public function __construct($value, $separator = 'auto')
{
if (is_array($value)) {
$this->value = $value;
$this->separator = $separator == 'auto' ? ', ' : $separator;
} elseif ($value == '()') {
$this->value = array();
$this->separator = $separator == 'auto' ? ', ' : $separator;
} elseif (list($list, $separator) = $this->_parse_list($value, $separator, true, SassScriptParser::$context)) {
$this->value = $list;
$this->separator = $separator == ',' ? ', ' : ' ';
} else {
throw new SassListException('Invalid SassList', SassScriptParser::$context->node);
}
}