function split(str, sep)
        if sep == nil then
                sep = "%s"
        end
        local t={} ; i=1
        for str in string.gmatch(str, "([^"..sep.."]+)") do
                t[i] = str:match "^%s*(.-)%s*$"
                i = i + 1
        end
        return t
end


local m = {}

function m.mpu_comp(frame)
  local wikichip = require("Module:wikichip")
	
  if not frame.args.list then
    return 'Error: Missing chip list to compare!'
  end
	
  local list = split(frame.args.list, ',')
  local chips = { }
  
  for key, chip_name in pairs(list) do
    local chip = wikichip:new(chip_name)
    if not chip.is_valid() then
    	return '<strong>"' .. chip_name .. '"</strong> cannot be found.';
	end
	chips[#chips+1] = chip
  end
  
  local table = mw.html.create('table')
  				:attr('style', 'border: 1px solid black; border-collapse: collapse;')
	local row
	
	-- models
	row = table:tag('tr')
	row:tag('td')
			:attr('style', 'border: 1px solid black; padding: 15px; text-align: center;'):wikitext('&nbsp;')
	for key,val in pairs(chips) do
		row:tag('td')
			:attr('style', 'border: 1px solid black; padding: 15px; text-align: center;')
			:wikitext(val.name())
	end
	
	-- designer
	row = table:tag('tr')
	row:tag('td')
			:attr('style', 'border: 1px solid black; padding: 1px; text-align: center;'):wikitext('Designer')
	for key,val in pairs(chips) do
		row:tag('td')
			:attr('style', 'border: 1px solid black; padding: 1px; text-align: center;')
			:wikitext('[[' .. val.designer() .. ']]')
	end
	
	-- manufacturer
	row = table:tag('tr')
	row:tag('td')
			:attr('style', 'border: 1px solid black; padding: 1px; text-align: center;'):wikitext('Manufacturer')
	for key,val in pairs(chips) do
		row:tag('td')
			:attr('style', 'border: 1px solid black; padding: 1px; text-align: center;')
			:wikitext('[[' .. val.manufacturer() .. ']]')
	end
  
  
  return table
end

return m