Hacker News: jakobnissen

New comment by jakobnissen in "Reducing undefined behavior in the C language"

jakobnissen — Fri, 09 Oct 2026 06:40:07 +0000

This is completely infeasible. A C compiler makes so many assumptions that UB does not occur that every program, even well functioning ones, would emit walls of warnings. Also, these warnings can't be silenced. Consider the integer division case: Should the warning be emitted every time division by zero is encountered at runtime? In that case, C would be much, much slower. Or should the compiler emit the warning whenever it can't prove at compile time that the divisor is not zero? In that case, you would get tonnes of situations where you can't fix the issue because you can't prove to the compiler it's not zero. Division by zero is a easy case. It gets much harder to emit warnings for aliasing assumptions, for example.

New comment by jakobnissen in "How Fast is Python 3.15?"

jakobnissen — Wed, 07 Oct 2026 06:15:22 +0000

So not much progress since 3.14 - but still progress! Personally, I think it's nice when my code automatically gets faster thanks to someone else's work, and I don't understand all the negative sentiment in this thread. Yes, of course Python is still a slow language. You hopefully knew that when you picked Python for your project.

New comment by jakobnissen in "Record-High 89% in U.S. Say Government Corruption Widespread"

jakobnissen — Sat, 05 Sep 2026 06:23:17 +0000

I don’t think that’s right. The US government cares a lot about what the public thinks about them. They propagandize actively on social media, the president puts his personal name onceverything, they are extremely persistent in their messaging to loyal reporters and so on.

I think they have discovered that what the public thinks simply no longer tracks what they actually do: "I could stand in the middle of Fifth Avenue and shoot somebody, and I wouldn't lose any voters“

New comment by jakobnissen in "How an MIT research project became the Julia programming language"

jakobnissen — Sat, 05 Sep 2026 05:28:22 +0000

No I don’t know how he gets that info. Most contributions to the language these days are AI assisted, but that’s a completely different matter. IMO if you can afford AI assistance, it would be irresponsible to not use it, given how good AIs are st bug finding and code review

New comment by jakobnissen in "How an MIT research project became the Julia programming language"

jakobnissen — Fri, 04 Sep 2026 18:40:45 +0000

You can not be serious in suggesting these aren’t straight up Python correctness bugs. Exactly the same kind that Yuri brought up as damning evidence of Julia unseriousness, but for Python with easily 25x the user base.

New comment by jakobnissen in "Mojo 1.0"

jakobnissen — Wed, 12 Aug 2026 10:03:43 +0000

Completely true, but Mojo approaches the problem from a different angle. Where Julia aims to blend fast and slow code seamlessly, Mojo's solution is to have a set of opt-in semantics that ensure fast code.

New comment by jakobnissen in "The true power of regular expressions (2012)"

jakobnissen — Mon, 03 Aug 2026 16:21:42 +0000

No, this is not splitting hairs. This is the author using the straight up wrong terminology. Regex can’t match HTML, and aren’t NP-complete. The fact that the author believes that “regex obviously means PCRE” is objectively wrong and misleading in the sense that all the things his article are about would have another conclusion if he actually talked about Regex.

It’s like if there was a library called QuickSort which also included a SAT solver and I then wrote an article about how you can solve SAT-equivalent problems with quicksort (“in the programmer sense, which obviously means a SAT solver”)

New comment by jakobnissen in "The true power of regular expressions (2012)"

jakobnissen — Mon, 03 Aug 2026 13:08:01 +0000

This article misleads you by conflating regular expressions with specific implementations like PCRE, which also does non-regex string matches. Annoyingly, the article does a good job of explaining what a regex is and what the limitations of regex are relative to PCRE, so the author should understand that what they are talking about when they talk about NP-complete string matching is not regex, but PCRE-specific features.

The distinction matters because regex absolutely can't match HTML, and because regex, unlike PCRE expressions, have guaranteed O(1) space and O(n) time complexity when matching a string of length n. When you use PCRE features for string matching, that may degrade to exponential time which makes it useless. For example, you can do denial of service PCRE attacks, but not denial of service regex attacks (unless you can query with some megabyte-large regex).

