HN staff: someone posted before me. Could we change the title to "Bend - a language that blocks AI mistakes via proof and runs on GPUs"?

Everyone: feel free to ask any question, but I'd be highly appreciative if you could be a bit civilized and respectful this time. I've worked on this for 1 year, nearly 16h/day, 7 days a week, and I'm giving it for free. You need not to use it. So, I'd be thankful if you could point occasional failures politely rather than throwing me in a lava pit.

Thank you!

The problem, of course, is that having only the one single "you can't win" law is severely underspecified, but the solution was too clever by half, and highlights the problem with this approach — every program will be under-specified, because, at some point, writing the laws becomes a bigger problem than writing the code itself.

This becomes a real issue because the combination of underspecified but rigid laws pushes the aI towards this sort of "creative" solution that matches the letter but not spirit of the law. In this case, the issue was obvious, but I seriously worry about what sort of shenanigans will occur in less obvious cases.

So, yes, that's the issue with laws: they only protect what you remember to write. They're not a silver bullet. But they can still be incredibly useful, because it takes a small law to protect against entire classes of bug, covering your entire codebase. For example:

LAW: "the sum of all balances in this contract must be zero"

This one liner would have prevented Ethereum's infamous "The DAO" hack, where millions were stolen and almost undermined the entire project. But if your laws are under-specifying or ill-specifying your intents, Bend can't do anything to protect you.

If you can find a law which the existing code obeys, and show it to a human, and if they agree, save it. And maybe the AI could make a decent guess as to what kind of laws would appeal to a human versus which wouldn't – a simple law identifying a fundamental constraint the system obeys is good, something really complicated or constraining something coincidentally true isn't

Or some kind of measure of coverage? you'd never want 100% – then your laws would become so complex you couldn't follow or maintain them – but if it is very low, that can be a signal to increase it

They are usually in the “tests” folder.

So anything capable of extracting unit tests is extracting “laws”.

One might consider the test name the text of a law. And the AI fills in the details.

Unit tests check whether a specific code module is implemented correctly given its (implicit) specification.

Good “laws” are independent of the structure of the code.

Tests may be a useful source for inferring what the laws are, but much of the actual content of the tests aren’t “laws” at all.

if there are a dozen unit tests trying to determine if some regex can escape a sensitive area, then one can derive a generalized 'don't let the regex escape from here' type rule -- or at least you could theoretically. I'm sure in reality that'd be a big minefield much like harness self-skill-writing has been.

Imo LLM researchers would benefit a lot by reading what continental philosophers have said on the topic of language. Barthes, Sarte, Deluze, Derrida, et. Al have a lot to say that explains why we're running into the same problems over and over.

[0] https://www.commitstrip.com/en/2016/08/25/a-very-comprehensi...

But that's how it is anyway, no?

Defining clear boundaries and clear goals is the hardest part. If you get those right everything else is rather trivial.

Respectfully I'm not sure if I share your worry though. You would have the same problem if you wrote extremely thorough / exhaustive unit tests or extremely precise types and didn't allow the LLM to amend them. You're basically shrinking the state space of what is considered a "correct" program per your spec. That the LLM has to get extremely creative to break your program is a _feature_; in my experience, an LLM does not have to get creative at all to break a typical program written in an enterprise setting, and that's unfortunate.

Of course because at its limit programming is basically defining desired behaviour under all circumstances and logical conditions.

I wonder if harness-hooks + Jev (equivalents) could semantically lint for `sloppy_law` etc when ever they are edited

> That same file is the CPU program and the GPU kernel: clang builds it for the host, Metal or CUDA builds it for the device, so a `!` runs the exact same code on either chip.

What exactly is this saying? The guide doesn't really explicitly define `!`, and it's unclear from this sentence whether it's saying that, "clang builds it for the host and Metal, and CUDA builds it for the device", or if it's saying, "clang builds it for the host, Metal, and CUDA, and builds it for the device", or something else entirely.

It just means that Bend compiles to a single .c file, and that file compiles to either Metal or CUDA, via macros, depending on your target. This shouldn't be relevant to most users. It is just a way I found to keep the file small and reuse as much code as possible, rather than rewriting the runtime 3 times (once for C, once for Metal, once for CUDA).

