Antonio Cuni

@antocuni
259 Followers
129 Following
45 Posts
HPy founder, PyPy core dev, PyScript core dev, doing Python and WASM stuff at #Anaconda
githubhttps://github.com/antocuni
twitterhttps://twitter.com/antocuni
websitehttp://antocuni.eu/
linkedinhttps://www.linkedin.com/in/antocuni/

If – on this grey Sunday morning – you would like to read a dozen pages about using tail calls for fast interpreters, then I have Excellent News for you:

https://www.mattkeeter.com/blog/2026-04-05-tailcall/

A tail-call interpreter in (nightly) Rust

Exploring tail-call-style interpreter implementation with an optimized Uxn emulator, on ARM, x86, and WebAssembly

I just published the 2nd part of the "Inside SPy" series. In this part, we will look at language semantics and what makes SPy "special" and different than CPython: phases of execution, redshifting, static typing, and metaprogramming.

https://antocuni.eu/2026/03/25/inside-spy-part-2-language-semantics/

Inside SPy, part 2: Language semantics

Language semantics: phases of execution, redshifting, static typing, and metaprogramming in SPy

20 years ago I did my first OSS commit.

Turned out to be a pretty good decision :)

https://antocuni.eu/2026/03/22/my-first-oss-commit-turns-20-today/

My first OSS commit turns 20 today

A bit of software archaeology and a personal retrospective

After weeks of procrastination, I finally wrote the first of a series of blog post which will try to give a detailed explanation of SPy.

In the first blog post I focus mostly on the *problem space* of why Python is slow, and the disconnection between what the language allows and how it's actually used in practice. Plus, I'll also give a hint on how SPy tries to solve these issues:

https://antocuni.eu/2025/10/29/inside-spy-part-1-motivations-and-goals/

Inside SPy, part 1: Motivations and Goals - Antonio Cuni's blog

Antonio Cuni's blog

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: https://discord.gg/ZN4afjvq?event=1424708124354285598

Google calendar link: https://lnkd.in/d3U62QNn

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.

Discord

Last week I was lucky to take part in the CPython Core Dev Sprint 🚀

I wrote a short summary of what I did during the sprint - including an annotated and extended version of my talk on tracing JITs: how they behave in real-world Python scenarios, plus some comparisons between PyPy’s JIT and CPython’s new JIT.

You can read it here:

👉 https://antocuni.eu/2025/09/24/tracing-jits-in-the-real-world--cpython-core-dev-sprint/

Tracing JITs in the real world @ CPython Core Dev Sprint

My experience at the CPython Core Dev Sprint

Accessing `obj.x` in Python might look trivial — but under the hood lies a surprisingly intricate chain of logic.

I wrote an annotated walkthrough of the CPython source code that makes it all happen:

https://antocuni.eu/2025/08/25/inside-cpythons-attribute-lookup/

Inside CPython's attribute lookup - Antonio Cuni's blog

I had a busy EuroPython in Prague:

- during the tutorial/summit days I gave short presentations at both the C API summit ("The HPy dilemma") and the WASM summit ("Updates from SPy land 🥸")

- then I delivered my main conference talk "Myths and fairy tales around Python performance".

I hope to write a more detailed post about EP discussions and impressions, but in the meantime, here are the slides of all the three talks:

https://antocuni.eu/2025/07/21/slides-for-my-europython-2025-talks/

At EuroPython, a main room full of people is following my friend Antonio Cuni's talk about "Myths and fairy tales around Python performance" 🐍

#EuroPython #EuroPython2025 #Python #Performance

CC @antocuni @europython

This evening I attended the speakers' dinner at EuroPython 2025. 🍻

As always, it's nice to have a moment of relaxation and exchange experiences and ideas with the other conference speakers. 🗣️

I met old and new friends this evening. 🫂

I'll see everyone else in Prague 🇨🇿

#EuroPython #EuroPython2025 #Speaker

CC @jezdez @freakboy3742 @mborus @thibaudcolas @knyghty @raffaellasuardini @antocuni @hugovk