Same — as someone building macOS utilities I have a soft spot for indie apps that tackle genuinely hard algorithmic problems and still manage to ship a clean UI. The gap between "technically interesting" and "actually usable by non-experts" is huge, and it looks like they've bridged it well here.
Nice writeup. I work on native macOS utilities and have dealt with file monitoring quite a bit. kqueue is reliable but the per-file descriptor requirement can get tricky when you need to watch large directory trees.
For anyone looking at this space, FSEvents is the higher-level alternative Apple provides. It watches directory-level changes without needing a file descriptor per file, which scales better for broad monitoring. But kqueue gives you more granular control, like detecting attribute changes or renames specifically, which FSEvents sometimes lumps together.
In practice I've found a combination works well: FSEvents for broad directory watching to catch that something changed, then kqueue for targeted monitoring of specific files you care about.
Love seeing niche Show HN projects like this. The choice of Fortran is wild but that's what makes it fun. As someone building small Mac utilities, I appreciate any project that proves you don't need a massive stack to ship something useful.
macOS has its own share of UI quirks too. The volume slider is fine, but app management is surprisingly bad for a platform that prides itself on UX. There's still no native way to quit all apps at once, and Activity Monitor feels stuck in 2005. Small UI tools that just get one thing right tend to stick around.
I switched to Ghostty a few months ago and it's become one of the apps I never close. The rendering speed is noticeably better than iTerm2, especially with large log outputs. Excited to see libghostty enabling projects like this — the idea of packaging TUIs as native desktop apps is really compelling for indie developers.