Pony

Last Week in Pony - October 11, 2026

Sean T. Allen — Sun, 11 Oct 2026 07:00:00 -0400

Once upon a time, I was in a band with a righteous man named Josh. Josh's day job was at "one of the big museums" in New York City. They had an exhibit of "punk fashion" or something ridiculous like that. The sort of thing that folks should want to take a piss out of.

John Lydon (aka Johnny Rotten) was going to be a guest at the opening but the museum muckity-mucks were worried he "might misbehave". Their concern was Josh's win. Josh was assigned to be John's shepherd for the evening and got to spend the entire night with a hilarious rock legend. We had a large blown up version of their end of night selfie in our practice space and I would regularly look at it and laugh.

What's that got to do with Pony? Well, if we want to stretch it, let's talk about how both Sylvan and I are very important to the history of Pony and we both love the Pistols and Public Image Limited. O and, because Sylvan sent me a link to Rise this week and I thought, "fuck yeah... that's a good theme song for the week".

Last Week in Pony - October 4, 2026

Sean T. Allen — Sun, 04 Oct 2026 07:00:00 -0400

I'm not going to pretend like this music that I have decided to include in this week's intro is in any way related to this last week in Pony except that I happened to listen to We Care a Lot and then was just like "OMFG, Chuck Mosley era Faith No More had a couple absolutely bangers and more people need to hear them". So hey, something something Pony stuff (you'll learn more below anyway), but be sure to listen to We Care A Lot and Anne's Song while you do you some Pony this week. Deal?!? Good. ON WITH THE SHOW!

Last Week in Pony - September 27, 2026

Sean T. Allen — Sun, 27 Sep 2026 07:00:00 -0400

Here's how it was: this past week was another week of "Sean breaks lots of stuff", but hey at least I'm breaking it in service of a drive towards Pony 1.0. My favorite change from this week though is getting the MacOS and Linux Pony targets using LLVM bitcode to compile and link. It opens up a bunch more optimizations and is a real "look ma! even faster!" moment. Which is really good. Now take this down, it's a real money shot.

Last Week in Pony - September 20, 2026

Sean T. Allen — Sun, 20 Sep 2026 07:00:00 -0400

Here's how it is. AC/DC's Back in Black was one of the first albums I owned. I loved that sucker so much. It was sadly the only album of theirs I owned for quite some time. Fortunately my friend Gary had several, but his father was a very strict and religious man — a preacher in fact. Gary hid his AC/DC albums under the bed and I would go over to Gary's house when his father wasn't home and we'd each use a glorious set of old school over-the-ear headphones to listen to AC/DC. Dirty Deeds was far and away my favorite album that Gary had.

But today, we are not here to talk about Dirty Deeds (btw, get the Aussie version, it's so good). We are here to talk about Pony and the fact that I keep breaking stuff as I push towards version 1.0. It's still a long way off but, I'm making a lot of solid forward progress. And I feel like celebrating and I want you to feel it too, so this week, let me make up for basically never doing AC/DC as the theme song and give you some Thunderstruck.

Last Week in Pony - September 13, 2026

Sean T. Allen — Sun, 13 Sep 2026 07:00:00 -0400

It's been a crazy week with lots of breaking changes. I promised lots of breaking changes in the last "Last Week in Pony" and I delivered. Two ponyc releases each with its own set of changes and a slew of ponylang org library releases to go along with them. With a week like that, there's clearly only one song that could serve as this week's theme song... bring on the dickies!

Last Week in Pony - September 6, 2026

Sean T. Allen — Sun, 06 Sep 2026 07:00:00 -0400

Welcome back kids. Or I guess, welcome back me? Anyway, we didn't have an issue last week because I jetted off to Fort Worth for a grand old time in the stockyards. Good times were had. Good times indeed. Because we missed a week, we are doubling up on theme songs. We are doing two versions of "Make Way for a Better Man Than You" — Charley Crockett and Willie Nelson.

It's an apropos pairing because Willie has been a huge part of my life (ask me about sitting on his lap as a kid) and if you have been paying close attention, you know I'm a huge Charley Crockett fan — in fact, the trip to Fort Worth was built around seeing him play at Billy Bob's. His show was amazing, including his tribute to Dolly Parton. She will be missed. O how she will be missed. So let's play this week's episode out with her version of Jolene.

