Docx reader: fix handling of oMathPara in w:p with other content.

Closes #8483.

The problem is that oMathPara can either occur at the block-level
(child of w:body) or at the inline level (child of w:p, potentially
with other content). We need to handle both cases.
Previously the code just assumed that if we had a w:p with an oMathPara,
the math would be the sole content.

This patch removes OMathPara as a constructor of BodyPart
and adds it as a constructor of ParPart.

Author: jgm

src/Text/Pandoc/Readers/Docx.hs

@@ -468,6 +468,8 @@ parPartToInlines' (ExternalHyperLink target children) = do
   return $ link target "" ils
 parPartToInlines' (PlainOMath exps) =
   return $ math $ writeTeX exps
+parPartToInlines' (OMathPara exps) =
+  return $ displayMath $ writeTeX exps
 parPartToInlines' (Field info children) =
   case info of
     HyperlinkField url -> parPartToInlines' $ ExternalHyperLink url children
@@ -793,8 +795,6 @@ bodyPartToBlocks (Tbl cap grid look parts) = do
                  (TableHead nullAttr headerCells)
                  [TableBody nullAttr 0 [] bodyCells]
                  (TableFoot nullAttr [])
-bodyPartToBlocks (OMathPara e) =
-  return $ para $ displayMath (writeTeX e)
 
 -- replace targets with generated anchors.
 rewriteLink' :: PandocMonad m => Inline -> DocxContext m Inline

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

@@ -242,7 +242,6 @@ data BodyPart = Paragraph ParagraphStyle [ParPart]
               | ListItem ParagraphStyle T.Text T.Text (Maybe Level) [ParPart]
               | Tbl T.Text TblGrid TblLook [Row]
               | TblCaption ParagraphStyle [ParPart]
-              | OMathPara [Exp]
               deriving Show
 
 type TblGrid = [Integer]
@@ -333,6 +332,7 @@ data ParPart = PlainRun Run
              | Chart                                              -- placeholder for now
              | Diagram                                            -- placeholder for now
              | PlainOMath [Exp]
+             | OMathPara [Exp]
              | Field FieldInfo [ParPart]
              deriving Show
 
@@ -703,10 +703,12 @@ pStyleIndentation style = (getParStyleField indent . pStyle) style
 
 elemToBodyPart :: NameSpaces -> Element -> D BodyPart
 elemToBodyPart ns element
-  | isElem ns "w" "p" element
-  , (c:_) <- findChildrenByName ns "m" "oMathPara" element = do
-      expsLst <- eitherToD $ readOMML $ showElement c
-      return $ OMathPara expsLst
+  | isElem ns "m" "oMathPara" element = do
+      expsLst <- eitherToD $ readOMML $ showElement element
+      parstyle <- elemToParagraphStyle ns element
+                  <$> asks envParStyles
+                  <*> asks envNumbering
+      return $ Paragraph parstyle [OMathPara expsLst]
 elemToBodyPart ns element
   | isElem ns "w" "p" element
   , Just (numId, lvl) <- getNumInfo ns element = do
@@ -1000,6 +1002,9 @@ elemToParPart' ns element
 elemToParPart' ns element
   | isElem ns "m" "oMath" element =
     fmap (return . PlainOMath) (eitherToD $ readOMML $ showElement element)
+elemToParPart' ns element
+  | isElem ns "m" "oMathPara" element =
+    fmap (return . OMathPara) (eitherToD $ readOMML $ showElement element)
 elemToParPart' _ _ = throwError WrongElem
 
 elemToCommentStart :: NameSpaces -> Element -> D [ParPart]