-- This module implements {{Roman}}.  local p = {}  -- This function implements the {{overline}} template. local function overline( s )  return mw.ustring.format( '<span style="text-decoration:overline;">%s</span>', s ) end  -- Gets the Roman numerals for a given numeral table. Returns both the string of -- numerals and the value of the number after it is finished being processed. local function getLetters( num, t )  local ret = {}  for _, v in ipairs( t ) do  local val, letter = unpack( v )  while num >= val do  num = num - val  table.insert( ret, letter )  end  end  return table.concat( ret ), num end  -- The main control flow of the module. local function _main( args )  -- Get input and exit displaying nothing if the input is bad.  local num = tonumber( args[ 1 ] )  if not num or num < 1 or num == math.huge then  return  end  num = math.floor( num )   -- Return a message for numbers too big to be expressed in Roman numerals.  if num >= 5000000 then  return args[ 2 ] or 'N/A'  end   local ret = ''  -- Find the Roman numerals for the large part of numbers 5000 and bigger.  -- The if statement is not strictly necessary, but makes the algorithm   -- more efficient for smaller numbers.  if num >= 5000 then  local bigRomans = {  { 1000000, 'M' },  { 900000, 'CM' }, { 500000, 'D' }, { 400000, 'CD' }, { 100000, 'C' },  { 90000, 'XC' }, { 50000, 'L' }, { 40000, 'XL' }, { 10000, 'X' },  { 5000, 'V' }  }  local bigLetters  bigLetters, num = getLetters( num, bigRomans )  ret = overline( bigLetters )  end   -- Find the Roman numerals for numbers 4999 or less.  local smallRomans = {  {1000, "M"},  {900, "CM"}, {500, "D"}, {400, "CD"}, {100, "C"},  {90, "XC"}, {50, "L"}, {40, "XL"}, {10, "X"},  {9, "IX"}, {5, "V"}, {4, "IV"}, {1, "I"}  }  local smallLetters = getLetters( num, smallRomans )  ret = ret .. smallLetters   return ret end  function p.main( frame )  -- If called via #invoke, use the args passed into the invoking  -- template, or the args passed to #invoke if any exist. Otherwise  -- assume args are being passed directly in from the debug console  -- or from another Lua module.  local origArgs  if frame == mw.getCurrentFrame() then  origArgs = frame:getParent().args  for k, v in pairs( frame.args ) do  origArgs = frame.args  break  end  else  origArgs = frame  end  -- Trim whitespace and remove blank arguments.  local args = {}  for k, v in pairs( origArgs ) do  if type( v ) == 'string' then  v = mw.text.trim( v )  end  if v ~= '' then  args[k] = v  end  end  return _main( args ) end  return p