arrayListPointer

<?php
        //Enter your code here, enjoy!
function arrayListPointer(...$index): Closure{
    $item = array_shift($index);
    $composeIndex = count($index) > 0 ? arrayListPointer(...$index) : function($x) {
        return $x;
    };
    return function($x) use ($item, $composeIndex) {
        return '['.$item.']'.$composeIndex($x);
    };
}
function getValue($key, $array, $defaultValue = null) 
{
    if (preg_match_all('#\[(?P<keys>.*?)\]#', $key, $matches)) {
        $keys    = $matches['keys'];
        $current = $array;
 
        foreach ($keys as $k) {
            if (!isset($current[$k])) {
                return $defaultValue;
            }
            $current = $current[$k];
        } 
        return $current;
    }
 
    return $defaultValue;
}
$t = arrayListPointer('aa', 'bb', 'cc', 'dd', 'ee');
echo '<PRE>';
print_r(getValue($t(''), $ary));
exit;