public function words(string $charlist = ''): MapInterface
    {
        $words = \str_word_count($this->value, 2, $charlist);
        $map = new Map('int', self::class);

        foreach ($words as $position => $word) {
            $map = $map->put($position, new self($word, $this->encoding));
        }

        return $map;
    }