require('Module:No globals')  local p = {}  function p._main(n, d)  local num = tonumber(n)  if not num then  error('Unable to convert "' .. tostring(n) .. '" to a number')  end  local decimals = tonumber(d)  if not decimals then  error('Unable to convert "' .. tostring(d) .. '" to a number')  end  local maxDecimals = 14 - math.floor(math.log10(num)) -- to allow a maximum of 15 significant figures, which is the highest guaranteed correct with doubles  if decimals > maxDecimals then decimals = maxDecimals end  local mult = 10^decimals  num = math.floor(num * mult + 0.5) / mult  if decimals < 0 then  return tostring(num)  else  return string.format('%.' .. decimals .. 'f', num)  end end  function p.main(frame)  local args, pargs = frame.args, frame:getParent().args  return p._main(mw.ext.ParserFunctions.expr(args[1] or pargs[1]), mw.ext.ParserFunctions.expr(args[2] or pargs[2])) end  return p