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CF Bolz-Tereick

@cfbolz.bsky.social
303 followers 217 following 40 posts

PyPy/RPython contributor. Half time teaching at Uni Düsseldorf. Works on dynamic language implementations. Love street art and art in public spaces, hiking, reading. they/them

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Reposted by CF Bolz-Tereick
rain 🌦️ @sunshowers.io · 19h
Update on yesterday's post about Anthropic ripping off Mononoke:
sunshowers.io
More on Anthropic's Scion ripping off Mononoke
Answering questions and concerns.
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mcc @dryad.technology · 14/10/2026
Gods are asleep. Post modernism
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CF Bolz-Tereick @cfbolz.bsky.social · 23/09/2026
Quinn is the absolute best, all her talks are amazing.
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Hila Peleg @hilacodes.bsky.social · 09/09/2026
The first annual Future of Property-Based Testing Workshop (FPBT'27) will be happening in Mexico City on January 12th (co-located with POPL'27)! Submissions are open now (deadline October 23rd); see popl27.sigplan.org/home/fpbt-2027 for details.
popl27.sigplan.org
FPBT 2027 - Future of Property-Based Testing - POPL 2027
Property-based testing has grown from a niche technique into a recognized discipline with a thriving research community and a considerable base of industrial practitioners. In fact, PBT is only increa...
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CF Bolz-Tereick @cfbolz.bsky.social · 24/07/2026
Herzlichen Dank für die aufwändige Aufarbeitung! Und viele kollegiale Grüße aus der Informatik
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CF Bolz-Tereick @cfbolz.bsky.social · 10/06/2026
It doesn't make any sense to us either (my kid, with a broken arm, and I just got sent from one radiology practice to another one for weird accident insurance reasons)
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CF Bolz-Tereick @cfbolz.bsky.social · 05/06/2026
@adriandaub.bsky.social @moiradonegan.bsky.social loving the plagiarism episode (and the podcast in general)! One thing that Guttenberg does now is extremely funny/weird: he has a podcast with Gysi! gysi-gegen-guttenberg.podigee.io
gysi-gegen-guttenberg.podigee.io
Gysi gegen Guttenberg – Der Deutschland Podcast
Gregor Gysi und Karl-Theodor zu Guttenberg sind zwei der populärsten und streitbarsten (Ex-) Politiker der letzten 30 Jahre. In diesem Podcast, prallen ihre Gegensätze erstmals richtig aufeinander. Je...
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CF Bolz-Tereick @cfbolz.bsky.social · 31/05/2026
I just blogged: 'Knownbits in Lean' cfbolz.de/posts/2026-k...
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CF Bolz-Tereick @cfbolz.bsky.social · 29/05/2026
I had read it before, read it again, still extremely funny
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Shriram Krishnamurthi @shriram.bsky.social · 29/05/2026
Startled to find out that there are young people who haven't read James Iry's magnificent "A Brief, Incomplete, and Mostly Wrong History of Programming Languages". Please drop what you're doing and head over. james-iry.blogspot.com/2009/05/brie...
james-iry.blogspot.com
A Brief, Incomplete, and Mostly Wrong History of Programming Languages
1801 - Joseph Marie Jacquard uses punch cards to instruct a loom to weave "hello, world" into a tapestry. Redditers of the time are not imp...
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Kiran @kirancodes.me · 06/05/2026
ML researchers know Python. Proof engineers know Lean. Never the two should meet.. Until now! Announcing Lean.py, effortless Lean to Python and Python to Lean bindings! - Write Lean tactics in Python - Access the Python ecosystem in Lean github.com/kiranandcode...
