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G-J van Rooyen

@gvrooyen.com
94 followers 64 following 151 posts

Director: Engineering & Innovation @ octoco.ltd. Associate Professor Extra-Ordinary in Industrial Engineering @ Stellenbosch University. programming languages · trail running · innovation management · startups · good wine · business · reading

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G-J van Rooyen @gvrooyen.com · 19/09/2026
Thinking of starting a fried fish takeout named "Batter Call Sole"
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Bryan Cantrill @bcantrill.bsky.social · 06/12/2025
Your intellectual fly is open bcantrill.dtrace.org/2025/12/05/y...
bcantrill.dtrace.org
Your intellectual fly is open | The Observation Deck
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G-J van Rooyen @gvrooyen.com · 28/08/2026
After several years on #Neovim, I'm going to give #Helix a spin! I've heard good things about it; keen to try something new
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G-J van Rooyen @gvrooyen.com · 25/08/2026
No cheating. Share the last photo of the sky from your camera roll
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Katie Mack @astrokatie.com · 10/04/2026
As far as I know there is literally no reason for this, it is just an incredibly lucky coincidence that we get to enjoy for free
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sabine 🐫🦀 / "use ocaml"; @sabine.sh · 06/03/2026
trying this linkedinfluencer thing to say OCaml and Domain Specific Languages www.linkedin.com/pulse/domain...
linkedin.com
Domain Specific Languages as AI Supervision Gates
Everyone's talking about AI agents. Autonomous this, agentic that.
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David Shiffman, Ph.D. 🦈 @whysharksmatter.bsky.social · 04/03/2026
“Fish” can be both singular (one individual) and plural (multiple individuals of the same species.) “Fishes” is multiple species. 🐠 Fish 🐠🐠🐠 Fish 🐠🐡🐟 Fishes Now you know. And knowing is half the battle.
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G-J van Rooyen @gvrooyen.com · 14/02/2026
How about: Roses are red Violets are blue Lucy glows pinkish Like when I see you
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G-J van Rooyen @gvrooyen.com · 26/01/2026
I've been thinking a lot about how coding agents can help us write more literate programs. gvrooyen.substack.com/p/literate-a...
gvrooyen.substack.com
Literate Agents
“We don’t really have any technical documentation in the data room yet, so you can just tell us what you need,” the CTO said.
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Simon Willison @simonwillison.net · 20/01/2026
This is great - it's about time someone updated the discourse on LLM energy usage to reflect that coding agents use massively more prompts than occasional questions to ChatGPT Simon estimates that a day of coding agent usage comes out close to the energy needed to run a dishwasher
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G-J van Rooyen @gvrooyen.com · 21/01/2026
Bluesky is pleasant; it's my first port of call nowadays. AI-safe but not hypey. I dip into X occasionally, very carefully, only stay in safe neighborhoods, and try not to say much. Uh, I'd avoid Mastodon altogether if you have radical thoughts like "LLMs can theoretically be useful too"... 😂
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G-J van Rooyen @gvrooyen.com · 20/01/2026
My experience with agentic coding (Amp) and OCaml has been super positive - as in one-shotting an entire application that I now use daily. My working theory is that the strong type system gives the agent a very strict and tight feedback loop for converging on a working solution
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G-J van Rooyen @gvrooyen.com · 10/01/2026
Also, I see they've just announced that the ad-supported tier gives you $10 worth of Claude Opus 4.5 tokens per day, which seems pretty useful: ampcode.com/news/amp-fre...
ampcode.com
The Frontier Is Now Free
$10/day for any mode, including smart with Opus 4.5
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G-J van Rooyen @gvrooyen.com · 10/01/2026
Have you had a look at Amp (ampcode.com)? Curated ensemble of models, and the CLI and IDE integrations are great. My team uses the paid plan, but the ad-supported free tier is apparently really good too
ampcode.com
Amp
Amp is a frontier coding agent that lets you wield the full power of leading models.
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Steven (with a PH) @sjksalisbury.bsky.social · 27/12/2025
Please bring the card machine with you when you bring the bill. I had the pollo con spinaci, I didn't return the ring to Mordor. You don't have to split this interaction across multiple volumes.
