protected function literal($what, $eatWhitespace = null)
    {
        if (! isset($eatWhitespace)) {
            $eatWhitespace = $this->eatWhiteDefault;
        }

        $len = strlen($what);

        if (strcasecmp(substr($this->buffer, $this->count, $len), $what) === 0) {
            $this->count += $len;

            if ($eatWhitespace) {
                $this->whitespace();
            }

            return true;
        }

        return false;
    }