-- This module takes a list of dates and adds a marker highlighting the closest -- date in the future.  local p = {} local lang = mw.language.getContentLanguage()  local function normalizeDate(timestamp)  local success, date = pcall(lang.formatDate, lang, 'Y-m-d', timestamp)  return success and date end  local function makeData(args)  local data, unsorted = {}, {}  for k, v in pairs(args) do  if type(k) == 'string' then  local datakey, num = k:match('^(.-)([1-9][0-9]*)$')  if datakey == 'item' or datakey == 'date' then  num = tonumber(num)  unsorted[num] = unsorted[num] or {}  unsorted[num][datakey] = v  elseif datakey then  error(string.format("invalid parameter '%s' detected", k), 3)  end  end  end  for num, t in pairs(unsorted) do  if t.item and t.date then  local date = normalizeDate(t.date)  if not date then  error(string.format(  "invalid date '%s' in parameter 'date%d'",  t.date, num  ), 3)  end  t.date = date  table.insert(data, t)  elseif t.item then  error(string.format(  "parameter 'item%d' was specified but parameter 'date%d' is missing",  num, num  ), 3)  else  error(string.format(  "parameter 'date%d' was specified but parameter 'item%d' is missing",  num, num  ), 3)  end  end  table.sort(data, function (t1, t2)  return t1.date < t2.date  end)  return data end  local function makeComparisonDate(gracePeriod)  local timestamp  if gracePeriod then  timestamp = 'now - ' .. gracePeriod  else  timestamp = 'now'  end  local date = normalizeDate(timestamp)  if date then  return date  else  error(string.format("invalid grace period '%s'", gracePeriod), 3)  end end  local function makeHighlighter(color)  color = color or '#FC6'  local highlighter = mw.html.create('span')  highlighter  :css('background-color', color)  :wikitext(lang:getArrow('forwards'))  return tostring(highlighter) end  function p._main(args)  local data = makeData(args)  local comparisonDate = makeComparisonDate(args.graceperiod)  local highlighter = args.highlighter or makeHighlighter(args.highlightercolor)  local root = mw.html.create('ul')  root  :addClass(args.class)  :cssText(args.style)  local doneHighlight = false  for i, t in ipairs(data) do  local item  if not doneHighlight and t.date >= comparisonDate then  doneHighlight = true  item = highlighter .. ' ' .. t.item  else  item = t.item  end  root  :newline()  :tag('li')  :wikitext(item)  end  root:newline()  return tostring(root) end  function p.main(frame)  local args = require('Module:Arguments').getArgs(frame, {  wrappers = 'Template:Highlighted date list'  })  return p._main(args) end  return p