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Pandoc Converters
-- This is a sample custom writer for pandoc. It produces output
-- that is very similar to that of pandoc's HTML writer.
-- There is one new feature: code blocks marked with class 'dot'
-- are piped through graphviz and images are included in the HTML
-- output using 'data:' URLs.
--
-- Invoke with: pandoc -t sample.lua
--
-- Note: you need not have lua installed on your system to use this
-- custom writer. However, if you do have lua installed, you can
-- use it to test changes to the script. 'lua sample.lua' will
-- produce informative error messages if your code contains
-- syntax errors.
-- Character escaping
local function escape(s, in_attribute)
return s:gsub("[<>&\"']",
function(x)
if x == '<' then
return '&lt;'
elseif x == '>' then
return '&gt;'
elseif x == '&' then
return '&amp;'
elseif x == '"' then
return '&quot;'
elseif x == "'" then
return '&#39;'
else
return x
end
end)
end
-- Helper function to convert an attributes table into
-- a string that can be put into HTML tags.
local function attributes(attr)
local attr_table = {}
for x,y in pairs(attr) do
if y and y ~= "" then
table.insert(attr_table, ' ' .. x .. '="' .. escape(y,true) .. '"')
end
end
return table.concat(attr_table)
end
-- Run cmd on a temporary file containing inp and return result.
local function pipe(cmd, inp)
local tmp = os.tmpname()
local tmph = io.open(tmp, "w")
tmph:write(inp)
tmph:close()
local outh = io.popen(cmd .. " " .. tmp,"r")
local result = outh:read("*all")
outh:close()
os.remove(tmp)
return result
end
-- Table to store footnotes, so they can be included at the end.
local notes = {}
-- Blocksep is used to separate block elements.
function Blocksep()
return "\n\n"
end
-- This function is called once for the whole document. Parameters:
-- body is a string, metadata is a table, variables is a table.
-- This gives you a fragment. You could use the metadata table to
-- fill variables in a custom lua template. Or, pass `--template=...`
-- to pandoc, and pandoc will add do the template processing as
-- usual.
function Doc(body, metadata, variables)
local buffer = {}
local function add(s)
table.insert(buffer, s)
end
local css_style = [[
<ac:structured-macro ac:macro-id="b7c0ac99-8feb-49c2-858c-870cd55df16b" ac:name="html" ac:schema-version="1">
<ac:parameter ac:name="atlassian-macro-output-type">INLINE</ac:parameter>
<ac:plain-text-body>
<![CDATA[
<style>
#captioned-image {
text-align: center;
}]] ..
"</style>]]></ac:plain-text-body></ac:structured-macro>"
add(css_style)
add(body)
if #notes > 0 then
add('<ol class="footnotes">')
for _,note in pairs(notes) do
add(note)
end
add('</ol>')
end
return table.concat(buffer,'\n') .. '\n'
end
-- The functions that follow render corresponding pandoc elements.
-- s is always a string, attr is always a table of attributes, and
-- items is always an array of strings (the items in a list).
-- Comments indicate the types of other variables.
function Str(s)
return escape(s)
end
function Space()
return " "
end
function SoftBreak()
return "\n"
end
function LineBreak()
return "<br/>"
end
function Emph(s)
return "<em>" .. s .. "</em>"
end
function Strong(s)
return "<strong>" .. s .. "</strong>"
end
function Subscript(s)
return "<sub>" .. s .. "</sub>"
end
function Superscript(s)
return "<sup>" .. s .. "</sup>"
end
function SmallCaps(s)
return '<span style="font-variant: small-caps;">' .. s .. '</span>'
end
function Strikeout(s)
return '<span style="text-decoration: line-through;">' .. s .. '</span>'
end
function Link(s, src, tit, attr)
if src and string.sub(src, 1, 11) == "confluence:" then
-- [Page Link](confluence:SPACE:Content Title)
for space, page in src:gsub('%%20',' '):gmatch('confluence:(%w+):([%w%s]+)')
do
return string.format('<ac:link><ri:page ri:space-key="%s" '..
