-- This module implements {{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( '<li style="line-height: inherit; margin: 0">%s</li>', 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 >= 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="%s"', attrType, table.concat( t, ' ' ) ) end  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 )   -- Get class, style and title data.  local div1class = formatAttributes( 'class', 'NavFrame', not args.expand and 'collapsed' )  local div1style = formatAttributes(  'style',  args.frame_style,  args.framestyle,  not ( args.frame_style or args.framestyle ) and 'border: none; padding: 0;'  )  local div2class = formatAttributes( 'class', 'NavHead' )  local div2style = formatAttributes(  'style',  'font-size: 105%; background: transparent; text-align: left;',  args.title_style,  args.titlestyle  )  local title = args.title or 'List'  local ulclass = formatAttributes( 'class', 'NavContent', args.hlist and 'hlist' )  local ulstyle = formatAttributes(  'style',  not args.bullets and 'list-style: none none; margin-left: 0;',  args.list_style,  args.liststyle,  not ( args.list_style or args.liststyle ) and 'text-align: left;',  'font-size: 105%; margin-top: 0; margin-bottom: 0; line-height: inherit;'  )   -- Build the list.  return mw.ustring.format(  '<div%s%s>\n<div%s%s>%s</div>\n<ul%s%s>%s</ul>\n</div>',  div1class, div1style, div2class, div2style, 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  return p