lua-filters.md

author	date	title
Albert Krewinkel John MacFarlane	January 10, 2020	Pandoc Lua Filters

Introduction

Pandoc has long supported filters, which allow the pandoc abstract syntax tree (AST) to be manipulated between the parsing and the writing phase. Traditional pandoc filters accept a JSON representation of the pandoc AST and produce an altered JSON representation of the AST. They may be written in any programming language, and invoked from pandoc using the --filter option.

Although traditional filters are very flexible, they have a couple of disadvantages. First, there is some overhead in writing JSON to stdout and reading it from stdin (twice, once on each side of the filter). Second, whether a filter will work will depend on details of the user's environment. A filter may require an interpreter for a certain programming language to be available, as well as a library for manipulating the pandoc AST in JSON form. One cannot simply provide a filter that can be used by anyone who has a certain version of the pandoc executable.

Starting with version 2.0, pandoc makes it possible to write filters in Lua without any external dependencies at all. A Lua interpreter (version 5.4) and a Lua library for creating pandoc filters is built into the pandoc executable. Pandoc data types are marshaled to Lua directly, avoiding the overhead of writing JSON to stdout and reading it from stdin.

Here is an example of a Lua filter that converts strong emphasis to small caps:

return {
  Strong = function (elem)
    return pandoc.SmallCaps(elem.content)
  end,
}

or equivalently,

function Strong(elem)
  return pandoc.SmallCaps(elem.content)
end

This says: walk the AST, and when you find a Strong element, replace it with a SmallCaps element with the same content.

To run it, save it in a file, say smallcaps.lua, and invoke pandoc with --lua-filter=smallcaps.lua.

Here's a quick performance comparison, converting the pandoc manual (MANUAL.txt) to HTML, with versions of the same JSON filter written in compiled Haskell (smallcaps) and interpreted Python (smallcaps.py):

Command Time

---

pandoc 1.01s pandoc --filter ./smallcaps 1.36s pandoc --filter ./smallcaps.py 1.40s pandoc --lua-filter ./smallcaps.lua 1.03s

As you can see, the Lua filter avoids the substantial overhead associated with marshaling to and from JSON over a pipe.

Lua filter structure

Lua filters are tables with element names as keys and values consisting of functions acting on those elements.

Filters are expected to be put into separate files and are passed via the --lua-filter command-line argument. For example, if a filter is defined in a file current-date.lua, then it would be applied like this:

pandoc --lua-filter=current-date.lua -f markdown MANUAL.txt

The --lua-filter option may be supplied multiple times. Pandoc applies all filters (including JSON filters specified via --filter and Lua filters specified via --lua-filter) in the order they appear on the command line.

Pandoc expects each Lua file to return a list of filters. The filters in that list are called sequentially, each on the result of the previous filter. If there is no value returned by the filter script, then pandoc will try to generate a single filter by collecting all top-level functions whose names correspond to those of pandoc elements (e.g., Str, Para, Meta, or Pandoc). (That is why the two examples above are equivalent.)

For each filter, the document is traversed and each element subjected to the filter. Elements for which the filter contains an entry (i.e. a function of the same name) are passed to Lua element filtering function. In other words, filter entries will be called for each corresponding element in the document, getting the respective element as input.

The return value of a filter function must be one of the following:

• nil: this means that the object should remain unchanged.
• a pandoc object: this must be of the same type as the input and will replace the original object.
• a list of pandoc objects: these will replace the original object; the list is merged with the neighbors of the original objects (spliced into the list the original object belongs to); returning an empty list deletes the object.

The function's output must result in an element of the same type as the input. This means a filter function acting on an inline element must return either nil, an inline, or a list of inlines, and a function filtering a block element must return one of nil, a block, or a list of block elements. Pandoc will throw an error if this condition is violated.

If there is no function matching the element's node type, then the filtering system will look for a more general fallback function. Two fallback functions are supported, Inline and Block. Each matches elements of the respective type.

Elements without matching functions are left untouched.

See module documentation for a list of pandoc elements.

Filters on element sequences

For some filtering tasks, it is necessary to know the order in which elements occur in the document. It is not enough then to inspect a single element at a time.

There are two special function names, which can be used to define filters on lists of blocks or lists of inlines.

[Inlines (inlines)]{#inlines-filter} : If present in a filter, this function will be called on all lists of inline elements, like the content of a Para (paragraph) block, or the description of an Image. The inlines argument passed to the function will be a List of Inline elements for each call.

[Blocks (blocks)]{#blocks-filter} : If present in a filter, this function will be called on all lists of block elements, like the content of a MetaBlocks meta element block, on each item of a list, and the main content of the Pandoc document. The blocks argument passed to the function will be a List of Block elements for each call.

These filter functions are special in that the result must either be nil, in which case the list is left unchanged, or must be a list of the correct type, i.e., the same type as the input argument. Single elements are not allowed as return values, as a single element in this context usually hints at a bug.

See "Remove spaces before normal citations" for an example.

This functionality has been added in pandoc 2.9.2.

Traversal order

The traversal order of filters can be selected by setting the key traverse to either 'topdown' or 'typewise'; the default is 'typewise'.

Example:

local filter = {
  traverse = 'topdown',
  -- ... filter functions ...
}
return filter

Support for this was added in pandoc 2.17; previous versions ignore the traverse setting.

Typewise traversal

Element filter functions within a filter set are called in a fixed order, skipping any which are not present:

1. functions for Inline elements,
2. the Inlines filter function,
3. functions for Block elements ,
4. the Blocks filter function,
5. the Meta filter function, and last
6. the Pandoc filter function.

It is still possible to force a different order by explicitly returning multiple filter sets. For example, if the filter for Meta is to be run before that for Str, one can write

-- ... filter definitions ...

return {
  { Meta = Meta },  -- (1)
  { Str = Str }     -- (2)
}

Filter sets are applied in the order in which they are returned. All functions in set (1) are thus run before those in (2), causing the filter function for Meta to be run before the filtering of Str elements is started.

Topdown traversal

It is sometimes more natural to traverse the document tree depth-first from the root towards the leaves, and all in a single run.

For example, a block list [Plain [Str "a"], Para [Str "b"]]{.haskell} will try the following filter functions, in order: Blocks, Plain, Inlines, Str, Para, Inlines, Str.

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.

For example, to exclude the contents of a footnote from being processed, one might write

traverse = 'topdown'
function Note (n)
  return n, false
end

Global variables

Pandoc passes additional data to Lua filters by setting global variables.

FORMAT : The global FORMAT is set to the format of the pandoc writer being used (html5, latex, etc.), so the behavior of a filter can be made conditional on the eventual output format.

PANDOC_READER_OPTIONS : Table of the options which were provided to the parser. (ReaderOptions)

PANDOC_WRITER_OPTIONS : Table of the options that will be passed to the writer. While the object can be modified, the changes will not be picked up by pandoc. (WriterOptions)

Accessing this variable in **custom writers** is
**deprecated**. Starting with pandoc 3.0, it is set to a
placeholder value (the default options) in custom writers.
Access to the actual writer options is provided via the
`Writer` or `ByteStringWriter` function, to which the options
are passed as the second function argument.

*Since: pandoc 2.17*

PANDOC_VERSION : Contains the pandoc version as a Version object which behaves like a numerically indexed table, most significant number first. E.g., for pandoc 2.7.3, the value of the variable is equivalent to a table {2, 7, 3}. Use tostring(PANDOC_VERSION) to produce a version string. This variable is also set in custom writers.

PANDOC_API_VERSION : Contains the version of the pandoc-types API against which pandoc was compiled. It is given as a numerically indexed table, most significant number first. E.g., if pandoc was compiled against pandoc-types 1.17.3, then the value of the variable will behave like the table {1, 17, 3}. Use tostring(PANDOC_API_VERSION) to produce a version string. This variable is also set in custom writers.

PANDOC_SCRIPT_FILE : The name used to involve the filter. This value can be used to find files relative to the script file. This variable is also set in custom writers.

PANDOC_STATE : The state shared by all readers and writers. It is used by pandoc to collect and pass information. The value of this variable is of type CommonState and is read-only.

pandoc : The pandoc module, described in the next section, is available through the global pandoc. The other modules described herein are loaded as subfields under their respective name.

lpeg : This variable holds the lpeg module, a package based on Parsing Expression Grammars (PEG). It provides excellent parsing utilities and is documented on the official LPeg homepage. Pandoc uses a built-in version of the library, unless it has been configured by the package maintainer to rely on a system-wide installation.

Note that the result of `require 'lpeg'` is not necessarily
equal to this value; the `require` mechanism prefers the
system's lpeg library over the built-in version.

re : Contains the LPeg.re module, which is built on top of LPeg and offers an implementation of a regex engine. Pandoc uses a built-in version of the library, unless it has been configured by the package maintainer to rely on a system-wide installation.

Note that the result of `require 're` is not necessarily
equal to this value; the `require` mechanism prefers the
system's lpeg library over the built-in version.

Pandoc Module

The pandoc Lua module is loaded into the filter's Lua environment and provides a set of functions and constants to make creation and manipulation of elements easier. The global variable pandoc is bound to the module and should generally not be overwritten for this reason.

Two major functionalities are provided by the module: element creator functions and access to some of pandoc's main functionalities.

Element creation

Element creator functions like Str, Para, and Pandoc are designed to allow easy creation of new elements that are simple to use and can be read back from the Lua environment. Internally, pandoc uses these functions to create the Lua objects which are passed to element filter functions. This means that elements created via this module will behave exactly as those elements accessible through the filter function parameter.

Exposed pandoc functionality

Some pandoc functions have been made available in Lua:

• walk_block and walk_inline allow filters to be applied inside specific block or inline elements;
• read allows filters to parse strings into pandoc documents;
• pipe runs an external command with input from and output to strings;
• the pandoc.mediabag module allows access to the "mediabag," which stores binary content such as images that may be included in the final document;
• the pandoc.utils module contains various utility functions.

Lua interpreter initialization

Initialization of pandoc's Lua interpreter can be controlled by placing a file init.lua in pandoc's data directory. A common use-case would be to load additional modules, or even to alter default modules.

The following snippet is an example of code that might be useful when added to init.lua. The snippet adds all Unicode-aware functions defined in the text module to the default string module, prefixed with the string uc_.

for name, fn in pairs(require 'text') do
  string['uc_' .. name] = fn
end

This makes it possible to apply these functions on strings using colon syntax (mystring:uc_upper()).

Debugging Lua filters

Many errors can be avoided by performing static analysis. luacheck may be used for this purpose. A Luacheck configuration file for pandoc filters is available at https://github.com/rnwst/pandoc-luacheckrc.

William Lupton has written a Lua module with some handy functions for debugging Lua filters, including functions that can pretty-print the Pandoc AST elements manipulated by the filters: it is available at https://github.com/wlupton/pandoc-lua-logging.

It is possible to use a debugging interface to halt execution and step through a Lua filter line by line as it is run inside Pandoc. This is accomplished using the remote-debugging interface of the package mobdebug. Although mobdebug can be run from the terminal, it is more useful run within the donation-ware Lua editor and IDE, ZeroBrane Studio. ZeroBrane offers a REPL console and UI to step-through and view all variables and state.

ZeroBrane doesn't come with Lua 5.4 bundled, but it can debug it, so you should install Lua 5.4, and then add mobdebug and its dependency luasocket using luarocks. ZeroBrane can use your Lua 5.4 install by adding path.lua = "/path/to/your/lua" in your ZeroBrane settings file. Next, open your Lua filter in ZeroBrane, and add require('mobdebug').start() at the line where you want your breakpoint. Then make sure the Project > Lua Interpreter is set to the "Lua" you added in settings and enable "Start Debugger Server" see detailed instructions here. Run Pandoc as you normally would, and ZeroBrane should break at the correct line.

Common pitfalls

AST elements not updated : A filtered element will only be updated if the filter function returns a new element to replace it. A function like the below has no effect, as the function returns no value:

``` lua
function Str (str)
  str.text = string.upper(str.text)
end
```

The correct version would be

``` lua
function Str (str)
  str.text = string.upper(str.text)
  return str
end
```

Pattern behavior is locale dependent : The character classes in Lua's pattern library depend on the current locale: E.g., the character © will be treated as punctuation, and matched by the pattern %p, on CP-1252 locales, but not on systems using a UTF-8 locale.

A reliable way to ensure unified handling of patterns and
character classes is to use the "C" locale by adding
`os.setlocale 'C'` to the top of the Lua script.

String library is not Unicode aware : Lua's string library treats each byte as a single character. A function like string.upper will not have the intended effect when applied to words with non-ASCII characters. Similarly, a pattern like [☃] will match any of the bytes \240, \159, \154, and \178, but won't match the "snowman" Unicode character.

Use the [pandoc.text](#module-text) module for Unicode-aware
transformation, and consider using using the lpeg or re
library for pattern matching.

Examples

The following filters are presented as examples. A repository of useful Lua filters (which may also serve as good examples) is available at https://github.com/pandoc/lua-filters.

Macro substitution

The following filter converts the string {{helloworld}} into emphasized text "Hello, World".

return {
  {
    Str = function (elem)
      if elem.text == "{{helloworld}}" then
        return pandoc.Emph {pandoc.Str "Hello, World"}
      else
        return elem
      end
    end,
  }
}

Center images in LaTeX and HTML output

For LaTeX, wrap an image in LaTeX snippets which cause the image to be centered horizontally. In HTML, the image element's style attribute is used to achieve centering.

-- Filter images with this function if the target format is LaTeX.
if FORMAT:match 'latex' then
  function Image (elem)
    -- Surround all images with image-centering raw LaTeX.
    return {
      pandoc.RawInline('latex', '\\hfill\\break{\\centering'),
      elem,
      pandoc.RawInline('latex', '\\par}')
    }
  end
end

-- Filter images with this function if the target format is HTML
if FORMAT:match 'html' then
  function Image (elem)
    -- Use CSS style to center image
    elem.attributes.style = 'margin:auto; display: block;'
    return elem
  end
end

Setting the date in the metadata

This filter sets the date in the document's metadata to the current date, if a date isn't already set:

function Meta(m)
  if m.date == nil then
    m.date = os.date("%B %e, %Y")
    return m
  end
end

Remove spaces before citations

This filter removes all spaces preceding an "author-in-text" citation. In Markdown, author-in-text citations (e.g., @citekey), must be preceded by a space. If these spaces are undesired, they must be removed with a filter.

local function is_space_before_author_in_text(spc, cite)
  return spc and spc.t == 'Space'
    and cite and cite.t == 'Cite'
    -- there must be only a single citation, and it must have
    -- mode 'AuthorInText'
    and #cite.citations == 1
    and cite.citations[1].mode == 'AuthorInText'
end

function Inlines (inlines)
  -- Go from end to start to avoid problems with shifting indices.
  for i = #inlines-1, 1, -1 do
    if is_space_before_author_in_text(inlines[i], inlines[i+1]) then
      inlines:remove(i)
    end
  end
  return inlines
end

Replacing placeholders with their metadata value

Lua filter functions are run in the order

Inlines → Blocks → Meta → Pandoc.

