Ask HN: What is the most beautiful piece of code you've ever read?

Post by WalterGR » Mon, Oct 28, 2019, 6:09 AM UTC

saagarjha wrote: post #46

I'd have to think long and hard for the most beautiful code I've ever read, but I think the classic K&R "strcpy" comes pretty close: void strcpy(char *s, char *t) { while (*s++ = *t++); } It's short, elegant, and quite readable to the trained eye–a bit sharp too, but if you use it right it's quite functional.

Post by anhldbk » Mon, Oct 28, 2019, 6:15 AM UTC

Post by enriquto » Mon, Oct 28, 2019, 6:19 AM UTC

    int dsf_find(int *t, int a)
    {
     if (a != t[a])
      t[a] = dsf_find(t, t[a]);
     return t[a];
    }

Post by labria » Mon, Oct 28, 2019, 6:22 AM UTC

  (define eval-expr
    (lambda (expr env)
      (pmatch expr
        [`,x (guard (symbol? x))
          (env x)]
        [`(lambda (,x) ,body)
          (lambda (arg)
            (eval-expr body (lambda (y)
                              (if (eq? x y)
                                  arg
                                  (env y)))))]
        [`(,rator ,rand)
         ((eval-expr rator env)
          (eval-expr rand env))])))

Post by numlock86 » Mon, Oct 28, 2019, 6:27 AM UTC

11235813213455 wrote: post #97

# Permutations of a list: - haskell: perms [] = [[]] perms xs = [ x:ps | x - js: (using https://github.com/tc39/proposal-slice-notation for conciseness) const perms = xs => xs.length === 0 ? [[]] : xs.flatMap((xi, i) => perms([...xs[0:i], ...xs[i+1:]).map(xsi => [xi, ...xsi]) # Cartesian product of 2 or n lists - haskell: cart2 xs ys = [(x,y) | x [[a]]; cartn [] = [[]] cartn(xs:xss) = [x:ys | x - js: const cart2 = (x…