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Faraday Security Enforcing and HyDE Recall

https://medium.com/@vektormemory/vektor-slipstream-real-tool-calling-faraday-security-enforcing-h...
1•vektormemory•2m ago•0 comments

Show HN: Open-source tool to sell your Claude Code and Codex sessions

https://github.com/cookiy-ai/sell-sessions-skill
1•YouchaoDong•5m ago•0 comments

Moving coding-agent guardrails from prompts to hooks

https://tesseracted-labs-blog.vercel.app/enforcing-coding-agent-guardrails-in-the-runtime-instead...
2•kkm•5m ago•0 comments

Intel TDX Remote Attestation Verifier Without Intel Trust Authority

https://zatona.dev/blog/intel-tdx-remote-attestation-verifier
1•dzatona•6m ago•0 comments

Saving Jet Fuel

https://tech.marksblogg.com/scikit-decide-openap-optimal-flight-planning.html
1•marklit•6m ago•0 comments

Ask HN: Why serialize documents to disk instead of memory-mapping runtime state?

1•ShengATsao•7m ago•0 comments

The Ex-Cop Who Stole Millions to Become a Real-Life Robin Hood

https://magazine.atavist.com/2026/the-bleeding-hearts-austria-robbery
1•gmays•8m ago•0 comments

"The Secret Life of Circuits" is here

https://blog.coredump.cx/p/the-secret-life-of-circuits-is-here
1•surprisetalk•8m ago•0 comments

Astra's chess reward hacking fell from 30% to 0% with a 95-word agreement

https://www.echohive.ai/can-an-agreement-reduce-ai-cheating-at-chess
2•echohive42•10m ago•0 comments

Gravity Linux – Linux for Apple Silicon M4 and Above

https://gravitylinux.org/blog/hello-gravity/
2•xlmnxp•11m ago•1 comments

Clarity Act Stalls in Senate as Crypto Bill Fails to Clear Key Vote

https://decrypt.co/378283/clarity-act-fails-senate-hurdle
3•consumer451•17m ago•0 comments

Update Security Baseline: Hardening Ubuntu Desktop 24.04/26.04 LTS

https://github.com/EugeXo/security-baseline-ubuntu
1•EugeXo•20m ago•0 comments

Introduction Video Gen in Img Play

https://apps.apple.com/az/app/img-play-ai-image-generator/id6745093585
1•hack88171•21m ago•0 comments

Google Project Genie. Explore infinitely diverse worlds

https://labs.google/fx/
2•fragmede•22m ago•0 comments

Understanding the Baby Boom

https://worksinprogress.co/issue/understanding-the-baby-boom/
1•debo_•22m ago•0 comments

Operation Epic Fury [pdf]

https://media.defense.gov/2026/Sep/09/2003993626/-1/-1/1/OEF_Q3_JUN2026_FINAL_508%20SECURE.PDF
2•layer8•24m ago•0 comments

Say No to AI Filters

https://percentshop.vercel.app/
1•vladavetisian•24m ago•0 comments

Digital Asset Market Clarity Act Fails in Senate

https://www.therage.co/clarity-act-fails-in-senate/
1•iamnothere•26m ago•0 comments

Salesforce in Claude

https://claude.com/blog/salesforce-in-claude
1•vertigoruntime•28m ago•0 comments

Has anyone made any money/successes making SaaS's with AI?

1•kraig911•29m ago•1 comments

Automatic Motor Learning Is the Secret to Our Effortless Walk

https://dailyneuron.com/automatic-motor-learning-effortless-walk/
1•MarlonPro•30m ago•0 comments

Recreating Voodoo Graphics and a Late-1990s Gaming PC on an FPGA

https://nand2mario.github.io/posts/2026/zsst-voodoo/
2•zdw•32m ago•0 comments

Run cloud agents on machines you manage

https://cursor.com/blog/self-hosted-machines
1•gmays•34m ago•0 comments

The State of Allocators in 2026 – 6 Months Later

https://cetra3.github.io/blog/state-of-allocators-2026-part-2/
1•agluszak•35m ago•0 comments