'ri:content-title="%s" /></ac:link>', space, page)
end
elseif src and string.sub(src, 1, 1) == "#" then
-- [Anchor Link](#anchor), taken from https://confluence.atlassian.com/doc/confluence-storage-format-790796544.html#ConfluenceStorageFormat-Links
return LinkToAnchor(escape(string.sub(src, 2, -1), true), s)
else
return "<a href='" .. escape(src,true) .. "' title='" ..
escape(tit,true) .. "'>" .. s .. "</a>"
end
end
function Image(s, src, tit, attr)
return "<img src='" .. escape(src,true) .. "' title='" ..
escape(tit,true) .. "'/>"
end
function Code(s, attr)
return "<code" .. attributes(attr) .. ">" .. escape(s) .. "</code>"
end
function InlineMath(s)
return "\\(" .. escape(s) .. "\\)"
end
function DisplayMath(s)
return "\\[" .. escape(s) .. "\\]"
end
function AnchorRef(anchorName)
return '<ac:structured-macro ac:name="anchor"><ac:parameter ac:name="">'.. anchorName .. '</ac:parameter></ac:structured-macro>'
end
function LinkToAnchor(anchorName, text)
return '<ac:link ac:anchor="' .. anchorName .. '"><ac:link-body>' .. text .. '</ac:link-body></ac:link>'
end
function Note(s)
local num = #notes + 1
-- add a list item with the note to t[he note table.
table.insert(notes, '<li>' .. AnchorRef("fn" .. num) .. s .. LinkToAnchor('fnref' .. num, '&#8617;') .. '</li>')
-- return the footnote reference, linked to the note.
return '<sup>' .. AnchorRef('fnref' .. num) .. LinkToAnchor('fn' .. num, num) .. '</sup>'
end
function Span(s, attr)
return "<span" .. attributes(attr) .. ">" .. s .. "</span>"
end
function RawInline(format, str)
if format == "html" then
return str
else
return ''
end
end
function Cite(s, cs)
local ids = {}
for _,cit in ipairs(cs) do
table.insert(ids, cit.citationId)
end
return "<span class=\"cite\" data-citation-ids=\"" .. table.concat(ids, ",") ..
"\">" .. s .. "</span>"
end
function Plain(s)
return s
end
function Para(s)
return "<p>" .. s .. "</p>"
end
-- lev is an integer, the header level.
function Header(lev, s, attr)
local attr_table = {}
local prefix = ""
for x,y in pairs(attr) do
if y and y ~= "" then
if x == "id" then
prefix = prefix .. AnchorRef(y)
else
attr_table[x] = y
end
end
end
return prefix .. "<h" .. lev .. attributes(attr_table) .. ">" .. s .. "</h" .. lev .. ">"
end
function BlockQuote(s)
return "<blockquote>\n" .. s .. "\n</blockquote>"
end
function HorizontalRule()
return "<hr/>"
end
function LineBlock(ls)
return '<div style="white-space: pre-line;">' .. table.concat(ls, '\n') ..
'</div>'
end
function CodeBlock(s, attr)
-- If code block has class 'dot', pipe the contents through dot
-- and base64, and include the base64-encoded png as a data: URL.
if attr.class and string.match(' ' .. attr.class .. ' ',' dot ') then
local png = pipe("base64", pipe("dot -Tpng", s))
return '<img src="data:image/png;base64,' .. png .. '"/>'
-- otherwise treat as code (one could pipe through a highlighter)
else
return "<pre><code" .. attributes(attr) .. ">" .. escape(s) ..
