Show HN: Mini J Interpreter in Rust, vibe coded (opens in new tab)

I did this entire project on my phone, using the Replit app and the github web interface. This should be pretty close to the functionality of the J incunabulum:

https://www.jsoftware.com/ioj/iojATW.htm

I ended up telling the agent to use Rust, partially because I thought that JavaScript / TypeScript was its comfort zone and I didn’t want to have it pulling in a bunch of stuff I didn’t understand, and partially because I’ve heard that LLMs are pretty bad at Rust and I wanted to see if it could actually do it.

I don’t know Rust too well, so I can’t judge the code, but my suspicion is that it’s quite bad. I’d be interested to hear that confirmed.