Lua filters: make attr argument optional in Table constructor

This changes the Lua API. It is highly unlikely for this change to
affect existing filters, since the documentation for the new Table
constructor (and type) was incomplete and partly wrong before.

The Lua API is now more consistent, as all constructors for elements
with attributes now take attributes as the last parameter.

data/pandoc.lua

@@ -556,18 +556,18 @@ M.RawBlock = M.Block:create_constructor(
 
 --- Creates a table element.
 -- @function Table
--- @tparam      Attr         attr       attributes
 -- @tparam      Caption      caption    table caption
 -- @tparam      {ColSpec,...} colspecs  column alignments and widths
 -- @tparam      TableHead    head       table head
 -- @tparam      {TableBody,..} bodies   table bodies
 -- @treturn     TableFoot    foot       table foot
+-- @tparam[opt] Attr         attr       attributes
 M.Table = M.Block:create_constructor(
   "Table",
-  function(attr, caption, colspecs, head, bodies, foot)
+  function(caption, colspecs, head, bodies, foot, attr)
     return {
       c = {
-        attr,
+        ensureAttr(attr),
         caption,
         List:new(colspecs),
         head,

doc/lua-filters.md

@@ -1104,6 +1104,9 @@ Values of this type can be created with the
 
 Fields:
 
+`attr`
+:   table attributes ([Attr])
+
 `caption`
 :   table caption ([Caption])
 
@@ -1120,8 +1123,14 @@ Fields:
 `foot`
 :   table foot ([TableFoot])
 
-`attr`
-:   element attributes ([Attr])
+`identifier`
+:   alias for `attr.identifier` (string)
+
+`classes`
+:   alias for `attr.classes` ([List] of strings)
+
+`attributes`
+:   alias for `attr.attributes` ([Attributes])
 
 `tag`, `t`
 :   the literal `Table` (string)
@@ -2144,15 +2153,12 @@ format, and functions to filter and modify a subtree.
 
     Returns: [RawBlock](#type-rawblock) object
 
-[`Table (attr, caption, colspecs, head, bodies, foot)`]{#pandoc.table}
+[`Table (caption, colspecs, head, bodies, foot[, attr])`]{#pandoc.table}
 
 :   Creates a table element.
 
     Parameters:
 
-    `attr`:
-    :   element attributes
-
     `caption`:
     :   table [caption](#type-caption)
 
@@ -2168,6 +2174,9 @@ format, and functions to filter and modify a subtree.
     `foot`:
     :   [table foot](#type-tablefoot)
 
+    `attr`:
+    :   element attributes
+
     Returns: [Table](#type-table) object
 
 ## Inline

src/Text/Pandoc/Lua/Marshaling/AST.hs

@@ -170,7 +170,7 @@ pushBlock = \case
   Plain blcks              -> pushViaConstructor "Plain" blcks
   RawBlock f cs            -> pushViaConstructor "RawBlock" f cs
   Table attr blkCapt specs thead tbody tfoot ->
-    pushViaConstructor "Table" attr blkCapt specs thead tbody tfoot
+    pushViaConstructor "Table" blkCapt specs thead tbody tfoot attr
 
 -- | Return the value at the given index as block if possible.
 peekBlock :: StackIndex -> Lua Block