Oskar Wickström

Recently, I published The Monospace Web, a minimalist design exploration. It all started with this innocent post, yearning for a simpler web. Perhaps too typewriter-nostalgic, but it was an interesting starting point. After some hacking and sharing early screenshots, @noteed asked for vertical alignment, and down the rabbit hole I went.

wickstrom.tech In the eternal search of a better text editor, I’ve recently gone back to Neovim. I’ve taken the time to configure it myself, with as few plugins and other cruft as possible. My goal is a minimalist editing experience, tailored for exactly those tasks that I do regularly, and nothing more. In this post, I’ll give a brief tour of my...

Lately I’ve been messing around with Python 3.12, discovering new features around typing and pattern matching. Combined with dataclasses, they provide support for a style of programming that I’ve employed in Kotlin and Typescript at work. That style in turn is based on what I’d do in OCaml or Haskell, like modelling data with algebraic data...

Quickstrom uses linear temporal logic (LTL) for specifying web applications. When explaining how it works, I’ve found that the basics of LTL are intuitive to newcomers. On the other hand, it’s not obvious how to specify real-world systems using LTL. That’s why I’m sharing some of my learnings and ideas from the past year in the form of blog posts.

In the last post I shared the results from testing TodoMVC implementations using WebCheck. The project has since been renamed Quickstrom (thank you, Tom) and is now released as open source.

In this post I’ll share the results from testing TodoMVC implementations using my new testing tool named WebCheck. I’ll explain how the specification works, what problems were found in the TodoMVC implementations, and what this means for my project.

Property-based testing (PBT) is a powerful testing technique that helps us find edge cases and bugs in our software. A challenge in applying PBT in practice is coming up with useful properties. This tutorial is based on a simple but realistic system under test (SUT), aiming to show some ways you can test and find bugs in such logic using PBT. It...

In the last article we looked at how Komposition automatically classifies moving and still segments in imported video media, how I went from ineffective testing by eye to finding curious bugs using property-based testing (PBT). If you haven’t read it, or its preceding posts, I encourage you to check them out first:

In the previous case study on property-based testing (PBT) in Komposition we looked at timeline flattening. This post covers the video classifier, how it was tested before, and the bugs I found when I wrote property tests for it.

In the first post of this series I introduced the Komposition screencast editor, and briefly explained the fundamentals of property-based testing (PBT). Furthermore, I covered how to write testable code, regardless of how you check your code with automated tests. Lastly, I highlighted some difficulties in using properties to perform component and...

This is the first in a series of posts about using property-based testing (PBT) within Komposition, a screencast editor that I’ve been working on during the last year. It introduces PBT and highlights some challenges in testing properties of an application like Komposition.

Haskell at Work, the screencast focused on Haskell in practice, is approaching its one year birthday. Today, I decided to stop taking donations through Patreon due to the negative stress I’ve been experiencing.

For the last six months I’ve been working on a screencast video editor called Komposition, and it’s now released and open source. This is an experience report, based on a talk from Lambda World Cádiz 2018, that’ll give an overview of Komposition’s design, implementation, testing, and planned future work.

This post introduces a declarative GTK+ architecture for Haskell which I’ve been working on during the journey with FastCut, a video editor specialized for my own screencast editing workflow. It outlines the motivation, introduces the packages and their uses, and highlights parts of the implementation.

In the first part of this series, we left off having made states explicit using Haskell data types. We concluded that state transitions were implicit, and that a mistake in implementation, making an erroneous state transition, would not be caught by the type system. We also noted that side effects performed at state transitions complicated...

Stateful programs often become complex beasts as they grow. Program state incohesively spread across a bunch of variables, spuriously guarded by even more variables, is what I refer to as implicit state. When working with such code, we have to reconstruct a model mentally, identifying possible states and transitions between them, to modify the...

While writing my talk “Finite-state machines? Your compiler wants in!”, I have worked on porting the Idris ST library to Haskell. I call it Motor.

Writing technical presentations that include code samples and diagrams can be really tedious. In mainstream presentation software, such as Keynote and PowerPoint, your workflow is likely to manually copy-and-paste source code from your editor into your slides. If you’re not using the drawing capabilities of your presentation software, you have to...

I have experimented with a test language encoded in tagless final style, instead of algebraic data types, to support the typed combinators beforeEach and beforeAll. Although the intended use is for PureScript Spec, I want to share the Haskell prototype I ended up with, and explain how I got there.

Since laying Oden aside, I have been getting back into PureScript, and started working on a project called Hyper that I would like to introduce you to.

I have decided to stop working on Oden.

I have worked intensively on the Oden User Guide lately, primarly on improving content, but also on providing high-quality PDF and HTML output formats with detailed control over typesetting.

Having tried a lot of color schemes for editors, especially for Vim, I have gotten quite picky. All right, very picky. Most of the time Vim has been configured to use Tomorrow Night or Gruvbox. Although they’re great, they have felt a bit over the top. Also, depending on where I’m sitting at the moment I use both dark and light backgrounds for...