Show HN: Jacquard, a programming language for AI-written, human-reviewed code

Show HN: Jacquard, a programming language for AI-written, human-reviewed code(github.com)

38 points by jbwinters 8 hours ago | 13 comments

I'm fascinated by the generative AI wave rolling over us, and wondered if AI could create a language that it might prefer using over the ones created by and for humans.

To create the design, I had AI analyze the ASTs of several mainstream languages plus a few of the conceptually groundbreaking but esoteric ones (listed in the README) and then create a new structure and new syntax. It was named after the Jacquard machine (https://en.wikipedia.org/wiki/Jacquard_machine), a precursor to Babbage's Analytical Engine (and punch cards).

The result reused a lot of existing ideas but combined them in what I found to be an interesting way. External/world effects are visible in function signatures, and the runtime requires explicit permission to touch the filesystem, network, etc. Effect interactions can be recorded and replayed to see what happens under different conditions or code. And since code is given a content-addressed semantic identity internally, renames and formatting changes don't require recompile or retesting.

Another piece that fell out of this was a testing framework called Warp, which combines replay, results caching, handler substitution, and a few other tools that I frankly wish I had when writing Python. There are a few examples available in the demos directory.

There's more to do, but it's installable and usable. I'm hoping people will have their agents digest the docs/SKILL.md file and maybe write a few programs or see where it might fit in their projects. It should be particularly useful in agent systems. If an agent says something is painful or you as a human find the code tough to understand, I'd like to hear about it so I can address it.

More detail here:

Repository: https://github.com/jbwinters/jacquard-lang

Further intro/human-oriented write-up here: https://research.friendmachine.co/jacquard/

andai 2 hours ago |

> External/world effects are visible in function signatures

Brilliant. I think Jai has something like that? Each function declares what it's going to touch (both read/write) globally, and I think you can specify that per block even.

I haven't used Jai (I think it's not out yet) but I remember the author talking about this and it sounded like a great idea.

It's related to the idea of pure functions being easy to reason about. Right now most languages don't even have a concept of pure functions, but the ones that do, just have two categories. When a function is messing with global state you do actually want to know what it's doing.

I think that can be statically computed (and displayed as IDE annotations or whatever) but specifying it explicitly sounds like a good practice either way.

I like that you're including other side effects (e.g. network) there too though, that's pretty cool!

Another thing I'm really interested in is proofs. Not necessarily total proofs (though we seem to be moving in that direction, at least for subsets of the codebase), but just normalizing rudimentary pre and post conditions checks.

I was thinking of setting it up so code can't even compile in release mode if those are missing. (Not every function would need them, but you at least want to state their absence explicitly.)

I was also thinking of setting up strictness levels per function, using hashing or something, so if a function is modified, you'd have to go through a process of double checking it again. And then functions labeled e.g. level 7 strict couldn't call ones with a lower proven strictness level, and so on. I'm told that I've basically been reinventing Ada from first principles so I should probably go and take a look at that...

Wait, your thing is doing hashing too... Woah. (I think that comes from proofs land or something?)

fwip 1 hour ago | |

AST hashing & effects are both used in Unison, if you want to check that out. I don't know that they have any proof-land stuff, though.

wren6991 2 hours ago |

Given how poorly LLMs do with writing prompts for LLMs, I'm not sure I'd trust their judgement in designing a language for LLMs.

> and the runtime requires explicit permission to touch the filesystem, network, etc

This feels like more of an OS problem (or library problem) than a language problem.

> Run one program against many worlds. The same code can run against the real network, a scripted fake, a recording of last week's traffic, or a probability model of how servers usually behave

How is the "world" model different from plain dependency injection?

embedding-shape 53 minutes ago | |

> Given how poorly LLMs do with writing prompts for LLMs, I'm not sure I'd trust their judgement in designing a language for LLMs.

Yeah agree, what I really want to see now, is a programming language for LLMs, designed by a human (although code could still be LLM-made I suppose), and see how both of them fare in various scenarios.

vineyardmike 2 hours ago | |

> How is the "world" model different from plain dependency injection?

In addition to what the other comment said, this "world" model is great for hermetic testing of complex code, LLM written or not. We've seen existing projects that intercept the OS level syscall for testing, replayability, etc. Building it into the language runtime, hopefully with better ergonomics from the start than a syscall, would be a welcome addition broadly.

inerte 2 hours ago | |

I've done a version of "world" for Sigil, a programming language I was kinda doing but stopped, also for agents. LLM generated article here https://inerte.github.io/sigil/articles/worlds-not-mocks/

But basically world is a bit more narrow, that moment where your code touches the outside world (logging, http, etc), you can swap that. It's sorta like DI but deliberately narrower, only the moments where code touches the outside world are swappable.. With DI in theory you can replace anything, which has its benefits, but at least personally I am not a big fan of mocks, except when they touch the outside world. So that's what's replaceable.

phildenhoff 1 hour ago |

Very cool -- I often thought that Unisons caching approach should be adopted more widely. Look forward to poking at it later!

sajithdilshan 2 hours ago |

I love how people create so many new things with AI, but to think how much tokens, and in turn money we all have collectively burned for these side projects is crazy.

unreal6 2 hours ago | |

As long as token costs are being subsidized, I don't mind that this is the result of the consumer surplus.

jpadkins 2 hours ago | |

it pales in comparison to all the brain cells burned chasing dumb ideas. Don't sweat it, and keep burning tokens in an effort to discover something great.

erelong 2 hours ago |

"Esperanto for Clankers"

Merkur 41 minutes ago | |

Yea, LLM remove the burden of typing - so if token cost don’t explode the new high-level languages will be above the current - and the new low-level language will maybe just weights…