Passing information from a higher level (e.g., metadata) to a lower level (e.g., inlines) is still possible by using two filters living in the same file:

local vars = {}

function get_vars (meta)
  for k, v in pairs(meta) do
    if pandoc.utils.type(v) == 'Inlines' then
      vars["%" .. k .. "%"] = {table.unpack(v)}
    end
  end
end

function replace (el)
  if vars[el.text] then
    return pandoc.Span(vars[el.text])
  else
    return el
  end
end

return {{Meta = get_vars}, {Str = replace}}

If the contents of file occupations.md is

---
name: Samuel Q. Smith
occupation: Professor of Oenology
---

Name

:   %name%

Occupation

:   %occupation%

then running pandoc --lua-filter=meta-vars.lua occupations.md will output:

<dl>
<dt>Name</dt>
<dd><p><span>Samuel Q. Smith</span></p>
</dd>
<dt>Occupation</dt>
<dd><p><span>Professor of Oenology</span></p>
</dd>
</dl>

Modifying pandoc's MANUAL.txt for man pages

This is the filter we use when converting MANUAL.txt to man pages. It converts level-1 headers to uppercase (using walk to transform inline elements inside headers), removes footnotes, and replaces links with regular text.

-- we use pandoc.text to get a UTF-8 aware 'upper' function
local text = pandoc.text

function Header(el)
    if el.level == 1 then
      return el:walk {
        Str = function(el)
            return pandoc.Str(text.upper(el.text))
        end
      }
    end
end

function Link(el)
    return el.content
end

function Note(el)
    return {}
end

Creating a handout from a paper

This filter extracts all the numbered examples, section headers, block quotes, and figures from a document, in addition to any divs with class handout. (Note that only blocks at the "outer level" are included; this ignores blocks inside nested constructs, like list items.)

-- creates a handout from an article, using its headings,
-- blockquotes, numbered examples, figures, and any
-- Divs with class "handout"

function Pandoc(doc)
    local hblocks = {}
    for i,el in pairs(doc.blocks) do
        if (el.t == "Div" and el.classes[1] == "handout") or
           (el.t == "BlockQuote") or
           (el.t == "OrderedList" and el.style == "Example") or
           (el.t == "Para" and #el.c == 1 and el.c[1].t == "Image") or
           (el.t == "Header") then
           table.insert(hblocks, el)
        end
    end
    return pandoc.Pandoc(hblocks, doc.meta)
end

Counting words in a document

This filter counts the words in the body of a document (omitting metadata like titles and abstracts), including words in code. It should be more accurate than wc -w run directly on a Markdown document, since the latter will count markup characters, like the # in front of an ATX header, or tags in HTML documents, as words. To run it, pandoc --lua-filter wordcount.lua myfile.md.

-- counts words in a document

words = 0

wordcount = {
  Str = function(el)
    -- we don't count a word if it's entirely punctuation:
    if el.text:match("%P") then
        words = words + 1
    end
  end,

  Code = function(el)
    _,n = el.text:gsub("%S+","")
    words = words + n
  end,

  CodeBlock = function(el)
    _,n = el.text:gsub("%S+","")
    words = words + n
  end
}

function Pandoc(el)
    -- skip metadata, just count body:
    el.blocks:walk(wordcount)
    print(words .. " words in body")
    os.exit(0)
end

Converting ABC code to music notation

This filter replaces code blocks with class abc with images created by running their contents through abcm2ps and ImageMagick's convert. (For more on ABC notation, see https://abcnotation.com.)

Images are added to the mediabag. For output to binary formats, pandoc will use images in the mediabag. For textual formats, use --extract-media to specify a directory where the files in the mediabag will be written, or (for HTML only) use --embed-resources.

-- Pandoc filter to process code blocks with class "abc" containing
-- ABC notation into images.
--
-- * Assumes that abcm2ps and ImageMagick's convert are in the path.
-- * For textual output formats, use --extract-media=abc-images
-- * For HTML formats, you may alternatively use --embed-resources

local filetypes = { html = {"png", "image/png"}
                  , latex = {"pdf", "application/pdf"}
                  }
local filetype = filetypes[FORMAT][1] or "png"
local mimetype = filetypes[FORMAT][2] or "image/png"

local function abc2eps(abc, filetype)
    local eps = pandoc.pipe("abcm2ps", {"-q", "-O", "-", "-"}, abc)
    local final = pandoc.pipe("convert", {"-", filetype .. ":-"}, eps)
    return final
end

function CodeBlock(block)
    if block.classes[1] == "abc" then
        local img = abc2eps(block.text, filetype)
        local fname = pandoc.sha1(img) .. "." .. filetype
        pandoc.mediabag.insert(fname, mimetype, img)
        return pandoc.Para{ pandoc.Image({pandoc.Str("abc tune")}, fname) }
    end
end

Building images with TikZ

This filter converts raw LaTeX TikZ environments into images. It works with both PDF and HTML output. The TikZ code is compiled to an image using pdflatex, and the image is converted from pdf to svg format using pdf2svg, so both of these must be in the system path. Converted images are cached in the working directory and given filenames based on a hash of the source, so that they need not be regenerated each time the document is built. (A more sophisticated version of this might put these in a special cache directory.)

local system = require 'pandoc.system'

local tikz_doc_template = [[
\documentclass{standalone}
\usepackage{xcolor}
\usepackage{tikz}
\begin{document}
\nopagecolor
%s
\end{document}
]]

local function tikz2image(src, filetype, outfile)
  system.with_temporary_directory('tikz2image', function (tmpdir)
    system.with_working_directory(tmpdir, function()
      local f = io.open('tikz.tex', 'w')
      f:write(tikz_doc_template:format(src))
      f:close()
      os.execute('pdflatex tikz.tex')
      if filetype == 'pdf' then
        os.rename('tikz.pdf', outfile)
      else
        os.execute('pdf2svg tikz.pdf ' .. outfile)
      end
    end)
  end)
end

extension_for = {
  html = 'svg',
  html4 = 'svg',
  html5 = 'svg',
  latex = 'pdf',
  beamer = 'pdf' }

local function file_exists(name)
  local f = io.open(name, 'r')
  if f ~= nil then
    io.close(f)
    return true
  else
    return false
  end
end

local function starts_with(start, str)
  return str:sub(1, #start) == start
end


function RawBlock(el)
  if starts_with('\\begin{tikzpicture}', el.text) then
    local filetype = extension_for[FORMAT] or 'svg'
    local fbasename = pandoc.sha1(el.text) .. '.' .. filetype
    local fname = system.get_working_directory() .. '/' .. fbasename
    if not file_exists(fname) then
      tikz2image(el.text, filetype, fname)
    end
    return pandoc.Para({pandoc.Image({}, fbasename)})
  else
   return el
  end
end

Example of use:

pandoc --lua-filter tikz.lua -s -o cycle.html <<EOF
Here is a diagram of the cycle:

\begin{tikzpicture}

\def \n {5}
\def \radius {3cm}
\def \margin {8} % margin in angles, depends on the radius

\foreach \s in {1,...,\n}
{
  \node[draw, circle] at ({360/\n * (\s - 1)}:\radius) {$\s$};
  \draw[->, >=latex] ({360/\n * (\s - 1)+\margin}:\radius)
    arc ({360/\n * (\s - 1)+\margin}:{360/\n * (\s)-\margin}:\radius);
}
\end{tikzpicture}
EOF

Lua type reference

This section describes the types of objects available to Lua filters. See the pandoc module for functions to create these objects.

Shared Properties

clone

clone ()

All instances of the types listed here, with the exception of read-only objects, can be cloned via the clone() method.

Usage:

local emph = pandoc.Emph {pandoc.Str 'important'}
local cloned_emph = emph:clone()  -- note the colon

Pandoc {#type-pandoc}

Pandoc document

Values of this type can be created with the pandoc.Pandoc constructor. Pandoc values are equal in Lua if and only if they are equal in Haskell.

blocks : document content (Blocks)

meta : document meta information (Meta object)

walk {#type-pandoc:walk}

walk(self, lua_filter)

Applies a Lua filter to the Pandoc element. Just as for full-document filters, the order in which elements are traversed can be controlled by setting the traverse field of the filter; see the section on [traversal order][Traversal order]. Returns a (deep) copy on which the filter has been applied: the original element is left untouched.

Parameters:

self : the element (Pandoc)

lua_filter : map of filter functions (table)

Result:

• filtered document (Pandoc)

Usage:

-- returns `pandoc.Pandoc{pandoc.Para{pandoc.Str 'Bye'}}`
return pandoc.Pandoc{pandoc.Para('Hi')}:walk {
  Str = function (_) return 'Bye' end,
}

Meta {#type-meta}

Meta information on a document; string-indexed collection of MetaValues.

Values of this type can be created with the pandoc.Meta constructor. Meta values are equal in Lua if and only if they are equal in Haskell.

MetaValue {#type-metavalue}

Document meta information items. This is not a separate type, but describes a set of types that can be used in places were a MetaValue is expected. The types correspond to the following Haskell type constructors:

• boolean → MetaBool
• string or number → MetaString
• Inlines → MetaInlines
• Blocks → MetaBlocks
• List/integer indexed table → MetaList
• string-indexed table → MetaMap

The corresponding constructors pandoc.MetaBool, pandoc.MetaString, pandoc.MetaInlines, pandoc.MetaBlocks, pandoc.MetaList, and pandoc.MetaMap can be used to ensure that a value is treated in the intended way. E.g., an empty table is normally treated as a MetaMap, but can be made into an empty MetaList by calling pandoc.MetaList{}. However, the same can be accomplished by using the generic functions like pandoc.List, pandoc.Inlines, or pandoc.Blocks.

Use the function pandoc.utils.type to get the type of a metadata value.

Block {#type-block}

Block values are equal in Lua if and only if they are equal in Haskell.

Common methods

walk {#type-block:walk}

walk(self, lua_filter)

Applies a Lua filter to the block element. Just as for full-document filters, the order in which elements are traversed can be controlled by setting the traverse field of the filter; see the section on [traversal order][Traversal order]. Returns a (deep) copy on which the filter has been applied: the original element is left untouched.

Note that the filter is applied to the subtree, but not to the self block element. The rationale is that otherwise the element could be deleted by the filter, or replaced with multiple block elements, which might lead to possibly unexpected results.

Parameters:

self : the element (Block)

lua_filter : map of filter functions (table)

Result:

• filtered block (Block)

Usage:

-- returns `pandoc.Para{pandoc.Str 'Bye'}`
return pandoc.Para('Hi'):walk {
  Str = function (_) return 'Bye' end,
}

BlockQuote {#type-blockquote}

A block quote element.

Values of this type can be created with the pandoc.BlockQuote constructor.

Fields:

content : block content (Blocks)

tag, t : the literal BlockQuote (string)

BulletList {#type-bulletlist}

A bullet list.

Values of this type can be created with the pandoc.BulletList constructor.

Fields:

content : list items (List of items, i.e., List of Blocks)

tag, t : the literal BulletList (string)

CodeBlock {#type-codeblock}

Block of code.

Values of this type can be created with the pandoc.CodeBlock constructor.

Fields:

text : code string (string)

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 CodeBlock (string)

DefinitionList {#type-definitionlist}

Definition list, containing terms and their explanation.

Values of this type can be created with the pandoc.DefinitionList constructor.

Fields:

content : list of items

tag, t : the literal DefinitionList (string)

Div {#type-div}

Generic block container with attributes.

Values of this type can be created with the pandoc.Div constructor.

Fields:

content : block content (Blocks)

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 Div (string)

Figure {#type-figure}

Figure with caption and arbitrary block contents.

Values of this type can be created with the pandoc.Figure constructor.

Fields:

content : block content (Blocks)

caption : figure caption (Caption)

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 Figure (string)

Header {#type-header}

Creates a header element.

Values of this type can be created with the pandoc.Header constructor.

Fields:

level : header level (integer)

content : inline content (Inlines)

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 Header (string)

HorizontalRule {#type-horizontalrule}

A horizontal rule.

Values of this type can be created with the pandoc.HorizontalRule constructor.

Fields:

tag, t : the literal HorizontalRule (string)

LineBlock {#type-lineblock}

A line block, i.e. a list of lines, each separated from the next by a newline.

Values of this type can be created with the pandoc.LineBlock constructor.

Fields:

content : inline content (List of lines, i.e. List of Inlines)

tag, t : the literal LineBlock (string)

OrderedList {#type-orderedlist}

An ordered list.

Values of this type can be created with the pandoc.OrderedList constructor.

Fields:

content : list items (List of items, i.e., List of Blocks)

listAttributes : list parameters (ListAttributes)

start : alias for listAttributes.start (integer)

style : alias for listAttributes.style (string)

delimiter : alias for listAttributes.delimiter (string)

tag, t : the literal OrderedList (string)

Para {#type-para}

A paragraph.

Values of this type can be created with the pandoc.Para constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Para (string)

Plain {#type-plain}

Plain text, not a paragraph.

Values of this type can be created with the pandoc.Plain constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Plain (string)

RawBlock {#type-rawblock}

Raw content of a specified format.

Values of this type can be created with the pandoc.RawBlock constructor.

Fields:

format : format of content (string)

text : raw content (string)

tag, t : the literal RawBlock (string)

Table {#type-table}

A table.

Values of this type can be created with the pandoc.Table constructor.

Fields:

attr : table attributes (Attr)

caption : table caption (Caption)

colspecs : column specifications, i.e., alignments and widths (List of ColSpecs)

head : table head (TableHead)

bodies : table bodies (List of TableBodys)

foot : table foot (TableFoot)

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)

A [table cell]{#type-table-cell} is a list of blocks.

Alignment{#type-alignment} is a string value indicating the horizontal alignment of a table column. AlignLeft, AlignRight, and AlignCenter leads cell content to be left-aligned, right-aligned, and centered, respectively. The default alignment is AlignDefault (often equivalent to centered).

Blocks {#type-blocks}

List of Block elements, with the same methods as a generic List. It is usually not necessary to create values of this type in user scripts, as pandoc can convert other types into Blocks wherever a value of this type is expected:

• a list of Block (or Block-like) values is used directly;
• a single Inlines value is wrapped into a Plain element;
• string values are turned into an Inlines value by splitting the string into words (see Inlines), and then wrapping the result into a Plain singleton.

Methods

Lists of type Blocks share all methods available in generic lists, see the pandoc.List module.

Additionally, the following methods are available on Blocks values:

walk {#type-blocks:walk}

walk(self, lua_filter)

Applies a Lua filter to the Blocks list. Just as for full-document filters, the order in which elements are traversed can be controlled by setting the traverse field of the filter; see the section on [traversal order][Traversal order]. Returns a (deep) copy on which the filter has been applied: the original list is left untouched.