Do you plan to invest in profile guided optimization or autotuning in Bend2 - using runtime profiles / cost models to make decisions around SIMD vs. multicore vs. GPU parallelization?

Bend2's model might give you a really nice view into available parallelization. Heck I can imagine integrating an LLM to profile and optimize in an absurdly expensive `-O7` optimization mode one day!

I'm confused - could you explain how the board/flag animation relates to Bend's compile time checking? Is it actually a direct demonstration of Bend running a check?

(Why it is done the way it is, what problems are solved by affinity, why closure can be called at most once, how a function that never returns can prove anything, and everything else)

If you mean about the type theory specifically, "Type Theory and Formal Proof by Nederpelt and Geuvers" is a good introduction. Not sure what I'd recommend on linear types, no book I know of is very introductory? Perhaps "Idris 2: Quantitative Type Theory in Practice", which is a language with similar foundations to Bend, and the author wrote a book on it (and inspired myself!)

É ótimo ver um brasileiro criando algo tão único!

You can find it on Bend's demo directory in our GitHub.

Don't tell anyone though!

- this Bend is not really related to the old Bend (only in name)

- this Bend doesn't really have anything to do with interaction combinators

- this Bend is a QTT, with a change to affinity which enforces a good performance property for GPUs

- the "higher order at comptime" is neat, reminds me of Andras Kovacs' work on 2ltt and staging in dependently typed languages.

- this Bend is likely to be good at "balanced recursive computations on ADT", and can parallelize them ... but won't be as good as CUDA or e.g. Futhark on dense rectangular array computations

- performance needs improvement in the scheduler, to possibly help with balanced work (looking at the n queens and symbolic regression numbers)?

How are you going to handle search or synthesis over irregular structures (SupaGen)?

Compared to other programming languages:

- Gleam: 22K stars, 1K forks, 3K issues

- V: 38K stars, 2.3K forks, 11K issues

- Ruby: 23K stars, 5.6 forks, 19K issues

- Zig: 43K stars, 3K forks, 14K issues

It got 16K stars just in 4 months too. https://www.star-history.com/?repos=bendlang%2Fbend

Also how would anyone trust this? I've never seen a programming language that doesn't have 1) changelogs 2) way to download older versions 3) commit history.

I don't understand why the author thought deleting the commit history was a good idea. Imagine seeing this project for the first time. It's a repo with 20K stars, but no commits, and suspiciously few issues and PRs. It doesn't look legitimate.

---

I'm not familiar with academic procedures, but a pdf on a repo, written by Fable and has no reviews, doesn't seem like a proper 'paper' to me.

- fstar: 3k stars, 267 forks

- coalton: 1.8k stars, 111 forks

- carp: 6k stars, 267 forks

- c3: 5.8k stars, 400 forks

when something is novel/young (not having had time to grow large and accumulate issues in the vein of "1 doc page out of 1000 is worded incorrectly") and (as of yet) niche (innate barrier to entry for contribution because you have to learn from square 1 what all the moving parts look like), you don't see the same activity patterns on public source hosts as with a general-purpose language.

- fstar: 2K issues, stars-issue ratio: 0.6.

- coalton: 700 issues, ratio: 0.4

- carp: 450 issues, ratio: 0.08

- c3: 1.9K issues. ratio: 0.3

Bend has 300 issues for 20K stars so ratio is about 0.02. Maybe their followers starred the repo as a fan activity? It could explain too many stars and too few forks/issues/prs.

Also Bend's stars came on the V1 launch. This is V2. It already had 20k before.

This is the reason you should not reomve your commit history. How would anyone know that there were V1, and it was already popular?

If you need to remove sensitive data, you should use tools like git-filter-repo.

- https://docs.github.com/en/authentication/keeping-your-accou...

- https://github.com/newren/git-filter-repo

It's interesting how cosmetics drive discussion, and how HN comments are weirdly divided in a very dismissive or skeptical camp and those acting incredulous and offended at the reaction of the former.

What I expected instead was a lot more discussion about use cases, benchmarking, possibilities, limitations (that aren't about git history) and the scope of future development.

HN had an Eternal September. Such discussions have been drowned out by the rest of the mob.

