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Gosha

That child-like delight when I figured out #SICP exercise 1.6, haha. I love this very much.

Exercise 1.6: Alyssa P. Hacker doesn’t see why `if` needs to be provided as a special form. “Why can’t I just define it as an ordinary procedure in terms of `cond`?” she asks. Alyssa’s friend Eva Lu Ator claims this can indeed be done, and she defines a new version of if: ``` (define (new-if predicate then-clause else-clause) (cond (predicate then-clause) (else else-clause))) ``` Eva demonstrates the program for Alyssa: ``` (new-if (= 2 3) 0 5) 5 (new-if (= 1 1) 0 5) 0 ``` Delighted, Alyssa uses new-if to rewrite the square-root program: ``` (define (sqrt-iter guess x) (new-if (good-enough? guess x) guess (sqrt-iter (improve guess x) x))) ``` What happens when Alyssa attempts to use this to compute square roots? Explain.
20 January at 6:15 | Open on merveilles.town
5 comments
フェリ―ペ

@gosha it's so good isn't it?! im stuck on exercise 1.11 for now

20 January at 10:50 | Open on merveilles.town
Alastair M. D. Touw

@gosha I love the little epiphanies that stay with you forever, but… Eva Lu Ator? 👏🏻😒

20 January at 12:20 | Open on mastodon.social
Gosha

@amdt A member of @neauoire‘s extended family? 🤔

20 January at 12:36 | Open on merveilles.town
Devine Lu Linvega

@gosha @amdt It's the name I use during halloween on the instance.

20 January at 15:51 | Open on merveilles.town
Kototama

@gosha you can do that in Haskell because it's lazy evaluated :blob_cat_peek:

20 January at 16:13 | Open on merveilles.town
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