Shopify / Royal Academy of Engineering Research Chair in Language Engineering. https://tratt.net/laurie/https://bsky.app/profile/ltratt.bsky.socialhttps://bsky.app/profile/ltratt.bsky.social/post/3mjjtbdxopc2rC interpreters underlie many of our most widely used language implementations -- but they're slow. Wouldn't it be great if we could turn them into JIT compiling VMs? This video shows what happens when we do just that to the normal Lua VM (first) and "yklua" (Lua w/JIT, second).15 Apr 2026 11:49 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mjjtbdxopc2rhttps://bsky.app/profile/ltratt.bsky.social/post/3mj54co7yis2kLast week I upgraded the encryption I use to be post-quantum. I then realised that if enough people do the same, "using quantum f/decryptt" probably becomes a meaningless use case. Is there a word which captures the concept of "changing X effects the future of Y, even though X and Y seem distinct"?10 Apr 2026 10:26 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mj54co7yis2khttps://bsky.app/profile/ltratt.bsky.social/post/3mi7n4pexq22jAt Wells this morning, we saw a Palm Sunday procession that - to the extent anything can trace itself back this far - seems to have started around 800 years ago, including hidden singers in the Cathedral's front. There was certainly plenty of incense which was distributed around by the strong winds!29 Mar 2026 17:07 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mi7n4pexq22jhttps://bsky.app/profile/ltratt.bsky.social/post/3mheih67i222iI was a judge for STEM for Britain yesterday, and I have to say: I was genuinely impressed by what I saw. Much was in fields I have no expertise in, but I still ended up learning things, because the explanations were so good. The winners are thoroughly deserving! https://bsky.app/profile/raeng.org.uk/post/3mhdy37h5yt2k [contains quote post or other embedded content]18 Mar 2026 22:02 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mheih67i222ihttps://bsky.app/profile/ltratt.bsky.social/post/3mgqd3imspc2wpizauth-1.0.11 is out, and ensures it keeps retrying in the face of transitory HTTP errors https://tratt.net/laurie/src/pizauth/10 Mar 2026 21:32 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mgqd3imspc2whttps://bsky.app/profile/ltratt.bsky.social/post/3mgcpb5f2o22fSometimes the best way to predict the future is to wait and see what happens.05 Mar 2026 11:33 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mgcpb5f2o22fhttps://bsky.app/profile/ltratt.bsky.social/post/3mga2o4gnh22wOne of the interesting consequences of LLMs/agents is that the short-term costs of boilerplate in code have plummeted. An interesting question is whether those costs are simply shunted to the future or whether they are permanently reduced.04 Mar 2026 10:19 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mga2o4gnh22whttps://bsky.app/profile/ltratt.bsky.social/post/3mfqtzimgms2cIt seems that I have been blessed with my first clawdbot (or similar) interactions on one of my repositories. I really hope this sort of noise doesn't end up (a) wasting maintainer's time (b) putting people off trying the underlying technology where it's actually useful.26 Feb 2026 09:10 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mfqtzimgms2chttps://bsky.app/profile/ltratt.bsky.social/post/3meqgv2zrns2pIn the futurementary Terminator, I don't remember Skynet starting off with open-source repositories https://theshamblog.com/an-ai-agent-published-a-hit-piece-on-me/ (I also strongly suggest following the link to the GitHub PR, because it makes much more sense with that as context).13 Feb 2026 11:50 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3meqgv2zrns2phttps://bsky.app/profile/ltratt.bsky.social/post/3meg2cqyom22pIn the past fortnight, 50% of my conversations have seen me say "today's AI cannot do that and we have no idea if and when it will". In the other 50% I've said "today's AI can do that, really, and you just need to try it". Our collective calibration is currently very wonky!09 Feb 2026 08:38 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3meg2cqyom22phttps://bsky.app/profile/ltratt.bsky.social/post/3mdlbgjsfvc2wScratched a Rust itch with an experimental new crate `test_stubs`. I have traits with lots of methods. "Proper" code should implement all methods, but test code need not. `test_stubs` means that test code doesn't have to manually create `todo!()` methods.29 Jan 2026 17:04 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mdlbgjsfvc2whttps://bsky.app/profile/ltratt.bsky.social/post/3mddp5av7a22wThere's nothing more surprising than an agent, in the middle of doing some useful refactoring, asking if it can run a Python script which solely prints "HI" (yes, in uppercase) to stdout.26 Jan 2026 16:48 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mddp5av7a22whttps://bsky.app/profile/ltratt.bsky.social/post/3mczh65navk23If you're thinking of applying to PLISS, you've got three days left! https://pliss.org/2026/registration.html22 Jan 2026 14:59 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mczh65navk23https://bsky.app/profile/ltratt.bsky.social/post/3mctt43zjsk27A first: I awoke to a PR on one of the Rust projects I maintain that results from a proposed fix to a rustc oversight. Our code should never