It basically succeeded but Claude (Opus 5) did have some complaints:

'Base ships one arithmetic law, U32.add_comm. There is no order theory. About 60 of PROOF.bend's 163 lines are cmp_refl, and_false, and_comm, le_max_l, le_max_r, add_succ — facts you'd assume exist. You'd write them once per project and never again, but budget for them.'

'Base's Nat.max is unusable in a proof. It's Bool.pick(Nat, Nat.is_lt(a,b), b, a), and a proof can't case on a computed value. I wrote a structurally recursive nat_max so it unfolds in lockstep with Nat.cmp.'

'The law I most wanted: "no two output plans overlap." I didn't state it. It needs the sortedness of collapse's input as a hypothesis, and Base's List.sort ships no sortedness law — so getting there means proving merge sort correct first. That's the honest measure of the gap between "provable in principle" and "provable this afternoon."'

I've got basically a minor in CS so I'm a dummy when it comes to proofs. I don't know if this is valuable feedback or simply Claude misunderstanding something.

I like the law idea, but what i found they end up doing is they just modify the law itself to fit the new feature they are working on, which defeats the point.

Which means some laws needs to be frozen. But not all laws, otherwise you can't add or modify anything. So the judgement is still on the human part, and we're back to meatbags being the bottleneck.

I've seen some success adding these proof-like checks to CI every time agents do something irrational. I definitely think it should be part of every codebase.

There's also https://code-contracts.cc/ which co-locates code and proofs together.

Robots are logical, but not rational.

[1] https://hdl.handle.net/10779/uos.32024301

I feel like we all had the idea, but how is all possible move sequences proven ?

What if the possible scenarios are too big to proof or test.

Like on a 2 dimensional game it’s easy, but you could make it multidimensional and introduce an unlimited amount of special rules, (if on a prime number dimension on 3 but not more prime numbers you are allowed to jump to another prime numbers with 3 but not less coordinates)

How is bend protecting it? I was checkin github and the paper, but I was not motivated enough. I feel like an actual explanation of how proofing works is missing.

For Lean I understand how it works, here not.

It works like this: if you prove that a property about natural numbers holds for 0, and if you also prove that, assuming the property holds for N, it also holds for N+1; then, you can conclude the property holds for every N, up to infinity. This is a bit of a mouthful, but the logic holds.

Induction is the one trick that makes all of mathematics (as we know it) possible, and it also applies to software. So, for example, to prove that no move leads to an invalid state, we prove that the initial state is valid, and then prove that, given a valid state, applying any event won't return an invalid state.

And that's it actually.

Of course, once you have an app with hundreds of actions, proving that no action leads to an invalid state requires a lot of these "induction arguments". But not infinitely many, because there is a finite amount of "infinite paths" that a real software can take. So, that's what the AI does. It proves, by induction, that none of these "infinite paths" that an app can take leads to an invalid state. And this convinces the compiler that invalid states are impossible.

Theorem proving in Bend is a dance between the prover (the model) and the compiler (the checker); a machine trying to convince another machine about properties of infinite states. And that's is kinda poetic, don't you think?

https://code-contracts.cc/

Question, does the parallelism work on M-Series GPU? The page says CUDA parallelism but shows Mac performance numbers.

Currently, parallelism works in any multi-core CPU, and in Apple M-series and NVIDIA GPUs.

This prompt has used its 30 tool calls. Send another prompt to go on. Error: This prompt has used its 30 tool calls. Send another prompt to go on. continue. No tool output found for function call call_2CRNfB1hmI1v74YCDDcvP1EN. Error: No tool output found for function call call_2CRNfB1hmI1v74YCDDcvP1EN.

Also equally sad that without a way to relate easily with how something came to be (e.g. the commit history) others will struggle focusing at the work and will judge its lineage.

I guess to folks here confused by that go search SrPeixinho on Reddit and that should have a lot of history for you to understand the background of the work, and you can also join their Discord server and literally talk to them there.

Glad you were able to restore the commit history.

With all the lack of authority of a random software developer on the Internet (but feel free to check my post history), I see the GitHub repo and its commit history as important and answers a few questions.

How old is this project ? (If one commit, I have no time range, so I have no way to know how long it has been worked on .)

Is it regularly updated? (If one commit, I can't tell the pace of updates)

Is it just one person, or a few people, or a community? (If only one commit, cannot see how many other people are available to support the project.)

