Getting ready for my #ecoop academy tutorial on programming systems!

On my way to #ecoop! (*) Don't miss Kristýna's talk about our work on formalising Vega on Tue (2026.ecoop.org/home/FTfJP-2...) and my Academy talk on programming systems on Wed (2026.ecoop.org/track/ecoop-...). (*) The first three connections are not Deutsche Bahn, so I'm optimistic :-)

My university has a fund for post-docs coming from abroad! If you are interested in working with me & our group on something related to programming systems and languages, from PL, HCI or historical & philosophical perspectives, get in touch (ideally in a few days...) See: cuni.cz/UKEN-178.html

📣What's new? The Novelty and Inequalities in Science symposium will be held in Prague (Oct. 8–9, 2026)! Please consider proposing an abstract on the topics of recognizing and rewarding novelty in science. More details: stss.flu.cas.cz/novelty2026 #scienceofscience #metascience #sociologyofscience 🧪

Programování není jen kód, je to kultura! 💻📜 Rektor UK Jiří Zima udělil prestižní Cenu Bedřicha Hrozného za tvůrčí počin a my máme obrovskou radost, že ji získal docent Tomáš Petříček z naší @mff.unikarlova.cuni.cz! 🏆

Do I replace: "massive blind spot: it focuses on" with "massive blind spot—it focuses on" and make my grant application look AI generated (*) but save the one character that I need to save? ____ (*) Regardless of whether it actually is or is not. That's a separate question!

I’m looking for participants for a paid user study on a prototype system for tabular programming (programming with tables / data frames). 2 hours • $50 Visa prepaid card Hoping to finish sessions by March 13. Details + sign up in 🧵 Reposts appreciated! 🙏

We created an exhibition to go along with my 𝐂𝐮𝐥𝐭𝐮𝐫𝐞𝐬 𝐨𝐟 𝐏𝐫𝐨𝐠𝐫𝐚𝐦𝐦𝐢𝐧𝐠 book! tomasp.net/cultures/exh... It tells the story of how programming concepts methodologies emerge amidst clashes and collaborations between cultures. 🖼If you want to display this at your university or conference, let me know!

👩‍💻 Dnes slavíme Mezinárodní den žen a dívek ve vědě. Na Matfyzu potkáváme každý den inspirativní vědkyně a studentky, které posouvají hranice technologií. 🚀 Děkujeme všem našim kolegyním a studentkám za jejich práci, preciznost a nadšení. Jste inspirací pro budoucí generace informatiček! 💙

The @undonecs.org programme has 27 (!!) talks asking some of the most fundamental questions about computer science. The early registration deadline is February 16th, so sign up soon: www.undonecs.org/2026/program... (Also, it costs between 10x and ∞x less than your regular ACM CS conference.)

After some *checks notes* umm.. 6 years, I released a new version of my composable data visualization library, adding support for images! compostjs.github.io/compost/demo... I still think this is the best way of doing composable data visualizations. See the paper: www.cambridge.org/core/journal...

It has arrived!!!

A new web page for my book! tomasp.net/cultures/ It has all the links you may need to get the open access PDF, buy a hardcopy or an ebook as well as some older talks & slides. If you run a podcast, conference or a user group, I'm always hapy to join & talk about something from the book!

I've now reached a stage in my career where I have to carefuly manage my time - and so I create a list of todo items to work on at the start of each month to keep myself organized!

arxiv.org/pdf/2601.14846 cc @dorchard.bsky.social

If you're thinking of applying to PLISS, you've got three days left! pliss.org/2026/registr...

My book in the newly published books bookshelf in the Cambridge University Bookshop! I got my first book on programming languages from there and used to wonder in basically every weekend to see what's new :-)

Can someone explain to me, why the "Basic" version of the ACM DL only gives me a link to a crappy "eReader" but the pro version includes link to the PDF? Did they build "eReader" just to frustrate users? Greasemonkey script to the rescue... but why?

@adamgryu.bsky.social We loved playing A Short Hike over the holiday break... and this was the result 😀 Thank you for creating a beautiful game!

Looking forward to coming to this amazing conference exploring the gaps in computer science research!

[email protected] and I are looking for a PostDoc to work on our EPSRC Project "INDIMO: Invariant Discovery and Monitoring for Message-Passing Programs". If you know someone, or are interested, please reach out! A few details here: jobs.royalholloway.ac.uk/Vacancy.aspx...

Do I know anyone in Cambridge who could stop by at the University Press Bookshop at the Market Square to take a picture of the newly published books? cc @dorchard.bsky.social @dynamicaspects.org @anil.recoil.org I've seen a physical copy of my book in the wild, so I'd love a picture from the source!

The open access version of Cultures of Programming is now available online. Just in time for the holiday break! Read it here: www.cambridge.org/core/books/c... If you prefer a real book, use PETRICK26 for a 20% discount (valid until January 31) at: www.cambridge.org/9781009492348

I have a bunch of very old #fsharp code running as Suave-based AppServices on Azure (net40, I know, I know). I've used up my free Azure credits, so this needs some kind of upgrade or migration. What's the least-work and most future-proof way to migrate this and host it at a reasonable cost?

What defines a correct program? What education makes a good programmer? The answer depends on what culture of programming you subscribe to! This has been a long time in the making, but my open access book on the history of programming is available for pre-order! www.cambridge.org/core/books/c...

In the last part of my tiny systems course, we get to implement a tiny version of the world's most widely used programming language! TinyExcel: www.youtube.com/watch?v=ghRA...

Next in my tiny systems course - write your own TinySelf! Learn about the genuinely elegant prototype-based object-oriented inspiration for JavaScript where everything is an object. www.youtube.com/watch?v=7Pre...

