Docx Reader: Remove DummyListItem type

Change 5527465c introduced a `DummyListItem` type in Docx/Parse.hs. In
retrospect, this seems like it mixes parsing and iterpretation
excessively. What's *really* going on is that we have a list item
without and associate level or numeric info. We can decide what to do
what that in Docx.hs (treat it like a list paragraph), but the parser
shouldn't make that decision.

This commit makes what is going on a bit more explicit. `LevelInfo` is
now a Maybe value in the `ListItem` type. If it's a Nothing, we treat
it as a ListParagraph. If it's a Just, it's a normal list item.

src/Text/Pandoc/Readers/Docx.hs

@@ -486,7 +486,7 @@ bodyPartToBlocks (Paragraph pPr parparts)
               return $ case isNull ils' of
                 True -> mempty
                 _ -> parStyleToTransform pPr $ para ils'
-bodyPartToBlocks (ListItem pPr numId lvl levelInfo parparts) = do
+bodyPartToBlocks (ListItem pPr numId lvl (Just levelInfo) parparts) = do
   let
     kvs = case levelInfo of
       (_, fmt, txt, Just start) -> [ ("level", lvl)
@@ -503,7 +503,7 @@ bodyPartToBlocks (ListItem pPr numId lvl levelInfo parparts) = do
                                    ]
   blks <- bodyPartToBlocks (Paragraph pPr parparts)
   return $ divWith ("", ["list-item"], kvs) blks
-bodyPartToBlocks (DummyListItem pPr _ parparts) = 
+bodyPartToBlocks (ListItem pPr _ _ _ parparts) = 
   let pPr' = pPr {pStyle = "ListParagraph": (pStyle pPr)}
   in
     bodyPartToBlocks $ Paragraph pPr' parparts

src/Text/Pandoc/Readers/Docx/Parse.hs

@@ -177,8 +177,7 @@ defaultParagraphStyle = ParagraphStyle { pStyle = []
 
 
 data BodyPart = Paragraph ParagraphStyle [ParPart]
-              | ListItem ParagraphStyle String String Level [ParPart]
-              | DummyListItem ParagraphStyle String [ParPart]
+              | ListItem ParagraphStyle String String (Maybe Level) [ParPart]
               | Tbl String TblGrid TblLook [Row]
               | OMathPara [Exp]
               deriving Show
@@ -565,9 +564,8 @@ elemToBodyPart ns element
     let parstyle = elemToParagraphStyle ns element sty
     parparts <- mapD (elemToParPart ns) (elChildren element)
     num <- asks envNumbering
-    case lookupLevel numId lvl num of
-     Just levelInfo -> return $ ListItem parstyle numId lvl levelInfo parparts
-     Nothing        -> return $ DummyListItem parstyle lvl parparts
+    let levelInfo = lookupLevel numId lvl num
+    return $ ListItem parstyle numId lvl levelInfo parparts
 elemToBodyPart ns element
   | isElem ns "w" "p" element = do
       sty <- asks envParStyles
@@ -576,11 +574,8 @@ elemToBodyPart ns element
       case pNumInfo parstyle of
        Just (numId, lvl) -> do
          num <- asks envNumbering
-         case lookupLevel numId lvl num of
-          Just levelInfo ->
-            return $ ListItem parstyle numId lvl levelInfo parparts
-          Nothing         ->
-            return $ DummyListItem parstyle lvl parparts
+         let levelInfo = lookupLevel numId lvl num
+         return $ ListItem parstyle numId lvl levelInfo parparts
        Nothing -> return $ Paragraph parstyle parparts
 elemToBodyPart ns element
   | isElem ns "w" "tbl" element = do