Use the new builders, modify readers to preserve empty headers

The Builder.simpleTable now only adds a row to the TableHead when the
given header row is not null. This uncovered an inconsistency in the
readers: some would unconditionally emit a header filled with empty
cells, even if the header was not present. Now every reader has the
conditional behaviour. Only the XWiki writer depended on the header
row being always present; it now pads its head as necessary.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/Text/Pandoc/Readers/HTML.hs b/src/Text/Pandoc/Readers/HTML.hs
index 30b812913..a48836446 100644
--- a/src/Text/Pandoc/Readers/HTML.hs
+++ b/src/Text/Pandoc/Readers/HTML.hs
@@ -516,7 +516,13 @@ pTable = try $ do
                        then replicate cols ColWidthDefault
                        else replicate cols (ColWidth (1.0 / fromIntegral cols))
                   else widths'
-  return $ B.table caption (zip aligns widths) head' rows
+  let toRow = Row nullAttr . map B.simpleCell
+      toHeaderRow l = if null l then [] else [toRow l]
+  return $ B.table (B.simpleCaption $ B.plain caption)
+                   (zip aligns widths)
+                   (TableHead nullAttr $ toHeaderRow head')
+                   [TableBody nullAttr 0 [] $ map toRow rows]
+                   (TableFoot nullAttr [])
 
 pCol :: PandocMonad m => TagParser m ColWidth
 pCol = try $ do