import SymPyTactic

example : (1 : Int) * 1 = 2 := by sympy
example : (3 : Int) * 4 = 12 := by sympy
example : (5 : Int) * 6 = 30 := by sympy/-- Expr-based equality check. Receives `Lean.Expr` trees (via the
`derive_python` Reflect registration) and delegates conversion entirely
to Python's `lean_to_sympy` module. -/
@[python "sympy_expr_eq_accept"]
def sympyExprEqAccept (lhs rhs : Lean.Expr) : IO Bool := do
  init ()
  let mod ← import_ "lean_to_sympy"
  let checkFn ← mod.getAttr "sympy_eq_check"
  let convFn ← mod.getAttr "expr_to_sympy"
  let lhsSy ← convFn.call #[← Py.ofLeanObj lhs]
  let rhsSy ← convFn.call #[← Py.ofLeanObj rhs]
  (← checkFn.call #[lhsSy, rhsSy]).toBool
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CF Bolz-Tereick @cfbolz.bsky.social · 06/05/2026
Germany has something similar! It's located in the same spot, an arrow shaped button. The arrow points the direction how to cross. If you press the button, it starts vibrating when it's green. youtu.be/SUZJ9rlu6Io?...
youtu.be
Aufgeklärt: DAS bewirkt der mysteriöse Knopf unter dem Ampelkasten
YouTube video by gofeminin
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CF Bolz-Tereick @cfbolz.bsky.social · 27/04/2026
I wonder how slow cpython running on Fil-C is though. I guess it's quite a bit worse?
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verijit @verijit.bsky.social · 17/04/2026
Hi! We build fast verilog simulators using just in time compilation. Our simulator outperforms existing verilog simulators by up to x100. verijit is a project by @cfbolz.bsky.social and Can Joshua Lehmann. Check out out demo video here: www. youtube.com/watch?v=PXgUsEjvAOY
youtube.com
Verijit – Up to 100x faster Verilog simulation
YouTube video by verijit
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Pavel @spavel.bsky.social · 28/03/2026
Make sure to rotate your pronouns periodically, so that if your gender becomes compromised, attackers can only access it for a short period of time.
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ee @durbin.ee · 21/01/2026
Some news, I’ll be departing the PSF as a staff member at the end of this week.
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CF Bolz-Tereick @cfbolz.bsky.social · 22/01/2026
Thanks for everything ee!
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CF Bolz-Tereick @cfbolz.bsky.social · 11/01/2026
😂 Just say the word
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CF Bolz-Tereick @cfbolz.bsky.social · 11/01/2026
There's a bunch operating in Germany and under protected building status, so they won't actually go away (might just be broken indefinitely or something). If you ever make it to Duisburg, let me know, we'll go to the town hall
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haha yeah @freshfleisch.bsky.social · 29/12/2025
we must imagine Sisyphus being directed to the boulder corporation’s outsourced mental health support service for up to 2 hours of free counselling per eternity
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CF Bolz-Tereick @cfbolz.bsky.social · 25/12/2025
www.der-postillon.com/2025/12/drog...
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Savannah Ostrowski @savannah.dev · 13/12/2025
I’m incredibly excited to serve on this coming term’s Steering Council! Working on CPython has been one of the most rewarding endeavours of my career. I’m so grateful to everyone who voted & honoured that so many placed their trust in me. peps.python.org/pep-8107/
peps.python.org
PEP 8107 – 2026 Term Steering Council election | peps.python.org
This document describes the schedule and other details of the 2025 election for the Python steering council, as specified in PEP 13. This is the steering council election for the 2026 term (i.e. Pytho...
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Martha Wells @marthawells.com · 11/12/2025
Re-upping this, since it's only available for two days:
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CF Bolz-Tereick @cfbolz.bsky.social · 05/12/2025
People have argued with me about every single square of this, on one channel or another 🤷‍♀️
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Julia Evans @b0rk.jvns.ca · 28/11/2025
it's happening!!! from now until the end of the day on Friday, November 28th (if it’s Friday anywhere, the sale’s still on!), all my pdf zines are 50% off, and print zines are 30% off! wizardzines.com
woman with shell necklace and a redirects belt accessory
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CF Bolz-Tereick @cfbolz.bsky.social · 28/11/2025
@tartanllama.xyz Building a Debugger got a review in c't, a big German computer magazine:
Photo of the German review of the book
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Manish @manishearth.bsky.social · 06/11/2025
lol @hikikomorphism.bsky.social just described Ea-Nāṡir as "CMOT Dibbler (Assyrian Edition)"
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Robbie Richardson @londonmikmaq.bsky.social · 06/09/2025
Tlingit artist Nicholas Galanin, “Architecture of return, escape (The British Museum)”, a deerskin map a floor plan of the British Museum and possible escape routes for various Indigenous cultural belongings held there.