𝐎𝐧 𝐭𝐡𝐞 𝐋𝐢𝐦𝐢𝐭𝐬 𝐨𝐟 𝐌𝐚𝐤𝐢𝐧𝐠 𝐏𝐫𝐨𝐠𝐫𝐚𝐦𝐦𝐢𝐧𝐠 𝐄𝐚𝐬𝐲 New paper with Joel Jakubovic We wrote this for my PhD supervisor Alan Mycroft's festschrift, where you can get away with having some fun when writing! With the hope it will be insightful and fun to read too :-) tomasp.net/academic/pap...

Another meeting of our Programming Languages and Systems group at @mff.unikarlova.cuni.cz - with more interactive theorem proving 🤨 Natty can check proofs in natural English language!

It turns out that debugging a system where everything is an object without some kind of object browser is impossible. So.... the TinySelf lab of my tiny programming systems course will have a truly innovative UI component :-)

The next lab from my tiny systems course is up. Learn how to write your own small implementation of the logic programming language Prolog in #fsharp! www.youtube.com/watch?v=KC7A...

F# 10 makes it possible to use let! .. and! to await two tasks in parallel. This brings back some memories!

What if we think about proof assistants/dependently typed languages as interactive programming systems? Discussion today @mff.unikarlova.cuni.cz (And yes, our building has fairly thick walls :-))

Booked my train tickets for a trip to a PhD defense in Aarhus! Maybe it's not faster than flying, but I get to go from a train station 10 minutes walk from where I live. 🚂👍

In the next lab from my Tiny Systems course, you learn how type inference in ML-like languages works and write your own Hindley-Milner inference algorithm! 🎞️ Watch the videos: www.youtube.com/watch?v=FUFQ... ⌨️ Get the #fsharp code: github.com/tpetricek/ti...

In the second lab of my Tiny Systems course, we write a small interactive BASIC interpreter, inspired by Commodore 64 (Dijkstra does not approve...) 🎞️Watch the videos on YouTube: www.youtube.com/watch?v=jR0m... ⌨️Get the source code here: github.com/tpetricek/ti...

I'm afraid I've just recorded a video for my Tiny Systems course on how great GOTO was in Commodore 64 BASIC :-) (Although, to be fair, I also mention some benefits of GOSUB and RETURN, which is included in bonus materials...)

Absolutely fascinating 1960 ad for the SAGE (Semi-Automatic Ground Environment) computer! www.youtube.com/watch?v=iCCL... For those curious about what this is, there is an excellent book by Rebecca Slayton that documents the software side of the missile defense: mitpress.mit.edu/978026254957...

To be honest, I feel this is bragging about doing poorly in a meaningless league table.

I'm trying to replace my beloved but long-defunct Atom with VS Code for editing LaTeX. How do I stop copilot from telling me that I can press "Ctrl+I"? I already disabled it using "github.copilot.enable", which hides the actual suggestions, but not this useless message...

I just uploaded videos for the first lab of my tiny systems. TinyML - Write your own tiny functional language interpreter! 🎞️Watch the videos on YouTube: www.youtube.com/playlist?lis... ⌨️Get the source code here: github.com/tpetricek/ti...

I'm teaching 𝗪𝗿𝗶𝘁𝗲 𝘆𝗼𝘂𝗿 𝗼𝘄𝗻 𝘁𝗶𝗻𝘆 𝗽𝗿𝗼𝗴𝗿𝗮𝗺𝗺𝗶𝗻𝗴 𝘀𝘆𝘀𝘁𝗲𝗺(𝘀)! again. I'll be posting the videos & tasks on YouTube too. In the first lecture, I explain what's a tiny system, why write one and show plenty of demos! 🎞️ Playlist: www.youtube.com/playlist?lis... 👉 More info: d3s.mff.cuni.cz/teaching/npr...

Deadline extension: 1 week. Please submit your talk proposals by October 16 (anywhere on Earth). bsky.app/profile/undo...

I'm at #uist2025 presenting our new work with @jonathoda.bsky.social! 𝗗𝗲𝗻𝗶𝗰𝗲𝗸 is a computational substrate for end-user programming that makes it easy to implement programming experiences like programming by demonstration, collaborative editing and more! tomasp.net/academic/pap...

Companion (Workshop) Proceedings for ‹Programming› 2025 are now available! Co-edited with @jonathoda.bsky.social and @tomasp.net. Thanks to the awesome OASIcs publishing team for getting this over the line. drops.dagstuhl.de/entities/vol...

Slides from my talk "Critical Architecture/Software Theory" at PPIG 2025 in Belgrade: tpetricek.github.io/Talks/2025/c... The talk has been a great excuse to organize some more ideas, on top of my earlier article on the topic: tomasp.net/architecture/

Announcing Undone CS 2026: 2nd conference on Undone science in Computer science A conference in computer science to pause and reflect on the epistemological and ethical dimensions of the field, through the concept of undone science Full call for presentations at www.undonecs.org/2026/cfp.html

In case someone liked Prague during @programming-conf.bsky.social so much they wanted to come for longer... 📢 Charles University has a funding scheme for established researchers - to join us for (initially) 6 months to 2 years. More info: cuni.cz/UKEN-2238.html

Anybody remembers Microsoft script encoder? A true gem from the MSDN archives of August 1999: web.archive.org/web/20021214... (The thing was clearly not very sophisticated: web.archive.org/web/20070103...)

For software to be malleable, we need ways of building and modifying programs that are accessible to many more people. Are you working on new interfaces for programming? Share your progress at the LIVE workshop! Submissions are due July 21st. liveprog.org (Happy to chat if you have questions!)