{"html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Ftmurata.hatenadiary.org%2Fentry%2F20100326%2F1269618206\" title=\"SICP\u554f\u984c4.20 - tmurata\u306e\u65e5\u8a18\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","description":"a. letrec\u5f0f\u3092let\u5f0f\u306b\u5909\u63db\u3057\u3001\u5c0e\u51fa\u3055\u308c\u305f\u5f0f\u3068\u3057\u3066\u5b9f\u88c5\u3059\u308b (define (letrec? exp) (tagged-list? exp 'letrec)) (define (letrec-parameters exp) (cadr exp)) (define (letrec-body exp) (cddr exp)) (define (letrec->let exp) (let ((vars (map (lambda (x) (list (car x) ''*unsigned*)) (letrec-parameters exp))) (vals (map (lambda (x) (\u2026","blog_title":"tmurata\u306e\u65e5\u8a18","categories":["SICP"],"url":"https://tmurata.hatenadiary.org/entry/20100326/1269618206","width":"100%","version":"1.0","title":"SICP\u554f\u984c4.20","image_url":null,"provider_url":"https://hatena.blog","published":"2010-03-26 00:43:26","author_name":"tmurata","blog_url":"https://tmurata.hatenadiary.org/","height":"190","type":"rich","provider_name":"Hatena Blog","author_url":"https://blog.hatena.ne.jp/tmurata/"}