tmurata https://blog.hatena.ne.jp/tmurata/ tmurataの日記 https://tmurata.hatenadiary.org/ SICP 集合の部分集合を作り出す手続きの次の定義 (define (subsets s) (if (null? s) (list ()) (let ((rest (subsets (cdr s)))) (append rest (map (lambda (x) (cons (car s) x)) rest))))) 実験 (subsets (list 1 2 3)) ; (() #0=(3) #1=(2) #2=(2 . #0#) (1) (1 . #0#) (1 . #1#) (1 . #2#)) うまくいかない…。何で? ということで、Google先生に聞いてみるとsubsetsの定義はこれでOK… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Ftmurata.hatenadiary.org%2Fentry%2F20090520%2F1242777513" title="SICP問題2.32 - 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 2009-05-20 08:58:33 rich https://tmurata.hatenadiary.org/entry/20090520/1242777513 1.0 100%