1 files changed, 7 insertions, 6 deletions
diff --git a/src/Text/Pandoc/Writers/Custom.hs b/src/Text/Pandoc/Writers/Custom.hs
index 6c4f92db0..733b29ac7 100644
--- a/src/Text/Pandoc/Writers/Custom.hs
+++ b/src/Text/Pandoc/Writers/Custom.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE FlexibleInstances  #-}
 {-# LANGUAGE NoImplicitPrelude  #-}
+{-# LANGUAGE OverloadedStrings  #-}
 {- |
    Module      : Text.Pandoc.Writers.Custom
    Copyright   : Copyright (C) 2012-2019 John MacFarlane
@@ -17,9 +18,9 @@ import Prelude
 import Control.Arrow ((***))
 import Control.Exception
 import Control.Monad (when)
-import Data.Char (toLower)
 import Data.List (intersperse)
 import qualified Data.Map as M
+import qualified Data.Text as T
 import Data.Text (Text, pack)
 import Data.Typeable
 import Foreign.Lua (Lua, Pushable)
@@ -36,16 +37,16 @@ import Text.Pandoc.Writers.Shared
 
 import qualified Foreign.Lua as Lua
 
-attrToMap :: Attr -> M.Map String String
+attrToMap :: Attr -> M.Map T.Text T.Text
 attrToMap (id',classes,keyvals) = M.fromList
     $ ("id", id')
-    : ("class", unwords classes)
+    : ("class", T.unwords classes)
     : keyvals
 
 newtype Stringify a = Stringify a
 
 instance Pushable (Stringify Format) where
-  push (Stringify (Format f)) = Lua.push (map toLower f)
+  push (Stringify (Format f)) = Lua.push (T.toLower f)
 
 instance Pushable (Stringify [Inline]) where
   push (Stringify ils) = Lua.push =<< inlineListToCustom ils
@@ -82,7 +83,7 @@ instance (Pushable a, Pushable b) => Pushable (KeyValue a b) where
     Lua.push v
     Lua.rawset (Lua.nthFromTop 3)
 
-data PandocLuaException = PandocLuaException String
+data PandocLuaException = PandocLuaException Text
     deriving (Show, Typeable)
 
 instance Exception PandocLuaException
@@ -99,7 +100,7 @@ writeCustom luaFile opts doc@(Pandoc meta _) = do
     -- check for error in lua script (later we'll change the return type
     -- to handle this more gracefully):
     when (stat /= Lua.OK) $
-      Lua.tostring' (-1) >>= throw . PandocLuaException . UTF8.toString
+      Lua.tostring' (-1) >>= throw . PandocLuaException . UTF8.toText
     rendered <- docToCustom opts doc
     context <- metaToContext opts
                (fmap (literal . pack) . blockListToCustom)