-- Experimental module for building complex HTML (e.g. infoboxes, navboxes) using a fluent interface  local HtmlBuilder = {}  local metatable = {}  metatable.__index = function(t, key)  local ret = rawget(t, key)  if ret then  return ret  end   ret = metatable[key]  if type(ret) == 'function' then  return function(...)  return ret(t, ...)  end  else  return ret  end end  metatable.__tostring = function(t)  local ret = {}  t._build(ret)  return table.concat(ret, '') end  metatable._build = function(t, ret)  if t.tagName then  table.insert(ret, '<' .. t.tagName)  for i, attr in ipairs(t.attributes) do  table.insert(ret, ' ' .. attr.name .. '="' .. attr.val .. '"')  end  if #t.styles > 0 then  table.insert(ret, ' style="')  for i, prop in ipairs(t.styles) do  if type(prop) == 'string' then -- added with cssText()  table.insert(ret, prop .. ';')  else -- added with css()  table.insert(ret, prop.name .. ':' .. prop.val .. ';')  end  end  table.insert(ret, '"')  end  if t.selfClosing then  table.insert(ret, ' /')  end  table.insert(ret, '>')  end  for i, node in ipairs(t.nodes) do  if node then  if type(node) == 'table' then  node._build(ret)  else  table.insert(ret, tostring(node))  end  end  end  if t.tagName and not t.unclosed and not t.selfClosing then  table.insert(ret, '</' .. t.tagName .. '>')  end end  metatable.node = function(t, builder)  if builder then  table.insert(t.nodes, builder)  end  return t end  metatable.wikitext = function(t, ...)  local vals = {...}  for i = 1, #vals do  if vals[i] then  table.insert(t.nodes, vals[i])  end  end  return t end  metatable.newline = function(t)  table.insert(t.nodes, '\n')  return t end  metatable.tag = function(t, tagName, args)  args = args or {}  args.parent = t  local builder = HtmlBuilder.create(tagName, args)  table.insert(t.nodes, builder)  return builder end  function getAttr(t, name)  for i, attr in ipairs(t.attributes) do  if attr.name == name then  return attr  end  end end  metatable.attr = function(t, name, val)  -- if caller sets the style attribute explicitly, then replace all styles previously added with css() and cssText()  if name == 'style' then  t.styles = {val}  return t  end   local attr = getAttr(t, name)  if attr then  attr.val = val  else  table.insert(t.attributes, {name = name, val = val})  end   return t end  metatable.addClass = function(t, class)  if class then  local attr = getAttr(t, 'class')  if attr then  attr.val = attr.val .. ' ' .. class  else  t.attr('class', class)  end  end   return t end  metatable.css = function(t, name, val)  if type(val) == 'string' or type(val) == 'number' then  for i, prop in ipairs(t.styles) do  if prop.name == name then  prop.val = val  return t  end  end   table.insert(t.styles, {name = name, val = val})  end   return t end  metatable.cssText = function(t, css)  if css then  table.insert(t.styles, css)  end  return t end  metatable.done = function(t)  return t.parent or t end  metatable.allDone = function(t)  while t.parent do  t = t.parent  end  return t end  function HtmlBuilder.create(tagName, args)  args = args or {}  local builder = {}  setmetatable(builder, metatable)  builder.nodes = {}  builder.attributes = {}  builder.styles = {}  builder.tagName = tagName  builder.parent = args.parent  builder.unclosed = args.unclosed or false  builder.selfClosing = args.selfClosing or false  return builder end  return HtmlBuilder