An animal hide covered in blue felt with a floor plan of a museum drawn on it
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CF Bolz-Tereick @cfbolz.bsky.social · 15/10/2025
Interpreter alignment chart
This alignment chart explores what counts as an "interpreter" across two dimensions: implementation (what form the interpreter takes) and input (what it processes).
Implementation Axis
Implementation Purist: An interpreter must be a program—software that executes on a computer.
Implementation Neutral: An interpreter must be electronic—it can be hardware or software, but requires circuits and electricity.
Implementation Rebel: An interpreter can be anything—no restriction on physical form or medium.
Input Axis
Input Purist: An interpreter works on a program—it must execute formal code or instructions.
Input Neutral: An interpreter works on text—it processes symbolic or written information.
Input Radical: An interpreter works on anything—no restriction on input type.
Examples Across the Spectrum

Lua (program processing programs)
CPU (electronic processing programs)
CEK-Machine (anything processing programs)
Excel (program processing text)
LLM (electronic processing text)
Shredder (anything processing text)
Doom (program processing anything)
TV (electronic processing anything)
Choir (anything processing anything)
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absolute horses @jcoglan.com · 14/10/2025
it has been 0 days since I wrote a tiny interpreter to prototype some new database features. you will never regret writing a tiny interpreter
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The Trandalorian @charliejaneanders.com · 14/10/2025
It's spooky season! So I reviewed four great recent scary books: Fiend by @almakatsu.bsky.social Moonflow by @bitterkarella.bsky.social Slashed Beauties by A Rushby You Weren't Meant to be Human by @ajwhiteauthor.bsky.social www.washingtonpost.com/books/2025/1...
washingtonpost.com
4 terrifying new novels to get you through the scariest season
With an emphasis on body horror, these books by Alma Katsu, Bitter Karella, Andrew Joseph White and A. Rushby will leave you with a lingering sense of dread.
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Denny Perez @dennyperez18.bsky.social · 09/10/2025
📣 The “People from PSF” interview series continues! 🐍💬Meet the people behind the @python.org staff, directors & contributors making the magic happen. 💟 Meet Deb Nicholson @eximious.bsky.social 🔗Read the full interview 👇 dennyperez.dev/projects/psf... #Python #PyLadies #PSF #PeopleFromPSF
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Antonio Cuni @antocuni.bsky.social · 06/10/2025
The SPy project is kicking off community calls! 🎙️ Join us tomorrow (Oct 7th, 17:30 CEST) on Discord to chat, ask questions, and meet other SPy folks. Everyone’s welcome! 💚 🥸 Discord link: discord.gg/ZN4afjvq?eve... Google calendar link: lnkd.in/d3U62QNn
discord.gg
Join the SPy lang Discord Server!
Check out the SPy lang community on Discord - hang out with 43 other members and enjoy free voice and text chat.
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CF Bolz-Tereick @cfbolz.bsky.social · 02/10/2025
Even his London post hints at transphobia in the paragraph about Lineham's arrest. A dog whistle anti trans people would recognize 😒
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Antonio Cuni @antocuni.bsky.social · 24/09/2025
Last week I was lucky to take part in the CPython Core Dev Sprint. This is a summary of what I did, including an annotated and extended version of my talk on tracing JITs in real-world Python scenarios, plus some comparisons between PyPy’s JIT and CPython’s new JIT. 👉 antocuni.eu/2025/09/24/t...
antocuni.eu
Tracing JITs in the real world @ CPython Core Dev Sprint
My experience at the CPython Core Dev Sprint
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The Midnight Society @midnightpals.bsky.social · 12/09/2025
hey we have a lot of fun here, living in a fascist dystopia and goofing on the very real lives being ruined by the state, it's great, things are fine, we love it! Why not enjoy the end of civilization with a good book? why not do it with MY book?? www.hachettebookgroup.com/titles/bitte...
hachettebookgroup.com
Moonflow
"A bizarre and fiercely original splatterpunk phantasmagoria of queerness. Deranged and gleefully weird as f*ck, this is an impressive debut from a singular...