And now, on with the show.

Just a reminder. We do really appreciate your donations. I'm asking everyone to pony up a monthly amount — even $10 would be huge. We are looking to add some new infrastructure and our monthly intake is pretty darn low, so... toss us a bone or eeerrr, whatever the appropriate equine idiom is.

And now, for real this time, on with the show!

Last Week in Pony - August 23, 2026

Sean T. Allen — Sun, 23 Aug 2026 07:00:00 -0400

Here's how it is. Back in 2017, we put in a style guide for Pony and without thinking about it, we accidentally encoded a serious footgun into it. Ooops. Shit. It wasn't noticed until this week when I was working on using pony-lint on the standard library. The style guide's operator continuation convention (binary operators at start of continuation lines) interacted badly with the parser. Pony has no ; or anything of the sort to end an expression, so to make something like returning a negative number work, the parser treats any - at the beginning of a line as negation, not subtraction. That silently broke Timer.abs for nine years. The convention is reversed and the linter now catches it.

So, what's the issue? Pony's syntax is a little clever. The style guide said put binary operators at the start of continuation lines. And oops, ya, that put you right into "incorrect."

Odds are, this isn't an issue for you. In all the ponylang organization code, I found exactly one instance of this as a problem. But it is still a footgun that was lurking. The style guide has been changed. No longer will it be:

pony a + b

for operator continuation. It will now be:

pony a + b

because that avoids the footgun. If you are using pony-lint, know that you will get a bunch of new errors because the rule was flipped around. And hey, it's just another data point in my campaign for "explicit is better than implicit" and my righteous campaign to make everyone realize that "clever" should be an insult.

And in the meantime, while you are reading about the mass of releases that happened this week, listen to the fairly apropos Effity Eff. Read quick though, it's a damn short song.

Last Week in Pony - August 16, 2026

Sean T. Allen — Sun, 16 Aug 2026 07:00:00 -0400

Here's how it was. Years ago, I auditioned to be the guitar player in the Heroine Sheiks. Aside from having quite possibly the best name in the history of all bands, they also had an incredible drummer who I really wanted to play with. It took a bit of chutzpah to audition because the guitar player being replaced was a NYC legend. Norman Westberg played some seriously weird and twisted and totally awesome guitar parts for the Swans and later the Heroine Sheiks.

As anyone who knows me can attest, I have chutzpah and was all over that audition. I didn't get the job. According to John, I was the runner up and "made a hell of an impression." Turns out I didn't mind not getting the gig because John left a few months later. I continued to listen to the Heroine Sheiks for years. Great band. So this week, while you're learning a bit about what's going on with Pony, enjoy some Heroine Sheiks goodness with Norman on guitar: Mas Suicide. And maybe think about how I'm just a chutzpah machine, ready to step in for Norman and years later, stepping in for Sylvan. And now, on with the show!

Pony's Arena Allocator

Sean T. Allen — Fri, 14 Aug 2026 07:00:00 -0400

Here's how it was. We'd been running stress tests on the TCP system in ponyc every day for a really long time. Those tests hadn't failed in forever. There's two ways you can look at "no tests are failing." Either your system is rock solid or your tests aren't covering enough of the codebase. I'd long felt that the lack of stress test failures was the result of "tests aren't good enough."

A few months back, I did something about that. I took the TCP stress tests that did the same thing on every run and added some "swarm testing goodness" — randomizing what they were doing and how they were being run, from run to run. A lot more code was getting exercised, and out popped a bunch of bugs.

This post is about one of those "bugs."

Last Week in Pony - August 9, 2026

Sean T. Allen — Sun, 09 Aug 2026 07:00:00 -0400

Two theme songs this week. Roger Miller's "Where Have All The Average People Gone" and Charley Crockett's "Where Have All the Honest People Gone". Mostly the same song, and I deeply relate to both. It was a big week. A cascade of bug fixes in ponylang/ssl rippled through the whole ecosystem, and sixteen releases went out the door.

