HTML writer: don't include alignment attribute for default table columns.

Previously these were given "left" alignment.  Better to leave off
alignment attributes altogether.

Closes #2694.

2 files changed, 19 insertions, 16 deletions

diff --git a/src/Text/Pandoc/Writers/HTML.hs b/src/Text/Pandoc/Writers/HTML.hs
index 6e199583e..c5b6a6db2 100644
--- a/src/Text/Pandoc/Writers/HTML.hs
+++ b/src/Text/Pandoc/Writers/HTML.hs
@@ -645,7 +645,7 @@ alignmentToString alignment = case alignment of
                                  AlignLeft    -> "left"
                                  AlignRight   -> "right"
                                  AlignCenter  -> "center"
-                                 AlignDefault -> "left"
+                                 AlignDefault -> ""
 
 tableItemToHtml :: WriterOptions
                 -> (Html -> Html)
@@ -658,7 +658,10 @@ tableItemToHtml opts tag' align' item = do
   let attribs = if writerHtml5 opts
                    then A.style (toValue $ "text-align: " ++ alignStr ++ ";")
                    else A.align (toValue alignStr)
-  return $ (tag' ! attribs $ contents) >> nl opts
+  let tag'' = if null alignStr
+                 then tag'
+                 else tag' ! attribs
+  return $ (tag'' $ contents) >> nl opts
 
 toListItems :: WriterOptions -> [Html] -> [Html]
 toListItems opts items = map (toListItem opts) items ++ [nl opts]
diff --git a/tests/tables.html b/tests/tables.html
index f5ddf3bcd..0a9ea413c 100644
--- a/tests/tables.html
+++ b/tests/tables.html
@@ -6,7 +6,7 @@
 <th align="right">Right</th>
 <th align="left">Left</th>
 <th align="center">Center</th>
-<th align="left">Default</th>
+<th>Default</th>
 </tr>
 </thead>
 <tbody>
@@ -14,19 +14,19 @@
 <td align="right">12</td>
 <td align="left">12</td>
 <td align="center">12</td>
-<td align="left">12</td>
+<td>12</td>
 </tr>
 <tr class="even">
 <td align="right">123</td>
 <td align="left">123</td>
 <td align="center">123</td>
-<td align="left">123</td>
+<td>123</td>
 </tr>
 <tr class="odd">
 <td align="right">1</td>
 <td align="left">1</td>
 <td align="center">1</td>
-<td align="left">1</td>
+<td>1</td>
 </tr>
 </tbody>
 </table>
@@ -37,7 +37,7 @@
 <th align="right">Right</th>
 <th align="left">Left</th>
 <th align="center">Center</th>
-<th align="left">Default</th>
+<th>Default</th>
 </tr>
 </thead>
 <tbody>
@@ -45,19 +45,19 @@
 <td align="right">12</td>
 <td align="left">12</td>
 <td align="center">12</td>
-<td align="left">12</td>
+<td>12</td>
 </tr>
 <tr class="even">
 <td align="right">123</td>
 <td align="left">123</td>
 <td align="center">123</td>
-<td align="left">123</td>
+<td>123</td>
 </tr>
 <tr class="odd">
 <td align="right">1</td>
 <td align="left">1</td>
 <td align="center">1</td>
-<td align="left">1</td>
+<td>1</td>
 </tr>
 </tbody>
 </table>
@@ -69,7 +69,7 @@
 <th align="right">Right</th>
 <th align="left">Left</th>
 <th align="center">Center</th>
-<th align="left">Default</th>
+<th>Default</th>
 </tr>
 </thead>
 <tbody>
@@ -77,19 +77,19 @@
 <td align="right">12</td>
 <td align="left">12</td>
 <td align="center">12</td>
-<td align="left">12</td>
+<td>12</td>
 </tr>
 <tr class="even">
 <td align="right">123</td>
 <td align="left">123</td>
 <td align="center">123</td>
-<td align="left">123</td>
+<td>123</td>
 </tr>
 <tr class="odd">
 <td align="right">1</td>
 <td align="left">1</td>
 <td align="center">1</td>
-<td align="left">1</td>
+<td>1</td>
 </tr>
 </tbody>
 </table>
@@ -192,13 +192,13 @@
 <td align="center">First</td>
 <td align="left">row</td>
 <td align="right">12.0</td>
-<td align="left">Example of a row that spans multiple lines.</td>
+<td>Example of a row that spans multiple lines.</td>
 </tr>
 <tr class="even">
 <td align="center">Second</td>
 <td align="left">row</td>
 <td align="right">5.0</td>
-<td align="left">Here's another one. Note the blank line between rows.</td>
+<td>Here's another one. Note the blank line between rows.</td>
 </tr>
 </tbody>
 </table>