QR error correction helps and hinders scanning

Memory mapping a file for reading sounds nice: turn inconvenient read calls and manual buffering into just simple indexing of a memory… but it does blocking IO under the hood, turn a &[u8] byte arrays into an async hazard and making “concurrent” async code actually run sequentially! Code affected likely runs slower, underutilises machine...

GitHub offers permalinks to versions of files and lines, within a repository. They’re easy to create (y keyboard shortcut) and have some nifty affordances like displaying a preview, plus they don’t become invalid as code changes. Use them! The permalinks use the commit hash of a particular version of the file, and thus the contents never changes,...

Encoding data in decimal requires many more characters than the same data encoded in base64—06513249 vs YWJj—but using decimal is better when stored in a QR code. The magic of QR modes means all those extra digits are stored efficiently, almost as though there was no encoding at all. Decimal encoding makes for QR codes that store more data, or...

Governments here in Australia have been telling us to keep distance from each other. Surprisingly, the same government has simultaneously put out posters that required people to get close, unnecessarily. They contain QR codes for contact-tracing check-ins that are small and dense, meaning they’re hard to scan. How could they be better? Here’s...

Taking shortcuts? Leaving edge-cases unconsidered and unhandled? Is this engineering?! My approach to programming and software engineering has been shaped by years of building open source compilers and libraries, where those edge cases matter, reliability is crucial and flexibility is important. It’s been a breath of fresh air to take a step back...