"</code></pre>"
end
end
function BulletList(items)
local buffer = {}
for _, item in pairs(items) do
table.insert(buffer, "<li>" .. item .. "</li>")
end
return "<ul>\n" .. table.concat(buffer, "\n") .. "\n</ul>"
end
function OrderedList(items)
local buffer = {}
for _, item in pairs(items) do
table.insert(buffer, "<li>" .. item .. "</li>")
end
return "<ol>\n" .. table.concat(buffer, "\n") .. "\n</ol>"
end
-- Revisit association list STackValue instance.
function DefinitionList(items)
local buffer = {}
for _,item in pairs(items) do
for k, v in pairs(item) do
table.insert(buffer,"<dt>" .. k .. "</dt>\n<dd>" ..
table.concat(v,"</dd>\n<dd>") .. "</dd>")
end
end
return "<dl>\n" .. table.concat(buffer, "\n") .. "\n</dl>"
end
-- Convert pandoc alignment to something HTML can use.
-- align is AlignLeft, AlignRight, AlignCenter, or AlignDefault.
function html_align(align)
if align == 'AlignLeft' then
return 'left'
elseif align == 'AlignRight' then
return 'right'
elseif align == 'AlignCenter' then
return 'center'
else
return 'left'
end
end
function table.shallow_copy(t)
local t2 = {}
for k,v in pairs(t) do
t2[k] = v
end
return t2
end
function CaptionedImage(src, tit, caption, attr)
local prefix = ""
if attr and attr['id'] ~= "" then
prefix = AnchorRef(attr['id'])
end
attr_cpy = table.shallow_copy(attr)
attr_cpy['id'] = "captioned-image"
return Div('<table><tbody><tr><td><ac:image><ri:attachment ri:filename="' .. escape(src,true) .. '" /></ac:image></td></tr><tr><td>' .. escape(caption) .. '</td></tr></tbody></table>', attr_cpy)
end
-- Caption is a string, aligns is an array of strings,
-- widths is an array of floats, headers is an array of
-- strings, rows is an array of arrays of strings.
function Table(caption, aligns, widths, headers, rows)
local buffer = {}
local function add(s)
table.insert(buffer, s)
end
add("<table>")
if caption ~= "" then
add("<caption>" .. caption .. "</caption>")
end
if widths and widths[1] ~= 0 then
for _, w in pairs(widths) do
-- io.write(string.format("%d%%", math.floor(w * 100)) )
add('<col width="' .. string.format("%d%%", math.ceil(w * 100)) .. '" />')
end
end
local header_row = {}
local empty_header = true
for i, h in pairs(headers) do
local align = html_align(aligns[i])
table.insert(header_row,'<th align="' .. align .. '">' .. h .. '</th>')
empty_header = empty_header and h == ""
end
if empty_header then
head = ""
else
add('<tr class="header">')
for _,h in pairs(header_row) do
add(h)
end
add('</tr>')
end
local class = "even"
for _, row in pairs(rows) do
class = (class == "even" and "odd") or "even"
add('<tr class="' .. class .. '">')
for i,c in pairs(row) do
add('<td align="' .. html_align(aligns[i]) .. '">' .. c .. '</td>')
end
add('</tr>')
end
add('</table>')
return table.concat(buffer,'\n')
end
function RawBlock(format, str)
if format == "html" then
return str
else
return ''
end
end
-- <ac:image ac:thumbnail="true" ac:height="225"><ri:attachment ri:filename="1-rabbit-junk.jpeg" /></ac:image>
function Div(s, attr)
local div_text = [[<ac:structured-macro ac:macro-id="57855606-2855-47df-ac05-f2cb358f1e23" ac:name="div" ac:schema-version="1">]]
for x,y in pairs(attr) do
if y and y ~= "" then
div_text = div_text .. string.format(' <ac:parameter ac:name="%s">%s</ac:parameter>', x, y)
end
end
div_text = div_text .. string.format(' <ac:rich-text-body>%s</ac:rich-text-body>\n</ac:structured-macro>', s)
return div_text
end
function DoubleQuoted(s)
return "&laquo;" .. s .. "&raquo;"
end
-- The following code will produce runtime warnings when you haven't defined
-- all of the functions you need for the custom writer, so it's useful
-- to include when you're working on a writer.
local meta = {}
meta.__index = function(_, key)
io.stderr:write(string.format("WARNING: Undefined function '%s'\n",key))
return function() return "" end
end
setmetatable(_G, meta)
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