError $ PandocLuaError (T.pack err)
 
 -- | Global variables which should always be set.
-defaultGlobals :: PandocIO [Global]
+defaultGlobals :: PandocMonad m => m [Global]
 defaultGlobals = do
   commonState <- getCommonState
   return

src/Text/Pandoc/Writers/Custom.hs

@@ -22,11 +22,12 @@ import qualified Data.Text as T
 import Data.Text (Text, pack)
 import Foreign.Lua (Lua, Pushable)
 import Text.DocLayout (render, literal)
-import Text.Pandoc.Class.PandocIO (PandocIO)
+import Control.Monad.IO.Class (MonadIO)
 import Text.Pandoc.Definition
 import Text.Pandoc.Lua (Global (..), runLua, setGlobals)
 import Text.Pandoc.Lua.Util (addField, dofileWithTraceback)
 import Text.Pandoc.Options
+import Text.Pandoc.Class (PandocMonad)
 import Text.Pandoc.Templates (renderTemplate)
 import Text.Pandoc.Writers.Shared
 
@@ -79,7 +80,8 @@ instance (Pushable a, Pushable b) => Pushable (KeyValue a b) where
     Lua.rawset (Lua.nthFromTop 3)
 
 -- | Convert Pandoc to custom markup.
-writeCustom :: FilePath -> WriterOptions -> Pandoc -> PandocIO Text
+writeCustom :: (PandocMonad m, MonadIO m)
+            => FilePath -> WriterOptions -> Pandoc -> m Text
 writeCustom luaFile opts doc@(Pandoc meta _) = do
   let globals = [ PANDOC_DOCUMENT doc
                 , PANDOC_SCRIPT_FILE luaFile