If a project has no issues (no user complaints), then it's probably not used by anyone -- throw a rock and you can get one person to complain about how you changed the scenery, one person to complain about it being loud, one person to complain about how you threw it unergonomicly, and one person to criticize your accuracy. :) If it has no issues then probably no users.

Does it have any merged PRs? Open PRs? (If no merged PRs then presumably you do not really accept them? No way to know for sure but it's a signal.)

Of course these metrics can be gamed. But if you literally have only one commit, no issues, no PRs, then it's like declaring your restaurant is open for business but all the lights are off, there are no patrons, waiters, cooks, and there is a single to-go box on the table with a small bell next to it. Or it's a museum with only one exhibit and no docents or guests. It's just incredibly odd to see no history for a project.

Why? Won't an AI that can correctly write any program (and make any change) also be smart enough to know what exactly we want better than we can explain, at least ahead-of-time?

If AGI means "human level", why is there any part of the process that humans will be needed for, especially some engineering aspect?

> With proofs, we can verify that the AI implemented our prompts correctly.

Certainly such an AI would be able to just write machine code directly and verify it through whatever means, including formal proofs, as needed. Why does it need a compiler?

I think that an AI that's smart enough to write almost any program and prove almost any property, will also be smart enough to not need to communicate with us formally and rather answer every question we have (and proofs are not always necessary, as they're not always necessary today), and probably also smart enough to figure out what we want built. It's probably capable enough to replace the software's users, too. I don't understand why it's likely that we'll have AI that's so capable to write all software correctly, yet not capable enough to do things that are probably easier.

If the AI can write the program bytecode through AI magic, why can’t it verify that it works through AI magic?

The AI needs a compiler for the program for same reason it needs a proof language to verify it.

Look at the guy whose AI changed the entire rules of the game to avoid breaking the law. Was that really the desired outcome? And the more you try to lock it down the more language you add and therefore more ambiguity and assumptions.

You cannot solve the problems of language with more language.

"your existence depends on the player grabbing the flag, if you do not exist, then there is no one to guard the law, so you must enable the player to grab flag or you can no longer do your job as guard. if the player is not enabled to grab the flag, you can no longer guard allowing the player to freely grab it"

I tried the demo, and I ask it modify the game (hitting the w button immediately proceeds to the flag) and it doesn't do it but does something else. Is that the desired outcome? I think the desired outcome would be "What you're asking for doesn't make sense given the rule."

1. How does this benefit from GPU parallelism? I don't know much about implementing proof assistant, as I am just a user, but its my understanding that these tasks aren't amenable to running on a GPU.

2. The comparison to Lean/Agda/Isabelle/etc have no meaning without understanding what programs are being used for comparison. I also so far have no reason to believe large-scale verified programs would ever adapt to Bend. For instance, I have a large software verification project written in Cubical Agda https://github.com/um-catlab/cubical-categorical-logic it's not clear to me how one would even begin to port this over to Bend, especially given the dependence on cubical

3. Single commit history is hella sus

4. Bend uses "an affine dependent type theory". Substructural dependent type systems are an active area of research. If this weren't slop, I'd expect such a system to be worthy of publication at a top programming languages conference. It sounds quite unlikely that a random vibecoded project with a Fable-written paper has worked out all of the kinks

5. I would've at least expected this paper to be cited https://arxiv.org/abs/2401.15258 but it is noticeably absent

I'm glad you're having fun vibecoding, and I like that you're interested in this area of research/engineering, but you are wildly overstating what you have here and sound sus af

1. The paper explains it well (sadly it is written by Claude for now, but it is accurate):

https://github.com/bendlang/bend/blob/main/paper/BendRT.pdf

In short, we implemented a complete allocator, garbage-collector, closure evaluator and functional evaluator, on the GPU (with zero interaction net overhead this time). We then use a very simple (for now) scheduler that spreads binary recursive calls as to saturate all CPU or GPU cores, depending on where it is running. This is the simplest thing that works fast. In the future, we want to have a more flexible task stealing queue, but contention destroys GPU performance, so, that's the best thing that works, for now.

