Comment by nemo1618 | Hacker News Reader

Comment by nemo1618 | Hacker News Reader

> The title is clickbait. I did not design and implement a programming language for the sole or even primary purpose of leaderboarding on Advent of Code.

I did: https://github.com/lukechampine/slouch

"Find all ten-letter words that contain each of the letters A, B, and C exactly once and that have the ninth letter K"

  :load wordlist wordlist.txt
  words wordlist | filter -:(len == 10 and .8 == "k")

A more interesting example: https://www.youtube.com/watch?v=i_zDbInYOpQ

AoC solutions here: https://github.com/lukechampine/advent/tree/master/2022

(The language has builtin commands for fetching inputs and submitting solutions)

How does that do the fiddly bit "contain each of the letters A, B, and C exactly once" ?

Shoot, I totally overlooked that part. Here's the proper version:

  :load wordlist wordlist.txt
  =hasABC { all (count _ x == 1) "abc" }
  words wordlist | filter -:(len == 10 and hasABC and .8 == "k")

Notes:

{ } defines a lambda with parameters named x,y,z,a,b,c...

_ is the same as in noulith -- it turns any expression into a lambda. Values can also be omitted from most expressions (e.g. len == 10) for the same effect.

-: takes a lambda with n parameters and turns it into a lambda that takes 1 parameter and replicates it n times.

That is neat!

You should write a longer post about it!

aight

Are you participating in AoC maybe? I might write some stuff.

It definitely has a kind of "I have something I want to do, let me hack at it" feel. Love anything that helps with that. :)

The lambda formation is something that will have to be gnawed at though.

> words wordlist | filter -:(len == 10 and .8 == "k")

This feels very similar to an APL or K solution.

Are those languages you're aware of?

Oh yes -- I've never developed serious competency in them, but Arthur Whitney and Aaron Hsu are among my programming heroes :)

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