Toymodel (By Semiqlassical) – Modular Sci-ML

https://semiqlassical.tech/toymodel/
1•banerjeeav•35m ago•1 comments

Cohere CEO says calls for coordinated slowdown amounts to 'cartel' behaviour

https://www.theglobeandmail.com/business/technology/article-cohere-ceo-aidan-gomez-criticizes-cal...
5•neom•36m ago•0 comments

Benchmark Fatigue

https://www.pcmag.com/opinions/why-ai-benchmarks-are-total-bs-and-how-openai-and-anthropic-use-th...
1•eazae•36m ago•0 comments

Anthropic Confirms Claude AI Use in Weapons and Surveillance

https://thedefensepost.com/2026/09/15/anthropic-claude-weapons-surveillance/
2•EA-3167•37m ago•0 comments

Late-life semaglutide treatment slows ageing and extends lifespan in female mice

https://www.nature.com/articles/s41586-026-10940-7
2•gmays•39m ago•0 comments

Skill Poisioning turning AI agents into malware droppers

https://ministryofcyberaffairs.com/news/skill-poisioning-turning-ai-agents-into-malware-droppers-...
1•giuliomagnifico•39m ago•0 comments
Open in hackernews

Understanding-j: An introduction to the J programming language that gets to the

https://github.com/bugsbugsbux/understanding-j
62•todsacerdoti•1y ago

Comments

prezjordan•1y ago
To the author: you can add a .devcontainer directory with a Dockerfile, allowing folks to try this in their browser with GitHub Codespaces

Shameless plug, feel free to copy my setup! https://github.com/jdan/try-j

userbinator•1y ago
Unintentional humour with how the title got cut off?
pixelpoet•1y ago
The title stops just short of the
johnisgood•1y ago
"to the point", I presume, based on its README.
pjmlp•1y ago
A side effect of the small length available for titles and the whole titles should not be editoralised point of view.
Jtsummers•1y ago
It's more an issue of todsacerdoti not checking their submission titles will fit, they do this a lot with their submissions. Abbreviating titles is not frowned upon when they don't fit, I've never had any reverted to something like this submission's title because I (for instance) shortened "United States" to "US" to shave off 11 characters.

In this case, cutting out the superfluous "programming language" part would get you "Understanding-j: An introduction to J that gets to the point" which would fit just fine. When in doubt, include the original title in a comment to explain the edit and let the mods sort it out later.

detaro•1y ago
It's hard to check if titles fit if you use a bot to repost from other sites.
Jtsummers•1y ago
Fair, they're lazy and can't be bothered to fix their bot even after 5 years of submitting messed up titles.
t-writescode•1y ago
From the doc,

  _3                  NB. negative numbers start with underscore
  _                   NB. sole underscore is infinity: a number
  __                  NB. negative infinity
Is this a standard I'm unaware of?
avmich•1y ago
The use of underscore for negative numbers is J's choice, explained e.g. here - https://www.jsoftware.com/docs/help807/jforc/preliminaries.h... .

Explicitly representing infinity, and working with it in some cases, allows to reduce number of exceptions...

Avshalom•1y ago
APL used ¯3 for negative 3; J went underscore to be similar but ascii.
gitroom•1y ago
Underscore stuff always throws me off - never quite got used to how J does it. Gotta respect the weird choices though.
jbverschoor•1y ago
Not the same as (Visual) J++. Great IDE btw
vintagedave•1y ago
I’ve recently come to be fascinated by J.

Twenty years ago, studying my computing degree, one semester we learned J. It was unlike anything I’d used before and the entire class found it confusing. The compiler / environment was reportedly written by one of the professors and it was routine to run into bugs; I remember puzzling through something, going to a tutor, and them just shrugging it off as a J interpreter issue. I never grokked it and simply passed the course.

But it keeps on recurring to me and I pause to think of J at the weirdest times. As I use more and more languages, I’ve become more fascinated by it. Just like Prolog (also one semester, but with a reliable environment.) I want to learn both better.

binary132•1y ago
I’ve been thinking for the past couple of years that the ideal programming language would be something like a combination of a concatenative language (a la FORTH) and an array programming language.
gnubison•1y ago
Uiua?
binary132•1y ago
interesting, I have not seen this one
preguntador•1y ago
12j34 is 12j + 34 or 12 + 34j?
quartern•1y ago
12 + 34j as per https://code.jsoftware.com/wiki/Vocabulary/Constants#Complex...