The function `global_filter` was used internally to get the implicitly
defined global filter. It was of little value to end-users, but caused
unnecessary code duplication in pandoc. The function has hence been
dropped. Internally, the global filter is now received by interpreting
the global table as lua filter.
This is a Lua API change.
The `pipe` and `read` utility functions are converted from hybrid
lua/haskell functions into full Haskell functions. This avoids the need
for intermediate `_pipe`/`_read` helper functions, which have dropped.
The integration with Lua's package/module system is improved: A
pandoc-specific package searcher is prepended to the searchers in
`package.searchers`. The modules `pandoc` and `pandoc.mediabag` can now
be loaded via `require`.
The `List` metatable is assigned to the tables which get passed to the
constructors `MetaBlocks`, `MetaInline`, and `MetaList`. This enables
the use of the resulting objects as lists. This is part of the changes
discussed in #4081.
Pandoc and Meta elements are now pushed by calling the respective
constructor functions of the pandoc Lua module. This makes serialization
consistent with the way blocks and inlines are pushed to lua and allows
to use List methods with the `blocks` value.
The List module is automatically loaded, but not assigned to a global
variable. It can be included in filters by calling `List = require
'List'`.
Lists of blocks, lists of inlines, and lists of classes are now given
`List` as a metatable, making working with them more convenient. E.g.,
it is now possible to concatenate lists of inlines using Lua's
concatenation operator `..` (requires at least one of the operants to
have `List` as a metatable):
function Emph (emph)
local s = {pandoc.Space(), pandoc.Str 'emphasized'}
return pandoc.Span(emph.content .. s)
end
Closes: #4081
Attribute lists are represented as associative lists in Lua. Pure
associative lists are awkward to work with. A metatable is attached to
attribute lists, allowing to access and use the associative list as if
the attributes were stored in as normal key-value pair in table.
Note that this changes the way `pairs` works on attribute lists. Instead
of producing integer keys and two-element tables, the resulting iterator
function now returns the key and value of those pairs. Use `ipairs` to
get the old behavior.
Warning: the new iteration mechanism only works if pandoc has been
compiled with Lua 5.2 or later (current default: 5.3).
The `pandoc.Attr` function is altered to allow passing attributes as
key-values in a normal table. This is more convenient than having to
construct the associative list which is used internally.
Closes#4071
The second argument of the OrderedList constructor, which should define
the list's attributes, is made optional. Default attributes are used if
the parameter is omitted.
Make Attr values accessible through through the keys `identifier`,
`classes` and `attributes`. This is already used in other elements with
attributes and is now fixed for Link and Image.
The pipe command is wrapped in a lua function, throwing a lua error if
the command returns with an error. A wrapper is needed as Haskell
functions exposed to lua may not throw lua errors due to limitations of
hslua.
The error handling is written such that a table can be returned as an
error object in the future. This is potentially useful when finer
control is required while catching the error in lua code. Current
limitations of hslua require error objects to be strings.
Functions with a name that corresponds to an AST element are included in
implicit pandoc filter, but both `Meta` and `Pandoc` were wrongly
ignored till now.
The Attr argument is made optional for all pandoc element constructors
which take such a parameter. The attr param is always the last argument
of the constructor functions, so the option to omit them makes it easier
to construct new pandoc elements by hand.
The implicitly defined global filter (i.e. all element filtering
functions defined in the global lua environment) is used if no filter is
returned from a lua script. This allows to just write top-level
functions in order to define a lua filter. E.g
function Emph(elem) return pandoc.Strong(elem.content) end
Attributes was written to behave much like a normal table, in order to
simplify working with it. However, all Attr containing elements were
changed to provide panflute-like accessors to Attr components, rendering
the previous approach unnecessary.
A single `read` function parsing pandoc-supported formats is added to
the module. This is simpler and more convenient than the previous method
of exposing all reader functions individually.
Meta elements that are treated as lua tables (i.e. MetaList,
MetaInlines, MetaBlocks, and MetaMap), are no longer wrapped in an
additional table but simply marked via a metatable. This allows
treating those meta values just like normal tables, while still making
empty elements of those values distinguishable.
Element attributes are pushed to the stack via the `Attributes`
function. `Attributes` creates an Attr like triple, but the triple also
allows table-like access to key-value pairs.
Provide functions `pandoc.SingleQuoted`, `pandoc.DoubleQuoted`,
`pandoc.DisplayMath`, and `pandoc.InlineMath` to allow simple building
of Math and Quoted elements.
Lua string are used to represent nullary data constructors. The previous
table-based representation was based on the JSON serialization, but can
be simplified. This also matches the way those arguments are passed to
custom writers.
Instead of taking only a single argument containing the pre-packed
element contents, `Inline` constructors now take the same arguments as
the respective filter and `Custom` writer function
* Add `--lua-filter` option. This works like `--filter` but takes pathnames of special lua filters and uses the lua interpreter baked into pandoc, so that no external interpreter is needed. Note that lua filters are all applied after regular filters, regardless of their position on the command line.
* Add Text.Pandoc.Lua, exporting `runLuaFilter`. Add `pandoc.lua` to data files.
* Add private module Text.Pandoc.Lua.PandocModule to supply the default lua module.
* Add Tests.Lua to tests.
* Add data/pandoc.lua, the lua module pandoc imports when processing its lua filters.
* Document in MANUAL.txt.
