T.P.Chunks changes.

+ Re-use `toTocTree` in constructing `chunkedTOC`.
  Previously we used an entirely different function toTOCTree'.
+ Improve `tocToList` so that it avoids empty lists of
  items that are omitted because they are below the toc depth.

pandoc-lua-engine:

+ Fix structure tests in light of last change.

T.P.Writers.ChunkedHTML:

+ Reuse `tocToList` in `buildTOC`.

T.P.Writers.EPUB:

+ Adjust EPUB writer for Chunks changes.

3 files changed, 45 insertions, 55 deletions

diff --git a/src/Text/Pandoc/Chunks.hs b/src/Text/Pandoc/Chunks.hs
index 3d144f325..196893f04 100644
--- a/src/Text/Pandoc/Chunks.hs
+++ b/src/Text/Pandoc/Chunks.hs
@@ -51,12 +51,14 @@ splitIntoChunks pathTemplate numberSections mbBaseLevel
                 chunklev (Pandoc meta blocks) =
    addNav .
    fixInternalReferences .
-   walk rmNavAttrs .
-   (\chunks -> ChunkedDoc{ chunkedMeta = meta
-                         , chunkedChunks = chunks
-                         , chunkedTOC = toTOCTree' chunks }) .
-   makeChunks chunklev pathTemplate meta .
-   makeSections numberSections mbBaseLevel $ blocks
+   walk rmNavAttrs $
+   ChunkedDoc{ chunkedMeta = meta
+             , chunkedChunks = chunks
+             , chunkedTOC = tocTree }
+ where
+  tocTree = fixTOCTreePaths chunks $ toTOCTree sections
+  chunks = makeChunks chunklev pathTemplate meta $ sections
+  sections = makeSections numberSections mbBaseLevel $ blocks
 
 -- | Add chunkNext, chunkPrev, chunkUp
 addNav :: ChunkedDoc -> ChunkedDoc
@@ -321,7 +323,7 @@ data SecInfo =
   { secTitle :: [Inline]
   , secNumber :: Maybe Text
   , secId :: Text
-  , secPath :: Text
+  , secPath :: Text -- including fragment, e.g. chunk001.html#section-one
   , secLevel :: Int
   } deriving (Show, Eq, Generic)
 
@@ -354,25 +356,22 @@ toTOCTree =
   go (Div _ [d@Div{}]) = go d -- #8402
   go _ = id
 
-toTOCTree' :: [Chunk] -> Tree SecInfo
-toTOCTree' =
-  Node SecInfo{ secTitle = []
-              , secNumber = Nothing
-              , secId = ""
-              , secPath = ""
-              , secLevel = 0 } . getNodes . filter (not . skippable)
+-- | Adjusts paths in the TOC tree generated by 'toTOCTree'
+-- to reflect division into Chunks.
+fixTOCTreePaths :: [Chunk] -> Tree SecInfo -> Tree SecInfo
+fixTOCTreePaths chunks = go ""
  where
-  skippable c = isNothing (chunkSectionNumber c) && chunkUnlisted c
-  getNodes :: [Chunk] -> [Tree SecInfo]
-  getNodes (c:cs) =
-    let (as, bs) = span (\d -> chunkLevel d > chunkLevel c) cs
-        secinfo = SecInfo{ secTitle = chunkHeading c,
-                           secNumber = chunkSectionNumber c,
-                           secId = chunkId c,
-                           secPath = T.pack $ chunkPath c,
-                           secLevel = chunkLevel c }
-     in Node secinfo (getNodes as) : getNodes bs
-  getNodes [] = []
+  idMap = foldr (\chunk -> M.insert (chunkId chunk) (chunkPath chunk))
+                mempty chunks
+  go :: FilePath -> Tree SecInfo -> Tree SecInfo
+  go fp (Node secinfo subtrees) =
+    let newpath = M.lookup (secId secinfo) idMap
+        fp' = fromMaybe fp newpath
+        fragment = case newpath of
+                     Nothing -> "#" <> secId secinfo
+                     Just _  -> "" -- link to top of file
+     in Node secinfo{ secPath = T.pack fp' <> fragment }
+             (map (go fp') subtrees)
 
 -- | Creates a TOC link to the respective document section.
 tocEntryToLink :: SecInfo -> [Inline]
@@ -385,19 +384,27 @@ tocEntryToLink secinfo = headerLink
   clean (Link _ xs _) = xs
   clean (Note _) = []
   clean x = [x]
-  ident = secId secinfo
+  anchor = if T.null (secPath secinfo)
+              then if T.null (secId secinfo)
+                      then ""
+                      else "#" <> secId secinfo
+              else secPath secinfo
   headerText = addNumber $ walk (concatMap clean) (secTitle secinfo)
-  headerLink = if T.null ident
+  headerLink = if T.null anchor
                   then headerText
-                  else [Link ("toc-" <> ident, [], [])
-                         headerText (secPath secinfo <> "#" <> ident, "")]
+                  else [Link ((if T.null (secId secinfo)
+                                  then ""
+                                  else "toc-" <> secId secinfo), [], [])
+                         headerText (anchor, "")]
 
