Module:Jctbtm

 local p = {}

 local types = mw.loadData("Module:Road data/RJL types")

 local columns = { -- Constants for how many columns different list types should have.
	default = 6, -- default
	exit = 7, -- default + exit number
	old = 8, -- default + exit number + old exit number
 }

 local function parameterParser(args)
	local keysParam = args.keys
	if not(keysParam) then return {} end
	local keys = mw.text.split(keysParam, ",")
	table.sort(keys)
	return keys
 end

 local function createLegend(key, html_object)
	local listargs = {
		class = 'jct-bottom-legend'
	}
	
	for _,v in ipairs(key) do
		local type = types[v]
		if type then
			table.insert(
				listargs,
				'<span class="jct-bottom-legend-color" style="background-color: ' ..
				type.color .. '">&nbsp;&nbsp;&nbsp;&nbsp;</span>&nbsp;&nbsp;<span class="nowrap">' ..
				type.jctbtm .. '</span>'
			)
		end
	end
	
	html_object:wikitext(require('Module:List').horizontal(listargs))
 end

 function p._jctbtm(args)

	local root = mw.html.create()
	
	local cols = args.col or columns[args[1]] or columns.default
	row = root
		:tag('tr')
			:tag('td')
				:attr('colspan', cols)
				:addClass('jct-bottom notheme')
				:wikitext(mw.getCurrentFrame():extensionTag{
					name = 'templatestyles', args = { src = 'Module:Jctbtm/styles.css' }
				})
					
	if (args.conv or 'yes') == 'yes' then
		row:wikitext("1.000&nbsp;mi = 1.609&nbsp;km; 1.000&nbsp;km = 0.621&nbsp;mi<br>")
	end
	
	local key = parameterParser(args)
	if key[1] then createLegend(key, row) end
	
	local keyParam = args.key
	if keyParam then -- This is a deprecated parameter
		local page = mw.title.getCurrentTitle()
		local pagename = page.prefixedText
		row:wikitext(string.format("[[Category:Jctbtm temporary tracking category|# %s]]", pagename))
	end
	
	row:wikitext(args.notes or args.key) -- If additional notes are provided, display them.
	
	if #row.nodes == 0 then
		return '|-\n|}'
	else
		return tostring(root) .. '\n|-\n|}'
	end
 end

 function p.jctbtm(frame)
	return p._jctbtm(require('Module:Arguments').getArgs(frame))
 end

 return p