[jdiff]

Definitely matches my experience as well. I've been working away on a very quirky, non-idiomatic 3D codebase, and LLMs are a mixed bag there. Y is down, there's no perspective distortion or Z buffer, there are no meshes, it's a weird place.

It's still useful to save me from writing 12 variations of x1 = sin(r2) - cos(r1) while implementing some geometric formula, but absolutely awful at understanding how those fit into a deeply atypical environment. Also have to put blinders on it. Giving it too much context just throws it back in that typical 3D rut and has it trying to slip in perspective distortion again.

[josephg]

Yeah I have the same experience. I’ve done some work on novel realtime text collaboration algorithms. For optimisation, I use some somewhat bespoke data structures. (Eg I’m using an order-statistic tree storing substring lengths with internal run-length encoding in the leaf nodes).

ChatGPT is pretty useless with this kind of code. I got it to help translate a run length encoded b-tree from rust to typescript. Even with a reference, it still introduced a bunch of new bugs. Some were very subtle.

[jitl]

It’s just not there yet but I think it will get there for translation kind of tasks quite capably in the next 12 months, especially if asked to translate a single file or a selection in a file line by line. Right now it’s quite bad which I find surprising. I have less confidence we’ll see whole-codebase or even module level understanding for novel topics in the next 24 months.

There’s also a question of quality of source data. At least in TypeScript/JavaScript land, the vast majority of code appears to be low quality and buggy or ignores important edge cases and so even when working on “boilerplate” it can produce code that appears to work but will fall over in production for 20% of users (for example string handling code that will tear Unicode graphemes like emoji).

[westmeal]

I gotta ask what are you actually doing because it sure sounds funky

[jdiff]

Working on extending the [Zdog](https://zzz.dog) library, adding some new types and tooling, patching bugs I run into on the way.

All the quirks inherit from it being based on (and rendering to) SVG. SVG is Y-down, Zdog only adds Z-forward. SVG only has layering, so Zdog only z-sorts shapes as wholes. Perspective distortion needs more than dead-simple affine transforms to properly render beziers, so Zdog doesn't bother.

The thing that really throws LLMs is the rendering. Parallel projection allows for optical 2D treachery, and Zdog makes heavy use of it. Spheres are rendered as simple 2D circles, a torus can be replicated with a stroked ellipse, a cylinder is just two ellipses and a line with a stroke width of $radius. LLMs struggle to even make small tweaks to existing objects/renderers.