have compiled, IMHO, so the rustc fix is a good one! For those interested in the rustc change: https://github.com/rust-lang/rust/pull/15068120 Jan 2026 09:16 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mctt43zjsk27https://bsky.app/profile/ltratt.bsky.social/post/3mcrp7wvd7s24When I read Walter Bagehot's (d. 1877) "The English Constitution" years ago, I was surprised at how much time he spent contrasting it to the US constitution. I now realise he had thought deeply about the plausible futures of both and how they could adapt and/or go wrong.19 Jan 2026 13:01 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mcrp7wvd7s24https://bsky.app/profile/ltratt.bsky.social/post/3mchi2tfzcs2cI've never been a fan of debuggers. Examining the state at the point of a crash rarely helps me: the problem is nearly always earlier in time. `printf` is more useful to follow the trail forwards.15 Jan 2026 11:27 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mchi2tfzcs2chttps://bsky.app/profile/ltratt.bsky.social/post/3mch7rmi3ak2gA reminder for those interested in PLISS 2026: there are 10 days left to register your interest. https://pliss.org/2026/registration.html15 Jan 2026 08:58 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mch7rmi3ak2ghttps://bsky.app/profile/ltratt.bsky.social/post/3mces4yrgo22gEven though I know from past experience how important it can be to avoid small memory allocations in performance critical code, the measurable effect of removing them still often surprises me.14 Jan 2026 09:49 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mces4yrgo22ghttps://bsky.app/profile/ltratt.bsky.social/post/3mcaqgwxoss2gI was recently asked how I choose what podcasts I listen to, and paused. Then I realised it's similar to how I choose what to read. In particular, for current affairs, I actively try to avoid just reinforcing my current opinions. I think this has helped make me wrong less often!12 Jan 2026 19:08 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mcaqgwxoss2ghttps://bsky.app/profile/ltratt.bsky.social/post/3mby55j43y22lLow-needle-drop Christmas trees are willing to delay their revenge: they wait until you remove them from the house before dropping dry, sharp, needles everywhere.09 Jan 2026 09:01 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mby55j43y22lhttps://bsky.app/profile/ltratt.bsky.social/post/3mbvxenxdg22lA few weeks ago I gave a talk "Some Things I've Learned About Software" that was unusual for me. I didn't program in it once. I didn't mention specific technologies. Instead I tried to look at the high-level things about software that I've slowly understood. https://www.youtube.com/watch?v=RJgDW2AERr808 Jan 2026 12:13 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mbvxenxdg22lhttps://bsky.app/profile/ltratt.bsky.social/post/3mbqmmsdgbk2iMore PLISS speakers announced! pliss.org/2026/06 Jan 2026 09:17 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mbqmmsdgbk2ihttps://bsky.app/profile/ltratt.bsky.social/post/3mabkfrnus22kI can't quite believe that we're now announcing the eighth Programming Language Implementation Summer School (PLISS), but we are --- in May next year, if you want to learn more about programming language implementations, this is the place to come!18 Dec 2025 16:02 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3mabkfrnus22khttps://bsky.app/profile/ltratt.bsky.social/post/3m7k66aa4jk2kemail has many detractors -- and I certainly grumble from time to time when I'm ploughing my way through mine -- but we still haven't come up with a sufficiently superior option for asynchronous communication that would make the pain of transition worth it.09 Dec 2025 08:52 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3m7k66aa4jk2khttps://bsky.app/profile/ltratt.bsky.social/post/3m6gvy4j6wc22For those interested in hearing me waffle about software in a public talk this Thursday in London, there's still a few hours left to register! https://www.eventbrite.co.uk/e/informatics-inaugural-lecture-professors-hana-chockler-and-laurence-tratt-tickets-175576963724925 Nov 2025 08:22 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3m6gvy4j6wc22https://bsky.app/profile/ltratt.bsky.social/post/3m62fa66zkc2oThis year's weather has apparently decided it's not going to muck around with any of that nonsense in the 5-12C range. On the plus side, some of my "summer" walks are doable again and they look lovely in the cold mornings!20 Nov 2025 08:51 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3m62fa66zkc2ohttps://bsky.app/profile/ltratt.bsky.social/post/3m5wivkbyc223Amongst the pleasures of living in Somerset is our village and street names. On Sunday, for example, I cycled through Gurney Slade and up Binegar Bottom. Note: I have checked this message carefully for typos.18 Nov 2025 19:46 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3m5wivkbyc223https://bsky.app/profile/ltratt.bsky.social/post/3m5u3baaxw22bThis weekend my wife wanted to watch a film called The Princess Bride. I hadn't heard of it. I was thus, to put it mildly, surprised to gradually realise that it has generated as many widespread memes as franchises seemingly 100x better known!17 Nov 2025 20:36 +0000at://did:plc:yosnop3soavtzfziy3cl6dfd/app.bsky.feed.post/3m5u3baaxw22b