FAWK: LLMs can write a language interpreter

Yes! I'm currently using copilot + antigravity to implement a language with ergonomic syntax and semantics that lowers cleanly to machine code targeting multiple platforms, with a focus on safety, determinism, auditability and fail-fast bugs. It's more work than I thought but the LLMs are very capable.

I was dreaming of a JS to machine code, but then thought, why not just start from scratch and have what I want? It's a lot of fun.

Curious why you do this with AI instead of just writing it yourself?

You should be able to whip up a Lexer, Parser and compiler with a couple weeks of time.

I'm not the previous user, but I imagine that weeks of investment might be a commitment one does not have.

I have implemented an interpreter for a very basic stack-based language (you can imagine it being one of the simplest interpreters you can have) and it took me a lot of time and effort to have something solid and functional.

Thus I can absolutely relate to the idea of having an LLM who's seen many interpreters lay out the ground for you and make you play as quickly as possible with your ideas while procrastinating delving in details till necessary.

What's the point of making something like this if you don't get to deeply understand what your doing?

What's the point of owning a car if you don't build it by hand yourself?

Anyway, all it will do is stop you being able to run as well as you used to be able to do when you had to go everywhere on foot.

Because he did it in a day, not a few weeks.

If I want to go from Bristol to Swindon, I could walk there in about 12 hours. It's totally possible to do it by foot. Or I could use a car and be there in an hour. There and back, with a full work day in-between done, in a day. Using the tool doesn't change what you can do, it speeds up getting the end result.

What is the point of car that on Mondays changes colour to blue and on each first Friday of the year explodes?

If neither you not anyone else can fix it, without more cost than making a proper one?

There is no end result. It's a toy language based on a couple of examples without a grammar where apparently the LLM used its standard (plagiarized) parser/lexer code and reiterated until the examples passed.

Automating one of the fun parts of CS is just weird.

So with this awesome "productivity" we now can have 10,000 new toy languages per day on GitHub instead of just 100?

That was exactly my thought. Why automate the coding part to create something that will be used for coding (and in itself can be automated , going buy the same logic)? This makes zero sense.

Code review exists.

Proper code review takes as long as writing the damn thing in the first place and is infinitely more boring. And you still miss things that would have been obvious while writing.

In this special case, you'd have to reverse engineer the grammar from the parser, calculate first/follow sets and then see if the grammar even is what you intended it to be.

I have made a lot of things using LLMs and I fully understood everything. It is doable.

Author did review the (also generated) tests, which as long as they're comprehensive enough for his purposes, all pass and coverage is very high, means things work well enough. Attempting to manually edit that code is a whole other thing though.

How deep do you need to know?

"Imagination is more important than knowledge."

At least for me that fits. I have quite enough graduate-level knowledge of physics, math, and computer science to rarely be stumped by a research paper or anything an LLM spits out. That may get me scorn from those tested on those subjects. Yet, I'm still an effective ignoramus.

If you could also automate away the reason for being in Swindon in the first place, would you still go?

That argument might work for certain kinds of applications (none I'd like to use, though), but for a programming language, nope.

I am using LLMs to speed up coding as well, but you have to be super vigilant, and do it in a very modular way.

It would be very new to me. I'd have to learn a lot to do that. And I can't spare the time or attention. It's more of a fun side project.

The machine code would also be tedious, tho fun. But I really can't spare the time for it.

I want something I can use, and something useful. It's not just a learning exercise. I get to understand it by following along.

The only reason for going to Swindon was to walk there?

If so then of course you still should go.

But the point making of a computer program usually isn't for "the walk".

Because this is someone in a "spiral" or "AI psychosis" Its pretty clear by how they are talking.

If they go far enough with it they will be forced to understand it deeply. The LLM provides more leverage at the beginning because this project is a final exam for a first semester undergrad PL course, therefore there are a billion examples of “vaguely Java/Python/C imperative language with objects and functions” to train the LLM on.

Ultimately though, the LLM is going to become less useful as the language grows past its capabilities. If the language author doesn’t have a sufficient map of the language and a solid plan at that point, it will be the blind leading the blind. Which is how most lang dev goes so it should all work out.

Lol thank you for this. It’s more worth I work than i thought!

Thank you for bringing this matter to our attention, TeodorDyakov and bgwalter. I am a member of the fun police, and I have placed keepamovin, and accomplice, My_Name under arrest, pending trial, for having fun wrong. If convicted, thet each face a 5 year sentence to a joyless marriage for healthcare without possiblity of time off for boring behavior. We take these matters pretty seriously, as crimes of this nature could lead to a bubble collapse, and the economy can't take that (or a joke), so good work there!

Yes, and the result is undoubtably trash. I have yet to see a single vibe-coded app or reasonably large/complex snippet which isn't either 1) almost an exact reproduction of a popular library, tutorial, etc. or 2) complete and utter trash.

So my question was, given that this is not a very hard thing to build properly, why not properly.

If you can automated away the reason for being at the destination, then there's no point in automating the way to get to the destination.

similar for automating creating an interpreter with nicer programming language features in order to build an app more easily when you can just automate creation of the app in the first place.

The choice with this kind of question is almost never between "do it properly or do it faster with LLMs".

It's between "do it with LLMs or don't do it at all" - because most people don't have the time to take on an ambitious project like implementing a new programming language just for fun.

They literally just made it to do AoC challenges, and shared it for fun (and publicity).

"Because it's a shiny toy that I want to play with" is a perfectly valid reason that still applies here. The invalid assumption in your premise is that people either enjoy coding or don't. The truth is that they enjoy coding some things but not others, and those preferences are very subjective.

I don't think that contradicts my comment in any way. It's not a programming language then, it is a fun language.