Reflections on 2023's hobby projects.

I’ve just finished migrating this site from Jekyll to Hakyll. The only noticeable changes are: slightly prettier page URLs, MathML support, and tweaks to syntax highlighting to compensate for using Pandoc. I paid special attention to preserving the Atom feed identifiers so that feed readers aren’t impacted.

Reflections this year's hobby projects.

Dream.In.Code was a programming help forum that ran from 2001 to the beginning of 2022. It was recently shut down due to hosting costs. My participation in Dream.In.Code, starting from 2009 and ending somewhere in 2013, represents the beginning of my life as a programmer. Over the past 10 or so years, programming has become a huge part of my life. I’d like to acknowledge the role this forum played in my development.

I’ve recently been working on web a graphics project where I played a Canvas API implementation against a WebGL implementation. When running the app in Firefox on Linux, I was surprised to find that the WebGL version was 10-30% slower (in frames per second) than the Canvas version.

I’m an experienced Haskell programmer, and I’ve been writing a lot of Rust lately. I recently ran into a little trouble when porting a simple function from Haskell to Rust. This article is a short description of my journey.

I’ve Googled this one too many times, so I’m writing it here for future reference.

Memory-sensitive languages like C++ and Rust use compile-time information to calculate sizes of datatypes. These sizes are used to inform alignment, allocation, and calling conventions in ways that improve runtime performance. Modern languages in this setting support generic types, but so far these languages only allow parameterisation over types, not type constructors. In this article I describe how to enable parameterisation over arbitrary type constructs, while still retaining compile-time calculation of datatype sizes.

I was first clued into this a while ago by a comment on Bob Harper’s blog that “exponentials are coinductive”, but it only really clicked for me today. Let’s get into it.

I’ve been using Agda on NixOS for a while (mostly via agda-mode in Emacs), but I remember it was a bit difficult to get going the very first time. Hopefully this becomes a searchable reference to getting it all set up quickly.

In his propositions as types talk, Philip Wadler contrasts programming languages that have been ‘invented’ with those that have been ‘discovered’. “And you can tell!” he exclaims, receiving giggles from the audience. Regardless of how you feel about mathematical platonism, I think Phil is pointing at a meaningful difference in the way certain ideas arise.

I love bound - it makes De Bruijn indices mindlessly easy. I also love Plated for all sorts of whole-program transformations. I think they’re two indispensible tools for working with programming languages. Unfortunately, they’re not compatible.

A certain algorithmic puzzle website has a problem that goes like this…

It’s difficult to learn functional programming without hearing about continuations. Often they’re mentioned while talking about boosting the performance of pure functional code, sometimes there’s talk of control flow, and occasionally with ‘time-travel’ thrown in there to make it all seem more obscure. It’s all true, but let’s start from the beginning.

LINQ is a system that provides a flexible query interface for .NET languages. It allows a user to write queries over arbitrary data using an in-built SQL-like syntax. This syntactic sugar is mapped to method calls at compile time, so any data structure that implements the correct methods can be used with LINQ.

Last semester I had to write a static website by hand with no templating resulting in a lot of duplicated code across multiple pages. I had already finished most of the project when I realised that the main page of the project should be named index.html instead of home.html. I renamed the file, but that left me with countless references to “home.html” that needed to be changed, and I wanted to change them all at once. Enter sed.

With so many programming languages and frameworks at our disposal, it is too easy to believe that knowledge of many tools is the defining characteristic of a good programmer. However, many experienced programmers will assert that it isn’t the languages you know, but your ability to solve problems that defines you as a programmer.

Monad transformers combine the functionality of two monads into one. They are often used as a way to “flatten” nested monads, but are also used to enable interactions between monads that, when used seperately, would be incredibly difficult to implement.