tmurata https://blog.hatena.ne.jp/tmurata/ tmurataの日記 https://tmurata.hatenadiary.org/ SICP (複素数を除く)各型について、その型のオブジェクトを塔の中で一レベル高める汎用手続きraise 演算の設計。 強制型変換(coercion)用の塔 complex ↑ real ↑ rational ↑ integer ; 汎用演算パッケージ (define (add x y) (apply-generic 'add x y)) (define (sub x y) (apply-generic 'sub x y)) (define (mul x y) (apply-generic 'mul x y)) (define (div x y) (apply-generic 'div x y)) (d… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Ftmurata.hatenadiary.org%2Fentry%2F20091007%2F1254871077" title="SICP問題2.83 - tmurataの日記" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2009-10-07 08:17:57 rich https://tmurata.hatenadiary.org/entry/20091007/1254871077 1.0 100%