pptx: Fix list level numbering

In PowerPoint, the content of a top-level list is at the same level as
the content of a top-level paragraph – the only difference is that a
list style has been applied.

At the moment, the pptx writer increments the paragraph level on each
list, turning what should be top-level lists into second-level lists.

This commit changes that logic, only incrementing the paragraph level on
continuation paragraphs of lists.

- Fixes https://github.com/jgm/pandoc/issues/4828
- Fixes https://github.com/jgm/pandoc/issues/4663

1 files changed, 17 insertions, 14 deletions

diff --git a/src/Text/Pandoc/Writers/Powerpoint/Presentation.hs b/src/Text/Pandoc/Writers/Powerpoint/Presentation.hs
index fe34d24dc..2f94dcc17 100644
--- a/src/Text/Pandoc/Writers/Powerpoint/Presentation.hs
+++ b/src/Text/Pandoc/Writers/Powerpoint/Presentation.hs
@@ -500,27 +500,23 @@ blockToParagraphs (Header _ (ident, _, _) ils) = do
 blockToParagraphs (BulletList blksLst) = do
   pProps <- asks envParaProps
   incremental <- listShouldBeIncremental
-  let lvl = pPropLevel pProps
   local (\env -> env{ envInList = True
-                    , envParaProps = pProps{ pPropLevel = lvl + 1
-                                           , pPropBullet = Just Bullet
+                    , envParaProps = pProps{ pPropBullet = Just Bullet
                                            , pPropMarginLeft = Nothing
                                            , pPropIndent = Nothing
                                            , pPropIncremental = incremental
                                            }}) $
-    concatMapM multiParBullet blksLst
+    concatMapM multiParList blksLst
 blockToParagraphs (OrderedList listAttr blksLst) = do
   pProps <- asks envParaProps
   incremental <- listShouldBeIncremental
-  let lvl = pPropLevel pProps
   local (\env -> env{ envInList = True
-                    , envParaProps = pProps{ pPropLevel = lvl + 1
-                                           , pPropBullet = Just (AutoNumbering listAttr)
+                    , envParaProps = pProps{ pPropBullet = Just (AutoNumbering listAttr)
                                            , pPropMarginLeft = Nothing
                                            , pPropIndent = Nothing
                                            , pPropIncremental = incremental
                                            }}) $
-    concatMapM multiParBullet blksLst
+    concatMapM multiParList blksLst
 blockToParagraphs (DefinitionList entries) = do
   incremental <- listShouldBeIncremental
   let go :: ([Inline], [[Block]]) -> Pres [Paragraph]
@@ -545,14 +541,21 @@ blockToParagraphs blk = do
   addLogMessage $ BlockNotRendered blk
   return []
 
--- Make sure the bullet env gets turned off after the first para.
-multiParBullet :: [Block] -> Pres [Paragraph]
-multiParBullet [] = return []
-multiParBullet (b:bs) = do
+-- | Make sure the bullet env gets turned off after the first paragraph, and
+-- indent any continuation paragraphs.
+multiParList :: [Block] -> Pres [Paragraph]
+multiParList [] = return []
+multiParList (b:bs) = do
   pProps <- asks envParaProps
   p <- blockToParagraphs b
-  ps <- local (\env -> env{envParaProps = pProps{pPropBullet = Nothing}}) $
-    concatMapM blockToParagraphs bs
+  let level = pPropLevel pProps
+  ps <- local (\env -> env
+                { envParaProps = pProps
+                  { pPropBullet = Nothing
+                  , pPropLevel = level + 1
+                  }
+                })
+        $ concatMapM blockToParagraphs bs
   return $ p ++ ps
 
 cellToParagraphs :: Alignment -> SimpleCell -> Pres [Paragraph]