5 files changed, 1064 insertions, 0 deletions

@@ -0,0 +1,17 @@
+function allwords ()
+    local line = io.read()
+    local pos = 1
+    return function ()
+        while line do
+            local s, e = string.find(line, "%w+", pos)
+            if s then
+                pos = e + 1
+                return string.sub(line, s, e)
+            else
+                line = io.read()
+                pos = 1
+            end
+        end
+        return nil
+    end
+end
@@ -0,0 +1,193 @@
+-- Pandoc "Just the text, Ma'am"
+-- (JTTM): a custom writer that
+-- strips everything except for
+-- the TEXT from a pandoc source
+-- vim: fdm=marker
+-- invoke with: pandoc -t jttm/jttm.lua
+
+-- Table to store footnotes so they are at the END of the document
+local notes = {}
+
+-- This function is called once for the whole document. Parameters:
+-- body is a string, metadata is a table, variables is a table.
+-- One could use some kind of templating
+-- system here; this just gives you a simple standalone HTML file.
+function Doc(body, metadata, variables)
+    local buffer = {}
+    local function add(s)
+        table.insert(buffer, s)
+    end
+    if metadata['title'] and metadata['title'] ~= "" then
+        add(string.upper(metadata['title']))
+    end
+    if metadata['subtitle'] and metadata['subtitle'] ~= "" then
+        add(": " .. metadata['subtitle'])
+    end
+    add("\n")
+    -- TODO: epigraph.content, epigraph.attrib, dedication, other metadata?
+    add(body)
+    -- TODO: add notes at the end.
+    return table.concat(buffer, '\n')
+end
+
+-- TODOs {{{
+function align(align)
+    -- TODO: is this necessary?
+end
+
+function Note(s)
+    -- TODO
+end
+
+-- convert Tables to csv? or tab-separated?
+function Table(caption, aligns, widths, headers, rows)
+    local buffer = {}
+    local function add(s)
+        table.insert(buffer, s)
+    end
+    add("\n\n")
+    if caption ~= "" then
+        add("[" .. caption .. "]")
+    end
+    -- TODO: finish
+end
+
+-- }}}
+-- Remove all formatting {{{
+function Blocksep()
+    return "\n\n"
+end
+function Emph(s)
+    return s
+end
+
+function Strong(s)
+    return s
+end
+
+function Subscript(s)
+    return s
+end
+
+function Superscript(s)
+    return s
+end
+
+function SmallCaps(s)
+    return s
+end
+
+function Strikeout(s)
+    return s
+end
+
+function Code(s, attr)
+    return s
+end
+
+function CodeBlock(s, attr)
+    return s
+end
+
+function InlineMath(s)
+    return s
+end
+
+function DisplayMath(s)
+    return s
+end
+
+function Span(s, attr)
+    return s
+end
+
+function Cite(s)
+    return s
+end
+
+function Plain(s)
+    return s
+end
+
+-- Links only include the link text
+function Link(s, src, tit)
+    return s
+end
+
+-- Images have nothing to give us
+-- (but add a space just in case)
+function Image(s, src, tit)
+    return " "
+end
+
+function Str(s)
+    return s
+end
+
+function Div(s, attr)
+    return s
+end
+
+function Space(s)
+    return " "
+end
+
+function LineBreak()
+    return "\n"
+end
+
+function Para(s)
+    -- add paragraphing
+    return s .. "\n\n"
+end
+-- }}}
+-- Leave just a little formatting {{{
+function Header(lev, s, attr)
+    if lev == 1 then
+        return "\n\n    " .. string.upper(s) .. "\n\n"
+    elseif lev == 2 then
+        return "\n    " .. string.upper(s) .. "\n"
+    else
+        return s
+    end
+end
+
+function Blockquote(s)
+    return "\n\n" .. string.gsub(s, "*\n", "    %0")
+end
+
+function HorizontalRule(s)
+    return "\n\n\n"
+end
+
+function BulletList(items)
+    local buffer = {}
+    for _, item in pairs(items) do
+        table.insert(buffer, "- " .. item .. "\n")
+    end
+    return "\n\n" .. table.concat(buffer, "\n") .. "\n\n"
+end
+
+function DefinitionList(items)
+    local buffer = {}
+    for _, item in pairs(items) do
+        for k, v in pairs(item) do
+            table.insert(buffer, "\n" .. k .. ":\n    " ..