New comment by jakobnissen in "Ruff v0.16.0 – Significant new updates – 413 default rules up from 59"

jakobnissen — Sun, 26 Jul 2026 11:15:01 +0000

Yes but the question is why Ruff has not released v1 yet. They’re clearly used in production and the entire purpose of v0.x is to signal a project is early in development and is expected to have coarse edges.

New comment by jakobnissen in "This blog is written in en-GB"

jakobnissen — Thu, 02 Jul 2026 13:03:16 +0000

But being non-inclusive by speaking to a particular cultural reference frame is not the same as being racist.

New comment by jakobnissen in "US Consumer Price Index up 4.2%"

jakobnissen — Wed, 10 Jun 2026 17:30:43 +0000

But that’s exactly what the inflation measures of the BLS is - someone doing the math on what all these things cost.

New comment by jakobnissen in "US Consumer Price Index up 4.2%"

jakobnissen — Wed, 10 Jun 2026 16:42:53 +0000

Why is the government measured inflation not the same as real inflation?

New comment by jakobnissen in "When AI Builds Itself: Our progress toward recursive self-improvement"

jakobnissen — Thu, 04 Jun 2026 18:18:39 +0000

Their outages are probably not due to their code though. It’s probably their infrastructure that can’t keep up. So seeing failures of infrastructure doesn’t really tell you anything about how good or bad Anthropic makes use of their models.

New comment by jakobnissen in "I was recently diagnosed with anti-NMDA receptor encephalitis"

jakobnissen — Wed, 03 Jun 2026 16:15:17 +0000

This sounds horrifying. It’s one of those stories that makes me think in just how many ways our bodies or minds can break or malfunction in terrifying ways. Any one of us could, right now, carry a lethal tumor that hasn’t been discovered.

Best of luck to you, and get well. I’m glad it didn’t get even worse before it was treated.

New comment by jakobnissen in "Electrobun 2.0 will be decoupled from Bun due to the Rust rewrite"

jakobnissen — Sat, 23 May 2026 14:46:12 +0000

But surely, whether or not the Internet mob moves on has no bearing on what actual lessons to learn from this saga. Will the vibe rewrite turn out to be a disaster or are LLMs already capable of writing human level code at this scale? That question is interesting no matter the level of attention this gets.

New comment by jakobnissen in "Everything in C is undefined behavior"

jakobnissen — Wed, 20 May 2026 09:33:09 +0000

I would guess that the continued success of Rust have shown that we don’t have to live with the user-hostility of C in order to write system programs. Therefore, people are understandably growing less and less patient with C and its unending bullshit.

Although I haven’t noticed a spike the last 6 months, just a slowly increasing realization that C isn’t fit for humans and should go the way of asbest: Don’t use it for anything new, and remove it where it already exists, unless doing so would be too expensive or disruptive.

New comment by jakobnissen in "Making Julia as Fast as C++ (2019)"

jakobnissen — Sat, 09 May 2026 15:58:08 +0000

The boring answer is that I don’t use huge dependencies that takes minutes to compile, and I don’t lean on the LSP - I tend to put more effort in reading the code.

In my experience you really gotta work with the tools the language gives you. Julia gives you Revise, so it’s a bit of a handicap not using it. Maybe analogous to writing Rust without an LSP.

I get that leaning on the LSP can become a habit, and also that the Julia LSP is quite poor, but I find it wild that rapid iteration for you is faster in Rust. I write Rust as well and can’t imagine how that would be the case.

New comment by jakobnissen in "GitHub Copilot code review will start consuming GitHub Actions minutes"

jakobnissen — Tue, 28 Apr 2026 18:21:52 +0000

You work for sandwiches and coffee, and not for a decent salary?

New comment by jakobnissen in "I did no work for a year and no one noticed"

jakobnissen — Mon, 27 Apr 2026 18:02:50 +0000

When people treat you badly, you confront them. If they won't change behaviour and you don't have any recourse, you avoid them. You *don't* compromise your own morals, and you *absolutely* don't advocate cheating in general.

New comment by jakobnissen in "Anthropic downgraded cache TTL on March 6th"

jakobnissen — Sun, 12 Apr 2026 09:12:43 +0000

Yeah I’ve seen this too. It’s difficult for me to tell if the complaints are due to a legitimate undisclosed nerf of Claude, or whether it’s just the initial awe of Opus 4.6 fading and people increasingly noticing its mistakes.