Parameters:

self : the list (Blocks)

lua_filter : map of filter functions (table)

Result:

• filtered list (Blocks)

Usage:

-- returns `pandoc.Blocks{pandoc.Para('Salve!')}`
return pandoc.Blocks{pandoc.Plain('Salve!)}:walk {
  Plain = function (p) return pandoc.Para(p.content) end,
}

Inline {#type-inline}

Inline values are equal in Lua if and only if they are equal in Haskell.

Common methods

walk {#type-inline:walk}

walk(self, lua_filter)

Applies a Lua filter to the Inline element. Just as for full-document filters, the order in which elements are traversed can be controlled by setting the traverse field of the filter; see the section on [traversal order][Traversal order]. Returns a (deep) copy on which the filter has been applied: the original element is left untouched.

Note that the filter is applied to the subtree, but not to the self inline element. The rationale is that otherwise the element could be deleted by the filter, or replaced with multiple inline elements, which might lead to possibly unexpected results.

Parameters:

self : the element (Inline)

lua_filter : map of filter functions (table)

Result:

• filtered inline element (Inline)

Usage:

-- returns `pandoc.SmallCaps('SPQR)`
return pandoc.SmallCaps('spqr'):walk {
  Str = function (s) return string.upper(s.text) end,
}

Cite {#type-cite}

Citation.

Values of this type can be created with the pandoc.Cite constructor.

Fields:

content : (Inlines)

citations : citation entries (List of Citations)

tag, t : the literal Cite (string)

Code {#type-code}

Inline code

Values of this type can be created with the pandoc.Code constructor.

Fields:

text : code string (string)

attr : 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 Code (string)

Emph {#type-emph}

Emphasized text

Values of this type can be created with the pandoc.Emph constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Emph (string)

Image {#type-image}

Image: alt text (list of inlines), target

Values of this type can be created with the pandoc.Image constructor.

Fields:

caption : text used to describe the image (Inlines)

src : path to the image file (string)

title : brief image description (string)

attr : 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 Image (string)

LineBreak {#type-linebreak}

Hard line break

Values of this type can be created with the pandoc.LineBreak constructor.

Fields:

tag, t : the literal LineBreak (string)

Link {#type-link}

Hyperlink: alt text (list of inlines), target

Values of this type can be created with the pandoc.Link constructor.

Fields:

attr : attributes (Attr)

content : text for this link (Inlines)

target : the link target (string)

title : brief link description

identifier : alias for attr.identifier (string)

classes : alias for attr.classes (List of strings)

attributes : alias for attr.attributes (Attributes)

tag, t : the literal Link (string)

Math {#type-math}

TeX math (literal)

Values of this type can be created with the pandoc.Math constructor.

Fields:

mathtype : specifier determining whether the math content should be shown inline (InlineMath) or on a separate line (DisplayMath) (string)

text : math content (string)

tag, t : the literal Math (string)

Note {#type-note}

Footnote or endnote

Values of this type can be created with the pandoc.Note constructor.

Fields:

content : (Blocks)

tag, t : the literal Note (string)

Quoted {#type-quoted}

Quoted text

Values of this type can be created with the pandoc.Quoted constructor.

Fields:

quotetype : type of quotes to be used; one of SingleQuote or DoubleQuote (string)

content : quoted text (Inlines)

tag, t : the literal Quoted (string)

RawInline {#type-rawinline}

Raw inline

Values of this type can be created with the pandoc.RawInline constructor.

Fields:

format : the format of the content (string)

text : raw content (string)

tag, t : the literal RawInline (string)

SmallCaps {#type-smallcaps}

Small caps text

Values of this type can be created with the pandoc.SmallCaps constructor.

Fields:

content : (Inlines)

tag, t : the literal SmallCaps (string)

SoftBreak {#type-softbreak}

Soft line break

Values of this type can be created with the pandoc.SoftBreak constructor.

Fields:

tag, t : the literal SoftBreak (string)

Space {#type-space}

Inter-word space

Values of this type can be created with the pandoc.Space constructor.

Fields:

tag, t : the literal Space (string)

Span {#type-span}

Generic inline container with attributes

Values of this type can be created with the pandoc.Span constructor.

Fields:

attr : attributes (Attr)

content : wrapped content (Inlines)

identifier : alias for attr.identifier (string)

classes : alias for attr.classes (List of strings)

attributes : alias for attr.attributes (Attributes)

tag, t : the literal Span (string)

Str {#type-str}

Text

Values of this type can be created with the pandoc.Str constructor.

Fields:

text : content (string)

tag, t : the literal Str (string)

Strikeout {#type-strikeout}

Strikeout text

Values of this type can be created with the pandoc.Strikeout constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Strikeout (string)

Strong {#type-strong}

Strongly emphasized text

Values of this type can be created with the pandoc.Strong constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Strong (string)

Subscript {#type-subscript}

Subscripted text

Values of this type can be created with the pandoc.Subscript constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Subscript (string)

Superscript {#type-superscript}

Superscripted text

Values of this type can be created with the pandoc.Superscript constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Superscript (string)

Underline {#type-underline}

Underlined text

Values of this type can be created with the pandoc.Underline constructor.

Fields:

content : inline content (Inlines)

tag, t : the literal Underline (string)

Inlines {#type-inlines}

List of Inline elements, with the same methods as a generic List. It is usually not necessary to create values of this type in user scripts, as pandoc can convert other types into Inlines wherever a value of this type is expected:

• lists of Inline (or Inline-like) values are used directly;
• single Inline values are converted into a list containing just that element;
• String values are split into words, converting line breaks into SoftBreak elements, and other whitespace characters into Spaces.

Methods

Lists of type Inlines share all methods available in generic lists, see the pandoc.List module.

Additionally, the following methods are available on Inlines values:

walk {#type-inlines:walk}

walk(self, lua_filter)

Applies a Lua filter to the Inlines list. Just as for full-document filters, the order in which elements are handled are Inline → Inlines → Block → Blocks. The filter is applied to all list items and to the list itself. Returns a (deep) copy on which the filter has been applied: the original list is left untouched.

Parameters:

self : the list (Inlines)

lua_filter : map of filter functions (table)

Result:

• filtered list (Inlines)

Usage:

-- returns `pandoc.Inlines{pandoc.SmallCaps('SPQR')}`
return pandoc.Inlines{pandoc.Emph('spqr')}:walk {
  Str = function (s) return string.upper(s.text) end,
  Emph = function (e) return pandoc.SmallCaps(e.content) end,
}

Element components

Attr {#type-attr}

A set of element attributes. Values of this type can be created with the pandoc.Attr constructor. For convenience, it is usually not necessary to construct the value directly if it is part of an element, and it is sufficient to pass an HTML-like table. E.g., to create a span with identifier "text" and classes "a" and "b", one can write:

local span = pandoc.Span('text', {id = 'text', class = 'a b'})

This also works when using the attr setter:

local span = pandoc.Span 'text'
span.attr = {id = 'text', class = 'a b', other_attribute = '1'}

Attr values are equal in Lua if and only if they are equal in Haskell.

Fields:

identifier : element identifier (string)

classes : element classes (List of strings)

attributes : collection of key/value pairs (Attributes)

Attributes {#type-attributes}

List of key/value pairs. Values can be accessed by using keys as indices to the list table.

Attributes values are equal in Lua if and only if they are equal in Haskell.

Caption {#type-caption}

The caption of a table, with an optional short caption.

Fields:

long : long caption (Blocks)

short : short caption (Inlines)

Cell {#type-cell}

A table cell.

Fields:

attr : cell attributes

alignment : individual cell alignment (Alignment).

contents : cell contents (Blocks).

col_span : number of columns spanned by the cell; the width of the cell in columns (integer).

row_span : number of rows spanned by the cell; the height of the cell in rows (integer).

identifier : alias for attr.identifier (string)

classes : alias for attr.classes (List of strings)

attributes : alias for attr.attributes (Attributes)

Citation {#type-citation}

Single citation entry

Values of this type can be created with the pandoc.Citation constructor.

Citation values are equal in Lua if and only if they are equal in Haskell.

Fields:

id : citation identifier, e.g., a bibtex key (string)

mode : citation mode, one of AuthorInText, SuppressAuthor, or NormalCitation (string)

prefix : citation prefix (Inlines)

suffix : citation suffix (Inlines)

note_num : note number (integer)

hash : hash (integer)

ColSpec {#type-colspec}

Column alignment and width specification for a single table column.

This is a pair, i.e., a plain table, with the following components:

1. cell alignment (Alignment).
2. table column width, as a fraction of the page width (number).

ListAttributes {#type-listattributes}

List attributes

Values of this type can be created with the pandoc.ListAttributes constructor.

Fields:

start : number of the first list item (integer)

style : style used for list numbers; possible values are DefaultStyle, Example, Decimal, LowerRoman, UpperRoman, LowerAlpha, and UpperAlpha (string)

delimiter : delimiter of list numbers; one of DefaultDelim, Period, OneParen, and TwoParens (string)

Row {#type-row}

A table row.

Fields:

attr : element attributes (Attr)

cells : list of table cells (List of Cells)

TableBody {#type-tablebody}

A body of a table, with an intermediate head and the specified number of row header columns.

Fields:

attr : table body attributes (Attr)

body : table body rows (List of Rows)

head : intermediate head (List of Rows)

row_head_columns : number of columns taken up by the row head of each row of a TableBody. The row body takes up the remaining columns.

TableFoot {#type-tablefoot}

The foot of a table.

Fields:

attr : element attributes (Attr)

rows : list of rows (List of Rows)

identifier : alias for attr.identifier (string)

classes : alias for attr.classes (List of strings)

attributes : alias for attr.attributes (Attributes)

TableHead {#type-tablehead}

The head of a table.

Fields:

attr : element attributes (Attr)

rows : list of rows (List of Rows)

identifier : alias for attr.identifier (string)

classes : alias for attr.classes (List of strings)

attributes : alias for attr.attributes (Attributes)

ReaderOptions {#type-readeroptions}

Pandoc reader options

Fields:

abbreviations : set of known abbreviations (set of strings)

columns : number of columns in terminal (integer)

default_image_extension : default extension for images (string)

extensions : string representation of the syntax extensions bit field (sequence of strings)

indented_code_classes : default classes for indented code blocks (list of strings)

standalone : whether the input was a standalone document with header (boolean)

strip_comments : HTML comments are stripped instead of parsed as raw HTML (boolean)

tab_stop : width (i.e. equivalent number of spaces) of tab stops (integer)

track_changes : track changes setting for docx; one of accept-changes, reject-changes, and all-changes (string)

WriterOptions {#type-writeroptions}

Pandoc writer options

Fields:

chunk_template : Template used to generate chunked HTML filenames (string)

cite_method : How to print cites -- one of 'citeproc', 'natbib', or 'biblatex' (string)

columns : Characters in a line (for text wrapping) (integer)

dpi : DPI for pixel to/from inch/cm conversions (integer)

email_obfuscation : How to obfuscate emails -- one of 'none', 'references', or 'javascript' (string)

epub_chapter_level : Header level for chapters, i.e., how the document is split into separate files (integer)

epub_fonts : Paths to fonts to embed (sequence of strings)

epub_metadata : Metadata to include in EPUB (string|nil)

epub_subdirectory : Subdir for epub in OCF (string)

extensions : Markdown extensions that can be used (sequence of strings)

highlight_style : Style to use for highlighting; see the output of pandoc --print-highlight-style=... for an example structure. The value nil means that no highlighting is used. (table|nil)

html_math_method : How to print math in HTML; one of 'plain', 'mathjax', 'mathml', 'webtex', 'katex', 'gladtex', or a table with keys method and url. (string|table)

html_q_tags : Use <q> tags for quotes in HTML (boolean)

identifier_prefix : Prefix for section & note ids in HTML and for footnote marks in markdown (string)

incremental : True if lists should be incremental (boolean)

listings : Use listings package for code (boolean)

number_offset : Starting number for section, subsection, ... (sequence of integers)

number_sections : Number sections in LaTeX (boolean)

prefer_ascii : Prefer ASCII representations of characters when possible (boolean)

reference_doc : Path to reference document if specified (string|nil)

reference_links : Use reference links in writing markdown, rst (boolean)

reference_location : Location of footnotes and references for writing markdown; one of 'end-of-block', 'end-of-section', 'end-of-document'. The common prefix may be omitted when setting this value. (string)

section_divs : Put sections in div tags in HTML (boolean)

setext_headers : Use setext headers for levels 1-2 in markdown (boolean)

slide_level : Force header level of slides (integer|nil)

tab_stop : Tabstop for conversion btw spaces and tabs (integer)

table_of_contents : Include table of contents (boolean)

template : Template to use (Template|nil)

toc_depth : Number of levels to include in TOC (integer)

top_level_division : Type of top-level divisions; one of 'top-level-part', 'top-level-chapter', 'top-level-section', or 'top-level-default'. The prefix top-level may be omitted when setting this value. (string)

variables : Variables to set in template; string-indexed table (table)

wrap_text : Option for wrapping text; one of 'wrap-auto', 'wrap-none', or 'wrap-preserve'. The wrap- prefix may be omitted when setting this value. (string)

CommonState {#type-commonstate}

The state used by pandoc to collect information and make it available to readers and writers.

Fields:

input_files : List of input files from command line (List of strings)

output_file : Output file from command line (string or nil)

log : A list of log messages in reverse order (List of LogMessages)

request_headers : Headers to add for HTTP requests; table with header names as keys and header contents as value (table)

resource_path : Path to search for resources like included images (List of strings)

source_url : Absolute URL or directory of first source file (string or nil)

user_data_dir : Directory to search for data files (string or nil)

trace : Whether tracing messages are issued (boolean)

verbosity : Verbosity level; one of INFO, WARNING, ERROR (string)

Doc {#type-doc}

Reflowable plain-text document. A Doc value can be rendered and reflown to fit a given column width.

The pandoc.layout module can be used to create and modify Doc values. All functions in that module that take a Doc value as their first argument are also available as Doc methods. E.g., (pandoc.layout.literal 'text'):render().

If a string is passed to a function expecting a Doc, then the string is treated as a literal value. I.e., the following two lines are equivalent:

test = pandoc.layout.quotes(pandoc.layout.literal 'this')
test = pandoc.layout.quotes('this')

Operators {#type-doc-operators}

.. {#type-doc.__concat}

Concatenate two Doc elements.

+ {#type-doc.__add}

Concatenate two Docs, inserting a reflowable space between them.

/ {#type-doc.__div}

If a and b are Doc elements, then a / b puts a above b.

// {#type-doc.__idiv}

If a and b are Doc elements, then a // b puts a above b, inserting a blank line between them.

List {#type-list}

A list is any Lua table with integer indices. Indices start at one, so if alist = {'value'} then alist[1] == 'value'.

Lists, when part of an element, or when generated during marshaling, are made instances of the pandoc.List type for convenience. The pandoc.List type is defined in the pandoc.List module. See there for available methods.

Values of this type can be created with the pandoc.List constructor, turning a normal Lua table into a List.

LogMessage {#type-logmessage}

A pandoc log message. Objects have no fields, but can be converted to a string via tostring.

