Lua 5.4 is used by default after this is merged. Packagers may still include Lua 5.3
instead by building pandoc with `--constraint='hslua <2.2'`.
Differences between 5.3 and 5.4 should not generally affect pandoc Lua filters.
See list of incompatible changes here <https://www.lua.org/manual/5.4/manual.html#8.1>
- Allow any type of callable object as argument to List
functions `filter`, `map`, and `find_if`. These previously
required the argument to be of type `function`, which was too
restrictive.
- Inline: the type of Image captions is now `Inlines` instead
of `List`.
The objects now also follow the principle that element attributes are
accessible through the `.attr` field. Rows in `TableHead` and
`TableFoot` are available via the `.rows` field. Row objects have a
`.cells` field, containing the list of table cells.
Closes: #7718
The traversal order of filters can now be selected by setting the key
`traverse` of the filter to either `'topdown'` or `'typewise'`; the
default remains `'typewise'`.
Topdown traversals can be cut short by returning `false` as a second
value from the filter function. No child-element of the returned element
is processed in that case.
- `walk` methods are added to `Block` and `Inline` values; the methods
are similar to `pandoc.utils.walk_block` and
`pandoc.utils.walk_inline`, but apply to filter also to the element
itself, and therefore return a list of element instead of a single
element.
- Functions of name `Doc` are no longer accepted as alternatives for
`Pandoc` filter functions. This functionality was undocumented.
The marshaling functions for pandoc's AST are extracted into a separate
package. The package comes with a number of changes:
- Pandoc's List module was rewritten in C, thereby improving error
messages.
- Lists of `Block` and `Inline` elements are marshaled using the new
list types `Blocks` and `Inlines`, respectively. These types
currently behave identical to the generic List type, but give better
error messages. This also opens up the possibility of adding
element-specific methods to these lists in the future.
- Elements of type `MetaValue` are no longer pushed as values which
have `.t` and `.tag` properties. This was already true for
`MetaString` and `MetaBool` values, which are still marshaled as Lua
strings and booleans, respectively. Affected values:
+ `MetaBlocks` values are marshaled as a `Blocks` list;
+ `MetaInlines` values are marshaled as a `Inlines` list;
+ `MetaList` values are marshaled as a generic pandoc `List`s.
+ `MetaMap` values are marshaled as plain tables and no longer
given any metatable.
- The test suite for marshaled objects and their constructors has
been extended and improved.
- A bug in Citation objects, where setting a citation's suffix
modified it's prefix, has been fixed.
