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Welcome to 2030. I own nothing, no privacy, and life's never been better (2016)

https://medium.com/world-economic-forum/welcome-to-2030-i-own-nothing-have-no-privacy-and-life-ha...
1•sssilver•22s ago•0 comments

Elon Musk Acquires $1B Stake in CNN's Parent Company

https://symby.com/news?_cid=101605177&preferredLanguage=en
1•Alien1Being•2m ago•0 comments

Who will become the new mathematicians of Math 2.0?

https://proofsandprompts.com/2026/10/20/who-will-become-the-new-mathematicians-of-math-2-0/
1•the-mitr•6m ago•0 comments

Who Wrote This Byte?

https://fzakaria.com/2026/10/23/who-wrote-this-byte
1•Sighery•12m ago•0 comments

No Pussyfooting (1973)

https://www.discogs.com/master/9824-Fripp-Eno-No-Pussyfooting?srsltid=AYCX9vI4P8C-IiZyut0mu3GJd_l...
2•erottern•13m ago•0 comments

Yab, yet Another Browser

https://yetanotherbrowser.com/#arc
1•nmiv•23m ago•1 comments

Pi, the coding agent, compiled ahead of time to one native executable

https://github.com/opensec-git/Pi-Bolt
1•thunderbong•25m ago•0 comments

Julia Returns to Tiobe's Top 20

https://tech-insider.org/tiobe-index-october-2026-python-julia-rust/
1•sumnole•26m ago•1 comments

Oura sues rival Ultrahuman again, threatening its U.S. smart ring comeback

https://techcrunch.com/2026/10/22/oura-sues-rival-ultrahuman-again-threatening-its-u-s-smart-ring...
1•Brajeshwar•26m ago•0 comments

Tehran has detailed plans to hit Gulf undersea cables if war resumes

https://www.timesofisrael.com/liveblog_entry/iranian-officials-tehran-has-detailed-plans-to-hit-g...
1•ghost-pooper•29m ago•0 comments

Uringscope: eBPF Tracer and Analyzer for io_uring

https://github.com/rch0wdhury/uringscope
1•tanelpoder•31m ago•1 comments

Regular Expression Matching Can Be Simple and Fast (2007)

https://swtch.com/~rsc/regexp/regexp1.html
2•giancarlostoro•34m ago•0 comments

Hitler's Eagle's Nest retreat 'completely ablaze'

https://www.telegraph.co.uk/world-news/2026/10/24/fire-hitler-eagles-nest-germany/
3•giuliomagnifico•37m ago•1 comments

Security Infrastructure for Developers and Agents

https://infisical.com/
2•measurablefunc•37m ago•0 comments

Filekin – PDF tools with no signup, no limits and no watermark

https://filekin.io/
1•LlamaCode•39m ago•0 comments

Indian government sites are serving revoked eMudhra certificates

https://captnemo.in/blog/2026/10/23/emsign-revoked-gov-in/
2•adityaathalye•39m ago•0 comments

The Age of Reasoning [pdf]

https://metisreasoning.ai/whitepaper/the-age-of-reasoning-2026-10.pdf
2•gmays•41m ago•0 comments

Misure di sicurezza rafforzate NIS: stato e preparazione

https://cyberpath-hq.com/blog/misure-sicurezza-rafforzate-nis/
1•ebalo55•51m ago•0 comments

Mamdani Makes a Splash with His Bidets

https://www.nytimes.com/2026/10/23/nyregion/bidets-zohran-mamdani-gracie-mansion.html
2•osnium123•53m ago•0 comments

Sam Altman: 'I No Longer Think We're Gonna Be Able to Just Patch All the Bugs'

https://gizmodo.com/sam-altman-i-no-longer-think-were-gonna-be-able-to-just-patch-all-the-bugs-20...
5•CharlesW•53m ago•1 comments

Hardwood - modern lightweight Java reader and writer for Parquet file format

https://hardwood.dev/1.1.0.Beta3/
1•hiyer•56m ago•0 comments

The Colors of a Soap Film

https://aseemrb.me/blog/colors-of-a-soap-film/
2•gregsadetsky•58m ago•0 comments

How close can pure functional programming get to C?

https://rtfeldman.com/fp-vs-c
3•stmonty•1h ago•0 comments

Show HN: A map of outdoor gyms and pull-up bars

https://openairworkout.com/
2•hunvreus•1h ago•0 comments

Show HN: Inference Cooperative, user-governed AI

https://inference.coop/
1•ntnsndr•1h ago•0 comments

CowAgent – Open-Source Super AI Assistant

https://cowagent.ai/en/
1•ankitg12•1h ago•0 comments

The Anger Machine (Joan Kirner Social Justice Oration 2026)

https://www.andrewleigh.com/speech_the_anger_machine_rebuilding_community_in_the_age_of_outrage_2...
6•femto•1h ago•1 comments

Show HN: Web Bot Auth SDK and SSH Utilty

https://messh.io
1•malviyamukul•1h ago•0 comments

Show HN: CallFlow – VS Code REST client that also captures your terminal's HTTP

https://smallhours.works/callflow/
1•arexey•1h ago•0 comments

Ruliobiology and the Theoretical Foundations of Biological Form

https://writings.stephenwolfram.com/2026/10/endless-forms-most-beautiful-and-most-wonderful-rulio...
1•alok-g•1h 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...