SimpleTable {#type-simpletable}

A simple table is a table structure which resembles the old (pre pandoc 2.10) Table type. Bi-directional conversion from and to Tables is possible with the pandoc.utils.to_simple_table and pandoc.utils.from_simple_table function, respectively. Instances of this type can also be created directly with the pandoc.SimpleTable constructor.

Fields:

caption : Inlines

aligns : column alignments (List of Alignments)

widths : column widths; a (List of numbers)

headers : table header row (List of simple cells, i.e., List of Blocks)

rows : table rows (List of rows, where a row is a list of simple cells, i.e., List of Blocks)

Template {#type-template}

Opaque type holding a compiled template.

Version {#type-version}

A version object. This represents a software version like "2.7.3". The object behaves like a numerically indexed table, i.e., if version represents the version 2.7.3, then

version[1] == 2
version[2] == 7
version[3] == 3
#version == 3   -- length

Comparisons are performed element-wise, i.e.

Version '1.12' > Version '1.9'

Values of this type can be created with the pandoc.types.Version constructor.

must_be_at_least

must_be_at_least(actual, expected [, error_message])

Raise an error message if the actual version is older than the expected version; does nothing if actual is equal to or newer than the expected version.

Parameters:

actual : actual version specifier (Version)

expected : minimum expected version (Version)

error_message : optional error message template. The string is used as format string, with the expected and actual versions as arguments. Defaults to "expected version %s or newer, got %s".

Usage:

PANDOC_VERSION:must_be_at_least '2.7.3'
PANDOC_API_VERSION:must_be_at_least(
  '1.17.4',
  'pandoc-types is too old: expected version %s, got %s'
)

Chunk {#type-chunk}

Part of a document; usually chunks are each written to a separate file.

Fields:

heading : heading text (Inlines)

id : identifier (string)

level : level of topmost heading in chunk (integer)

number : chunk number (integer)

section_number : hierarchical section number (string)

path : target filepath for this chunk (string)

up : link to the enclosing section, if any ([Chunk][]|nil)

prev : link to the previous section, if any ([Chunk][]|nil)

next : link to the next section, if any ([Chunk][]|nil)

unlisted : whether the section in this chunk should be listed in the TOC even if the chunk has no section number. (boolean)

contents : the chunk's block contents (Blocks)

ChunkedDoc {#type-chunkeddoc}

A Pandoc document divided into [Chunks]{#type-chunk}.

The table of contents info in field toc is rose-tree structure represented as a list. The node item is always placed at index 0; subentries make up the rest of the list. Each node item contains the fields title (Inlines), number (string|nil), id (string), path (string), and level (integer).

Fields:

chunks : list of chunks that make up the document (list of Chunks).

meta : the document's metadata (Meta)

toc : table of contents information (table)

Module pandoc

Fields and functions for pandoc scripts; includes constructors for document tree elements, functions to parse text in a given format, and functions to filter and modify a subtree.

Fields {#pandoc-fields}

readers {#pandoc.readers}

Set of formats that pandoc can parse. All keys in this table can be used as the format value in pandoc.read. (table)

writers {#pandoc.writers}

Set of formats that pandoc can generate. All keys in this table can be used as the format value in pandoc.write. (table)

Functions {#pandoc-functions}

Pandoc {#pandoc.Pandoc}

Pandoc (blocks[, meta])

Parameters:

blocks : document contents (Blocks)

meta : document metadata (Meta)

Returns:

• new Pandoc document (Pandoc)

Meta {#pandoc.Meta}

Meta (meta)

Parameters:

meta : table containing meta information (table)

Returns:

• new Meta table (table)

MetaBlocks {#pandoc.MetaBlocks}

MetaBlocks (content)

Creates a value to be used as a MetaBlocks value in meta data; creates a copy of the input list via pandoc.Blocks, discarding all non-list keys.

Parameters:

content : block content (Blocks)

Returns:

• list of Block elements (Blocks)

MetaBool {#pandoc.MetaBool}

MetaBool (bool)

Parameters:

bool : true or false (boolean)

Returns:

• input, unchanged (boolean)

MetaInlines {#pandoc.MetaInlines}

MetaInlines (inlines)

Creates a value to be used as a MetaInlines value in meta data; creates a copy of the input list via pandoc.Inlines, discarding all non-list keys.

Parameters:

inlines : inline elements (Inlines)

Returns:

• list of Inline elements (Inlines)

MetaList {#pandoc.MetaList}

MetaList (values)

Creates a value to be used as a MetaList in meta data; creates a copy of the input list via pandoc.List, discarding all non-list keys.

Parameters:

values : value, or list of values (MetaValue|{MetaValue,...})

Returns:

• list of meta values (List{unknown-type="List"})

MetaMap {#pandoc.MetaMap}

MetaMap (key_value_map)

Creates a value to be used as a MetaMap in meta data; creates a copy of the input table, keeping only pairs with string keys and discards all other keys.

Parameters:

key_value_map : a string-indexed map of meta values (table)

Returns:

• map of meta values (table)

MetaString {#pandoc.MetaString}

MetaString (s)

Creates a value to be used as a MetaString in meta data; this is the identity function for boolean values and exists only for completeness.

Parameters:

s : string value (string)

Returns:

• unchanged input (string)

BlockQuote {#pandoc.BlockQuote}

BlockQuote (content)

Creates a block quote element

Parameters:

content : block content (Blocks)

Returns:

• BlockQuote element (Block)

BulletList {#pandoc.BulletList}

BulletList (items)

Creates a bullet list.

Parameters:

items : list items ({Blocks,...})

Returns:

• BulletList element (Block)

CodeBlock {#pandoc.CodeBlock}

CodeBlock (text[, attr])

Creates a code block element.

Parameters:

text : code string (string)

attr : element attributes (Attr)

Returns:

• CodeBlock element (Block)

DefinitionList {#pandoc.DefinitionList}

DefinitionList (content)

Creates a definition list, containing terms and their explanation.

Parameters:

content : definition items ([{{Inlines, {Blocks,...}},...}]{unknown-type="{{Inlines, {Blocks,...}},...}"})

Returns:

• DefinitionList element (Block)

Div {#pandoc.Div}

Div (content[, attr])

Creates a div element

Parameters:

content : block content (Blocks)

attr : element attributes (Attr)

Returns:

• Div element (Block)

Figure {#pandoc.Figure}

Figure (content[, caption[, attr]])

Creates a Figure element.

Parameters:

content : figure block content (Blocks)

caption : figure caption (Caption)

attr : element attributes (Attr)

Returns:

• Figure object (Block)

Header {#pandoc.Header}

Header (level, content[, attr])

Creates a header element.

Parameters:

level : heading level ([integer]{unknown-type="integer"})

content : inline content (Inlines)

attr : element attributes (Attr)

Returns:

• Header element (Block)

HorizontalRule {#pandoc.HorizontalRule}

HorizontalRule ()

Creates a horizontal rule.

Returns:

• HorizontalRule element (Block)

LineBlock {#pandoc.LineBlock}

LineBlock (content)

Creates a line block element.

Parameters:

content : lines ({Inlines,...})

Returns:

• LineBlock element (Block)

OrderedList {#pandoc.OrderedList}

OrderedList (items[, listAttributes])

Creates an ordered list.

Parameters:

items : list items ({Blocks,...})

listAttributes : list parameters (ListAttributes)

Returns:

• OrderedList element (Block)

Para {#pandoc.Para}

Para (content)

Creates a para element.

Parameters:

content : inline content (Inlines)

Returns:

• Para element (Block)

Plain {#pandoc.Plain}

Plain (content)

Creates a plain element.

Parameters:

content : inline content (Inlines)

Returns:

• Plain element (Block)

RawBlock {#pandoc.RawBlock}

RawBlock (format, text)

Creates a raw content block of the specified format.

Parameters:

format : format of content (string)

text : raw content (string)

Returns:

• RawBlock element (Block)

Table {#pandoc.Table}

Table (caption, colspecs, head, bodies, foot[, attr])

Creates a table element.

Parameters:

caption : table caption (Caption)

colspecs : column alignments and widths ({ColSpec,...})

head : table head (TableHead)

bodies : table bodies ({TableBody,...})

foot : table foot (TableFoot)

attr : element attributes (Attr)

Returns:

• Table element (Block)

Blocks {#pandoc.Blocks}

Blocks (block_like_elements)

Creates a Blocks list.

Parameters:

block_like_elements : List where each element can be treated as a Block value, or a single such value. (Blocks)

Returns:

• list of block elements (Blocks)

Cite {#pandoc.Cite}

Cite (Inlines, citations)

Creates a Cite inline element

Parameters:

Inlines : placeholder content ([content]{unknown-type="content"})

citations : List of Citations ({Citation{unknown-type="Citation"},...})

Returns:

• cite element (Inline)

Code {#pandoc.Code}

Code (code[, attr])

Creates a Code inline element

Parameters:

code : code string (string)

attr : additional attributes (Attr)

Returns:

• code element (Inline)

Emph {#pandoc.Emph}

Emph (content)

Creates an inline element representing emphasized text.

Parameters:

content : inline content (Inlines)

Returns:

• new object (Inline)

Image {#pandoc.Image}

Image (caption, src[, title[, attr]])

Creates an Image element

Parameters:

caption : text used to describe the image (Inlines)

src : path to the image file (string)

title : brief image description (string)

attr : image attributes (Attr)

Returns:

• Image element (Inline)

LineBreak {#pandoc.LineBreak}

LineBreak ()

Create a LineBreak inline element

Returns:

• line break (Inline)

Link {#pandoc.Link}

Link (content, target[, title[, attr]])

Creates a link inline element, usually a hyperlink.

Parameters:

content : text for this link (Inlines)

target : the link target (string)

title : brief link description (string)

attr : link attributes (Attr)

Returns:

• link element (Inline)

Math {#pandoc.Math}

Math (mathtype, text)

Creates a Math element, either inline or displayed.

Parameters:

mathtype : rendering specifier ([MathType]{unknown-type="MathType"})

text : math content (string)

Returns:

• math element (Inline)

Note {#pandoc.Note}

Note (content)

Creates a Note inline element

Parameters:

content : footnote block content (Blocks)

Returns:

• note (Inline)

Quoted {#pandoc.Quoted}

Quoted (quotetype, content)

Creates a Quoted inline element given the quote type and quoted content.

Parameters:

quotetype : type of quotes ([QuoteType]{unknown-type="QuoteType"})

content : inlines in quotes (Inlines)

Returns:

• quoted element (Inline)

RawInline {#pandoc.RawInline}

RawInline (format, text)

Creates a raw inline element

Parameters:

format : format of content (string)

text : string content (string)

Returns:

• raw inline element (Inline)

SmallCaps {#pandoc.SmallCaps}

SmallCaps (content)

Creates text rendered in small caps

Parameters:

content : inline content (Inlines)

Returns:

• new object (Inline)

SoftBreak {#pandoc.SoftBreak}

SoftBreak ()

Creates a SoftBreak inline element.

Returns:

• soft break (Inline)

Space {#pandoc.Space}

Space ()

Create a Space inline element

Returns:

• new space (Inline)

Span {#pandoc.Span}

Span (content[, attr])

Creates a Span inline element

Parameters:

content : inline content (Inlines)

attr : additional attributes (Attr)

Returns:

• Span object (Inline)

Str {#pandoc.Str}

Str (text)

Creates a Str inline element

Parameters:

text : (string)

Returns:

• Str object (Inline)

Strikeout {#pandoc.Strikeout}

Strikeout (content)

Creates text which is struck out.

Parameters:

content : inline content (Inlines)

Returns:

• new object (Inline)

Strong {#pandoc.Strong}

Strong (content)

Creates a Strong element, whose text is usually displayed in a bold font.

Parameters:

content : inline content (Inlines)

Returns:

• new object (Inline)

Subscript {#pandoc.Subscript}

Subscript (content)

Creates a Subscript inline element

Parameters:

content : inline content (Inlines)

Returns:

• new object (Inline)

Superscript {#pandoc.Superscript}

Superscript (content)

Creates a Superscript inline element

Parameters:

content : inline content (Inlines)

Returns:

• new object (Inline)

Underline {#pandoc.Underline}

Underline (content)

Creates an Underline inline element

Parameters:

content : inline content (Inlines)

Returns:

• new object (Inline)

Inlines {#pandoc.Inlines}

Inlines (inline_like_elements)

Converts its argument into an Inlines list:

• copies a list of Inline elements into a fresh list; any string s within the list is treated as pandoc.Str(s);
• turns a single Inline into a singleton list;
• splits a string into Str-wrapped words, treating interword spaces as Spaces or SoftBreaks.

Parameters:

inline_like_elements : List where each element can be treated as an Inline value, or just a single such value. (Inlines)

Returns:

• list of inline elements (Inlines)

Attr {#pandoc.Attr}

Attr ([identifier[, classes[, attributes]]])

Create a new set of attributes

Parameters:

identifier : element identifier (string|table|Attr)

classes : element classes ({string,...})

attributes : table containing string keys and values (table|AttributeList)

Returns:

• new Attr object (Attr)

Cell {#pandoc.Cell}

Cell (blocks[, align[, rowspan[, colspan[, attr]]]])

Create a new table cell.

Parameters:

blocks : cell contents (Blocks)

align : text alignment; defaults to AlignDefault (Alignment)

rowspan : number of rows occupied by the cell; defaults to 1 ([integer]{unknown-type="integer"})

colspan : number of columns occupied by the cell; defaults to 1 ([integer]{unknown-type="integer"})

attr : cell attributes (Attr)

Returns:

• new Cell object (Cell)

AttributeList {#pandoc.AttributeList}

AttributeList (attribs)

Parameters:

attribs : an attribute list (table|AttributeList)

Returns:

• new AttributeList object (AttributeList)

Citation {#pandoc.Citation}

Citation (id, mode[, prefix[, suffix[, note_num[, hash]]]])

Creates a single citation.

Parameters:

id : citation ID (e.g. BibTeX key) (string)

mode : citation rendering mode ([CitationMode]{unknown-type="CitationMode"})

prefix : (Inlines)

suffix : (Inlines)

note_num : note number ([integer]{unknown-type="integer"})

hash : hash number ([integer]{unknown-type="integer"})

Returns:

• new citation object (Citation{unknown-type="Citation"})

ListAttributes {#pandoc.ListAttributes}

ListAttributes ([start[, style[, delimiter]]])

Creates a new ListAttributes object.

Parameters:

start : number of the first list item ([integer]{unknown-type="integer"})

style : style used for list numbering (string)

delimiter : delimiter of list numbers (string)

Returns:

• new ListAttributes object (ListAttributes)

Row {#pandoc.Row}

Row ([cells[, attr]])

Creates a table row.

Parameters:

cells : list of table cells in this row ({Cell,...})

attr : row attributes (Attr)

Returns:

• new Row object (Row)

TableFoot {#pandoc.TableFoot}

TableFoot ([rows[, attr]])

Creates a table foot.

