I started writing this post because, for whatever reason, I keep forgetting what the difference is between a ring and a group, which is funny to me because I never forget the difference between a semiring and a semigroup – although other people do, because it’s quite easy to forget! So, I wanted a fast reference to the kinds of algebraic structures that I am most often dealing with in one way or another, usually because I’m writing Haskell (which has some reliance on terminology and structure from abstract algebra and category theory) or I’m trying to read a book about category theory and they keep talking about “groups.” Wikipedia, of course, defines all these structures, and that’s fine, but what I need in those times is more of a refresher than an in-depth explanation.

We recently ran across a strange higgs-bugson that manifested itself in a critical system that stores and distributes the firm’s trading activity data, called Gord. (A higgs-bugson is a bug that is reported in practice but difficult to reproduce, named for the Higgs boson, a particle which was theorized in the 1960s but only found in 2013.) In this post I’ll walk you through the process I took to debug it. I tried to write down relevant details as they came up, so see if you can guess what the bug is while reading along.

This web app displays notes and slides in separate windows,
keeping both synchronised.
It accepts simple, double-width, or double-height PDF presentations:

This post is all about speculative compilation, or just speculation for short, in the context of the JavaScriptCore virtual machine.

In modern Java, the visitor pattern is no longer needed. Using sealed types and switches with pattern matching achieves the same goals with less code and less complexity.

My take on what could be a project template for Django advanced usage, with modern tooling (for Python and UI dependencies, as well as configuration/environment management), but not too opinionated.

This blog series creates a small operating system in the Rust programming language. Each post is a small tutorial and includes all needed code.

I’ve used a lot of tools over the years, which means I’ve seen a lot of tools hit a plateau. That’s not always a problem; sometimes …

Most functional languages rely on some garbage collection for automatic memory management. They usually eschew reference counting in favor of a tracing garbage collector, which has less bookkeeping overhead at runtime. On the other hand, having an exact reference count of each value can enable optimizations, such as destructive updates. We explore these optimization opportunities in the context of an eager, purely functional programming language. We propose a new mechanism for efficiently reclaiming memory used by nonshared values, reducing stress on the global memory allocator. We describe an approach for minimizing the number of reference counts updates using borrowed references and a heuristic for automatically inferring borrow annotations. We implemented all these techniques in a new compiler for an eager and purely functional programming language with support for multi-threading. Our preliminary experimental results demonstrate our approach is competitive and often outperforms state-of-the-art compilers.

Between our ESP32 prokaryotic organisms and our 24/7 Internet-enabled megafauna servers, there exists a vast and loosely-defined ecosystem of things the B2B world likes to call computer appliances. Picture a bespoke Pi 4 packaged up neatly with some Python scripts, a little fancy plastic embossing, and maybe a well-guarded id_ed25519.pub in case you end up in hot water during the (long - very long, stable cash flow for generations long) maintenance contract, and you’re in the ballpark.

Living specification of the IRC protocol. Does not include brand new behavior, just existing behavior present in IRC software and/or networks (new extensions are IRCv3's area).