OMath parser: Change signature of exported function.

This changes the signature of the exported `readOMML` to `String ->
Either String [Exp]`, so it can now, in theory, be slotted into
TeXMath. It doesn't have any real error reporting yet, but that might
make more sense once I put it in a branch, and understand how it works
in the other readers.

It also now reads strings that parse to either oMath or oMathPara
elements. Note that the distinction is lost in the output. It's up to
the caller to remember the display type.

src/Text/Pandoc/Readers/Docx.hs

@@ -321,7 +321,7 @@ runToInlines (InlineDrawing fp bs) = do
   modify $ \s -> s { docxMediaBag = insertMedia fp Nothing bs mediaBag }
   return [Image [] (fp, "")]
 
-  
+
 
 
 parPartToInlines :: ParPart -> DocxContext [Inline]
@@ -507,10 +507,9 @@ bodyPartToBlocks (Tbl cap _ look (r:rs)) = do
       widths = replicate size 0 :: [Double]
 
   return [Table caption alignments widths hdrCells cells]
-bodyPartToBlocks (OMathPara exps) = do
-  return [Para $
-          map (\e -> Math DisplayMath (writeTeX e))
-          exps]
+bodyPartToBlocks (OMathPara e) = do
+  return [Para [Math DisplayMath (writeTeX e)]]
+
 
 -- replace targets with generated anchors.
 rewriteLink :: Inline -> DocxContext Inline

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

@@ -38,11 +38,20 @@ import Data.Maybe (mapMaybe, fromMaybe)
 import Data.List (intersperse)
 import qualified Text.TeXMath.Types as TM
 
-readOMML :: Element -> Maybe [TM.Exp]
-readOMML element  | isElem "m" "oMath" element =
-  Just $ concat $ mapMaybe (elemToExps') (elChildren element)
-readOMML _ = Nothing
+readOMML :: String -> Either String [TM.Exp]
+readOMML s | Just e <- parseXMLDoc s =
+  case elemToOMML e of
+    Just exs -> Right exs
+    Nothing   -> Left "xml file was not an <m:oMathPara> or <m:oMath> element."
+readOMML _ = Left "Couldn't parse OMML file"
 
+elemToOMML :: Element -> Maybe [TM.Exp]
+elemToOMML element  | isElem "m" "oMathPara" element = do
+  let expList = mapMaybe elemToOMML (elChildren element)
+  return $ map (\l -> if length l == 1 then (head l) else TM.EGrouped l) expList
+elemToOMML element  | isElem "m" "oMath" element =
+  Just $ concat $ mapMaybe (elemToExps') (elChildren element)
+elemToOMML _ = Nothing
 
 isElem :: String -> String -> Element -> Bool
 isElem prefix name element =

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

@@ -86,6 +86,10 @@ maybeToD :: Maybe a -> D a
 maybeToD (Just a) = return a
 maybeToD Nothing = throwError DocxError
 
+eitherToD :: Either a b -> D b
+eitherToD (Right b) = return b
+eitherToD (Left _)  = throwError DocxError
+
 concatMapM        :: (Monad m) => (a -> m [b]) -> [a] -> m [b]
 concatMapM f xs   =  liftM concat (mapM f xs)
 
@@ -150,7 +154,7 @@ defaultParagraphStyle = ParagraphStyle { pStyle = []
 data BodyPart = Paragraph ParagraphStyle [ParPart]
               | ListItem ParagraphStyle String String Level [ParPart]
               | Tbl String TblGrid TblLook [Row]
-              | OMathPara [[Exp]]
+              | OMathPara [Exp]
               deriving Show
 
 type TblGrid = [Integer]
@@ -475,7 +479,7 @@ elemToBodyPart ns element
   | isElem ns "w" "p" element
   , (c:_) <- findChildren (elemName ns "m" "oMathPara") element =
       do
-        expsLst <- mapD (\e -> (maybeToD $ readOMML e)) (elChildren c)
+        expsLst <- eitherToD $ readOMML $ showElement c
         return $ OMathPara expsLst
 elemToBodyPart ns element
   | isElem ns "w" "p" element
@@ -575,7 +579,7 @@ elemToParPart ns element
       Nothing     -> ExternalHyperLink "" runs
 elemToParPart ns element
   | isElem ns "m" "oMath" element =
-    (maybeToD $ readOMML element) >>= (return . PlainOMath)
+    (eitherToD $ readOMML $ showElement element) >>= (return . PlainOMath)
 elemToParPart _ _ = throwError WrongElem
 
 lookupFootnote :: String -> Notes -> Maybe Element