This article was discussed on Hacker News.

I love when my current problem can be solved with a state machine. They’re fun to design and implement, and I have high confidence about correctness. They tend to:

1. Present minimal, tidy interfaces
2. Require few, fixed resources
3. Hold no opinions about input and output
4. Have a compact, concise implementation
5. Be easy to reason about

State machines are perhaps one of those concepts you heard about in college but never put into practice. Maybe you use them regularly. Regardless, you certainly run into them regularly, from regular expressions to traffic lights.

This article was discussed on Hacker News.

Machine learning is a trendy topic, so naturally it’s often used for inappropriate purposes where a simpler, more efficient, and more reliable solution suffices. The other day I saw an illustrative and fun example of this: Neural Network Cars and Genetic Algorithms. The video demonstrates 2D cars driven by a neural network with weights determined by a generic algorithm. However, the entire scheme can be replaced by a first-degree polynomial without any loss in capability. The machine learning part is overkill.

This article was discussed on Hacker News.

Pixelmusement produces videos about MS-DOS games and software. Each video ends with a short, randomly-selected listing of financial backers. In ADG Filler #57, Kris revealed the selection process, and it absolutely fits the channel’s core theme: a QBasic program. His program relies on QBasic’s built-in pseudo random number generator (PRNG). Even accounting for the platform’s limitations, the PRNG is much poorer quality than it could be. Let’s discuss these weaknesses and figure out how to make the selection more fair.

British Square is a 1978 abstract strategy board game which I recently discovered from a YouTube video. It’s well-suited to play by pencil-and-paper, so my wife and I played a few rounds to try it out. Curious about strategies, I searched online for analysis and found nothing whatsoever, meaning I’d have to discover strategies for myself. This is exactly the sort of problem that nerd snipes, and so I sunk a couple of evenings building an analysis engine in C — enough to fully solve the game and play perfectly.

Repository: British Square Analysis Engine (and prebuilt binaries)

This article was discussed on Hacker News.

This past May I put together my own C and C++ development distribution for Windows called w64devkit. The entire release weighs under 80MB and requires no installation. Unzip and run it in-place anywhere. It’s also entirely offline. It will never automatically update, or even touch the network. In mere seconds any Windows system can become a reliable development machine. (To further increase reliability, disconnect it from the internet.) Despite its simple nature and small packaging, w64devkit is almost everything you need to develop any professional desktop application, from a command line utility to a AAA game.

Python asyncio has support for asynchronous networking, subprocesses, and interprocess communication. However, it has nothing for asynchronous file operations — opening, reading, writing, or closing. This is likely in part because operating systems themselves also lack these facilities. If a file operation takes a long time, perhaps because the file is on a network mount, then the entire Python process will hang. It’s possible to work around this, so let’s build a utility that can asynchronously open and close files.

This article was discussed on Hacker News and critiqued on Wandering Thoughts (2, 3).

Command line interfaces have varied throughout their brief history but have largely converged to some common, sound conventions. The core originates from unix, and the Linux ecosystem extended it, particularly via the GNU project. Unfortunately some tools initially appear to follow the conventions, but subtly get them wrong, usually for no practical benefit. I believe in many cases the authors simply didn’t know any better, so I’d like to review the conventions.

This article was discussed on Hacker News.

A common situation in asyncio Python programs is asynchronous initialization. Some resource must be initialized exactly once before it can be used, but the initialization itself is asynchronous — such as an asyncpg database. Let’s talk about a couple of solutions.

Ever since I worked out how to render video from scratch some years ago, it’s been an indispensable tool in my software development toolbelt. It’s the first place I reach when I need to display some graphics, even if it means having to do the rendering myself. I’ve used it often in throwaway projects in a disposable sort of way. More recently, though, I’ve kept better track of these animations since some of them are pretty cool, and I’d like to look a them again. This post is a showcase of some of these projects.

This week I was debugging a misbehaving Python program that makes significant use of Python’s asyncio. The program would eventually take very long periods of time to respond to network requests. My first suspicion was a CPU-heavy coroutine hogging the thread, preventing the socket coroutines from running, but an inspection with pdb showed this wasn’t the case. Instead, the program’s author had made a couple of fundamental mistakes using asyncio. Let’s discuss them using small examples.