10 comments

  • periodjet 6 minutes ago
    Finally, a sane and enjoyable read about a coding project. Feel like it’s been months since we had one of these that wasn’t filled to the brim with bluesky/mastodon-flavored whining about AI.

    Kudos to the author. A fun read, thank you for sharing.

  • unixhero 18 minutes ago
    Rar means weird in Norwegian and adorable in Swedish. Just for an anecdote.
    • mhitza 13 minutes ago
      Rare, in Romanian.
  • davidsong 1 hour ago
    I spent a fortnight using Claude to create specs for every version of RAR, then another using gpt-5.5 to write compressors in Rust.

    It's not fast and it's not pretty, but it works.

    • esafak 59 minutes ago
      > It’s sloppy, it’s slow, it’s almost two megabytes in size and somewhat worse than WinRAR on compression.

      As mathematicians say, optimization is left as an exercise to the reader. You did the hard part.

  • rebolek 9 minutes ago
    > "For the last 15 months or so my hobby has been shouting at Claude"

    How can you shout at Claude when it’s

    1) foobaring, bamblabooing and fghrtawing all the time without telling you what’s going on

    2) when it finally interacts, it’s asking for a permission you told it 30 seconds ago "yes and do not ever ask me again until heat death of the Universe"

    3) and after all of that, it just spits out: "you’re out of tokens, give up your liver or wait until next Trump’s war"

  • xphos 38 minutes ago
    Would it really take 5 years to develop rare compress and decompression that seems an extreme overestimate in time. I don't know of the compressor decompression but that seems really high
    • q3k 29 minutes ago
      Yeah, sounds closer to a 5 week thing, if you know what you're doing.
  • npn 14 minutes ago
    Rar is proprietary. Good luck.
  • slopinthebag 43 minutes ago
    How do we know it's actually correct?
    • perching_aix 40 minutes ago
      By using it.
      • repelsteeltje 38 minutes ago
        It works == it's correct?
        • perching_aix 35 minutes ago
          Yes? What do you think fuzzing, unit testing, integration testing is for? It's an empirical evaluation of correctness. Literally just try and see.

          For actual correctness verification in the strong sense, you'd need to start from a specification written in a formal language so that it's machine checkable, which if I had to guess not even win.rar GmbH has.

          • repelsteeltje 29 minutes ago
            I hope the developers of, say, the brakes in my car don't interpret 'software correctness' the way you do.

            Added, later: hey you changed your comment, added a whole paragraph.

            • perching_aix 16 minutes ago
              I added the second paragraph about formal verification at the same time you posted, in anticipation that you'd immediately dig your heels into it otherwise, despite me highlighting that the other methods are merely empirical.

              I was immediately proven right once I pressed "update". That said, I have now deleted my snarky response that followed. Not in the game of capitalizing off of the human equivalent of a race condition.

              I should make a browser addon to delay posting, this is the 2nd time this happens in the past few days.

              Edit:

              Nevermind, it's already a feature built into the site. Turned it on. I wonder if it applies to edits also...

              Nope, doesn't seem to. Oh well, should still help.

              • repelsteeltje 10 minutes ago
                Haha, off course! The three major sources of software failures: off by one errors and race conditions.
            • throw1234567891 17 minutes ago
              They used to. Now they have systems, standards, and experience. There are only so many ways you can do brakes on the car.
            • atiedebee 19 minutes ago
              I hope the brakes in my car don't need developers
              • pixl97 14 minutes ago
                I think you underestimate the complexity of modern braking systems.
        • mjr00 36 minutes ago
          This is Rust we're talking about. It doesn't even need to work; as long as it compiles, it's correct.
          • dataflow 3 minutes ago
            [delayed]
          • speedgoose 31 minutes ago

                use std::fs::File;
                use std::io::prelude::*;
                
                fn main() -> std::io::Result<()> {
                    let mut file = File::create("content.txt")?;
                    file.write_all(b"3!")?;
                    Ok(())
                }
  • cactusplant7374 1 hour ago
    > and it almost earned me an OpenAI ban

    Were you flagged for a cybersecurity violation?

    • gibspaulding 50 minutes ago
      > Well, it turned out that at some time during spec investigation, Claude needed to understand authenticity verification which is a paid feature. With a context full of reverse engineering tools it cracked WinRAR and bypassed product registration, then dutifully documented its crimes in the spec. The docs, when viewed, triggered OpenAI’s alarms and stopped it dead in its tracks. I squashed this out of the git history, and decided not to implement the feature at all.

      You can draw your own conclusions as to what this says about the state of agentic development.

  • themafia 1 hour ago
    > But, it works, and the world now has a free software RAR implementation.

    Does it? How are you legally intending to use copyright to license this machine output? How would you know it's not encumbered in any way?

    • perching_aix 37 minutes ago
      Really unsure why this is getting downvoted, to my understanding this is a massive, unsettled concern.

      It wasn't even a disasm/pseudocode to formal spec flow, and then a separate human implementation. The same human has been in the loop throughout, and large parts of it were generated directly.

      It's basically guaranteed tainted.

      • ameliaquining 17 minutes ago
        I read the post you're replying to as saying "this is copyright-encumbered and nonfree because it's a derivative work of everything in Claude's and GPT-5.5's training corpus", which is an argument I find fairly tiresome. (Realistically, if courts actually rule that this is the case, this tiny little project will be the least of anyone's concerns.)

        "This is copyright-encumbered and nonfree because it's a derivative work of the legacy RAR binaries" is a different argument (and seems like it depends on details of the setup that were somewhat glossed over in the post).

      • charcircuit 20 minutes ago
        The human wasn't looking at the copyrighted code and was giving high level steering instructions. If you look at the spec generated it doesn't look like a derivative work of the copyrighted material. The program was generated from the spec. It seems mostly fine from my perspective.
  • Imustaskforhelp 44 minutes ago
    Kudos, this is a really cool project (even if it might be AI generated), I have starred the repo, (3rd starrer here)

    One thing I have been curious at is are there any ways to stop a rar compression mid way and then continue it later?

    Like suppose I have a compression happening for a large file, then would there be a possibility with this project to shut down the computer mid compression and continue it after starting it again?

    I would really love it if you can add this functionality!