protected function compileSelectors($selectors)
    {
        $out = array();

        foreach ($selectors as $s) {
            if (is_array($s)) {
                list(, $value) = $s;
                $out[] = $this->compileValue($this->reduce($value));
            } else {
                $out[] = $s;
            }
        }

        return $out;
    }