A nested list can be ordered or unordered

src/MdToHTML.hs

@@ -292,7 +292,8 @@ parseListNested = do
   let firstCharParser = string "    " <++ string "\t"
   let restOfLineParser = manyTill get (void (char '\n') <++ eof)
   lines <- greedyParse1 (firstCharParser *> restOfLineParser)
-  let linesParsed = fst $ leftmostLongestParse parseUnorderedList (init $ unlines lines)
+  let linesParsed = fst $ leftmostLongestParse (parseUnorderedList <++ parseOrderedList) (init $ unlines lines)
+  when (null (show linesParsed)) pfail
   return linesParsed
 
 -- Parse an unordered list line item.