+                         table.concat(v, "\n    "))
+        end
+    end
+    return "\n\n" .. table.concat(buffer, "\n") .. "\n\n"
+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)
+
@@ -0,0 +1,226 @@
+-- Pandoc River writer
+-- it takes out all formatting, leaving only a river of text
+-- running down the page: one word per line
+-- vim: fdm=marker
+-- invoke with: pandoc -t river.lua
+
+local function flow(s)
+    return s:gsub("%s+", "\n")
+end
+
+local function nude(s)
+    -- Expand contractions
+    s = s:gsub("'%a+%s", function (x)
+        if x == "'ll" then
+            return " will "
+        elseif x == "'ve" then
+            return " have "
+        elseif x == "'re" then
+            return " are "
+        else
+            return x
+        end
+    end)
+    -- Get rid of quotes around words
+    s = s:gsub('"', ' ')
+    s = s:gsub("%s+'", ' ')
+    s = s:gsub("'%s+", ' ')
+    -- Remove HTML entities
+    s = s:gsub('&.-;', ' ')
+    s = s:gsub('%b<>', ' ')
+    -- Remove end-of-line backslashes
+    s = s:gsub('%s+\\$', ' ')
+    -- Remove dashes (not hyphens)
+    s = s:gsub('%-%-+', ' ')
+    s = s:gsub('%-%s', ' ')
+    -- Remove general punctuation
+    s = s:gsub('[%.!%?:;,%[%]%(%)<>]', ' ')
+    -- Remove extra spaces
+    s = s:gsub('%s+', ' ')
+    return s:lower()
+end
+
+-- This function is called once for the whole document. Parameters:
+-- body is a string, metadata is a table, variables is a table.
+-- One could use some kind of templating
+-- system here; this just gives you a simple standalone HTML file.
+function Doc(body, metadata, variables)
+    local buffer = ""
+    local function add(s)
+        buffer = buffer .. nude(s) .. "\n"
+    end
+    if metadata['title'] then
+        add(metadata['title'])
+    end
+    if metadata['subtitle'] then
+        add(metadata['subtitle'])
+    end
+    -- TODO: epigraph.content, epigraph.attrib, dedication, other metadata?
+    add(body)
+    return flow(buffer)
+end
+
+-- Remove all formatting {{{
+function Note(s)
+    return nude(s)
+end
+
+function Blocksep()
+    return "\n"
+end
+function Emph(s)
+    return nude(s)
+end
+
+function Strong(s)
+    return nude(s)
+end
+
+function Subscript(s)
+    return nude(s)
+end
+
+function Superscript(s)
+    return nude(s)
+end
+
+function SmallCaps(s)
+    return nude(s)
+end
+
+function Strikeout(s)
+    return nude(s)
+end
+
+function Code(s, attr)
+    return nude(s)
+end
+
+function CodeBlock(s, attr)
+    return nude(s)
+end
+
+function InlineMath(s)
+    return nude(s)
+end
+
+function DisplayMath(s)
+    return nude(s)
+end
+
+function Span(s, attr)
+    return nude(s)
+end
+
+function Cite(s)
+    return nude(s)
+end
+
+function Plain(s)
+    return nude(s)
+end
+
+-- Links only include the link text
+function Link(s, src, tit)
+    return nude(s)
+end
+
+-- Images have nothing to give us
+-- (but add a space just in case)
+function Image(s, src, tit)
+    return "\n"
+end
+
+function CaptionedImage(s, src, tit)
+    return "\n"
+end
+
+function Str(s)
+    return nude(s)
+end
+
+function Div(s, attr)
+    return nude(s)
+end
+
+function Space(s)
+    return "\n"
+end
+
+function LineBreak()
+    return "\n"
+end
+
+function Para(s)
+    return nude(s)
+end
+
+function Header(lev, s, attr)
+    return nude(s)
+end
+
+function BlockQuote(s)
+    return nude(s)
+end
+
+function HorizontalRule()
+    return "\n"
+end
+
+function BulletList(items)
+    local buffer = ""
+    for _, item in pairs(items) do
+        buffer = buffer .. nude(item) .. "\n"
+    end
+    return buffer .. "\n"
+end
+
+function OrderedList(items)
+    local buffer = ""
+    for _, item in pairs(items) do
+        buffer = buffer .. nude(item) .. "\n"
+    end
+    return buffer .. "\n"
+end
+
+function DefinitionList(items)
+    local buffer = ""
+    for _, item in pairs(items) do
+        for k, v in pairs(item) do
+            buffer = buffer .. nude(k) .. "\n" .. nude(v) .. "\n"
+        end
+    end
+    return buffer .. "\n"
+end
+
+function Table(caption, aligns, widths, headers, rows)
+    local buffer = ""
+    local function add(s)
+        buffer = buffer .. nude(s) .. "\n"
+    end
+    if caption ~= "" then
+        add(caption)
+    end
+    for _,h in pairs(headers) do
+        add(h)
+    end
+    for _, row in pairs(rows) do
+        for _, cell in pairs(row) do
+            add(cell)
+        end
+    end
+    return buffer
+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)
+
@@ -0,0 +1,324 @@
+-- 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.