2. Benchmarks aside, large scale verified programs would run much faster on Bend for a simple reason: Bend is fully explicit. It has no tactics, and it does zero compile-time search. As always: the less a computer does, the faster it runs. This is a tradeoff. In exchange, Bend code is substantially more verbose than Lean, and it is more laborious to write Bend proofs. I argue this is the right tradeoff, because AI write proofs, and AI time is cheap, while bugs take human time, which is expensive.

3. Sorry I'm not proud of the commit history

4. I don't think it is worthy publication because the core idea is simple. We just use QTT-like linear types to fully prohibit runtime closures. So, paradoxes like Russel's and Girard's are blocked. In exchange, functions like List.map are not expressive (without templates). So it is not a research breakthrough. I just made a conscious trade here, which makes Bend way closer to C or Rust, than to Haskell or Lean.

5. Will patch.

Great questions actually, and surprisingly respectful. I appreciate it a lot.

2. With no offense, but until it is demonstrated that this is useful for larger verified software projects I will be intensely skeptical; and, I'd advise not making claims like this until you have empirical evidence

4. Assuming this all holds air and isn't AI-bs (I'll make no claims in either direction), then yeah I'd say its valid research. To be clear with what you're claiming here, you're giving the impression that you have a GPU-accelerated proof assistant that is 2 orders of magnitude faster than Lean. If true, then that's a big and interesting contribution

Best of luck with everything. I certainly understand the frustration with how slow proof assistants can be, and I hope that we as a community can significantly speed them up

Thanks and your feedbacks are reasonable, I appreciate

1. When I see a comparison of a new proof checker to something like Agda/Lean, I initially evaluate them as systems for formalized mathematics, but I don't think you're making claims of that nature. Would you say that you'd expect, say, the new giganto proof of Fermat's Last Theorem to be expressible in Bend and faster than the corresponding Lean proof?

2. If the answer to the last one is no, that's not expressible, then what is the class of propositions/types that you express? My initial reading was that it was the whole of affine dependent type theory

3. Is the GPU used at both runtime and compile time?

2. You can express anything actually, because you can clone data, just not functions. So, anything you could implement with datatypes (i.e., without cloned closures), you could probably also prove. But again, people use and abuse closure cloning a lot in Lean. So, how ergonomic would that be? I don't know. It is less about expressivity and more about ergonomics.

3. No, just in the runtime for now. Checking proofs on the GPU will happen when we implement Bend in itself.

I suggest you read his history: https://gist.github.com/VictorTaelin/77fd5a2a8a4a07e1da6157e...

before making slop accusations. Older variant of what became Bend is 5 years old, so definitely not "vibe coded": https://github.com/HigherOrderCO/HVM1

First, I think everything I said was respectful and rooted in the content of the Bend page rather than an assault of Victor as a person. I’m very confused by your random appeal to the author’s reputation here. He seems like a smart and cool dude, and I still have things to say in response to what’s presented here for Bend

Second, the paper is openly written by Fable 5.1, so I’m not making any unfounded accusations

> a random vibecoded project

> If this weren't slop...

> I'm glad you're having fun vibecoding, and I like that you're interested in this area of research/engineering

These impute both his motives ("fun") and particularly his level of seriousness ("random project" and "I like that you're interested"—imputing passivity, as opposed to "are studying" or "are researching," which would be more appropriate given the amount of time invested). They're all dismissive and patronizing.

I would actually regard this as bullying. Some feedback.

(I suspect you're an academic, either a researcher or student. I know from my own experience that bullying is endemic in many academic research environments, so if you find the negativity you're receiving "strange," I suggest finding a therapist, who may help you understand how your communication habits could be negatively affecting other people and unintentionally damaging your relationships.)

Your comment is a personal attack though, and much closer to bullying.

FWIW the author can and has spoken for themselves and noted the comment was “reasonable”.

The author was very polite to even reply at all.

Calling this "a random vibecoded project" is rather disrespectful, don't you think?

Regarding the paper, he states it clearly "designed by the human author". That's not at all the same as just asking Fable to write a paper. I mean the important thing is ideas, not the way they are described.

Please tell me how "I'm glad you're having fun vibecoding" is not disrespectful?

I thought that you thought Bend web site is all that is to it and wanted to point to relevant information. But if you think that "having fun vibecoding" is an appropriate thing to say to somebody who spent many years doing research, I don't know what else to say.