 -- | Generate a table of contents of the given depth.
 tocToList :: Int -> Tree SecInfo -> Block
-tocToList tocDepth (Node _ subtrees)
-  = BulletList (toItems subtrees)
+tocToList tocDepth (Node _ subtrees) = BulletList (toItems subtrees)
  where
   toItems = map go . filter isBelowTocDepth
   isBelowTocDepth (Node sec _) = secLevel sec <= tocDepth
   go (Node secinfo xs) =
-    Plain (tocEntryToLink secinfo) : [BulletList (toItems xs) | not (null xs)]
+    Plain (tocEntryToLink secinfo) :
+      case toItems xs of
+        [] -> []
+        ys -> [BulletList ys]
diff --git a/src/Text/Pandoc/Writers/ChunkedHTML.hs b/src/Text/Pandoc/Writers/ChunkedHTML.hs
index 5efcfb0ab..61dcdbd80 100644
--- a/src/Text/Pandoc/Writers/ChunkedHTML.hs
+++ b/src/Text/Pandoc/Writers/ChunkedHTML.hs
@@ -28,7 +28,7 @@ import Text.Pandoc.Class (PandocMonad, getPOSIXTime, runPure,
 import Text.Pandoc.MediaBag (mediaItems)
 import qualified Data.ByteString.Lazy as BL
 import Text.Pandoc.Chunks (splitIntoChunks, Chunk(..), ChunkedDoc(..),
-                           SecInfo(..))
+                           SecInfo(..), tocToList)
 import Data.Text (Text)
 import Data.Tree
 import qualified Data.Text as T
@@ -86,9 +86,8 @@ writeChunkedHTML opts (Pandoc meta blocks) = do
   let Node secinfo secs = chunkedTOC chunkedDoc
   let tocTree = Node secinfo{ secTitle = docTitle meta,
                               secPath = "index.html" } secs
-  let tocBlocks = buildTOC opts tocTree
   renderedTOC <- writeHtml5String opts{ writerTemplate = Nothing }
-                    (Pandoc nullMeta tocBlocks)
+                    (Pandoc nullMeta [buildTOC opts tocTree])
   let opts' = opts{ writerVariables =
                         defField "table-of-contents" renderedTOC
                       $ writerVariables opts }
@@ -110,22 +109,8 @@ addMedia il@(Image _ _ (src,_))
   return il
 addMedia il = return il
 
-buildTOC :: WriterOptions -> Tree SecInfo -> [Block]
-buildTOC opts tocTree = buildTOCPart tocTree
- where
-  buildTOCPart (Node secinfo subsecs) =
-    Plain [Link nullAttr
-            ((maybe [] (\num ->
-               if writerNumberSections opts
-                  then [Span ("",["toc-section-number"],[])
-                                  [Str num, Space]]
-                  else []) (secNumber secinfo))
-             ++ secTitle secinfo)
-            (secPath secinfo, "") | secLevel secinfo > 0] :
-    if null subsecs
-       then []
-       else [BulletList (map buildTOCPart $ filter aboveThreshold subsecs)]
-  aboveThreshold (Node sec _) = secLevel sec <= writerTOCDepth opts
+buildTOC :: WriterOptions -> Tree SecInfo -> Block
+buildTOC opts = tocToList (writerTOCDepth opts)
 
 chunkToEntry :: PandocMonad m
              => WriterOptions -> Meta -> Chunk -> Chunk -> m Entry
diff --git a/src/Text/Pandoc/Writers/EPUB.hs b/src/Text/Pandoc/Writers/EPUB.hs
index 832ddb0b2..7faad746e 100644
--- a/src/Text/Pandoc/Writers/EPUB.hs
+++ b/src/Text/Pandoc/Writers/EPUB.hs
@@ -842,8 +842,7 @@ createTocEntry opts meta metadata plainTitle (Node _ secs) = do
                    [("id", "navPoint-" <> tshow n)] $
                       [ unode "navLabel" $ unode "text" title'
                       , unode "content" !
-                          [("src", "text/" <> secPath secinfo <>
-                                               "#" <> secId secinfo)] $ ()
+                          [("src", "text/" <> secPath secinfo)] $ ()
                       ] ++ subs
 
   let tpNode = unode "navPoint" !  [("id", "navPoint-0")] $
@@ -921,8 +920,7 @@ createNavEntry opts meta metadata
           return $ Just $ unode "li" !
                    [("id", "toc-li-" <> tshow n)] $
                       (unode "a" !
-                        [("href", "text/" <> secPath secinfo <>
-                                             "#" <> secId secinfo)]
+                        [("href", "text/" <> secPath secinfo)]
                         $ titElements)
                        : case subs of
                            [] -> []