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.

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

Extra is different than More. Extra is finishing those two screens, but then researching a new library for form validation that might reduce the boilerplate code. Or it's learning ways to protect against common security vulnerabilities from data entry. These little off-ramps from the main highway of Normal Work could be dead-ends and not have any practical value to the project. But they might also be important contributions. And that's the thing with Extra. While the tangible value to the project is uncertain (it could be nothing this time or it could be something), the value to you is real.

A somewhat compact implementation of the awk programming language

Permacomputing is both a concept and a community of practice oriented around issues of resilience and regenerativity in computer and network technology inspired by permaculture.

A lightning post on logic programming in Haskell to construct a workout weekly schedule given the set of exercises, days and constraints.

Most programming language ecosystems provide assert functions in their testing libraries but not Go's. Go's standard testing package follows a more direct and to-the-point approach.

build2 is an open source (MIT), cross-platform build toolchain that aims to approximate Rust Cargo's convenience for developing and packaging C/C++ projects while providing more depth and flexibility, especially in the build system.

Using systemd to avoid having to write some risky code

Aurora: An extensible, Python-based static site generator.

Comparison between types of API tokens.