Editing Module:Navbox with collapsible groups

-- This module implements {{Navbox with collapsible groups}}
local q = {}
local Navbox = require('Module:Navbox')

-- helper functions
local function concatstrings(s)
	local r = table.concat(s, '')
	if r:match('^%s*$') then r = nil end
	return r
end

local function concatstyles(s)
	local r = table.concat(s, ';')
	while r:match(';%s*;') do
		r = mw.ustring.gsub(r, ';%s*;', ';')
	end
	if r:match('^%s*;%s*$') then r = nil end
	return r
end

function q._navbox(pargs)
	-- table for args passed to navbox
	local targs = {}

	-- process args
	local passthrough = {
		['name']=true,['navbar']=true,['state']=true,['border']=true,
		['bodyclass']=true,['groupclass']=true,['listclass']=true,
		['style']=true,['bodystyle']=true,['basestyle']=true,
		['title']=true,['titleclass']=true,['titlestyle']=true,
		['above']=true,['aboveclass']=true,['abovestyle']=true,
		['below']=true,['belowclass']=true,['belowstyle']=true,
		['image']=true,['imageclass']=true,['imagestyle']=true,
		['imageleft']=true,['imageleftstyle']=true
	}
	for k,v in pairs(pargs) do
		if k and type(k) == 'string' then
			if passthrough[k] then
				targs[k] = v
			elseif (k:match('^list[0-9][0-9]*$') 
					or k:match('^content[0-9][0-9]*$') ) then
				local n = mw.ustring.gsub(k, '^[a-z]*([0-9]*)$', '%1')
				if (targs['list' .. n] == nil and pargs['group' .. n] == nil
					and pargs['sect' .. n] == nil and pargs['section' .. n] == nil) then
					targs['list' .. n] = concatstrings(
						{pargs['list' .. n] or '', pargs['content' .. n] or ''})
				end
			elseif (k:match('^group[0-9][0-9]*$') 
					or k:match('^sect[0-9][0-9]*$') 
					or k:match('^section[0-9][0-9]*$') ) then
				local n = mw.ustring.gsub(k, '^[a-z]*([0-9]*)$', '%1')
				if targs['list' .. n] == nil then
					local titlestyle = concatstyles(
						{pargs['groupstyle'] or '',pargs['secttitlestyle'] or '', 
							pargs['group' .. n .. 'style'] or '', 
							pargs['section' .. n ..'titlestyle'] or ''})
					local liststyle = concatstyles(
						{pargs['liststyle'] or '', pargs['contentstyle'] or '', 
							pargs['list' .. n .. 'style'] or '', 
							pargs['content' .. n .. 'style'] or ''})
					local title = concatstrings(
						{pargs['group' .. n] or '', 
							pargs['sect' .. n] or '',
							pargs['section' .. n] or ''})
					local list = concatstrings(
						{pargs['list' .. n] or '', 
							pargs['content' .. n] or ''})
					local state = (pargs['abbr' .. n] and pargs['abbr' .. n] == pargs['selected']) 
						and 'uncollapsed' or pargs['state' .. n] or 'collapsed'
					
					targs['list' .. n] = Navbox._navbox(
						{'child', navbar = 'plain', state = state,
						basestyle = pargs['basestyle'],
						title = title, titlestyle = titlestyle,
						list1 = list, liststyle = liststyle,
						listclass = pargs['list' .. n .. 'class'],
						image = pargs['image' .. n],
						imageleft = pargs['imageleft' .. n],
						listpadding = pargs['listpadding']})
				end
			end
		end
	end
	-- ordering of style and bodystyle
	targs['style'] = concatstyles({targs['style'] or '', targs['bodystyle'] or ''})
	targs['bodystyle'] = nil
	
	-- child or subgroup
	if targs['border'] == nil then targs['border'] = pargs[1] end

	return Navbox._navbox(targs)
end

function q.navbox(frame)
	local pargs = require('Module:Arguments').getArgs(frame, {wrappers = {'Template:Navbox with collapsible groups'}})

	-- Read the arguments in the order they'll be output in, to make references number in the right order.
	local _
	_ = pargs.title
	_ = pargs.above
	for i = 1, 20 do
		_ = pargs["group" .. tostring(i)]
		_ = pargs["list" .. tostring(i)]
	end
	_ = pargs.below

	return q._navbox(pargs)
end

return q