Module:Authority control

function outputError( message, cat )
    local str = '<span class="error">' .. message .. '</span>'
    if cat then
        str = str .. '[[Category:' .. cat .. ']]'
    end
    return str
end

function viafLink( id )
    if not string.match( id, '^%d+$' ) then
        return outputError( 'The VIAF id ' .. id .. ' is not valid.', 'Wikipedia articles with faulty authority control identifiers (VIAF)' )
    end
    return '<span class="uid">[http://viaf.org/viaf/' .. id .. ' ' .. id .. ']</span>'
end

local config = {
    { 'VIAF', '[[Virtual International Authority File|VIAF]]', 0, viafLink }
}
    
local p = {}

function p.authorityControl( frame )
    local parentArgs = frame.getParent().args
    --Create rows
    local lines = {}
    for k, conf in config do
        if parentArgs[conf[0]] and parentArgs[conf[0]] ~= '' then
            table.append( lines, conf[1] .. ': ' .. conf[3]( parentArgs[conf[0]] ) )
        end
    end

    local Navbox = require('Module:Navbox')
    return navbox._navbox( {
        name  = 'Authority control',
        bodyclass = 'hlist',
        group1 = '[[Authority control]]',
        list1 = table.concat( lines, '*' )
    } )
end