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Andrew Turley @aturls.bsky.social · 02/11/2025
Look folks gen AI videos are out in the wild so if you weren't already being careful about sharing rage bait videos then now is a great time to start If you can't trace a video back to a trusted source then I recommend leaving it where it is, like a slice of bologna you found on the street
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Scott Hanselman 🌮 @scott.hanselman.com · 11/10/2025
Minor medical situation on the flight and it’s cool that my wife is able to jump up and help out when they ask for a licensed medical professional. One day someone will need a regular expression so I stay ready.
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James Hell Brooks @kleinman.bsky.social · 01/10/2025
RIP Jane Goodall, by all accounts a wonderful woman who loved this Far Side cartoon
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G-J van Rooyen @gvrooyen.com · 28/07/2025
With the sad passing of Tom Lehrer, a flashback to the place where I heard one of his songs for the very 1st time more than three decades ago
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Al Yankovic @alyankovic.bsky.social · 15/07/2025
nytimes.com
Weird Al Is Enjoying His Rock-Star Moment
At Weird Al Yankovic’s sold-out Madison Square Garden debut, pop culture’s foremost song parodist was feeling the love.
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G-J van Rooyen @gvrooyen.com · 11/07/2025
Maine attraction!
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G-J van Rooyen @gvrooyen.com · 07/07/2025
Had a vampire marathon this weekend with my son: Nosferatu (1922), Shadow of the Vampire (2000), Nosferatu (2024). Highly recommended watching order 🧛🏻
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G-J van Rooyen @gvrooyen.com · 28/06/2025
Oh nice, I saw your tweet about that Robert Caro passage a couple of weeks ago. I was briefly intrigued and wondered where it came from, but things were a bit too busy to dig deeper. The Power Broker is now in my library; really looking forward to start dipping into it
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Oliver Darkshire @deathbybadger.bsky.social · 27/06/2025
have been confused for days about insane cats invading our yard and destroying the plants for no reason only to find out I have accidentally planted fucking catnip all over the place, I am this neighborhoods feline drug lord, ive devasted their society
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G-J van Rooyen @gvrooyen.com · 25/06/2025
Out of interest, what was your takeaway from the jj experiment? I found it quite difficult to break my git muscle memory on shared work repos
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G-J van Rooyen @gvrooyen.com · 21/06/2025
Rereading an old fantasy novel from my youth. The protagonist names are all bouba; the villains outlandishly kiki
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G-J van Rooyen @gvrooyen.com · 17/06/2025
I switched to Arch a bit more then a week ago – 1st time with Linux as my main OS in more than a decade. Incredibly impressed by how mature, sleek, and customizable everything has become. And my entire Steam library is playable here now, with better performance than on Windows! Not switching back.
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G-J van Rooyen @gvrooyen.com · 31/05/2025
:fistpump:
Screenshot of the "Gleam" section of the StackOverflow Developer Survey. Both "Worked with" and "Want to work with" are checked.
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G-J van Rooyen @gvrooyen.com · 28/05/2025
Ek steel hierdie en maak dit "net hoed, geen stoet"
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G-J van Rooyen @gvrooyen.com · 26/05/2025
The prompt string I use in my `.zshrc` to just show the current minimal change ID. Since the working copy is always committed, no need to check for any uncommitted changes.
A `jj_prompt_info()` zsh function that generates a string with the current minimal commit identifier.
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G-J van Rooyen @gvrooyen.com · 25/05/2025
Love using plain chat as a scratchpad where I can back-and-forth with the AI until I get what I need (I've been desperate to turn my bank's old email statements into flexible machine-readable data for DECADES) and then just ask for a prompt that I can use in future or pass along to an agent
An LLM-generated prompt to give to LLMs. It describes the desired CSV structure, gives key instructions based on prior troubleshooting, and a clear description of the output artefact.
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Scott Hanselman 🌮 @scott.hanselman.com · 17/05/2025
The word “login” comes from throwing a log attached to a rope with knots overboard a ship to see how many knots go by over time (see also, knots as speed). You’d then put that info in the “log book.” You’d “log in” on a regular basis. This wasn’t from 1959, it was likely from 1689! Etymology baby!
