This month in Julia world - 2025-09

A monthly newsletter, mostly on julia internals, digestible for casual observers. A biased, incomplete, editorialized list of what a clique of us found interesting this month, with contributions from the community.

For recent news on Julia and interesting conversations with community members, check out the JuliaDispatch podcast (on many platforms, including youtube and spotify). Highlights from the newsletter get discussed (with more context) during some episodes.

Julia 1.12 is released. Many of the improvements in it have been discussed in the past on this newsletter. Check out the blogpost for a good summary.

Properly cut JuliaCon 2025 videos are being released on youtube.

JuliaCon 2026 will happen from August 10th to August 15th 2026 in Germany.

“Internals” Fora and Core Repos (Slack/Zulip/Discourse/Github):

  • JuliaLowering.jl has been seeing a flurry of activity in the last couple of months. Julia has a syntactic pass that parses text into an abstract syntax tree and a lowering pass that takes care of macros and desugaring. Historically this was done in lisp, leading to difficulty with introspection and tooling like Revise.jl, also making macros harder to debug. JuliaSyntax.jl reimplemented the parser in pure Julia and JuliaLowering.jl is the final piece of the puzzle, implementing all of the “lowering” in Julia itself. The link above is to one of many improvements from the last few weeks, this one in particular focusing on simplifying and more neatly organizing the lowering logic.
  • Julia is on track to have the fanciest REPL history search in the land with recent proposed changes.
  • TypedCallable, is a proposal for better supporting optimized calls to runtime-known functions with compile-time known arguments. The underlying goal is to better support closures, especially with ahead-of-time compilation to binaries.
  • Julia supports Unicode 17 now. Julia programmers have long lamented that Unicode does not support proper latin alphabet superscripts for all letters. Small superscript q is supported now though. See this wiki page for a full list of unicode sub/super script characters.
  • Base.Cartesian is now a public part of the Julia API.
  • PSA: Given that there is no type filtering capabilities in julia’s try, it is important to not forget to use rethrow().
  • The :greedy scheduler now better prioritizes having work for all threads.
  • Do not use Base.get_extension in library code, as it can wreak havoc on precompilation. Appropriate solution discussed in this PR.
  • Cleaning up some (unsafe) constructor functions for strings and substrings.

In search of contributors and new maintainers (specify novice/moderate/expert and internals/domain background necessary):

Ecosystem Fora, Maintenance, and Colab Promises (Slack/Zulip/Discourse/Github):

  • Many improvements to the PythonCall ecosystem for integration (in both directions) between Julia and Python.
  • JSON.jl had a breaking release with many improvements. It comes with a fantastic migration guide.
  • Bonito.jl has existed for a while as a wonderful way to have reactive web pages written in Julia, but now there is a proper announcement after steady small improvements for many years.
  • SymBoltz.jl – a very impressive showcase of the capabilities of ModelingToolkit.jl, a symbolic-numeric, approximation-free and differentiable linear Einstein-Boltzmann solver for cosmology
  • AccessibleModels.jl: Automatic UI and Model Fitting for Arbitrary Objects
  • MoleculeHub: A set of cheminformatics tools in Julia
  • Durbyn.jl: Time Series Forecasting in Julia
  • PlutoBook.jl wraps around the C++ library PlutoBook for lightweight converter between html and pdf. (no relationship to Pluto.jl)
  • NoSleep.jl: Keep Julia awake for long calculations
  • WebAuthn.jl: WebAuthn enables passwordless, phishing-resistant login using public-key cryptography.

See also: French community newsletter, community calendar, minutes of triage meetings, Turing.jl newsletter

Please feel free to post below with your own interesting finds, or in-depth explanations, or questions about these developments.

If you would like to help with the draft for next month, please drop your short, well formatted, linked notes in this shared document. Some of it might survive by the time of posting

32 Likes

I thought it was great that Effort.jl received some attention last month.

I was planning to add it to the newsletter, but I ended up forgetting about it.

4 Likes

That was quick!