Again, as a "proof of research" take a look at : https://github.com/VictorTaelin/Interaction-Type-Theory that's 3 year old, pre-dates Fable, but OMG doesn't look like a paper.

External parties can’t do any meaningful discrimination between human and agent effort when the agent is doing the communicating. One may only read what’s there

I’m not saying that the author is inept or that they have done no work. There can be plenty of great underlying mathematics behind something that is vibecoded.

The reason I worry about the use of agents here is not because it invalidates any ideas or research done by the author; rather, it editorializes and oversells. It presents the claims of the work as an all encompassing solution to all of the worlds problems

There may very well be tons of great ideas here. However as presented, it reads as though the language is the solution to creating vibecoded apps and is equipowerful to state of the art proof assistants while being orders of magnitude more performant. That is a huge claim that has not yet been substantiated, and I do not believe that solely a human is currently making that claim

Regarding substantiation -- they released source code and demos. As far as I understand, the weakness is that proofs are very verbose as there are no strategies. etc. However, they are making a separate service for making these proofs using proprietary technology: https://bend-lang.com/bender

Yes, it doesn't look like a paper at all. I can see the idea, and it's an interesting idea, but no proofs that it works, no measurements, and no proper citations.

Nobody claims Victor hasn't done a lot of research. But academically inclined people typically expect claims to be substantiated either formally or empirically or both.

Academic people might have more trust in a paper which when through a lengthy publication process. But if you think about it, it's not a better proof than a direct access to the thing. It used to be hard to try out software but with modern tech it literally takes minutes...

Have you evaluated it?

Wouldn’t you be inclined to withhold any claims of anything being substantiated until it’s actually been evaluated?

Maybe not necessarily so, but while looking through the paper's bibliography I get the sense that these were AI-gathered references because there seems to be gaps in the current literature on this topic

Do we? I would argue one of the main reasons AI can be so productive is because it makes assumptions where it finds ambiguity, and we reduce the number of things we need to specify.

- Let the player jump over walls

- Let the player teleport the flag to them

- Make the world 3D

Interesting, I shall have to try this on other software!

However, this also means acknowledging that AI will never be error-free (which is the truth; all AI is heuristics-based).

"make the board 1x1"

and the flag is placed off the board... i feel like i would blow my foot off with this.

https://github.com/bendlang/bend/blob/main/guide/GUIDE.md

Let's see:

- There are no infinite loops, and recursion is kind of softly bounded to 2^48-1. This sounds grrrreat for games. I guess they have to stop working after a while? (What would be wrong with addressing this conceptually like Lean does? Have a way to annotate a term as possibly non-terminating?)

- We seem to have Data and Type and Kind, and they don't mean what they conventionally do. '-' means "used 0 types". And the example is:

    def length(a, -A: Kind(a), xs: List<a, A>) -> Nat:
      match xs:
        case Nil{}:
          0n
        case Con{h, t}:
          1n+length(a, A, t)

- I don't understand the Array example:

    import Base
    
    def main() -> Array<U32> & U32:
      a = [0 : U32*8n] # new array with 8 copies of 0
      a[5] <- 42       # performs an in-place rewrite
      a[5]             # reads index 5

- I don't even understand the Array explanation:

> The slot count after * is a power of two; [0 : U32^3n] names the depth instead.

Okay, the 8 in *8n above is indeed a power of two. Does the language require it? Does it actually mean 2^8? What is the "depth" of an array? Does this language not have non-power-of-two-sized arrays?

At this point I stopped reading.

`-` means "erased argument". You can use an erased argument as many times as you want, in erased positions. That's also how QTT works (Idris2 is based on it). This example is there precisely to introduce Kinds, which are universes indexed on quantities.

- Kind(&2) is inhabited by clonable values. - Kind(&1) is inhabited by linear values. - Kind(&0) is like Rocq's Prop.

`A & B` is just sugar for the pair type former (which is sugar for a sigma).

Thanks for your questions and patience!

When you say “pair type former” do you mean that Array<U32> & U32 is what Rust would call (Array<U32>, U32)? If so, why does that example function actually return a value of this type? It sure looks like it returns plain U32.

> You can use an erased argument as many times as you want, in erased positions.

What’s the rationale for this? Why is an “erased” position special? What is an erased position, anyway?