Last Week in Pony - August 2, 2026

Sean T. Allen — Sun, 02 Aug 2026 07:00:00 -0400

This week's theme song is "This Corrosion" by The Sisters of Mercy. No reason. I do so love it, and that's reason enough. I've been at it hard, and there's a lot to show for it. This is a big one.

Last Week in Pony - July 19, 2026

Sean T. Allen — Sun, 19 Jul 2026 07:00:00 -0400

Pony might be great but Bob Wills is still the king. Sometimes though, sometimes George Jones comes along and does one of your songs even better than you did, like "Roly Poly". Just so good. That's it. That's the intro. On with the news!

Last Week in Pony - July 12, 2026

Sean T. Allen — Sun, 12 Jul 2026 07:00:00 -0400

This week's theme song is Van Morrison's "Caravan". It's a banger. Turn it up. That's enough. So you know it's got soul. Does it tie in with anything in this issue of Last Week in Pony? I could probably invent something, but really, I just love to drop something I've been enjoying lately in here every week because why not? If I'm going to write all this stuff up every week, I deserve a few indulgences.

Last Week in Pony - July 5, 2026

Sean T. Allen — Sun, 05 Jul 2026 07:00:00 -0400

This week's theme song is Player's "Baby Come Back". People ask me sometimes how many people use Pony, whether it's used in production. The honest answer to both is that I have no idea. We've never had much visibility into who's out there. Every so often a hint comes through that someone is shipping Pony for real, and then it goes quiet again.

Last Week in Pony - June 28, 2026

Sean T. Allen — Sun, 28 Jun 2026 07:00:06 -0400

This week's theme song is The Shallaras' "I Put Something in Your Drink". The Shallaras are two people. One plays drums and guitar at the same time. The other plays sax and sings. Two people, and they sound like a whole band. I think about that a lot, how much a small group can get done. That was this week.

Improving Runtime Test Coverage

Sean T. Allen — Fri, 26 Jun 2026 21:00:00 -0400

Pony's runtime has a set of stress tests. They run in CI, each one a program that exercises the runtime over and over for an extended period of time: one passes messages between actors without a break, another opens and closes network connections again and again, sending data back and forth. The idea is that the more you push on a part of the runtime you think is bug-prone, and the longer you keep at it, the more likely you are to shake out a bug that only turns up once in a while. For the runtime, bug-prone means "susceptible to concurrency issues". And we hammer away at those areas as much as we can. Or try to anyway. That was the idea.

Last Week in Pony - June 21, 2026

Sean T. Allen — Sun, 21 Jun 2026 07:00:06 -0400

This week's theme song is Willie Nelson's "Midnight Rider". There's no clever reason behind it. It's a great song, it brims with energy, and this was a week with energy to spare. Sometimes a theme is just a vibe, a feel. This one fits.

Look Ma, I put a compiler in the compiler

Sean T. Allen — Fri, 19 Jun 2026 20:00:00 -0400

Calling C from Pony is usually easy. You write the FFI declarations, you call the function, you're done. Sometimes it isn't that easy: you need to call a macro, so there's no symbol to bind to. Or you have to fill in a struct by hand before you can pass it in. Or the calling convention is one Pony's FFI can't express. C has all kinds of little oddities that don't line up with Pony. When you hit one of those oddities, it is time to reach for a shim: a small piece of C between Pony and the library. Building it and shipping it has always been the hard part. Not anymore.

Last Week in Pony - June 14, 2026

Sean T. Allen — Sun, 14 Jun 2026 07:00:06 -0400

This week's theme song is The Rubberbandits' "Horse Outside", and it's completely brilliant. It's a man at a wedding telling everyone to keep their cars. Fuck your Honda Civic, he's got a horse outside. Pony spent the week in that exact mood. Fuck your external linker, it's gone. Fuck your second build system, ponyc compiles your C shims itself now. That last one came together so fast it just felt good. Pony is the fucking horse outside.

Last Week in Pony - June 7, 2026

Sean T. Allen — Sun, 07 Jun 2026 07:00:06 -0400

This week's theme song is Willie Nelson's "Uncloudy Day". Last week shipped with some brimstone in it, and this week the skies cleared. No releases went out, but main kept filling up, and the headline is that RFC 86 is implemented. The stdlib json package now has a way to turn any JsonValue back into a string.