Andrew Healey

software engineer @vercel • I write about performance, compilers, puzzles, &more on my website • @recursecenter alum

[Andrew Healey @healeycodes]

I wrote a very fast disk usage program for macOS

most of the popular disk usage CLIs aren't using getattrlistbulk to reduce the number of syscalls required to scan directories (it's free real estate)

[Andrew Healey @healeycodes]

https://t.co/gJiiXbyxMZ

hope you've been enjoying the C posts

[Andrew Healey @healeycodes]

quickjs is GOATed

delightful API surface

I was able to hack together a tiny runtime and event loop v quickly with it

[Andrew Healey @healeycodes]

read my notes and code snippets and thoughts
https://t.co/wBy0yo2VUI

[Andrew Healey @healeycodes]

I built a tiny shell with C so I could learn more about syscalls and pipes

great fun

I found C to be quite suited for the task (fork, execvp) ... until I had to manage some string lifetime stuff 🥲

[Andrew Healey @healeycodes]

glad y'all like this one 🫡

[Andrew Healey @healeycodes]

https://t.co/QCS2yn8Qoc

[Andrew Healey @healeycodes]

I suggested to my friend that writing a semaphore is fairly trivial but when I sat down to write one I was pretty humbled

the edge cases around context cancellation are no joke

more notes and my solution below down there ⇣

[Andrew Healey @healeycodes]

here's the full post about it https://t.co/gf5qcuxS8N

[Andrew Healey @healeycodes]

I built a solver for NYT's daily Pips puzzle

I started with a brute-force search and optimized it to be 16× more efficient (by the number of nodes that need to be checked)

[Andrew Healey @healeycodes]

I also made a search-tree view that I used to debug the solver and get a feel for how it behaved with different optimizations

[Andrew Healey @healeycodes]

full post is up!

https://t.co/yaZXMY0oq3

[Andrew Healey @healeycodes]

I made a Forth compiler and VM with some visualizations for the tokenization->bytecode->VM steps

here's the VM running (it's calculating the 10th Fib. sequence)

[Andrew Healey @healeycodes]

and here's tokens -> bytecode

[Andrew Healey @healeycodes]

added sheep! they spawn when a chunk is created and then randomly walk around, avoiding obstacles (added very rudimentary 'entity system')

added torch flicker (sine wave whose phase is derived from cell coords, scales with light level so cells nearer a torch flicker a bit more)

[Andrew Healey @healeycodes]

playing around with an idea for an article called 'the algorithms behind minecraft'

probably with everything in 2d

I've just got terrain generation working in a canvas

[Andrew Healey @healeycodes]

added stone, and ore veins (based on seed, and placed via biased random walk)

added torches/BFS lighting (attenuates by 1 per cell, blocked by stone/ore)

I'm cheating a bit with the lighting because there's just a dark overlay that is reduced by the lighting effect

[Andrew Healey @healeycodes]

@typesanitizer @ballingt yeah! Piet is really cool. I think there are also 3d (!) esolangs but I can't find good docs for them

[Andrew Healey @healeycodes]

I made a small 2d programming language called icepath

I wanted the same vibe as the ice puzzles in the johto caves in pokemon gold and silver

🧊 sliding around a cave and hitting opcodes

[Andrew Healey @healeycodes]

read about how it works and see more demo programs!

https://t.co/WDFIC5Tfnw