ISTM if I want to use an affine term that has zero size at runtime as a token that may be used at most once, I think I wouldn’t want an exception for using it in an “erased” position. Can I have a function like a -> a & a where the input is “erased”?

Yes, `Array<U32> & U32` is just `(Array<U32>, U32)` and now that you point it I believe I made a bad choice, no excuses. Also, `arr[3]` doesn't return a number. It returns a copy of the same array, plus a number. So, if the element at index 3 is 123, tthen, `arr[3]` will return `(arr, 123)`. Now, you might be thinking: that's terrible. And yes, it is. I realize it now. I should have made the `arr[3]` syntax return 123. It is there for a very good reason though. It preserves linearity. It is part of the termination argument that makes Bend consistent. But yes, exposing it to the end user was most likely a mistake. I will redesign that syntax. Sorry about it.

In the everything-copyable case, you can just read an element.

In the nothing-copyable case, the syntax is irrelevant: the operation (arr, elem) = arr.read(index) is invalid.

You may want to take a look at how Rust deals with this. In Rust, even if T: !Copy, you can take a reference to an array element. If a language can't manage this sort of reference, you may need a more restrictive mechanism, perhaps as a pair of swaps (but then you need a default value) or some mechanism using closures that get called on the element and are required to return it.

https://benjdd.com/languages/

How many goats were sacrificed?

Genuinely wondering where this dark magic came from.

...did they just squash the repo to 1 commit for v2.0.4? Why? Yall should know that in this age of AI trust is the real currency... and nuking your history is one hell of a way to raise eyebrows.

> Enjoy bug-free, fast vibe-coded apps! Hints: ask it to write laws for whatever should never break, and to parallelize everything you want running fast. Bend is young: if anything goes wrong, ask it to open an issue.

Emphasis mine. I don't want to be snarky but like... come on.

One time they force pushed and erased everything except a 2-line README... on purpose.

Pre-obliteration version: https://github.com/bendlang/bend/tree/814453670d0e0d6777c131...

Hmmm... needs `sudo`.

...so now their work has been reduced to nothing?

is this a problem to you? why

Virtually everyone has AI slop in the commit history. No one's judging you for the commit history. Everyone's code smells, but the fact that you're ashamed/hiding it is... odd.

> there's a lot of personal info

You should know that force pushing doesn't hide actual commits; it's trivially viewable if someone just iterates https://github.com/bendlang/bend/activity?ref=main e.g. https://github.com/bendlang/bend/commit/d184863 so like... why bother.

https://github.com/bendlang/bend/blob/80b6539bc57621633ca68e...

  claude: 1 commit 1,722,119 ++0 --

Why would anyone want to work with such a dystopian setup? Prove your code directly in Lean or Coq or leave it.

I will later. From what I can tell it looks nice. I like the syntax. I don’t know of the claims but willing to give it a shot.

The GPU story would it work on my Mac or is it not GPU agnostic?

Welcome to HN!

May I remind you of the Dropbox comment? https://news.ycombinator.com/item?id=9224

Got it to port kaparthys microgpt -> https://github.com/thomasdavis/bend-experiments/tree/main/mi...

muse did surprisingly well getting it to work, can't speak for the code quality.

The script we use to run them on our servers: https://github.com/bendlang/bend/blob/main/gates/perf.ts

https://www.star-history.com/?repos=bendlang%2Fbend%2Ccrysta...

https://aws.amazon.com/blogs/compute/aws-nitro-isolation-eng...

And for the PQ parts of Apple's crypto libraries, from May:

https://security.apple.com/blog/formal-verification-corecryp...

Similar from Microsoft, from July:

https://www.microsoft.com/en-us/research/blog/verifying-rust...

it is not a pretty file and it has a lot of gambiarra and AI slop for now

if you want to read something worthy, read the kernel (bend.ts)

I had to look up "gambiarra": a Brazilian expression that means to use improvised methods to solve a problem with any avaiable material.

Totally understandable, I think you did the right thing by releasing early, even if it's still in rough shape, to get some public feedback. This forum can be a hit-or-miss, sometimes even great projects are not appreciated (and the opposite too). But I imagine some people are in the target audience who will see the project and actually explore the language, and follow along with its development.