What is the best first language when learning how to program? There have been many opinions over the years, each with their own selling point: BASIC was created for beginners, Python is executable pseudocode, JavaScript runs everywhere on the web, and so on. However, I would argue that the truly best language has been right under our nose the whole time: the Unix shell.
When I was still researching this fabled obscure language called Lisp one thing people kept saying about it is that “Lisp is a programmable programming language”, but I could never figure out what they meant by that. It sounds like a smug buzzword or like a gimmick from an academic toy language. Lisp programmers have gotten so used to metaprogramming in Lisp that they seem to forget that it is either an entirely alien concept to people, or something people have been burned by too often (like every C programmer).
When I first learned about rotation matrices they appeared quite “magic”; if you squinted your eyes a bit it sort of made sense, and if you did the math you could prove that the matrix does indeed perform the rotation and that all the group properties are met, but none of that explains where that form comes from, why it works. In this blog post I will explore a way to derive the formula for rotation matrices step by step. If you wish to follow along you need only basic knowledge of linear algebra and trigonometry.
I use GitLab to host my various projects, but it is always a good idea to be able to have an automatic mirror set up. It adds redundancy in case something goes wrong with GitLab, and having a mirror on a popular site like GitHub allows people to file issues without signing up for a less popular service. I am writing this down for myself so I don't have to figure out how to set up a mirror every time anew. This was written for GitLab version 12.0.0.
In order to make writing Awk scripts easier I have written a new Neovim plugin: Awk-ward.nvim (GitHub mirror). This plugins allows you to edit an Awk script or its input, and see the output live as you are making changes.
When I wrote guile-messagepack I needed an object to represent the nil
value, which embodies the concept of "nothingness" or "no value" in
MessagePack. None of the existing objects like #f or '() were adequate,
so I decided to make a new one: nothing. It does not make sense for there to
be multiple instance of nothing, so it had to be a singleton. In this blog
post I will describe a way of creating such a singleton.
There is a great article by Glenn Fiedler titled “Fix Your Timestep!” in which the author explains various approaches to writing a game loop and concludes with a loop that provides a fixed time step for simulation. If you are not familiar with this topic go read the article first and come back later. The author has written the implementation in C or C++ using a lot of mutation and looping, so I wanted to give a purely functional approach a shot.
During the development of REPL.nvim I had to be able to test the plugin without relying on any particular REPL present on the development system. The solution was to create a mock REPL, a shell script which acts like a really dumb REPL. Here is the code:
If you were to run the Workshop through an HTML validator you would notice a lot of warnings about the document outline. What is going on here? HTML 5 defines an outline algorithm which allows browsers and assistive technologies to create an outline of the page. In theory a blind person could ask their reader for the outline of the page and get a sort of table of contents which they could use to quickly jump to a specific part of the page.
Recently I have been working on a small Cocoa app and one of the things I
needed to do was highlight an NSImageView when the user is hovering above it
while dragging a file. You would think that it's a very simple task, and you
would be right, but judging by some of the things on the internet it looks like
an unsolved problem.