I collected my thoughts on why mutexes suck; and what we can do about it. chrispenner.ca/posts/mutexes #STM #concurrency #parallelism #mutexes #Haskell

🚀 New deep dive: Distributed System Engineering in Unison In our latest blog post, take a look at the design of the Volturno library: a distributed stream processing engine built atop Unison Cloud. www.unison-lang.org/blog/volturn...

🤯 Unison in the browser!? Dan Freeman's new library, Proscenium, runs Unison code in WebAssembly. Its companion library, @dfreeman/playbill, contains a walk-through of various features and live examples on Unison Cloud! Play a game in your browser entirely in Unison; better yet, write your own!

📽️ Here's a quick video for anyone just getting started with Unison. The gist of it: install the UCM, create a scratch file in the right place, and have fun programming!

Don't get too hung up on #Monads, there are other ways to sequence effects; including Arrows; and they provide even better static analysis! Let me know what you think :) #Haskell chrispenner.ca/posts/arrow-...

I'd really like to speak with whoever thought it was a good idea for the public and private JWK's to be represented by the same type, have the same name, with just a few missing parameters... Ah yes, the presence or absence of this "d" parameter could tank my entire company... seems safe to me :|

Having a 3D printer at home is such a life-hack. Just printed some custom french-cleats to hang a giant 7ft long painting and it made it 10x easier.

I've spent hours over the last months writing a post about how mutexes suck and everyone should use STM instead; but have come to the realization that even STM is more complex than necessary. What's your decision-making process when building a concurrent and/or parallel system? See mine below 👇

I wrote about AI and programming. About the identity challenges we are facing as programmers and the potential erasure of craft. There's a fun little easter egg in the header as well :) hojberg.xyz/the-programm...

I'm very pleased to call Simon ( @hojberg.xyz ) my co-worker, team-mate and friend, go check out this wonderfully written take. hojberg.xyz/the-programm...

IMO we shouldn't be trying so hard to solve "the expression problem"; We should make it easy to update existing functions when types change, but it shouldn't always "silently work" with the new type; oftentimes existing functionality needs a human to look over it when there are changes!

What do folks out there do for error handling in concurrent tasks in #Haskell? For now I've settled on having an error `TMVar`, then use a `ki` structured concurrency scope which forks all my jobs and ends in an `(Right <$> awaitAll) <|> (Left <$> readTMVar errVar)`

TIL callCC's return value isn't rank 2 polymorphic (but you can just route it through Void and use `absurd` to make it rank 2 polymorphic) Spent too long staring at the error wondering why it wasn't working haha. #Haskell github.com/haskell/mtl/...

Huh, TIL that `Text.lines != Text.splitOn "\n"` when the string ends in a newline.

You can now spin up Unison Cloud clusters on your own infrastructure! ✅ Build elastic distributed systems and services in vastly less code ✅ Fast, typed RPC ✅ Deployments in seconds ✅ Free to get started youtu.be/0sZqI1XoGLY

Interesting article by @chrispenner.ca about why monads aren't the solution to everything, and a functor I've never crossed paths with called selective applicatives. Still absorbing it, but great read as always. Check it out if that's your thing. chrispenner.ca/posts/expres...

New blog post! #Haskell is built on a foundation of Monads, but are they really the optimal way to sequence effects or should we keep looking for something better? What's the big deal with Applicatives and Selective Applicatives? Read on! chrispenner.ca/posts/expres...

✨ The new dependents view shows everywhere a definition is used, broken down by category, as a separate card in Unison Share and the Unison Desktop app. Your codebase is a bidirectional graph! You should be able to walk it as such.

📽️ New to the Unison workflow? We’re making short videos to walk you through the basics. Follow along here: www.youtube.com/watch?v=QJ1h...

I'm pretty stoked on how well WASM seems to be working for languages that target it (not that there aren't difficulties there). Even more stoked for these updates!

It may in fact be a VeryBadIdea™ but I'm extremely tempted to duct tape my soldering iron to my 3D printer and use it to wood-burn the grid lines on the Go board I'm building...

We all know AI is unreliable, but what's the worst case you've seen? #zig This one made me exhale sharply through my nose today:

Programming languages really need a way to expose functions as "you can import this within this project and tests, but it's not public to other libraries"; somewhere in-between fully public and fully private.

The GHC developers are very pleased to announce the availability of the first alpha prerelease of GHC 9.14.1. Highlights: * Major improvements to the Specialiser * SSE/AVX support in the x86 native backend * Significant improvements in the GHCi debugger blog.haskell.org/ghc-9-14-1-a... #Haskell

Ah yes, I was just wondering how I could make my CI _less_ deterministic...

