Module:Collapsible list
local p = {}
 
 local function gettitlestyletracking( ts )
 	if not ts then return '' end
 	ts = mw.ustring.gsub(mw.ustring.lower(ts), '%s', '')
 	local tsvals = mw.text.split(ts, ';')
 	table.sort(tsvals)
 	local skey = table.concat(tsvals,';')
 	skey = mw.ustring.gsub(skey, '^;', '')
 	skey = mw.text.encode(mw.text.encode(skey),'%c%[%]=')
 	if (mw.ustring.match(';' .. ts, ';background:') or mw.ustring.match(';' .. ts, ';background%-color:')) 
 		and mw.ustring.match(';' .. ts, ';text%-align:') then 
 		return '[[Category:Pages using collapsible list with both background and text-align in titlestyle|' .. skey .. ' ]]'
 	end
 	return '[[Category:Pages using collapsible list without both background and text-align in titlestyle|' .. skey .. ' ]]'
 end
 
 local function getListItem( data )
     if not type( data ) == 'string' then
         return ''
     end
     return mw.ustring.format( '&lt;li style=&quot;line-height: inherit; margin: 0&quot;&gt;%s&lt;/li&gt;', data )
 end
 
 -- Returns an array containing the keys of all positional arguments
 -- that contain data (i.e. non-whitespace values).
 local function getArgNums( args )
     local nums = {}
     for k, v in pairs( args ) do
         if type( k ) == 'number' and
             k &gt;= 1 and
             math.floor( k ) == k and
             type( v ) == 'string' and
             mw.ustring.match( v, '%S' ) then
                 table.insert( nums, k )
         end
     end
     table.sort( nums )
     return nums
 end
 
 -- Formats a list of classes, styles or other attributes.
 local function formatAttributes( attrType, ... )
     local attributes = { ... }
     local nums = getArgNums( attributes )
     local t = {}
     for i, num in ipairs( nums ) do
         table.insert( t, attributes[ num ] )
     end
     if #t == 0 then
         return '' -- Return the blank string so concatenation will work.
     end
     return mw.ustring.format( ' %s=&quot;%s&quot;', attrType, table.concat( t, ' ' ) )
 end
 
 -- TODO: use Module:List. Since the update for this comment is routine,
 -- this is blocked without a consensus discussion by
 -- [[MediaWiki_talk:Common.css/Archive_15#plainlist_+_hlist_indentation]]
 -- if we decide hlist in plainlist in this template isn't an issue, we can use
 -- module:list directly
 -- [https://en.wikipedia.org/w/index.php?title=Module:Collapsible_list/sandbox&amp;oldid=1130172480]
 -- is an implementation (that will code rot slightly I expect)
 local function buildList( args )
     -- Get the list items.
     local listItems = {}
     local argNums = getArgNums( args )
     for i, num in ipairs( argNums ) do
         table.insert( listItems, getListItem( args[ num ] ) )
     end
     if #listItems == 0 then
         return ''
     end
     listItems = table.concat( listItems )
 
 	-- hack around mw-collapsible show/hide jumpiness by looking for text-alignment
 	-- by setting a margin if centered
 	local textAlignmentCentered = 'text%-align%s*:%s*center'
 	local centeredTitle = (args.title_style and args.title_style:lower():match(textAlignmentCentered)
 		or args.titlestyle and args.titlestyle:lower():match(textAlignmentCentered))
 	local centeredTitleSpacing
 	if centeredTitle then
 		centeredTitleSpacing = 'margin: 0 4em'
 	else
 		centeredTitleSpacing = ''
 	end
 
     -- Get class, style and title data.
     local collapsibleContainerClass = formatAttributes(
     	'class',
     	'collapsible-list',
     	'mw-collapsible',
     	not args.expand and 'mw-collapsed'
     )
     local collapsibleContainerStyle = formatAttributes(
         'style',
          -- mostly work around .infobox-full-data defaulting to centered
         'text-align: left;',
         args.frame_style,
         args.framestyle
     )
     local collapsibleTitleStyle = formatAttributes(
         'style',
         'line-height: 1.6em; font-weight: bold;',
         args.title_style,
         args.titlestyle
     )
     local jumpyTitleStyle = formatAttributes(
         'style',
         centeredTitleSpacing
     )
     local title = args.title or 'பட்டியல்'
     local ulclass = formatAttributes( 'class', 'mw-collapsible-content', args.hlist and 'hlist' )
     local ulstyle = formatAttributes( 
         'style',
         'margin-top: 0; margin-bottom: 0; line-height: inherit;',
         not args.bullets and 'list-style: none; margin-left: 0;',
         args.list_style,
         args.liststyle
     )
     
     local hlist_templatestyles = ''
     if args.hlist then
     	hlist_templatestyles = mw.getCurrentFrame():extensionTag{
     		name = 'templatestyles', args = { src = 'Hlist/styles.css' }
     	}
     end
     
     -- Build the list.
     return mw.ustring.format( 
         '%s&lt;div%s%s&gt;\n&lt;div%s&gt;&lt;div%s&gt;%s&lt;/div&gt;&lt;/div&gt;\n&lt;ul%s%s&gt;%s&lt;/ul&gt;\n&lt;/div&gt;',
         hlist_templatestyles, collapsibleContainerClass, collapsibleContainerStyle,
         collapsibleTitleStyle, jumpyTitleStyle, title, ulclass, ulstyle, listItems
     ) .. gettitlestyletracking(args.title_style or args.titlestyle)
 end
 
 function p.main( frame )
     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
     
     local args = {}
     for k, v in pairs( origArgs ) do
         if type( k ) == 'number' or v ~= '' then
             args[ k ] = v
         end
     end
     return buildList( args )
 end