Docx reader: Let headers use exisiting id.

Previously we always generated an id for headers (since they wouldn't
bring one from Docx). Now we let it use an existing one if
possible. This should allow us to recurs through anchor spans.

1 files changed, 10 insertions, 6 deletions

diff --git a/src/Text/Pandoc/Readers/Docx.hs b/src/Text/Pandoc/Readers/Docx.hs
index f74b2b6d6..83b34ad00 100644
--- a/src/Text/Pandoc/Readers/Docx.hs
+++ b/src/Text/Pandoc/Readers/Docx.hs
@@ -431,21 +431,25 @@ makeHeaderAnchor bs = case viewl $ unMany bs of
 makeHeaderAnchor' :: Block -> DocxContext Block
 -- If there is an anchor already there (an anchor span in the header,
 -- to be exact), we rename and associate the new id with the old one.
-makeHeaderAnchor' (Header n (_, classes, kvs) ils)
+makeHeaderAnchor' (Header n (ident, classes, kvs) ils)
   | (c:_) <- filter isAnchorSpan ils
-  , (Span (ident, ["anchor"], _) cIls) <- c = do
+  , (Span (anchIdent, ["anchor"], _) cIls) <- c = do
     hdrIDMap <- gets docxAnchorMap
-    let newIdent = uniqueIdent ils (Set.fromList $ M.elems hdrIDMap)
+    let newIdent = if null ident
+                   then uniqueIdent ils (Set.fromList $ M.elems hdrIDMap)
+                   else ident
         newIls = concatMap f ils where f il | il == c   = cIls
                                             | otherwise = [il]
-    modify $ \s -> s {docxAnchorMap = M.insert ident newIdent hdrIDMap}
+    modify $ \s -> s {docxAnchorMap = M.insert anchIdent newIdent hdrIDMap}
     return $ Header n (newIdent, classes, kvs) newIls
 -- Otherwise we just give it a name, and register that name (associate
 -- it with itself.)
-makeHeaderAnchor' (Header n (_, classes, kvs) ils) =
+makeHeaderAnchor' (Header n (ident, classes, kvs) ils) =
   do
     hdrIDMap <- gets docxAnchorMap
-    let newIdent = uniqueIdent ils (Set.fromList $ M.elems hdrIDMap)
+    let newIdent = if null ident
+                   then uniqueIdent ils (Set.fromList $ M.elems hdrIDMap)
+                   else ident
     modify $ \s -> s {docxAnchorMap = M.insert newIdent newIdent hdrIDMap}
     return $ Header n (newIdent, classes, kvs) ils
 makeHeaderAnchor' blk = return blk