<?php
if (isset($a)) {
/* code */
}
if (isset($a, $b)) {
/* code */
}
if (isset($a['a']['b'], $b, $c[0][1])) {
/* code */
}
<?php
require_once('vendor/autoload.php');
$idn = new \idna_convert(array('idn_version' => 2008));
echo $idn->encode('lübeck.de'); // prints 'xn--lbeck-kva.de'
echo $idn->decode('xn--lbeck-kva.de') // prints 'lübeck.de'