> A portable GUI interface is a hard problem, unless you mean "a browser window without an URL bar" and your controls are HTML/CSS components[…]

> […] an abstraction layer on top of several genuinely different systems[…]

> […] wxWidgets is perhaps the closest we can get[…]

For good reasons—because you'll likely exhaust yourself or starve of resources before you finish the project, and because it also doesn't tend to help with the readability of the codebase—it should be ingrained in all programmers to be strongly against "portability" approaches that try to make platform X work like platform Y by providing implementations of Y APIs that work on platform X. (See also yesterday's news by Wasmer about their AI-coded approach[1].) The goal is almost always better achieved by defining, up front, the minimum interface that the program needs to be able to work on the host—which forms the kind of abstraction you're talking about—and then connecting that to the actual host APIs (which usually suck to use, anyway), repeating for each platform. Almost.

Desktop UI toolkit APIs are one exception to this—which is unfortunate, because it's like the one use case where people actually try to do the opposite of the usual impulse, and we're all worse off for it.

The major desktop platforms are so few, and the APIs are so stable and so slow-moving, that it's well past the point where the cross-platform native app solution should have been adopting/implementing the platform Y APIs everywhere, where "platform Y" is Cocoa[2]. Like, at the latest, the Oracle v. Google decision in 2021 should have been the last hurdle. People get weird about this, though, and confuse APIs with implementations, or conflate Cocoa with Objective-C (and/or a mandate to program in Objective-C), or think this amounts to a claim that this means we should all be using GNUStep. It's not. It's not any of things. It's very simple: the window-and-widget APIs across all desktops should be Cocoa-shaped. That's it.

1. <https://wasmer.io/posts/edgejs-safe-nodejs-using-wasm-sandbo...>

2. <https://news.ycombinator.com/item?id=30359206>

Stdwin: Standard window interface by Guido Van Rossum [pdf]