Comment by llm_trw

12 days ago

I find the difficulty of the chapters goes as the square of their number. Viz. Chapter 5 is 25 times as hard as chapter 1. I also find that basically no one goes past chapter 4. I've only ever seen one good talk on it and the guy was so far down the esolang rabbit hole that he had an IBM apl keyboard.

3 comments

llm_trw

bear8642 12 days ago

Not sure I'd call APL an esolang - it's just an old language focused on array manipulation like you'd find in numpy

llm_trw 11 days ago

      life ← {⊃1 ⍵ ∨.∧ 3 4 = +/ +⌿ ¯1 0 1 ∘.⊖ ¯1 0 1 ⌽¨ ⊂⍵}

https://aplwiki.com/wiki/John_Scholes%27_Conway%27s_Game_of_...

I'm not sure how you don't call that an eso lang.

bear8642 11 days ago

Would you prefer something like this numpy then?

  def life(x):
    y = np.array([np.roll(x, -1), np.roll(x, 0),np.roll(x, 1)])
    y = np.array([np.roll(y, -1, 1), np.roll(y, 0, 1),np.roll(y, 1, 1)])
    z = y.sum(1).sum(0)
    a = np.array([3 == z, 4==z])
    c = np.logical_and(np.array([np.ones(x.shape), x]), a)
    return np.logical_or(c[0], c[1])

Video of Scholes building up the life APL expression can be seen here: https://www.youtube.com/watch?v=a9xAKttWgP4