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 new `pandoc.Inlines` function behaves identical on string input, but
allows other Inlines-like arguments as well.
The `pandoc.utils.text` function could be written as
function pandoc.utils.text (x)
assert(type(x) == 'string')
return pandoc.Inlines(x)
end
The function converts a string to `Inlines`, treating interword spaces
as `Space`s or `SoftBreak`s. If you want a `Str` with literal spaces,
use `pandoc.Str`.
Closes: #7709
The `lpeg` and `re` modules are loaded into globals of the respective
name, but they are not necessarily registered as loaded packages. This
ensures that
- the built-in library versions are preferred when setting the globals,
- a shared library is used if pandoc has been compiled without `lpeg`,
and
- the `require` mechanism can be used to load the shared library if
available, falling back to the internal version if possible and
necessary.
Reader options can now be passed as an optional third argument to
`pandoc.read`. The object can either be a table or a ReaderOptions value
like `PANDOC_READER_OPTIONS`. Creating new ReaderOptions objects is
possible through the new constructor `pandoc.ReaderOptions`.
Closes: #7656
A new type `SimpleTable` is made available to Lua filters. It is
similar to the `Table` type in pandoc versions before 2.10;
conversion functions from and to the new Table type are provided.
Old filters using tables now require minimal changes and can use,
e.g.,
if PANDOC_VERSION > {2,10,1} then
pandoc.Table = pandoc.SimpleTable
end
and
function Table (tbl)
tbl = pandoc.utils.to_simple_table(tbl)
…
return pandoc.utils.from_simple_table(tbl)
end
to work with the current pandoc version.
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.
Lists of Inline and Block elements can now be filtered via `Inlines` and
`Blocks` functions, respectively. This is helpful if a filter conversion
depends on the order of elements rather than a single element.
For example, the following filter can be used to remove all spaces
before a citation:
function isSpaceBeforeCite (spc, cite)
return spc and spc.t == 'Space'
and cite and cite.t == 'Cite'
end
function Inlines (inlines)
for i = #inlines-1,1,-1 do
if isSpaceBeforeCite(inlines[i], inlines[i+1]) then
inlines:remove(i)
end
end
return inlines
end
Closes: #6038
This follows the advise on the Lua
website (https://www.lua.org/about.html#name):
> […] "Lua" is a name, the name of the Earth's moon and the name of the
> language. Like most names, it should be written in lower case with an
> initial capital, that is, "Lua".
The functions `table.insert`, `table.remove`, and `table.sort` are added
to pandoc.List elements. They can be used as methods, e.g.
local numbers = pandoc.List {2, 3, 1}
numbers:sort() -- numbers is now {1, 2, 3}
Links and anchors now follow consistent conventions, like lowercase-only
anchor names.
This breaks some links to specific sections in the document, but will
make it much easier to link documentation in the future.
Metadata defaults can be given via the command line `--metadata-file`.
Adding raw format snippets is a common use case for Lua filters, so it
seems sensible to provide an example.
Thanks to @efx for proposing this filter.
Closes: pandoc/lua-filters#70