Parameters:

rows : list of table rows ({Row,...})

attr : table foot attributes (Attr)

Returns:

• new TableFoot object (TableFoot)

TableHead {#pandoc.TableHead}

TableHead ([rows[, attr]])

Creates a table head.

Parameters:

rows : list of table rows ({Row,...})

attr : table head attributes (Attr)

Returns:

• new TableHead object (TableHead)

SimpleTable {#pandoc.SimpleTable}

SimpleTable (caption, align, widths, header, rows)

Usage:

local caption = "Overview"
local aligns = {pandoc.AlignDefault, pandoc.AlignDefault}
local widths = {0, 0} -- let pandoc determine col widths
local headers = {{pandoc.Plain({pandoc.Str "Language"})},
                 {pandoc.Plain({pandoc.Str "Typing"})}}
local rows = {
  {{pandoc.Plain "Haskell"}, {pandoc.Plain "static"}},
  {{pandoc.Plain "Lua"}, {pandoc.Plain "Dynamic"}},
}
simple_table = pandoc.SimpleTable(
  caption,
  aligns,
  widths,
  headers,
  rows
)

Parameters:

caption : table caption (Inlines)

align : column alignments ({Alignment,...})

widths : relative column widths ({number,...})

header : table header row ({Blocks,...})

rows : table rows ({{Blocks,...},...})

Returns:

• new SimpleTable object (SimpleTable)

Constants

[AuthorInText]{#pandoc.authorintext}

: Author name is mentioned in the text.

See also: [Citation](#type-citation)

[SuppressAuthor]{#pandoc.suppressauthor}

: Author name is suppressed.

See also: [Citation](#type-citation)

[NormalCitation]{#pandoc.normalcitation}

: Default citation style is used.

See also: [Citation](#type-citation)

[DisplayMath]{#pandoc.displaymath}

: Math style identifier, marking that the formula should be show in "display" style, i.e., on a separate line.

See also: [Math](#type-math)

[InlineMath]{#pandoc.inlinemath}

: Math style identifier, marking that the formula should be show inline.

See also: [Math](#type-math)

[SingleQuote]{#pandoc.singlequote}

: Quote type used with Quoted, indicating that the string is enclosed in single quotes.

See also: [Quoted](#type-quoted)

[DoubleQuote]{#pandoc.doublequote}

: Quote type used with Quoted, indicating that the string is enclosed in double quotes.

See also: [Quoted](#type-quoted)

[AlignLeft]{#pandoc.alignleft}

: Table cells aligned left.

See also: [Table](#type-alignment)

[AlignRight]{#pandoc.alignright}

: Table cells right-aligned.

See also: [Table](#type-alignment)

[AlignCenter]{#pandoc.aligncenter}

: Table cell content is centered.

See also: [Table](#type-alignment)

[AlignDefault]{#pandoc.aligndefault}

: Table cells are alignment is unaltered.

See also: [Table](#type-alignment)

[DefaultDelim]{#pandoc.defaultdelim}

: Default list number delimiters are used.

See also: [ListAttributes](#type-listattributes)

[Period]{#pandoc.period}

: List numbers are delimited by a period.

See also: [ListAttributes](#type-listattributes)

[OneParen]{#pandoc.oneparen}

: List numbers are delimited by a single parenthesis.

See also: [ListAttributes](#type-listattributes)

[TwoParens]{#pandoc.twoparens}

: List numbers are delimited by a double parentheses.

See also: [ListAttributes](#type-listattributes)

[DefaultStyle]{#pandoc.defaultstyle}

: List are numbered in the default style

See also: [ListAttributes](#type-listattributes)

[Example]{#pandoc.example}

: List items are numbered as examples.

See also: [ListAttributes](#type-listattributes)

[Decimal]{#pandoc.decimal}

: List are numbered using decimal integers.

See also: [ListAttributes](#type-listattributes)

[LowerRoman]{#pandoc.lowerroman}

: List are numbered using lower-case roman numerals.

See also: [ListAttributes](#type-listattributes)

[UpperRoman]{#pandoc.upperroman}

: List are numbered using upper-case roman numerals

See also: [ListAttributes](#type-listattributes)

[LowerAlpha]{#pandoc.loweralpha}

: List are numbered using lower-case alphabetic characters.

See also: [ListAttributes](#type-listattributes)

[UpperAlpha]{#pandoc.upperalpha}

: List are numbered using upper-case alphabetic characters.

See also: [ListAttributes](#type-listattributes)

[sha1]{#pandoc.sha1}

: Alias for pandoc.utils.sha1 (DEPRECATED, use pandoc.utils.sha1 instead).

Other constructors

ReaderOptions (opts) {#pandoc.readeroptions}

Creates a new ReaderOptions value.

Parameters

opts : Either a table with a subset of the properties of a ReaderOptions object, or another ReaderOptions object. Uses the defaults specified in the manual for all properties that are not explicitly specified. Throws an error if a table contains properties which are not present in a ReaderOptions object. (ReaderOptions|table)

Returns: new ReaderOptions object

Usage:

-- copy of the reader options that were defined on the command line.
local cli_opts = pandoc.ReaderOptions(PANDOC_READER_OPTIONS)

-- default reader options, but columns set to 66.
local short_colums_opts = pandoc.ReaderOptions {columns = 66}

WriterOptions (opts) {#pandoc.writeroptions}

Creates a new WriterOptions value.

Parameters

opts : Either a table with a subset of the properties of a WriterOptions object, or another WriterOptions object. Uses the defaults specified in the manual for all properties that are not explicitly specified. Throws an error if a table contains properties which are not present in a WriterOptions object. (WriterOptions|table)

Returns: new WriterOptions object

Usage:

-- copy of the writer options that were defined on the command line.
local cli_opts = pandoc.WriterOptions(PANDOC_WRITER_OPTIONS)

-- default writer options, but DPI set to 300.
local short_colums_opts = pandoc.WriterOptions {dpi = 300}

Helper functions

pipe (command, args, input) {#pandoc.pipe}

Runs command with arguments, passing it some input, and returns the output.

Parameters:

command : program to run; the executable will be resolved using default system methods (string).

args : list of arguments to pass to the program (list of strings).

input : data which is piped into the program via stdin (string).

Returns:

• Output of command, i.e. data printed to stdout (string)

Raises:

• A table containing the keys command, error_code, and output is thrown if the command exits with a non-zero error code.

Usage:

local output = pandoc.pipe("sed", {"-e","s/a/b/"}, "abc")

walk_block (element, filter) {#pandoc.walk_block}

Apply a filter inside a block element, walking its contents. Returns a (deep) copy on which the filter has been applied: the original element is left untouched.

Parameters:

element : the block element

filter : a Lua filter (table of functions) to be applied within the block element

Returns: the transformed block element

walk_inline (element, filter) {#pandoc.walk_inline}

Apply a filter inside an inline element, walking its contents. Returns a (deep) copy on which the filter has been applied: the original element is left untouched.

Parameters:

element : the inline element

filter : a Lua filter (table of functions) to be applied within the inline element

Returns: the transformed inline element

read (markup[, format[, reader_options]]) {#pandoc.read}

Parse the given string into a Pandoc document.

The parser is run in the same environment that was used to read the main input files; it has full access to the file-system and the mediabag. This means that if the document specifies files to be included, as is possible in formats like LaTeX, reStructuredText, and Org, then these will be included in the resulting document. Any media elements are added to those retrieved from the other parsed input files.

The format parameter defines the format flavor that will be parsed. This can be either a string, using + and - to enable and disable extensions, or a table with fields format (string) and extensions (table). The extensions table can be a list of all enabled extensions, or a table with extensions as keys and their activation status as values (true or 'enable' to enable an extension, false or 'disable' to disable it).

Note: The extensions field in reader_options is ignored, as the function will always use the format extensions specified via the format parameter.

Parameters:

markup : the markup to be parsed (string|Sources)

format : format specification; defaults to "markdown". See the description above for a complete description of this parameter. (string|table)

reader_options : options passed to the reader; may be a ReaderOptions object or a table with a subset of the keys and values of a ReaderOptions object; defaults to the default values documented in the manual. (ReaderOptions|table)

Returns: pandoc document (Pandoc)

Usage:

local org_markup = "/emphasis/"  -- Input to be read
local document = pandoc.read(org_markup, "org")
-- Get the first block of the document
local block = document.blocks[1]
-- The inline element in that block is an `Emph`
assert(block.content[1].t == "Emph")

write (doc[, format[, writer_options]]) {#pandoc.write}

Converts a document to the given target format.

Note: The extensions field in writer_options is ignored, as the function will always use the format extensions specified via the format parameter.

Parameters:

doc : document to convert (Pandoc)

format : format specification; defaults to "html". See the documentation of pandoc.read for a complete description of this parameter. (string|table)

writer_options : options passed to the writer; may be a WriterOptions object or a table with a subset of the keys and values of a WriterOptions object; defaults to the default values documented in the manual. (WriterOptions|table)

Returns:

• converted document (string)

Usage:

local doc = pandoc.Pandoc(
  {pandoc.Para {pandoc.Strong 'Tea'}}
)
local html = pandoc.write(doc, 'html')
assert(html == "<p><strong>Tea</strong></p>")

write_classic (doc[, writer_options]) {#pandoc.write_custom}

Runs a classic custom Lua writer, using the functions defined in the current environment.

Parameters:

doc : document to convert (Pandoc)

writer_options : options passed to the writer; may be a WriterOptions object or a table with a subset of the keys and values of a WriterOptions object; defaults to the default values documented in the manual. (WriterOptions|table)

Returns:

• converted document (string)

Usage:

-- Adding this function converts a classic writer into a
-- new-style custom writer.
function Writer (doc, opts)
  PANDOC_DOCUMENT = doc
  PANDOC_WRITER_OPTIONS = opts
  loadfile(PANDOC_SCRIPT_FILE)()
  return pandoc.write_classic(doc, opts)
end

Module pandoc.cli

Command line options and argument parsing.

Fields {#pandoc.cli-fields}

default_options {#pandoc.cli.default_options}

Default CLI options, using a JSON-like representation. (table)

Functions {#pandoc.cli-functions}

parse_options {#pandoc.cli.parse_options}

parse_options (args)

Parses command line arguments into pandoc options. Typically this function will be used in stand-alone pandoc Lua scripts, taking the list of arguments from the global arg.

Parameters:

args : list of command line arguments ({string,...})

Returns:

• parsed options, using their JSON-like representation. (table)

Since: 3.0

repl {#pandoc.cli.repl}

repl ([env])

Starts a read-eval-print loop (REPL). The function returns all values of the last evaluated input. Exit the REPL by pressing ctrl-d or ctrl-c; press F1 to get a list of all key bindings.

The REPL is started in the global namespace, unless the env parameter is specified. In that case, the global namespace is merged into the given table and the result is used as _ENV value for the repl.

Specifically, local variables cannot be accessed, unless they are explicitly passed via the env parameter; e.g.

function Pandoc (doc)
  -- start repl, allow to access the `doc` parameter
  -- in the repl
  return pandoc.cli.repl{ doc = doc }
end

Note: it seems that the function exits immediately on Windows, without prompting for user input.

Parameters:

env : Extra environment; the global environment is merged into this table. (table)

Returns:

The result(s) of the last evaluated input, or nothing if the last input resulted in an error.

Since: 3.1.2

Module pandoc.utils

This module exposes internal pandoc functions and utility functions.

Functions {#pandoc.utils-functions}

blocks_to_inlines {#pandoc.utils.blocks_to_inlines}

blocks_to_inlines (blocks[, sep])

Squash a list of blocks into a list of inlines.

Usage

local blocks = {
  pandoc.Para{ pandoc.Str 'Paragraph1' },
  pandoc.Para{ pandoc.Emph 'Paragraph2' }
}
local inlines = pandoc.utils.blocks_to_inlines(blocks)
assert(
  inlines == pandoc.Inlines {
    pandoc.Str 'Paragraph1',
    pandoc.Linebreak(),
    pandoc.Emph{ pandoc.Str 'Paragraph2' }
  }
)

Parameters:

blocks : List of Block elements to be flattened. (Blocks)

sep : List of Inline elements inserted as separator between two consecutive blocks; defaults to {pandoc.LineBreak()}. (Inlines)

Returns:

• (Inlines)

Since: 2.2.3

citeproc {#pandoc.utils.citeproc}

citeproc (doc)

Process the citations in the file, replacing them with rendered citations and adding a bibliography. See the manual section on citation rendering for details.

Usage:

-- Lua filter that behaves like `--citeproc`
function Pandoc (doc)
  return pandoc.utils.citeproc(doc)
end

Parameters:

doc : document (Pandoc)

Returns:

• processed document (Pandoc)

Since: 2.19.1

equals {#pandoc.utils.equals}

equals (element1, element2)

Test equality of AST elements. Elements in Lua are considered equal if and only if the objects obtained by unmarshaling are equal.

This function is deprecated. Use the normal Lua == equality operator instead.

Parameters:

element1 : (any)

element2 : (any)

Returns:

• Whether the two objects represent the same element (boolean)

Since: 2.5

from_simple_table {#pandoc.utils.from_simple_table}

from_simple_table (simple_tbl)

Creates a Table block element from a SimpleTable. This is useful for dealing with legacy code which was written for pandoc versions older than 2.10.

Usage:

local simple = pandoc.SimpleTable(table)
-- modify, using pre pandoc 2.10 methods
simple.caption = pandoc.SmallCaps(simple.caption)
-- create normal table block again
table = pandoc.utils.from_simple_table(simple)

Parameters:

simple_tbl : (SimpleTable)

Returns:

• table block element (Block)

Since: 2.11

make_sections {#pandoc.utils.make_sections}

make_sections (number_sections, baselevel, blocks)

Converts a list of Block elements into sections. Divs will be created beginning at each Header and containing following content until the next Header of comparable level. If number_sections is true, a number attribute will be added to each Header containing the section number. If base_level is non-null, Header levels will be reorganized so that there are no gaps, and so that the base level is the level specified.

Parameters:

number_sections : whether section divs should get an additional number attribute containing the section number. (boolean)

baselevel : shift top-level headings to this level ([integer]{unknown-type="integer"}|nil)

blocks : list of blocks to process (Blocks)

Returns:

• blocks with sections (Blocks)

Since: 2.8

normalize_date {#pandoc.utils.normalize_date}

normalize_date (date)

Parse a date and convert (if possible) to "YYYY-MM-DD" format. We limit years to the range 1601-9999 (ISO 8601 accepts greater than or equal to 1583, but MS Word only accepts dates starting 1601). Returns nil instead of a string if the conversion failed.

Parameters:

date : the date string (string)

Returns:

• normalized date, or nil if normalization failed. ([string or nil]{unknown-type="string or nil"})

Since: 2.0.6

references {#pandoc.utils.references}

references (doc)

Get references defined inline in the metadata and via an external bibliography. Only references that are actually cited in the document (either with a genuine citation or with nocite) are returned. URL variables are converted to links.

