alt Hacker News> I wonder what adaptations will be necessary to make AIs work better on Lisp.
Some are going to nitpick that Clojure isn't as lispy as, say, Common Lisp but I did experiment with Claude Code CLI and my paid Anthropic subscription (Sonnet 4.6 mostly) and Clojure.
It is okay'ish. I got it to write a topological sort and pure (no side effect) functions taking in and returning non-totally-trivial data structures (maps in maps with sets and counters etc.). But apparently it's got problems with...
... drumroll ...
The number of parentheses. It's so bad that the author of figwheel (a successful ClojureScript project) is working on a Clojure MCP that fixes parens in Clojure code spoutted by AI (well the project does more than that, but the description literally says it's "designed to handle Clojure parentheses reliably").
You can't make that up: there's literally an issue with the number of closing parens.
Now... I don't think giving an AI access to a Lisp REPL and telling it: "Do this by bumping on the guardrails left and right until something is working" is the way to go (yet?) for Clojure code.
I'm passing it a codebase (not too big, so no context size issue) and I know what I want: I tell it "Write a function which takes this data structure in and that other parameter, the function must do xxx, the function must return the same data structure out". Before that I told it to also implement tests (relatively easy for they're pure functions) for each function it writes and to run tests after each function it implements or modify.
And it's doing okay.
Replies
I am lazy: when an LLM messes up parenthesis when working with any Lisp language I just quickly fix the mismatch myself rather than try to fix the tooling.
Sometimes LLMs astonish me with what the code they can write. Other times I have to laugh or cry.
As an example, I asked claude 3.5 back when that was the latest to indent all the code in my file by four more spaces. The file was about 700 lines long. I got a busy spinner for two minutes then it said, "OK, first 50 lines done, now I'll do the rest" and got another busy spinner and it said, "this is taking too long. I'm going to write a program to do it", which of course it had no problem doing. The point is that it is superhuman at some things and completely brain-dead about others, and counting parens is one of those things I wouldn't expect it to be good at.
I had that issue with the AI doing some CL dabbling.
Things, on the whole, were fine, save for the occasional, rogue (or not) parentheses.
The AI would just go off the rails trying to solve the problem. I told it that if it ever encountered the problem to let me know and not try to fix it, I’d do it.
I think you're right. Try asking GPT-5 this:
> Are the parentheses in ((((()))))) balanced?
There was a thread about this the other day [1]. It's the same issue as "count the r's in strawberry." Tokenization makes it hard to count characters. If you put that string into OpenAI's tokenizer, [2] this is how they are grouped:
Token 1: ((((
Token 2: ()))
Token 3: )))
Which of course isn't at all how our minds would group them together in order to keep track of them.
[1] https://news.ycombinator.com/item?id=47615876 [2] https://platform.openai.com/tokenizer