Pptx writer: Apply speaker snotes to metadata slide if applicable.

If the slide deck has a metadata slide (with author, title, etc) and
has speaker notes before any body content, the speaker notes will be
applied to the metadata slide. If there is no metadata slide, pandoc
will behave as before.

src/Text/Pandoc/Writers/Powerpoint/Presentation.hs

@@ -680,28 +680,32 @@ blocksToSlide' _ [] spkNotes = do
                  }
     spkNotes
 
-handleNotes :: Block -> Pres ()
-handleNotes (Div (_, ["notes"], _) blks) =
-  local (\env -> env{envInSpeakerNotes=True}) $ do
-  spNotes <- SpeakerNotes <$> concatMapM blockToParagraphs blks
-  modify $ \st -> st{stSpeakerNotes = (stSpeakerNotes st) <> spNotes}
-handleNotes _ = return ()
+blockToSpeakerNotes :: Block -> Pres SpeakerNotes
+blockToSpeakerNotes (Div (_, ["notes"], _) blks) =
+  local (\env -> env{envInSpeakerNotes=True}) $
+  SpeakerNotes <$> concatMapM blockToParagraphs blks
+blockToSpeakerNotes _ = return mempty
 
-handleAndFilterNotes' :: [Block] -> Pres [Block]
-handleAndFilterNotes' blks = do
-  mapM_ handleNotes blks
+handleSpeakerNotes :: Block -> Pres ()
+handleSpeakerNotes blk = do
+  spNotes <- blockToSpeakerNotes blk
+  modify $ \st -> st{stSpeakerNotes = (stSpeakerNotes st) <> spNotes}
+
+handleAndFilterSpeakerNotes' :: [Block] -> Pres [Block]
+handleAndFilterSpeakerNotes' blks = do
+  mapM_ handleSpeakerNotes blks
   return $ filter (not . isNotesDiv) blks
 
-handleAndFilterNotes :: [Block] -> Pres ([Block], SpeakerNotes)
-handleAndFilterNotes blks = do
+handleAndFilterSpeakerNotes :: [Block] -> Pres ([Block], SpeakerNotes)
+handleAndFilterSpeakerNotes blks = do
   modify $ \st -> st{stSpeakerNotes = mempty}
-  blks' <- walkM handleAndFilterNotes' blks
+  blks' <- walkM handleAndFilterSpeakerNotes' blks
   spkNotes <- gets stSpeakerNotes
   return (blks', spkNotes)
 
 blocksToSlide :: [Block] -> Pres Slide
 blocksToSlide blks = do
-  (blks', spkNotes) <- handleAndFilterNotes blks
+  (blks', spkNotes) <- handleAndFilterSpeakerNotes blks
   slideLevel <- asks envSlideLevel
   blocksToSlide' slideLevel blks' spkNotes
 
@@ -759,6 +763,13 @@ getMetaSlide  = do
                        }
          mempty
 
+addSpeakerNotesToMetaSlide :: Slide -> [Block] -> Pres (Slide, [Block])
+addSpeakerNotesToMetaSlide (Slide sldId layout@(MetadataSlide _ _ _ _) spkNotes) blks =
+  do let (ntsBlks, blks') = span isNotesDiv blks
+     spkNotes' <- mconcat <$> mapM blockToSpeakerNotes ntsBlks
+     return (Slide sldId layout (spkNotes <> spkNotes'), blks')
+addSpeakerNotesToMetaSlide sld blks = return (sld, blks)
+
 makeTOCSlide :: [Block] -> Pres Slide
 makeTOCSlide blks = local (\env -> env{envCurSlideId = tocSlideId}) $ do
   opts <- asks envOpts
@@ -871,7 +882,16 @@ emptySlide (Slide _ layout notes) = (notes == mempty) && (emptyLayout layout)
 blocksToPresentationSlides :: [Block] -> Pres [Slide]
 blocksToPresentationSlides blks = do
   opts <- asks envOpts
-  metadataslides <- maybeToList <$> getMetaSlide
+  mbMetadataSlide <- getMetaSlide
+  -- if the metadata slide exists, we try to add any speakerNotes
+  -- which immediately follow it. We also convert from maybe to a
+  -- list, so that it will be able to add together more easily with
+  -- the other lists of slides.
+  (metadataslides, blks') <- case mbMetadataSlide of
+                                 Just sld ->
+                                   do (s, bs) <- addSpeakerNotesToMetaSlide sld blks
+                                      return ([s], bs)
+                                 Nothing -> return ([], blks)
   -- As far as I can tell, if we want to have a variable-length toc in
   -- the future, we'll have to make it twice. Once to get the length,
   -- and a second time to include the notes slide. We can't make the
@@ -882,7 +902,7 @@ blocksToPresentationSlides blks = do
   -- For now, though, since the TOC slide is only length 1, if it
   -- exists, we'll just get the length, and then come back to make the
   -- slide later
-  blksLst <- splitBlocks blks
+  blksLst <- splitBlocks blks'
   bodySlideIds <- mapM
                   (\n -> runUniqueSlideId $ "BodySlide" ++ show n)
                   (take (length blksLst) [1..] :: [Integer])
@@ -893,7 +913,7 @@ blocksToPresentationSlides blks = do
   endNotesSlideBlocks <- makeEndNotesSlideBlocks
   -- now we come back and make the real toc...
   tocSlides <- if writerTableOfContents opts
-               then do toc <- makeTOCSlide $ blks ++ endNotesSlideBlocks
+               then do toc <- makeTOCSlide $ blks' ++ endNotesSlideBlocks
                        return [toc]
                else return []
   -- ... and the notes slide. We test to see if the blocks are empty,