OP here.

Thanks for reading and for the thoughtful feedback!

> Only real criticism I have here, is I would not include any code in a design doc, unless it is really really vitally important.;

Yeah, that's fair. If I were setting guidelines for a large org, I'd maybe discourage code snippets in design docs, as it's hard to know when is too much. At my last company, the dev team was just 3-4 people, and I found it helpful to have little snippets in design docs especially when we're talking about semantics of a new library or how to migrate existing code to a new system.

> Orthogonal to the article, but this line of thinking (including the link to the classic 2000 "Things You Should Never Do, Part I" article[0]) may be worth reviewing in the post-LLM world; for all their flaws, LLMs are spectacular at language-to-language translation, and we already have one major project released[1] that shows porting a relatively large and mature project from one language to another is possible.

Yeah, I agree this could change with LLMs, but I think Joel is still correct up to today. Bun is an interesting case because it's friendliest possible conditions for an LLM rewrite (self-contained inputs and outputs, easy to test old implementation and new implementation side by side, huge test corpus w/ third-party tests). I haven't followed it closely, but it seems like the jury's still kind of out as to whether the rewrite was a good idea.