Docx reader: Support new table features.

* Column spans
* Row spans
  - The spec says that if the `val` attribute is ommitted, its value
    should be assumed to be `continue`, and that its values are
    restricted to {`restart`, `continue`}. If the value has any other
    value, I think it seems reasonable to default it to `continue`. It
    might cause problems if the spec is extended in the future by adding
    a third possible value, in which case this would probably give
    incorrect behaviour, and wouldn't error.
* Allow multiple header rows
* Include table description in simple caption
  - The table description element is like alt text for a table (along
    with the table caption element). It seems like we should include
    this somewhere, but I’m not 100% sure how – I’m pairing it with the
    simple caption for the moment. (Should it maybe go in the block
    caption instead?)
* Detect table captions
  - Check for caption paragraph style /and/ either the simple or
    complex table field. This means the caption detection fails for
    captions which don’t contain a field, as in an example doc I added
    as a test. However, I think it’s better to be too conservative: a
    missed table caption will still show up as a paragraph next to the
    table, whereas if I incorrectly classify something else as a table
    caption it could cause havoc by pairing it up with a table it’s
    not at all related to, or dropping it entirely.
* Update tests and add new ones

Partially fixes: #6316

1 files changed, 7 insertions, 12 deletions

diff --git a/test/docx/table_variable_width.native b/test/docx/table_variable_width.native
index 43ac40cca..ff1cc0dc4 100644
--- a/test/docx/table_variable_width.native
+++ b/test/docx/table_variable_width.native
@@ -4,7 +4,8 @@
  ,(AlignDefault,ColWidth 1.9882415820416888e-2)
  ,(AlignDefault,ColWidth 0.22202030999465527)
  ,(AlignDefault,ColWidth 0.4761090326028862)
- ,(AlignDefault,ColWidth 1.0689470871191876e-4)]
+ ,(AlignDefault,ColWidth 1.0689470871191876e-4)
+ ,(AlignDefault,ColWidth 0.26178514163548905)]
  (TableHead ("",[],[])
  [Row ("",[],[])
   [Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
@@ -13,33 +14,27 @@
    []
   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
    [Plain [Str "h3"]]
-  ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+  ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 2)
    [Plain [Str "h4"]]
   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
    [Plain [Str "h5"]]]])
  [(TableBody ("",[],[]) (RowHeadColumns 0)
   []
   [Row ("",[],[])
-   [Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+   [Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 3)
     [Plain [Str "c11"]]
    ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
     []
-   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
-    []
-   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
-    []
-   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 2)
     []]
   ,Row ("",[],[])
    [Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
     []
-   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 2)
     [Plain [Str "c22"]]
    ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
     [Plain [Str "c23"]]
-   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
-    []
-   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 1)
+   ,Cell ("",[],[]) AlignDefault (RowSpan 1) (ColSpan 2)
     []]])]
  (TableFoot ("",[],[])
  [])]