+-- One could use some kind of templating
+-- system here; this just gives you a simple standalone HTML file.
+function Doc(body, metadata, variables)
+  local buffer = {}
+  local function add(s)
+    table.insert(buffer, s)
+  end
+  add('<!DOCTYPE html>')
+  add('<html>')
+  add('<head>')
+  add('<title>' .. (metadata['title'] or '') .. '</title>')
+  add('</head>')
+  add('<body>')
+  if metadata['title'] and metadata['title'] ~= "" then
+    add('<h1 class="title">' .. metadata['title'] .. '</h1>')
+  end
+  for _, author in pairs(metadata['author'] or {}) do
+    add('<h2 class="author">' .. author .. '</h2>')
+  end
+  if metadata['date'] and metadata['date'] ~= "" then
+    add('<h3 class="date">' .. metadata.date .. '</h3>')
+  end
+  add(body)
+  if #notes > 0 then
+    add('<ol class="footnotes">')
+    for _,note in pairs(notes) do
+      add(note)
+    end
+    add('</ol>')
+  end
+  add('</body>')
+  add('</html>')
+  return table.concat(buffer,'\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 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 '<del>' .. s .. '</del>'
+end
+
+function Link(s, src, tit)
+  return "<a href='" .. escape(src,true) .. "' title='" ..
+         escape(tit,true) .. "'>" .. s .. "</a>"
+end
+
+function Image(s, src, tit)
+  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 Note(s)
+  local num = #notes + 1
+  -- insert the back reference right before the final closing tag.
+  s = string.gsub(s,
+          '(.*)</', '%1 <a href="#fnref' .. num ..  '">&#8617;</a></')
+  -- add a list item with the note to the note table.
+  table.insert(notes, '<li id="fn' .. num .. '">' .. s .. '</li>')
+  -- return the footnote reference, linked to the note.
+  return '<a id="fnref' .. num .. '" href="#fn' .. num ..
+            '"><sup>' .. num .. '</sup></a>'
+end
+
+function Span(s, attr)
+  return "<span" .. attributes(attr) .. ">" .. s .. "</span>"
+end
+
+function Cite(s)
+  return "<span class=\"cite\">" .. 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)
+  return "<h" .. lev .. attributes(attr) ..  ">" .. s .. "</h" .. lev .. ">"
+end
+
+function BlockQuote(s)
+  return "<blockquote>\n" .. s .. "\n</blockquote>"
+end
+
+function HorizontalRule()
+  return "<hr/>"
+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
+
+-- 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
+      add('<col width="' .. string.format("%d%%", 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 Div(s, attr)
+  return "<div" .. attributes(attr) .. ">\n" .. s .. "</div>"
+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)
+
@@ -0,0 +1,304 @@
+-- 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.
+-- One could use some kind of templating
+-- system here; this just gives you a simple standalone HTML file.
+function Doc(body, metadata, variables)
+    local buffer = {}
+    for k, v in pairs(metadata) do
+        if type(v) == "string" then
+            table.insert(buffer, string.upper(k) .. ': ' .. v)
+        else
+            table.insert(buffer, string.upper(k) .. ': ' .. table.concat(v))
+        end
+    end
+    return table.concat(buffer, "\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 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 '<del>' .. s .. '</del>'
+end
+
+function Link(s, src, tit)
+  return "<a href='" .. escape(src,true) .. "' title='" ..
+         escape(tit,true) .. "'>" .. s .. "</a>"
+end
+
+function Image(s, src, tit)
+  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 Note(s)
+  local num = #notes + 1
+  -- insert the back reference right before the final closing tag.
+  s = string.gsub(s,
+          '(.*)</', '%1 <a href="#fnref' .. num ..  '">&#8617;</a></')
+  -- add a list item with the note to the note table.
+  table.insert(notes, '<li id="fn' .. num .. '">' .. s .. '</li>')
+  -- return the footnote reference, linked to the note.
+  return '<a id="fnref' .. num .. '" href="#fn' .. num ..
+            '"><sup>' .. num .. '</sup></a>'
+end
+
+function Span(s, attr)
+  return "<span" .. attributes(attr) .. ">" .. s .. "</span>"
+end
+
+function Cite(s)
+  return "<span class=\"cite\">" .. 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)
+  return "<h" .. lev .. attributes(attr) ..  ">" .. s .. "</h" .. lev .. ">"
+end
+
+function BlockQuote(s)
+  return "<blockquote>\n" .. s .. "\n</blockquote>"
+end
+
+function HorizontalRule()
+  return "<hr/>"
+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
+
+-- 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
+      add('<col width="' .. string.format("%d%%", 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 Div(s, attr)
+  return "<div" .. attributes(attr) .. ">\n" .. s .. "</div>"
+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)
+
+