The structure used represent reference values corresponds to that used in CSL JSON; the return value can be use as references metadata, which is one of the values used by pandoc and citeproc when generating bibliographies.

Usage:

-- Include all cited references in document
function Pandoc (doc)
  doc.meta.references = pandoc.utils.references(doc)
  doc.meta.bibliography = nil
  return doc
end

Parameters:

doc : document (Pandoc)

Returns:

• lift of references. (table)

Since: 2.17

run_json_filter {#pandoc.utils.run_json_filter}

run_json_filter (doc, filter[, args])

Filter the given doc by passing it through a JSON filter.

Parameters:

doc : the Pandoc document to filter (Pandoc)

filter : filter to run (string)

args : list of arguments passed to the filter. Defaults to {FORMAT}. ({string,...})

Returns:

• filtered document (Pandoc)

Since: 2.1.1

run_lua_filter {#pandoc.utils.run_lua_filter}

run_lua_filter (doc, filter[, env])

Filter the given doc by passing it through a Lua filter.

The filter will be run in the current Lua process.

Parameters:

doc : the Pandoc document to filter (Pandoc)

filter : filepath of the filter to run (string)

env : environment to load and run the filter in (table)

Returns:

• filtered document (Pandoc)

Since: 3.2.1

sha1 {#pandoc.utils.sha1}

sha1 (input)

Computes the SHA1 hash of the given string input.

Parameters:

input : (string)

Returns:

• hexadecimal hash value (string)

Since: 2.0.6

stringify {#pandoc.utils.stringify}

stringify (element)

Converts the given element (Pandoc, Meta, Block, or Inline) into a string with all formatting removed.

Parameters:

element : some pandoc AST element ([AST element]{unknown-type="AST element"})

Returns:

• A plain string representation of the given element. (string)

Since: 2.0.6

to_roman_numeral {#pandoc.utils.to_roman_numeral}

to_roman_numeral (n)

Converts an integer < 4000 to uppercase roman numeral.

Usage:

local to_roman_numeral = pandoc.utils.to_roman_numeral
local pandoc_birth_year = to_roman_numeral(2006)
-- pandoc_birth_year == 'MMVI'

Parameters:

n : positive integer below 4000 ([integer]{unknown-type="integer"})

Returns:

• A roman numeral. (string)

Since: 2.0.6

to_simple_table {#pandoc.utils.to_simple_table}

to_simple_table (tbl)

Converts a table into an old/simple table.

Usage:

local simple = pandoc.utils.to_simple_table(table)
-- modify, using pre pandoc 2.10 methods
simple.caption = pandoc.SmallCaps(simple.caption)
-- create normal table block again
table = pandoc.utils.from_simple_table(simple)

Parameters:

tbl : a table (Block)

Returns:

• SimpleTable object (SimpleTable)

Since: 2.11

type {#pandoc.utils.type}

type (value)

Pandoc-friendly version of Lua's default type function, returning type information similar to what is presented in the manual.

The function works by checking the metafield __name. If the argument has a string-valued metafield __name, then it returns that string. Otherwise it behaves just like the normal type function.

Usage:

-- Prints one of 'string', 'boolean', 'Inlines', 'Blocks',
-- 'table', and 'nil', corresponding to the Haskell constructors
-- MetaString, MetaBool, MetaInlines, MetaBlocks, MetaMap,
-- and an unset value, respectively.

function Meta (meta)
  print('type of metavalue `author`:', pandoc.utils.type(meta.author))
end

Parameters:

value : any Lua value (any)

Returns:

• type of the given value (string)

Since: 2.17

Version {#pandoc.utils.Version}

Version (v)

Creates a Version object.

Parameters:

v : version description ([version string, list of integers, or integer]{unknown-type="version string, list of integers, or integer"})

Returns:

• new Version object (Version)

Module pandoc.mediabag

The pandoc.mediabag module allows accessing pandoc's media storage. The "media bag" is used when pandoc is called with the --extract-media or (for HTML only) --embed-resources option.

The module is loaded as part of module pandoc and can either be accessed via the pandoc.mediabag field, or explicitly required, e.g.:

local mb = require 'pandoc.mediabag'

Functions {#pandoc.mediabag-functions}

delete {#pandoc.mediabag.delete}

delete (filepath)

Removes a single entry from the media bag.

Parameters:

filepath : Filename of the item to deleted. The media bag will be left unchanged if no entry with the given filename exists. (string)

Since: 2.7.3

empty {#pandoc.mediabag.empty}

empty ()

Clear-out the media bag, deleting all items.

Since: 2.7.3

fetch {#pandoc.mediabag.fetch}

fetch (source)

Fetches the given source from a URL or local file. Returns two values: the contents of the file and the MIME type (or an empty string).

The function will first try to retrieve source from the mediabag; if that fails, it will try to download it or read it from the local file system while respecting pandoc's "resource path" setting.

Usage:

local diagram_url = 'https://pandoc.org/diagram.jpg'
local mt, contents = pandoc.mediabag.fetch(diagram_url)

Parameters:

source : path to a resource; either a local file path or URI (string)

Returns:

• The entry's MIME type, or nil if the file was not found. (string)
• Contents of the file, or nil if the file was not found. (string)

Since: 2.0

fill {#pandoc.mediabag.fill}

fill (doc)

Fills the mediabag with the images in the given document. An image that cannot be retrieved will be replaced with a Span of class "image" that contains the image description.

Images for which the mediabag already contains an item will not be processed again.

Parameters:

doc : document from which to fill the mediabag (Pandoc)

Returns:

• modified document (Pandoc)

Since: 2.19

insert {#pandoc.mediabag.insert}

insert (filepath, mimetype, contents)

Adds a new entry to pandoc's media bag. Replaces any existing media bag entry the same filepath.

Usage:

local fp = 'media/hello.txt'
local mt = 'text/plain'
local contents = 'Hello, World!'
pandoc.mediabag.insert(fp, mt, contents)

Parameters:

filepath : filename and path relative to the output folder. (string)

mimetype : the item's MIME type; omit if unknown or unavailable. (string)

contents : the binary contents of the file. (string)

Since: 2.0

items {#pandoc.mediabag.items}

items ()

Returns an iterator triple to be used with Lua's generic for statement. The iterator returns the filepath, MIME type, and content of a media bag item on each invocation. Items are processed one-by-one to avoid excessive memory use.

This function should be used only when full access to all items, including their contents, is required. For all other cases, list should be preferred.

Usage:

for fp, mt, contents in pandoc.mediabag.items() do
  -- print(fp, mt, contents)
end

Returns:

Iterator triple:

• The iterator function; must be called with the iterator state and the current iterator value.
• Iterator state -- an opaque value to be passed to the iterator function.
• Initial iterator value.

Since: 2.7.3

list {#pandoc.mediabag.list}

list ()

Get a summary of the current media bag contents.

Usage:

-- calculate the size of the media bag.
local mb_items = pandoc.mediabag.list()
local sum = 0
for i = 1, #mb_items do
    sum = sum + mb_items[i].length
end
print(sum)

Returns:

• A list of elements summarizing each entry in the media bag. The summary item contains the keys path, type, and length, giving the filepath, MIME type, and length of contents in bytes, respectively. (table)

Since: 2.0

lookup {#pandoc.mediabag.lookup}

lookup (filepath)

Lookup a media item in the media bag, and return its MIME type and contents.

Usage:

local filename = 'media/diagram.png'
local mt, contents = pandoc.mediabag.lookup(filename)

Parameters:

filepath : name of the file to look up. (string)

Returns:

• The entry's MIME type, or nil if the file was not found. (string)
• Contents of the file, or nil if the file was not found. (string)

Since: 2.0

write {#pandoc.mediabag.write}

write (dir[, fp])

Writes the contents of mediabag to the given target directory. If fp is given, then only the resource with the given name will be extracted. Omitting that parameter means that the whole mediabag gets extracted. An error is thrown if fp is given but cannot be found in the mediabag.

Parameters:

dir : path of the target directory (string)

fp : canonical name (relative path) of resource (string)

Since: 3.0

Module pandoc.List

This module defines pandoc's list type. It comes with useful methods and convenience functions.

Constructor

[pandoc.List([table])]{#pandoc.list}

: Create a new List. If the optional argument table is given, set the metatable of that value to pandoc.List. This is an alias for pandoc.List:new([table]).

Metamethods

pandoc.List:__concat (list) {#pandoc.list:__concat}

Concatenates two lists.

Parameters:

list : second list concatenated to the first

Returns: a new list containing all elements from list1 and list2

pandoc.List:__eq (a, b) {#pandoc.list:__eq}

Compares two lists for equality. The lists are taken as equal if and only if they are of the same type (i.e., have the same non-nil metatable), have the same length, and if all elements are equal.

Parameters:

a, b : any Lua object

Returns:

• true if the two lists are equal, false otherwise.

Methods

pandoc.List:at {#pandoc.list:at}

:at (index[, default])

Returns the element at the given index, or default if the list contains no item at the given position.

Negative integers count back from the last item in the list.

Parameters:

index : element position (integer)

default : the default value that is returned if the index is out of range (any)

Returns:

• the list item at index, or default.

pandoc.List:clone () {#pandoc.list:clone}

Returns a (shallow) copy of the list. (To get a deep copy of the list, use walk with an empty filter.)

pandoc.List:extend (list) {#pandoc.list:extend}

Adds the given list to the end of this list.

Parameters:

list : list to appended

pandoc.List:find (needle, init) {#pandoc.list:find}

Returns the value and index of the first occurrence of the given item.

Parameters:

needle : item to search for

init : index at which the search is started

Returns: first item equal to the needle, or nil if no such item exists.

pandoc.List:find_if (pred, init) {#pandoc.list:find_if}

Returns the value and index of the first element for which the predicate holds true.

Parameters:

pred : the predicate function

init : index at which the search is started

Returns: first item for which `test` succeeds, or nil if no such item exists.

pandoc.List:filter (pred) {#pandoc.list:filter}

Returns a new list containing all items satisfying a given condition.

Parameters:

pred : condition items must satisfy.

Returns: a new list containing all items for which `test` was true.

pandoc.List:includes (needle, init) {#pandoc.list:includes}

Checks if the list has an item equal to the given needle.

Parameters:

needle : item to search for

init : index at which the search is started

Returns: true if a list item is equal to the needle, false otherwise

pandoc.List:insert ([pos], value) {#pandoc.list:insert}

Inserts element value at position pos in list, shifting elements to the next-greater index if necessary.

This function is identical to table.insert.

Parameters:

pos : index of the new value; defaults to length of the list + 1

value : value to insert into the list

pandoc.List:iter ([step]) {#pandoc.list:iter}

Create an iterator over the list. The resulting function returns the next value each time it is called.

Usage:

for item in List{1, 1, 2, 3, 5, 8}:iter() do
  -- process item
end

Parameters:

step : step width with which to step through the list. Negative step sizes will cause the iterator to start from the end of the list. Defaults to 1. (integer)

Returns:

• iterator (function)

pandoc.List:map (fn) {#pandoc.list:map}

Returns a copy of the current list by applying the given function to all elements.

Parameters:

fn : function which is applied to all list items.

pandoc.List:new([table]) {#pandoc.list:new}

Create a new List. If the optional argument table is given, set the metatable of that value to pandoc.List.

The function also accepts an iterator, in which case it creates a new list from the return values of the iterator function.

Parameters:

table : table which should be treatable as a list; defaults to an empty table

Returns: the updated input value

pandoc.List:remove ([pos]) {#pandoc.list:remove}

Removes the element at position pos, returning the value of the removed element.

This function is identical to table.remove.

Parameters:

pos : position of the list value that will be removed; defaults to the index of the last element

Returns: the removed element

pandoc.List:sort ([comp]) {#pandoc.list:sort}

Sorts list elements in a given order, in-place. If comp is given, then it must be a function that receives two list elements and returns true when the first element must come before the second in the final order (so that, after the sort, i < j implies not comp(list[j],list[i])). If comp is not given, then the standard Lua operator < is used instead.

Note that the comp function must define a strict partial order over the elements in the list; that is, it must be asymmetric and transitive. Otherwise, no valid sort may be possible.

The sort algorithm is not stable: elements considered equal by the given order may have their relative positions changed by the sort.

This function is identical to table.sort.

Parameters:

comp : Comparison function as described above.

Module pandoc.format

Information about the formats supported by pandoc.

Functions {#pandoc.format-functions}

all_extensions {#pandoc.format.all_extensions}

all_extensions (format)

Returns the list of all valid extensions for a format. No distinction is made between input and output; an extension can have an effect when reading a format but not when writing it, or vice versa.

Parameters:

format : format name (string)

Returns:

• all extensions supported for format ([FormatExtensions]{unknown-type="FormatExtensions"})

Since: 3.0

default_extensions {#pandoc.format.default_extensions}

default_extensions (format)

Returns the list of default extensions of the given format; this function does not check if the format is supported, it will return a fallback list of extensions even for unknown formats.

Parameters:

format : format name (string)

Returns:

• default extensions enabled for format ([FormatExtensions]{unknown-type="FormatExtensions"})

Since: 3.0

extensions {#pandoc.format.extensions}

extensions (format)

Returns the extension configuration for the given format. The configuration is represented as a table with all supported extensions as keys and their default status as value, with true indicating that the extension is enabled by default, while false marks a supported extension that's disabled.

This function can be used to assign a value to the Extensions global in custom readers and writers.

Parameters:

format : format identifier (string)

Returns:

• extensions config (table)

Since: 3.0

from_path {#pandoc.format.from_path}

from_path (path)

Parameters:

path : file path, or list of paths (string|{string,...})

Returns:

• format determined by heuristic (string|nil)

Since: 3.1.2

Module pandoc.image

Basic image querying functions.

Functions {#pandoc.image-functions}

size {#pandoc.image.size}

size (image[, opts])

Returns a table containing the size and resolution of an image; throws an error if the given string is not an image, or if the size of the image cannot be determined.

The resulting table has four entries: width, height, dpi_horz, and dpi_vert.

The opts parameter, when given, should be either a WriterOptions object such as PANDOC_WRITER_OPTIONS, or a table with a dpi entry. It affects the calculation for vector image formats such as SVG.

Parameters:

image : image data (string)

opts : writer options (WriterOptions|table)

Returns:

• image size information or error message (table)

Since: 3.1.13

format {#pandoc.image.format}

format (image)

Returns the format of an image as a lowercase string.

Formats recognized by pandoc include png, gif, tiff, jpeg, pdf, svg, eps, and emf.

Parameters:

image : binary image data (string)

Returns:

• image format, or nil if the format cannot be determined (string|nil)

Since: 3.1.13

Module pandoc.json

JSON module to work with JSON; based on the Aeson Haskell package.

