PowerPoint writer: Start numbering at appopriate numbers.

Starting numbers for ordered lists were previously ignored. Now we
specify the number if it is something other than 1.

Closes: #5709

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

@@ -861,7 +861,7 @@ paragraphToElement par = do
             (case pPropBullet $ paraProps par of
                Just Bullet -> []
                Just (AutoNumbering attrs') ->
-                 [mknode "a:buAutoNum" [("type", autoNumberingToType attrs')] ()]
+                 [mknode "a:buAutoNum" (autoNumAttrs attrs') ()]
                Nothing -> [mknode "a:buNone" [] ()]
             )
   paras <- concat <$> mapM paraElemToElements (paraElems par)
@@ -1872,10 +1872,14 @@ getContentType fp
       Just $ presML ++ ".slideLayout+xml"
   | otherwise = Nothing
 
-autoNumberingToType :: ListAttributes -> String
-autoNumberingToType (_, numStyle, numDelim) =
-  typeString ++ delimString
+autoNumAttrs :: ListAttributes -> [(String, String)]
+autoNumAttrs (startNum, numStyle, numDelim) =
+  numAttr ++ typeAttr
   where
+    numAttr = if startNum == 1
+              then []
+              else [("startAt", show startNum)]
+    typeAttr = [("type", typeString ++ delimString)]
     typeString = case numStyle of
       Decimal -> "arabic"
       UpperAlpha -> "alphaUc"

test/Tests/Writers/Powerpoint.hs

@@ -59,6 +59,10 @@ tests = groupPptxTests [ pptxTests "Inline formatting"
                          def
                          "pptx/lists.native"
                          "pptx/lists.pptx"
+                       , pptxTests "start ordered list at specified num"
+                         def
+                         "pptx/start_numbering_at.native"
+                         "pptx/start_numbering_at.pptx"
                        , pptxTests "tables"
                          def
                          "pptx/tables.native"

test/pptx/start_numbering_at.native

@@ -0,0 +1,9 @@
+[Header 2 ("example-numbering-mwe",[],[]) [Str "Example",Space,Str "numbering",Space,Str "MWE"]
+,Para [Str "This",Space,Str "is",Space,Str "a",Space,Str "slide",Space,Str "with",Space,Str "examples",Space,Str "in",Space,Str "(1)",Space,Str "and",Space,Str "(2)"]
+,OrderedList (1,Example,TwoParens)
+ [[Plain [Str "First"]]
+ ,[Plain [Str "Second"]]]
+,Header 2 ("a-second-slide",[],[]) [Str "A",Space,Str "second",Space,Str "slide"]
+,Para [Str "This",Space,Str "second",Space,Str "slide",Space,Str "has",Space,Str "a",Space,Str "third",Space,Str "example",Space,Str "in",Space,Str "(3)."]
+,OrderedList (3,Example,TwoParens)
+ [[Plain [Str "Third"]]]]