Module:Collapsible list

-- This module implements .
local p = {}
local function getListItem( data )
 if not type( data ) == 'string' then
 return ''
 end
 return mw.ustring.format( '%s', 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%;',
 args.title_style,
 args.titlestyle,
 not ( args.title_style or args.titlestyle ) and 'background: transparent; text-align: left;'
 )
 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( 
 '\n%s\n%s\n',
 div1class, div1style, div2class, div2style, title, ulclass, ulstyle, listItems
 )
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