Is the non-#haskell part of the world aware STM exists? I see a few languages have somewhat broken implementations... #STM is truly a revolutionary tool for any kind of async/concurrent/parallel programming and new languages would do well to ensure they can implement it well!

You should add debugging views to your database. #postgres #databases chrispenner.ca/posts/views-...

🧙 For fans of optics and traversals and other such functional programming wizardry, here's Unison's own @chrispenner.ca, explaining how he composed custom Traversable instances to speed up Unison Share database queries!

Nifty trick to save some memory and cpu with caching, but using weak pointers so values clean themselves up when they're no longer referenced. #Haskell chrispenner.ca/posts/intern...

Anyone have recommendations for a good app for having people sign up for a mailing list? I'd like to keep in touch with folks across platforms, and it looks like MailChimp decided to delete my entire existing mailing list due to inactivity, so I guess I'll be starting over... 😑

as we all know every programmer's dream job is to never have to code again and instead just manage PRs with unreliable code and communicate with the unreliable entities who wrote it

I was wondering why everyone is suddenly planning to move out of GitHub

I think folks often go to _great_ lengths to avoid being just a little less type-safe or to avoid just a _little_ boilerplate, often at the expense of simplicity, adaptability and clarity.

New blog post! chrispenner.ca/posts/traver... Here's a technique for refactoring nested code for batch workflows, specifically when loading data from a database. I got up to 300x improvements on some codepaths with a relatively mechanical transformation.

I also learned that prompting an AI just isn't fun for me. I enjoyed playing with the game, and thinking up features, but the prompting was annoying and frustrating. I really enjoy the craft of writing code, if my career turns from crafting code to babysitting a bot I'll be very sad.

Ultimately, the takeaway for me is: * It's a great tool for getting a small artifact like this. It fulfills a need I had, and was very low investment. * I didn't learn a damn thing. I don't know any more rust, I don't understand WebGPU, I didn't learn how to structure a game.

I built a fully-functioning in-browser mobile Go Game for local play in a couple hours yesterday, or should I say, an AI Agent did. chrispenner.ca/rugo I'll summarize my experience with the tool;

Just merged native MCP server support to @unison-lang.org . It comes with all the usual vibe-coding caveats for sure, but also teaches agents how to read documentation, type check code, and even lets them search Unison Share, so it’s actually quite good at explaining projects and how they work 😄

GHC has slow compile times because otherwise the #Haskell programmers would be far too productive. Balance must be maintained.

it's hard to put it into words but #jj-vcs has rewired my brain into thinking about commits more "meaningfully". i think git—and to a large extent github—have made commits feel "cheap", something you don't put much thought into. just a thing you have to do before you "push your change".

A deployment pipeline that ships your code to staging, and hides the “Deploy to prod” button somewhere in your app on staging. You have to dig through your app, running your new code, to find it.

Very cool!

Cool trick for finding bottlenecks in your concurrent systems; sometimes you can just literally print where you're currently blocked.

When people talk about 'inherent' complexity they're probably talking about an authorization system or a notification system 😵‍💫 I will say that designing flexible and performant versions of each of these has been a great design challenge though, a lot of fun to figure out 🙂

Did you know that #Unison Share is a full-featured code-repository and collaboration platform that *doesn't have a single unit test*? Here's how that works: chrispenner.ca/posts/transc... (*spoiler*: it's great!) @unison-lang.org

Saw someone asking about a Haskell debugger on Reddit today and realized how _weird_ it is that Haskell doesn't really have a good story here, but also how weird it is that I don't ever find myself reaching for one. Maybe I'm sufficiently stockholmed into TDD (Trace driven development) by now?

💝 We encourage everyone to take inspiration from Unison's core ideas and practices. The more programming languages and tools challenge the status quo, the faster "outlandish" becomes "obviously better." Here's @chrispenner.ca on three things other languages should steal from Unison:

It is absolutely bonkers to me that there still isn't a standard way to just see which functions a python module exposes. I know it's dynamic enough to generate new ones at runtime, but like, I'm just tryin' to look at docs!

I'm officially adding Notification Systems to my list of inherently hard problems. I've got: * Cache invalidation * Authorization * Notification Systems What's on your list?

🤝 We've just added collaborator support to Unison Share! You can now add fellow Unison devs to your projects with these roles: 👁️ View – Read & download 🔧 Maintain – Read, download, merge & write 🔑 Admin – Full admin permissions Try it out here: share.unison-lang.org/