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G-J van Rooyen @gvrooyen.com · 15/05/2025
I think the git workflow bit is worth talking and writing about even more. This is definitely a topic I'll pick up with my team. I love how new tools can unexpectedly level-up old tools – thanks for pointing this one out!
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G-J van Rooyen @gvrooyen.com · 15/05/2025
"Speech is a clumsiness and writing an impoverishment," to quote Richard Rhodes somewhat out of context
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G-J van Rooyen @gvrooyen.com · 15/05/2025
I'm a huge fan of diagrams to communicate with an LLM. It feels as if the Mermaid syntax is so clear and uncluttered with formatting concerns (it just relates concepts) that it maps more directly to the model's own latent space than its translation into natural language would
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G-J van Rooyen @gvrooyen.com · 14/05/2025
This feels right out of Snow Crash. Read the wrong text and you might catch a serious mind-altering (or -destroying) neuro-linguistic virus. (It's thrilling! Like a new frontier still waiting to be tamed)
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G-J van Rooyen @gvrooyen.com · 13/05/2025
I'm unsure why Putin is looking so pissed about this
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Martin Fowler @martinfowler.com · 30/04/2025
NEW POST Even experienced developers fumble around when working with a new platform. Unmesh Joshi shows how using an LLM helped him learn how to use an unfamiliar toolset. martinfowler.com/articles/exp...
martinfowler.com
Building TMT Mirror Visualization with LLM: A Step-by-Step Journey
Notes from my Thoughtworks colleagues on AI-assisted software delivery
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Kevin M. Kruse @kevinmkruse.bsky.social · 25/04/2025
I’ve never had someone take a honk as a conversation starter before but there we are
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Kevin M. Kruse @kevinmkruse.bsky.social · 25/04/2025
Guy nearly hit me in traffic, so I honked at him. Next stop light, he pulls up next to me and rolls down his window. “You got somethin’ to say to me?!” “Yeah, I think you’re a shitty driver. That’s what the honk was for.”
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G-J van Rooyen @gvrooyen.com · 22/04/2025
Oblivion Remastered looks absolutely BEAUTIFUL. Can still vividly remember the anticipation 20 years ago, and the live reveal brings back all those feels
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G-J van Rooyen @gvrooyen.com · 19/04/2025
This court order is literature
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Katie Mack @astrokatie.com · 15/04/2025
An astronomy professor colleague of mine once relayed trying to explain to his students why it was important that they actually write their class reports themselves. “The point is not to teach ME about neutron stars,” he said.
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Oregon 🕎🎲 @oregonthedm.bsky.social · 09/04/2025
Biggest commitment to a 3 second joke I've ever seen
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G-J van Rooyen @gvrooyen.com · 09/04/2025
Why vim uses hjkl for movement, ESC to change modes, and why ~ represents the home directory in Unix. It's all thanks to the beautiful ADM-3A terminal that was born in the same year as me! catonmat.net/why-vim-uses... #retrocomputing #vim #neovim
catonmat.net
Here is why vim uses hjkl keys as arrow keys
I was reading about vim the other day and found out why it used `hjkl` keys as arrow keys. When Bill Joy created the vi text editor he used the ADM-3A terminal, which had the arrows on hjkl keys. Natu...
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G-J van Rooyen @gvrooyen.com · 05/04/2025
This is terrible. The 50% (!!) US trade tariff on Lesotho, who mainly manufactures jeans for brands like Levi's and Calvin Klein, risks wiping out half of their exports. www.news24.com/fin24/econom...
news24.com
Baffled Lesotho seeks to engage with US on jeans tariffs | Business
Lesotho scrambled to put together a delegation on Friday to head to Washington to engage with the US on tariffs that risk wiping out nearly half of its exports, its trade minister said, in what could ...
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G-J van Rooyen @gvrooyen.com · 05/04/2025
Reminds me of the beautiful "I, Pencil" from the 1958 essay by Leonard Read. "not a single person on the face of this earth knows how to make me" mises.org/mises-daily/...
mises.org
I, Pencil
This classic article by Leonard Read illustrates how completely dependent the world is on the division of labor.
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eraldo.bsky.social @eraldo.bsky.social · 03/04/2025
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Existential Comics @existentialcomics.com · 31/03/2025
The Frog and the Scorpion From a Rational Point of View existentialcomics.com/comic/596
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