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Elizabeth Bear @matociquala.bsky.social · 18/08/2025
2008, I am driving back across the Canadian border from Montreal with @stillsostrange.bsky.social and @batwrangler.bsky.social in my tiny1998 Honda Civic sedan.
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Kate @katef.bsky.social · 14/07/2025
happy analog gender week nerds 💛🤍💜🖤
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CF Bolz-Tereick @cfbolz.bsky.social · 05/07/2025
Anil Dash wrote this post about this question: bsky.app/profile/anil... Thanks for being so cool Danielle!
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CF Bolz-Tereick @cfbolz.bsky.social · 29/06/2025
There was a new movie this year! And the one before that was the highest grossing German movie in 2023 😅
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CF Bolz-Tereick @cfbolz.bsky.social · 28/06/2025
The books series is unbelievably popular in Germany, until today. It's called The Three Question Marks here and my eight year old devours it. There are extra novels that were written just for the German market, radio plays, movies, two spinoff series etc. en.wikipedia.org/wiki/German_...
en.wikipedia.org
German editions of the Three Investigators - Wikipedia
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Shriram Krishnamurthi @shriram.bsky.social · 26/06/2025
OMG no!!! I still think Knuth's deep dive from "I want to write about algorithms" to "I need typesetting software" to "I need fonts" to "I need font software" to "I need software to write software" may be the most epic software exploration in human history, and kids these days have NO IDEA about it.
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The PyPy Project @pypyproject.bsky.social · 15/06/2025
New blog post by @cfbolz.bsky.social: "How fast can the RPython GC allocate?" pypy.org/posts/2025/0...
pypy.org
How fast can the RPython GC allocate?
While working on a paper about allocation profiling in VMProf I got curious about how quickly the RPython GC can allocate an object. I wrote a small RPython benchmark program to get an idea of the ord
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CF Bolz-Tereick @cfbolz.bsky.social · 12/06/2025
It's 100 copies of that loop that are traced in 34ms. But yes, I hope so!
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CF Bolz-Tereick @cfbolz.bsky.social · 12/06/2025
This is mainly due to the double interpretation overhead: the meta-tracing interpreter will execute the Python interpreter, while the latter executes one iteration of the Python loop.
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CF Bolz-Tereick @cfbolz.bsky.social · 12/06/2025
"How slow is the tracing interpreter of PyPy's meta-tracing JIT?" cfbolz.de/posts/speed-... Spoiler: for the microbenchmark I tried, the slowdown of the meta-tracing interpreter is about 900x
cfbolz.de
How slow is the tracing interpreter of PyPy's meta-tracing JIT?
I wanted to investigate the warmup behavior of the PyPy interpreter, so I wrote a somewhat arbitrary microbenchmark: all_results = set() num = int(sys.argv[1]) class A(object): pass def main():
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CF Bolz-Tereick @cfbolz.bsky.social · 22/05/2025
Want me to stick it in an envelope and mail it to you?
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CF Bolz-Tereick @cfbolz.bsky.social · 21/05/2025
@keleshev.com not sure whether you already saw, but Compiling to Assembly from Scratch got a review in c't 9/25 (the largest German IT magazine)
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The PyPy Project @pypyproject.bsky.social · 21/05/2025
We just merged an improvement to the PyPy JIT heap optimizations: type based alias analysis for Python instances. Work was done by @cfbolz.bsky.social and their student Nico Rittinghaus.
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