Org reader: subject full doc tree to headline transformations

Emacs parses org documents into a tree structure, which is then
post-processed during exporting. The reader is changed to do the same,
turning the document into a single tree of headlines starting at
level 0.

Fixes: #3695

2 files changed, 37 insertions, 6 deletions

diff --git a/src/Text/Pandoc/Readers/Org/Blocks.hs b/src/Text/Pandoc/Readers/Org/Blocks.hs
index fa2f7fac5..52e990584 100644
--- a/src/Text/Pandoc/Readers/Org/Blocks.hs
+++ b/src/Text/Pandoc/Readers/Org/Blocks.hs
@@ -33,7 +33,7 @@ module Text.Pandoc.Readers.Org.Blocks
   ) where
 
 import Text.Pandoc.Readers.Org.BlockStarts
-import Text.Pandoc.Readers.Org.DocumentTree (headline, headlineToBlocks)
+import Text.Pandoc.Readers.Org.DocumentTree (documentTree, headlineToBlocks)
 import Text.Pandoc.Readers.Org.Inlines
 import Text.Pandoc.Readers.Org.Meta (metaExport, metaKey, metaLine)
 import Text.Pandoc.Readers.Org.ParserState
@@ -62,11 +62,11 @@ import Data.Monoid ((<>))
 -- | Get a list of blocks.
 blockList :: PandocMonad m => OrgParser m [Block]
 blockList = do
-  initialBlocks  <- blocks
-  headlines      <- sequence <$> manyTill (headline blocks inline 1) eof
+  headlines      <- documentTree blocks inline
   st             <- getState
-  headlineBlocks <- fmap mconcat . mapM headlineToBlocks $ runF headlines st
-  return . B.toList $ (runF initialBlocks st) <> headlineBlocks
+  headlineBlocks <- headlineToBlocks $ runF headlines st
+  -- ignore first headline, it's the document's title
+  return . drop 1 . B.toList $ headlineBlocks
 
 -- | Get the meta information saved in the state.
 meta :: Monad m => OrgParser m Meta
diff --git a/src/Text/Pandoc/Readers/Org/DocumentTree.hs b/src/Text/Pandoc/Readers/Org/DocumentTree.hs
index 53ec2ef57..8c2a8482a 100644
--- a/src/Text/Pandoc/Readers/Org/DocumentTree.hs
+++ b/src/Text/Pandoc/Readers/Org/DocumentTree.hs
@@ -28,7 +28,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 Parsers for org-mode headlines and document subtrees
 -}
 module Text.Pandoc.Readers.Org.DocumentTree
-  ( headline
+  ( documentTree
   , headlineToBlocks
   ) where
 
@@ -43,11 +43,42 @@ import Text.Pandoc.Readers.Org.BlockStarts
 import Text.Pandoc.Readers.Org.Parsing
 import Text.Pandoc.Readers.Org.ParserState
 
+import qualified Data.Map as Map
 import qualified Text.Pandoc.Builder as B
 
 --
 -- Org headers
 --
+
+-- | Parse input as org document tree.
+documentTree :: PandocMonad m
+             => OrgParser m (F Blocks)
+             -> OrgParser m (F Inlines)
+             -> OrgParser m (F Headline)
+documentTree blocks inline = do
+  initialBlocks <- blocks
+  headlines <- sequence <$> manyTill (headline blocks inline 1) eof
+  title <- fmap (getTitle . unMeta) . orgStateMeta <$> getState
+  return $ do
+    headlines' <- headlines
+    initialBlocks' <- initialBlocks
+    title' <- title
+    return Headline
+      { headlineLevel = 0
+      , headlineTodoMarker = Nothing
+      , headlineText = B.fromList title'
+      , headlineTags = mempty
+      , headlineProperties = mempty
+      , headlineContents = initialBlocks'
+      , headlineChildren = headlines'
+      }
+ where
+  getTitle :: Map.Map String MetaValue -> [Inline]
+  getTitle metamap =
+    case Map.lookup "title" metamap of
+      Just (MetaInlines inlns) -> inlns
+      _ -> []
+
 newtype Tag = Tag { fromTag :: String }
   deriving (Show, Eq)