Fields {#pandoc.json-fields}

null {#pandoc.json.null}

Value used to represent the null JSON value. (light userdata)

Functions {#pandoc.json-functions}

decode {#pandoc.json.decode}

decode (str[, pandoc_types])

Creates a Lua object from a JSON string. If the input can be decoded as representing an Inline, Block, Pandoc, Inlines, or Blocks element the function will return an object of the appropriate type. Otherwise, if the input does not represent any of the AST types, the default decoding is applied: Objects and arrays are represented as tables, the JSON null value becomes null, and JSON booleans, strings, and numbers are converted using the Lua types of the same name.

The special handling of AST elements can be disabled by setting pandoc_types to false.

Parameters:

str : JSON string (string)

pandoc_types : whether to use pandoc types when possible. (boolean)

Returns:

• decoded object (any)

Since: 3.1.1

encode {#pandoc.json.encode}

encode (object)

Encodes a Lua object as JSON string.

If the object has a metamethod with name __tojson, then the result is that of a call to that method with object passed as the sole argument. The result of that call is expected to be a valid JSON string, but this is not checked.

Parameters:

object : object to convert (any)

Returns:

• JSON encoding of the given object (string)

Since: 3.1.1

Module pandoc.log

Access to pandoc's logging system.

Functions {#pandoc.log-functions}

info {#pandoc.log.info}

info (message)

Reports a ScriptingInfo message to pandoc's logging system.

Parameters:

message : the info message (string)

Since: 3.2

silence {#pandoc.log.silence}

silence (fn)

Applies the function to the given arguments while preventing log messages from being added to the log. The warnings and info messages reported during the function call are returned as the first return value, with the results of the function call following thereafter.

Parameters:

fn : function to be silenced (function)

Returns:

List of log messages triggered during the function call, and any value returned by the function.

Since: 3.2

warn {#pandoc.log.warn}

warn (message)

Reports a ScriptingWarning to pandoc's logging system. The warning will be printed to stderr unless logging verbosity has been set to ERROR.

Parameters:

message : the warning message (string)

Since: 3.2

Module pandoc.path

Module for file path manipulations.

Fields {#pandoc.path-fields}

separator {#pandoc.path.separator}

The character that separates directories. (string)

search_path_separator {#pandoc.path.search_path_separator}

The character that is used to separate the entries in the PATH environment variable. (string)

Functions {#pandoc.path-functions}

directory {#pandoc.path.directory}

directory (filepath)

Gets the directory name, i.e., removes the last directory separator and everything after from the given path.

Parameters:

filepath : path (string)

Returns:

• The filepath up to the last directory separator. (string)

Since: 2.12

filename {#pandoc.path.filename}

filename (filepath)

Get the file name.

Parameters:

filepath : path (string)

Returns:

• File name part of the input path. (string)

Since: 2.12

is_absolute {#pandoc.path.is_absolute}

is_absolute (filepath)

Checks whether a path is absolute, i.e. not fixed to a root.

Parameters:

filepath : path (string)

Returns:

• true iff filepath is an absolute path, false otherwise. (boolean)

Since: 2.12

is_relative {#pandoc.path.is_relative}

is_relative (filepath)

Checks whether a path is relative or fixed to a root.

Parameters:

filepath : path (string)

Returns:

• true iff filepath is a relative path, false otherwise. (boolean)

Since: 2.12

join {#pandoc.path.join}

join (filepaths)

Join path elements back together by the directory separator.

Parameters:

filepaths : path components ({string,...})

Returns:

• The joined path. (string)

Since: 2.12

make_relative {#pandoc.path.make_relative}

make_relative (path, root[, unsafe])

Contract a filename, based on a relative path. Note that the resulting path will never introduce .. paths, as the presence of symlinks means ../b may not reach a/b if it starts from a/c. For a worked example see this blog post.

Parameters:

path : path to be made relative (string)

root : root path (string)

unsafe : whether to allow .. in the result. (boolean)

Returns:

• contracted filename (string)

Since: 2.12

normalize {#pandoc.path.normalize}

normalize (filepath)

Normalizes a path.

• // makes sense only as part of a (Windows) network drive; elsewhere, multiple slashes are reduced to a single path.separator (platform dependent).
• / becomes path.separator (platform dependent).
• ./ is removed.
• an empty path becomes .

Parameters:

filepath : path (string)

Returns:

• The normalized path. (string)

Since: 2.12

split {#pandoc.path.split}

split (filepath)

Splits a path by the directory separator.

Parameters:

filepath : path (string)

Returns:

• List of all path components. ({string,...})

Since: 2.12

split_extension {#pandoc.path.split_extension}

split_extension (filepath)

Splits the last extension from a file path and returns the parts. The extension, if present, includes the leading separator; if the path has no extension, then the empty string is returned as the extension.

Parameters:

filepath : path (string)

Returns:

• filepath without extension (string)
• extension or empty string (string)

Since: 2.12

split_search_path {#pandoc.path.split_search_path}

split_search_path (search_path)

Takes a string and splits it on the search_path_separator character. Blank items are ignored on Windows, and converted to . on Posix. On Windows path elements are stripped of quotes.

Parameters:

search_path : platform-specific search path (string)

Returns:

• list of directories in search path ({string,...})

Since: 2.12

treat_strings_as_paths {#pandoc.path.treat_strings_as_paths}

treat_strings_as_paths ()

Augment the string module such that strings can be used as path objects.

Since: 2.12

Module pandoc.structure

Access to the higher-level document structure, including hierarchical sections and the table of contents.

Functions {#pandoc.structure-functions}

make_sections {#pandoc.structure.make_sections}

make_sections (blocks[, opts])

Puts Blocks into a hierarchical structure: a list of sections (each a Div with class "section" and first element a Header).

The optional opts argument can be a table; two settings are recognized: If number_sections is true, a number attribute containing the section number will be added to each Header. If base_level is an integer, then Header levels will be reorganized so that there are no gaps, with numbering levels shifted by the given value. Finally, an integer slide_level value triggers the creation of slides at that heading level.

Note that a WriterOptions object can be passed as the opts table; this will set the number_section and slide_level values to those defined on the command line.

Usage:

local blocks = {
  pandoc.Header(2, pandoc.Str 'first'),
  pandoc.Header(2, pandoc.Str 'second'),
}
local opts = PANDOC_WRITER_OPTIONS
local newblocks = pandoc.structure.make_sections(blocks, opts)

Parameters:

blocks : document blocks to process (Blocks|Pandoc)

opts : options (table)

Returns:

• processed blocks (Blocks)

Since: 3.0

slide_level {#pandoc.structure.slide_level}

slide_level (blocks)

Find level of header that starts slides (defined as the least header level that occurs before a non-header/non-hrule in the blocks).

Parameters:

blocks : document body (Blocks|Pandoc)

Returns:

• slide level ([integer]{unknown-type="integer"})

Since: 3.0

split_into_chunks {#pandoc.structure.split_into_chunks}

split_into_chunks (doc[, opts])

Converts a Pandoc document into a ChunkedDoc.

Parameters:

doc : document to split (Pandoc)

opts

: Splitting options.

The following options are supported:

    `path_template`
    :   template used to generate the chunks' filepaths
        `%n` will be replaced with the chunk number (padded with
        leading 0s to 3 digits), `%s` with the section number of
        the heading, `%h` with the (stringified) heading text,
        `%i` with the section identifier. For example,
        `"section-%s-%i.html"` might be resolved to
        `"section-1.2-introduction.html"`.

        Default is `"chunk-%n"` (string)

    `number_sections`
    :   whether sections should be numbered; default is `false`
        (boolean)

    `chunk_level`
    :   The heading level the document should be split into
        chunks. The default is to split at the top-level, i.e.,
        `1`. (integer)

    `base_heading_level`
    :   The base level to be used for numbering. Default is `nil`
        (integer|nil)

(table)

Returns:

• (ChunkedDoc)

Since: 3.0

table_of_contents {#pandoc.structure.table_of_contents}

table_of_contents (toc_source[, opts])

Generates a table of contents for the given object.

Parameters:

toc_source : list of command line arguments (Blocks|Pandoc|ChunkedDoc)

opts : options (WriterOptions)

Returns:

• Table of contents as a BulletList object (Block)

Since: 3.0

Module pandoc.system

Access to the system's information and file functionality.

Fields {#pandoc.system-fields}

arch {#pandoc.system.arch}

The machine architecture on which the program is running. (string)

os {#pandoc.system.os}

The operating system on which the program is running. (string) The most common values are darwin (macOS), freebsd, linux, linux-android, mingw32 (Windows), netbsd, openbsd.

Functions {#pandoc.system-functions}

cputime {#pandoc.system.cputime}

cputime ()

Returns the number of picoseconds CPU time used by the current program. The precision of this result may vary in different versions and on different platforms.

Returns:

• CPU time in picoseconds ([integer]{unknown-type="integer"})

Since: 3.1.1

environment {#pandoc.system.environment}

environment ()

Retrieves the entire environment as a string-indexed table.

Returns:

• A table mapping environment variable names to their value. (table)

Since: 2.7.3

get_working_directory {#pandoc.system.get_working_directory}

get_working_directory ()

Obtain the current working directory as an absolute path.

Returns:

• The current working directory. (string)

Since: 2.8

list_directory {#pandoc.system.list_directory}

list_directory ([directory])

List the contents of a directory.

Parameters:

directory : Path of the directory whose contents should be listed. Defaults to .. (string)

Returns:

• A table of all entries in directory, except for the special entries (. and ..). (table)

Since: 2.19

make_directory {#pandoc.system.make_directory}

make_directory (dirname[, create_parent])

Create a new directory which is initially empty, or as near to empty as the operating system allows. The function throws an error if the directory cannot be created, e.g., if the parent directory does not exist or if a directory of the same name is already present.

If the optional second parameter is provided and truthy, then all directories, including parent directories, are created as necessary.

Parameters:

dirname : name of the new directory (string)

create_parent : create parent directory if necessary (boolean)

Since: 2.19

remove_directory {#pandoc.system.remove_directory}

remove_directory (dirname[, recursive])

Remove an existing, empty directory. If recursive is given, then delete the directory and its contents recursively.

Parameters:

dirname : name of the directory to delete (string)

recursive : delete content recursively (boolean)

Since: 2.19

with_environment {#pandoc.system.with_environment}

with_environment (environment, callback)

Run an action within a custom environment. Only the environment variables given by environment will be set, when callback is called. The original environment is restored after this function finishes, even if an error occurs while running the callback action.

Parameters:

environment : Environment variables and their values to be set before running callback (table)

callback : Action to execute in the custom environment (function)

Returns:

The results of the call to callback.

Since: 2.7.3

with_temporary_directory {#pandoc.system.with_temporary_directory}

with_temporary_directory (parent_dir, templ, callback)

Create and use a temporary directory inside the given directory. The directory is deleted after the callback returns.

Parameters:

parent_dir : Parent directory to create the directory in. If this parameter is omitted, the system's canonical temporary directory is used. (string)

templ : Directory name template. (string)

callback : Function which takes the name of the temporary directory as its first argument. (function)

Returns:

The results of the call to callback.

Since: 2.8

with_working_directory {#pandoc.system.with_working_directory}

with_working_directory (directory, callback)

Run an action within a different directory. This function will change the working directory to directory, execute callback, then switch back to the original working directory, even if an error occurs while running the callback action.

Parameters:

directory : Directory in which the given callback should be executed (string)

callback : Action to execute in the given directory (function)

Returns:

The results of the call to callback.

Since: 2.7.3

Module pandoc.layout

Plain-text document layouting.

Fields {#pandoc.layout-fields}

blankline {#pandoc.layout.blankline}

Inserts a blank line unless one exists already. (Doc)

cr {#pandoc.layout.cr}

A carriage return. Does nothing if we're at the beginning of a line; otherwise inserts a newline. (Doc)

empty {#pandoc.layout.empty}

The empty document. (Doc)

space {#pandoc.layout.space}

A breaking (reflowable) space. (Doc)

Functions {#pandoc.layout-functions}

after_break {#pandoc.layout.after_break}

after_break (text)

Creates a Doc which is conditionally included only if it comes at the beginning of a line.

An example where this is useful is for escaping line-initial . in roff man.

Parameters:

text : content to include when placed after a break (string)

Returns:

• new doc (Doc)

Since: 2.18

before_non_blank {#pandoc.layout.before_non_blank}

before_non_blank (doc)

Conditionally includes the given doc unless it is followed by a blank space.

Parameters:

doc : document (Doc)

Returns:

• conditional doc (Doc)

Since: 2.18

blanklines {#pandoc.layout.blanklines}

blanklines (n)

Inserts blank lines unless they exist already.

Parameters:

n : number of blank lines ([integer]{unknown-type="integer"})

Returns:

• conditional blank lines (Doc)

Since: 2.18

braces {#pandoc.layout.braces}

braces (doc)

Puts the doc in curly braces.

Parameters:

doc : document (Doc)

Returns:

• doc enclosed by {}. (Doc)

Since: 2.18

brackets {#pandoc.layout.brackets}

brackets (doc)

Puts the doc in square brackets

Parameters:

doc : document (Doc)

Returns:

• doc enclosed by []. (Doc)

Since: 2.18

cblock {#pandoc.layout.cblock}

cblock (doc, width)

Creates a block with the given width and content, aligned centered.

Parameters:

doc : document (Doc)

width : block width in chars ([integer]{unknown-type="integer"})

Returns:

• doc, aligned centered in a block with max width chars per line. (Doc)

Since: 2.18

chomp {#pandoc.layout.chomp}

chomp (doc)

Chomps trailing blank space off of the doc.

Parameters:

doc : document (Doc)

Returns:

• doc without trailing blanks (Doc)

Since: 2.18

concat {#pandoc.layout.concat}

concat (docs[, sep])

Concatenates a list of Docs.

Parameters:

docs : list of Docs ([`{Doc,...}`]{unknown-type="{Doc,...}"})

sep : separator (default: none) (Doc)

Returns:

• concatenated doc (Doc)

Since: 2.18

double_quotes {#pandoc.layout.double_quotes}

double_quotes (doc)

Wraps a Doc in double quotes.

Parameters:

doc : document (Doc)

Returns:

• doc enclosed by " chars (Doc)

Since: 2.18

flush {#pandoc.layout.flush}

flush (doc)

Makes a Doc flush against the left margin.

Parameters:

doc : document (Doc)

Returns:

• flushed doc (Doc)

Since: 2.18

hang {#pandoc.layout.hang}

hang (doc, ind, start)

Creates a hanging indent.

Parameters:

doc : document (Doc)

ind : indentation width ([integer]{unknown-type="integer"})

start : document (Doc)

Returns:

• doc prefixed by start on the first line, subsequent lines indented by ind spaces. (Doc)

Since: 2.18

inside {#pandoc.layout.inside}

inside (contents, start, end)

Encloses a Doc inside a start and end Doc.

Parameters:

contents : document (Doc)

start : document (Doc)

end : document (Doc)

Returns:

• enclosed contents (Doc)

Since: 2.18

lblock {#pandoc.layout.lblock}

lblock (doc, width)

Creates a block with the given width and content, aligned to the left.

