Paris Scala User Group : conférences mensuelles sur Scala, son écosystème, la programmation fonctionnelle, etc.
Paris, France
Joined May 2014
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ParisScalaUG retweeted
Jane Street showed the code that's made them billions, written in a language from 1996 that almost everyone else has abandoned.
Ron Minsky:
"type systems turn out to be a really good tool for catching a surprising number of mistakes"
the whole bet is on the type system. the compiler catches errors before the code even runs.
the Option type forces you to handle the case where a value is missing. a skipped null check that crashes Python in prod simply won't compile in OCaml.
"the compiler essentially forces you to do case analysis"
in trading a single bug costs millions, so the priority is reliability, not speed of development.
33 minutes, and you'll see the code that holds up the billions of one of the most secretive funds on Wall Street.
bookmark it. this is worth more than any $500 vibe-coding course. ↓
Jane Street made more in trading than JPMorgan, Goldman and everyone else on Wall Street, dropped Copilot and Claude, and trained its own AI model.
John Crepezzi: "there's probably more OCaml code inside Jane Street than in the entire world outside our walls"
A Jane Street AI engineer spent 16 minutes explaining how the hedge fund pulls in nearly $40 billion a year.
"Every 20 seconds the system takes a snapshot of the developer's workspace with the build status. when the build goes from red to green, it means someone just fixed a bug. they pull exactly those moments as real edits and train the model on them, and then RL rewards only the changes that compile and pass the tests."
bookmark it, the best lecture on AI and hedge funds ↓
ParisScalaUG retweeted
Congratulations @odersky for receiving the Programming Languages Achievement Award @icfp_conference - well deserved! :)
I can only confirm what it says on the citation, your work deeply impacted how I view programming.
Let's work towards making #Scala a continued success!
ParisScalaUG retweeted
Junior PM: I'm shipping everything on time, team loves me, but my manager says I'm "not strategic enough." I'm exhausted trying to figure out what that means.
Senior PM: What did you tell him you accomplished last quarter?
Junior PM: Delivered 5 features, reduced tech debt, improved team velocity by 15%.
Senior PM: And what did he hear?
Junior PM: That I delivered 5 features?
Senior PM: He heard "I kept the team busy with stuff that doesn't move numbers I get asked about."
Junior PM: But velocity improvement is strategic.
Senior PM: To who?
Junior PM: To... the team?
Senior PM: Your manager spends 20 minutes a week with his director explaining why you exist. Can he use velocity to justify your headcount?
Junior PM: I... probably not.
Senior PM: What business metrics did those 5 features move?
Junior PM: Three were tech debt, one was a sales request, one was compliance. We don't really measure impact on that stuff.
Senior PM: There's your problem. Half your work is invisible by design.
Junior PM: But that work was necessary. The platform would break without it.
Senior PM: I believe you. Your manager's director doesn't care.
Junior PM: That seems unfair.
Senior PM: It is unfair. It's also how companies work. Your manager gets grilled about revenue and retention, not platform stability.
Junior PM: So I should have said no to the tech debt?
Senior PM: You probably couldn't. But you should have framed it differently.
Junior PM: How?
Senior PM: "Prevented $200K in potential downtime costs" sounds better than "reduced tech debt."
Junior PM: But I don't have that number.
Senior PM: Then you're fighting organizational reality without weapons.
Junior PM: I don't have analytics support or time to instrument everything.
Senior PM: Most junior PMs don't. That's the trap - you get judged on business impact but don't get business resources.
Junior PM: So what do I do?
Senior PM: Acknowledge the game is rigged, then play it anyway.
Junior PM: Meaning?
Senior PM: Make allies in sales and marketing. They have the numbers you need. Shadow customer calls. Connect your work to their goals.
Junior PM: That feels political.
Senior PM: Everything above a certain level is political. The choice isn't political vs pure. It's visible vs irrelevant.
Junior PM: What if I try this and my manager still doesn't care?
Senior PM: Then you learn your manager doesn't know how to evaluate PM work. That's a different problem - one you solve by finding a better manager.
Junior PM: This is harder than just building good products.
Senior PM: Building good products is table stakes. Surviving organizational dysfunction while building good products - that's the actual job.
ParisScalaUG retweeted
Why should you learn an FP lang?
Almost every programming language feature you love was invented in an FP lang decades before it became mainstream:
- Garbage collection (lisp, 1950s)
- Generics (ML, 1978)
- Closures (scheme 1975)
- Sum types and pattern matching (NPL 1970s)
Pour ceux qui sont a @DevoxxFR , on se retrouve à 20h pour parler de modélisation de domaines en Scala.
A tout à l'heure.
mobile.devoxx.com/events/dev…
We continue with the presentation of Jamie Thompson (Scala center): "How do we optimise Scala build times?".
Thank you @data_dome for hosting us tonight, and thank you for our speakers Monica McGuigan and @bishabosha. We like to see you again in Paris.
ParisScalaUG retweeted
Here are the slides for my talk on Free at the @ParisScalaUG , which was great fun and I hope not too obscure: nrinaudo.github.io/talks/fre…
Hello 👋, pour le meetup d'octobre du PSUG, @Mobiskill nous accueille le 26 octobre pour le talk : "La monade discutablement gratuite" (par @NicolasRinaudo).
Les inscriptions c'est par ici:
meetup.com/paris-scala-user-…
A bientôt.
ParisScalaUG retweeted
We look forward to seeing you at tonight's London Scala Talks, from 6pm at Quantexa! We have a packed schedule tonight, checkout the lineup here meetup.com/london-scala/even…
Pour rappel, on se retrouve tout à l'heure chez @TeadsFR pour le talk de @chrilves: "Comparons Scala et Rust".
Pour ceux qui ne pourront pas être là, merci d'annuler votre inscription au meetup.
A toute à l'heure.
Hello 👋,
Pour ce meetup de rentrée du PSUG, @TeadsFR / @TeadsInnovation nous accueille le 28 septembre pour le talk : "Comparons Scala et Rust" (par @chrilves).
Les inscriptions c'est par ici: meetup.com/paris-scala-user-…
A bientôt.
Hello 👋,
Pour ce meetup de rentrée du PSUG, @TeadsFR / @TeadsInnovation nous accueille le 28 septembre pour le talk : "Comparons Scala et Rust" (par @chrilves).
Les inscriptions c'est par ici: meetup.com/paris-scala-user-…
A bientôt.
ParisScalaUG retweeted
As we prepare the conference for this year, at the end of October, you can check the talks from our fantastic speakers :
youtube.com/@scalaio/playlis…
(yes, we don't have the talks for 2013)
On continue la session chez @ContentSquareFR avec le talk sur le scheduling de data pipeline de @heapoverflow.