Parameters:

doc : document (Doc)

width : block width in chars ([integer]{unknown-type="integer"})

Returns:

• doc put into block with max width chars per line. (Doc)

Since: 2.18

literal {#pandoc.layout.literal}

literal (text)

Creates a Doc from a string.

Parameters:

text : literal value (string)

Returns:

• doc containing just the literal string (Doc)

Since: 2.18

nest {#pandoc.layout.nest}

nest (doc, ind)

Indents a Doc by the specified number of spaces.

Parameters:

doc : document (Doc)

ind : indentation size ([integer]{unknown-type="integer"})

Returns:

• doc indented by ind spaces (Doc)

Since: 2.18

nestle {#pandoc.layout.nestle}

nestle (doc)

Removes leading blank lines from a Doc.

Parameters:

doc : document (Doc)

Returns:

• doc with leading blanks removed (Doc)

Since: 2.18

nowrap {#pandoc.layout.nowrap}

nowrap (doc)

Makes a Doc non-reflowable.

Parameters:

doc : document (Doc)

Returns:

• same as input, but non-reflowable (Doc)

Since: 2.18

parens {#pandoc.layout.parens}

parens (doc)

Puts the doc in parentheses.

Parameters:

doc : document (Doc)

Returns:

• doc enclosed by (). (Doc)

Since: 2.18

prefixed {#pandoc.layout.prefixed}

prefixed (doc, prefix)

Uses the specified string as a prefix for every line of the inside document (except the first, if not at the beginning of the line).

Parameters:

doc : document (Doc)

prefix : prefix for each line (string)

Returns:

• prefixed doc (Doc)

Since: 2.18

quotes {#pandoc.layout.quotes}

quotes (doc)

Wraps a Doc in single quotes.

Parameters:

doc : document (Doc)

Returns:

• doc enclosed in '. (Doc)

Since: 2.18

rblock {#pandoc.layout.rblock}

rblock (doc, width)

Creates a block with the given width and content, aligned to the right.

Parameters:

doc : document (Doc)

width : block width in chars ([integer]{unknown-type="integer"})

Returns:

• doc, right aligned in a block with max width chars per line. (Doc)

Since: 2.18

vfill {#pandoc.layout.vfill}

vfill (border)

An expandable border that, when placed next to a box, expands to the height of the box. Strings cycle through the list provided.

Parameters:

border : vertically expanded characters (string)

Returns:

• automatically expanding border Doc (Doc)

Since: 2.18

render {#pandoc.layout.render}

render (doc[, colwidth[, style]])

Render a Doc. The text is reflowed on breakable spaces to match the given line length. Text is not reflowed if the line line length parameter is omitted or nil.

Parameters:

doc : document (Doc)

colwidth : Maximum number of characters per line. A value of nil, the default, means that the text is not reflown. ([integer]{unknown-type="integer"})

style : Whether to generate plain text or ANSI terminal output. Must be either 'plain' or 'ansi'. Defaults to 'plain'. (string)

Returns:

• rendered doc (string)

Since: 2.18

is_empty {#pandoc.layout.is_empty}

is_empty (doc)

Checks whether a doc is empty.

Parameters:

doc : document (Doc)

Returns:

• true iff doc is the empty document, false otherwise. (boolean)

Since: 2.18

height {#pandoc.layout.height}

height (doc)

Returns the height of a block or other Doc.

Parameters:

doc : document (Doc)

Returns:

• doc height ([integer]{unknown-type="integer"}|string)

Since: 2.18

min_offset {#pandoc.layout.min_offset}

min_offset (doc)

Returns the minimal width of a Doc when reflowed at breakable spaces.

Parameters:

doc : document (Doc)

Returns:

• minimal possible width ([integer]{unknown-type="integer"}|string)

Since: 2.18

offset {#pandoc.layout.offset}

offset (doc)

Returns the width of a Doc as number of characters.

Parameters:

doc : document (Doc)

Returns:

• doc width ([integer]{unknown-type="integer"}|string)

Since: 2.18

real_length {#pandoc.layout.real_length}

real_length (str)

Returns the real length of a string in a monospace font: 0 for a combining character, 1 for a regular character, 2 for an East Asian wide character.

Parameters:

str : UTF-8 string to measure (string)

Returns:

• text length ([integer]{unknown-type="integer"}|string)

Since: 2.18

update_column {#pandoc.layout.update_column}

update_column (doc, i)

Returns the column that would be occupied by the last laid out character.

Parameters:

doc : document (Doc)

i : start column ([integer]{unknown-type="integer"})

Returns:

• column number ([integer]{unknown-type="integer"}|string)

Since: 2.18

bold {#pandoc.layout.bold}

bold (doc)

Puts a Doc in boldface.

Parameters:

doc : document (Doc)

Returns:

• bolded Doc (Doc)

Since: 3.4.1

italic {#pandoc.layout.italic}

italic (doc)

Puts a Doc in italics.

Parameters:

doc : document (Doc)

Returns:

• styled Doc (Doc)

Since: 3.4.1

underlined {#pandoc.layout.underlined}

underlined (doc)

Underlines a Doc.

Parameters:

doc : document (Doc)

Returns:

• styled Doc (Doc)

Since: 3.4.1

strikeout {#pandoc.layout.strikeout}

strikeout (doc)

Puts a line through the Doc.

Parameters:

doc : document (Doc)

Returns:

• styled Doc (Doc)

Since: 3.4.1

fg {#pandoc.layout.fg}

fg (doc, color)

Set the foreground color.

Parameters:

doc : document (Doc)

color : One of 'black', 'red', 'green', 'yellow', 'blue', 'magenta' 'cyan', or 'white'. (string)

Returns:

• styled Doc (Doc)

Since: 3.4.1

bg {#pandoc.layout.bg}

bg (doc, color)

Set the background color.

Parameters:

doc : document (Doc)

color : One of 'black', 'red', 'green', 'yellow', 'blue', 'magenta' 'cyan', or 'white'. (string)

Returns:

• styled Doc (Doc)

Since: 3.4.1

Types {#pandoc.layout-types}

Doc {#type-pandoc.Doc}

See the description above.

Module pandoc.scaffolding

Scaffolding for custom writers.

Fields {#pandoc.scaffolding-fields}

Writer {#pandoc.scaffolding.Writer}

An object to be used as a Writer function; the construct handles most of the boilerplate, expecting only render functions for all AST elements (table)

Module pandoc.text

UTF-8 aware text manipulation functions, implemented in Haskell.

The text module can also be loaded under the name text, although this is discouraged and deprecated.

-- uppercase all regular text in a document:
function Str (s)
  s.text = pandoc.text.upper(s.text)
  return s
end

Functions {#pandoc.text-functions}

fromencoding {#pandoc.text.fromencoding}

fromencoding (s[, encoding])

Converts a string to UTF-8. The encoding parameter specifies the encoding of the input string. On Windows, that parameter defaults to the current ANSI code page; on other platforms the function will try to use the file system's encoding.

The set of known encodings is system dependent, but includes at least UTF-8, UTF-16BE, UTF-16LE, UTF-32BE, and UTF-32LE. Note that the default code page on Windows is available through CP0.

Parameters:

s : string to be converted (string)

encoding : target encoding (string)

Returns:

• UTF-8 string (string)

Since: 3.0

len {#pandoc.text.len}

len (s)

Returns the length of a UTF-8 string, i.e., the number of characters.

Parameters:

s : UTF-8 encoded string (string)

Returns:

• length ([integer]{unknown-type="integer"}|string)

Since: 2.0.3

lower {#pandoc.text.lower}

lower (s)

Returns a copy of a UTF-8 string, converted to lowercase.

Parameters:

s : UTF-8 string to convert to lowercase (string)

Returns:

• Lowercase copy of s (string)

Since: 2.0.3

reverse {#pandoc.text.reverse}

reverse (s)

Returns a copy of a UTF-8 string, with characters reversed.

Parameters:

s : UTF-8 string to revert (string)

Returns:

• Reversed s (string)

Since: 2.0.3

sub {#pandoc.text.sub}

sub (s, i[, j])

Returns a substring of a UTF-8 string, using Lua's string indexing rules.

Parameters:

s : UTF-8 string (string)

i : substring start position ([integer]{unknown-type="integer"})

j : substring end position ([integer]{unknown-type="integer"})

Returns:

• text substring (string)

Since: 2.0.3

toencoding {#pandoc.text.toencoding}

toencoding (s[, enc])

Converts a UTF-8 string to a different encoding. The encoding parameter defaults to the current ANSI code page on Windows; on other platforms it will try to guess the file system's encoding.

The set of known encodings is system dependent, but includes at least UTF-8, UTF-16BE, UTF-16LE, UTF-32BE, and UTF-32LE. Note that the default code page on Windows is available through CP0.

Parameters:

s : UTF-8 string (string)

enc : target encoding (string)

Returns:

• re-encoded string (string)

Since: 3.0

upper {#pandoc.text.upper}

upper (s)

Returns a copy of a UTF-8 string, converted to uppercase.

Parameters:

s : UTF-8 string to convert to uppercase (string)

Returns:

• Uppercase copy of s (string)

Since: 2.0.3

Module pandoc.template

Handle pandoc templates.

Functions {#pandoc.template-functions}

apply {#pandoc.template.apply}

apply (template, context)

Applies a context with variable assignments to a template, returning the rendered template. The context parameter must be a table with variable names as keys and Doc, string, boolean, or table as values, where the table can be either be a list of the aforementioned types, or a nested context.

Parameters:

template : template to apply (Template)

context : variable values (table)

Returns:

• rendered template (Doc)

Since: 3.0

compile {#pandoc.template.compile}

compile (template[, templates_path])

Compiles a template string into a Template object usable by pandoc.

If the templates_path parameter is specified, then it should be the file path associated with the template. It is used when checking for partials. Partials will be taken only from the default data files if this parameter is omitted.

An error is raised if compilation fails.

Parameters:

template : template string (string)

templates_path : parameter to determine a default path and extension for partials; uses the data files templates path by default. (string)

Returns:

• compiled template (Template)

Since: 2.17

default {#pandoc.template.default}

default ([writer])

Returns the default template for a given writer as a string. An error is thrown if no such template can be found.

Parameters:

writer : name of the writer for which the template should be retrieved; defaults to the global FORMAT. (string)

Returns:

• raw template (string)

Since: 2.17

get {#pandoc.template.get}

get (filename)

Retrieve text for a template.

This function first checks the resource paths for a file of this name; if none is found, the templates directory in the user data directory is checked. Returns the content of the file, or throws an error if no file is found.

Parameters:

filename : name of the template (string)

Returns:

• content of template file (string)

Since: 3.2.1

meta_to_context {#pandoc.template.meta_to_context}

meta_to_context (meta, blocks_writer, inlines_writer)

Creates template context from the document's Meta data, using the given functions to convert Blocks and Inlines to Doc values.

Parameters:

meta : document metadata (Meta)

blocks_writer : converter from Blocks to Doc values (function)

inlines_writer : converter from Inlines to Doc values (function)

Returns:

• template context (table)

Since: 3.0

Module pandoc.types

Constructors for types that are not part of the pandoc AST.

Functions {#pandoc.types-functions}

Version {#pandoc.types.Version}

Version (version_specifier)

Parameters:

version_specifier : A version string like '2.7.3', a Lua number like 2.0, a list of integers like {2,7,3}, or a Version object. (string|number|{[integer]{unknown-type="integer"},...}|Version)

Returns:

• New Version object. (Version)

Since: 2.7.3

Module pandoc.zip

Functions to create, modify, and extract files from zip archives.

The module can be called as a function, in which case it behaves like the zip function described below.

Zip options are optional; when defined, they must be a table with any of the following keys:

• recursive: recurse directories when set to true;
• verbose: print info messages to stdout;
• destination: the value specifies the directory in which to extract;
• location: value is used as path name, defining where files are placed.
• preserve_symlinks: Boolean value, controlling whether symbolic links are preserved as such. This option is ignored on Windows.

Functions {#pandoc.zip-functions}

Archive {#pandoc.zip.Archive}

Archive ([bytestring_or_entries])

Reads an Archive structure from a raw zip archive or a list of Entry items; throws an error if the given string cannot be decoded into an archive.

Parameters:

bytestring_or_entries : binary archive data or list of entries; defaults to an empty list (string|{zip.Entry,...})

Returns:

• new Archive (zip.Archive)

Since: 3.0

Entry {#pandoc.zip.Entry}

Entry (path, contents[, modtime])

Generates a ZipEntry from a filepath, uncompressed content, and the file's modification time.

Parameters:

path : file path in archive (string)

contents : uncompressed contents (string)

modtime : modification time ([integer]{unknown-type="integer"})

Returns:

• a new zip archive entry (zip.Entry)

Since: 3.0

read_entry {#pandoc.zip.read_entry}

read_entry (filepath[, opts])

Generates a ZipEntry from a file or directory.

Parameters:

filepath : (string)

opts : zip options (table)

Returns:

• a new zip archive entry (zip.Entry)

Since: 3.0

zip {#pandoc.zip.zip}

zip (filepaths[, opts])

Package and compress the given files into a new Archive.

Parameters:

filepaths : list of files from which the archive is created. ({string,...})

opts : zip options (table)

Returns:

• a new archive (zip.Archive)

Since: 3.0

Types {#pandoc.zip-types}

zip.Archive {#type-pandoc.zip.Archive}

Properties {#type-pandoc.zip.Archive-properties}

entries {#type-pandoc.zip.Archive.entries}

Files in this zip archive ({zip.Entry,...})

Methods {#type-pandoc.zip.Archive-methods}

bytestring {#pandoc.zip.Archive.bytestring}

bytestring (self)

Returns the raw binary string representation of the archive.

Parameters:

self : (zip.Archive)

Returns:

• bytes of the archive (string)

extract {#pandoc.zip.Archive.extract}

extract (self[, opts])

Extract all files from this archive, creating directories as needed. Note that the last-modified time is set correctly only in POSIX, not in Windows. This function fails if encrypted entries are present.

Parameters:

self : (zip.Archive)

opts : zip options (table)

zip.Entry {#type-pandoc.zip.Entry}

Properties {#type-pandoc.zip.Entry-properties}

modtime {#type-pandoc.zip.Entry.modtime}

Modification time (seconds since unix epoch) ([integer]{unknown-type="integer"})

path {#type-pandoc.zip.Entry.path}

Relative path, using / as separator (zip.Entry)

Methods {#type-pandoc.zip.Entry-methods}

contents {#pandoc.zip.Entry.contents}

contents (self[, password])

Get the uncompressed contents of a zip entry. If password is given, then that password is used to decrypt the contents. An error is throws if decrypting fails.

Parameters:

self : (zip.Entry)

password : password for entry (string)

Returns:

• binary contents (string)

symlink {#pandoc.zip.Entry.symlink}

symlink (self)

Returns the target if the Entry represents a symbolic link, and nil otherwise. Always returns nil on Windows.

Parameters:

self : (zip.Entry)

Returns:

• link target if entry represents a symbolic link (string|nil)